Table of Contents

Chapter 1: Characteristics and Classification

Movement
- Action made by an organism causing a change of position/place.
Respiration
- Chemical reactions that take place in cells that break down nutrient molecules and release energy for metabolism.
Sensitivity
- Ability to sense stimuli in the internal or external environment and make appropriate responses.
Growth
- Permanent increase in size and dry mass, by an increase in cell number or both.
Reproduction
- The process that makes more of the same kind of organism.
Excretion
- Removal from organisms of waste products of metabolism, toxic materials, and excess substances.
Nutrition
- Taking in materials for growth, energy, and development.

Species

A group of organisms that can reproduce to produce fertile offspring.

Binomial Naming System

A way to make classification standard.
The scientific name consists of the Genus and Species.
Genus starts with a capital letter, species with a lowercase letter.
Example: Homo sapiens (Scientific name for humans!).

Why Do We Classify Organisms?

To identify those at risk of extinction.
To understand evolutionary relationships.

How Do We Classify Organisms?

By studying its morphology and anatomy:
- Morphology: Study of the form or outward appearance of organisms.
- Anatomy: Study of internal structure by dissection.
Sequences of DNA and amino acids in proteins are a more accurate way of classification.
Each species has its unique number of chromosomes and sequence of bases in DNA, making it different from other species (Humans have 46 chromosomes).
Organisms with recent ancestors have DNA that’s more similar than distant ancestors.

Hierarchical Classification

All living things classify under:
- Kingdom
- Phylum
- Class
- Order
- Genus
- Species

All living things have certain features in common, such as:

Presence of cytoplasm, cell membrane, and DNA (genetic material).
Ribosomes (in cytoplasm) floating freely or attached to membranes called rough endoplasmic reticulum.
Ribosomes make the proteins and enzymes involved in respiration.

Whittaker’s Five Kingdom Scheme

The five kingdoms include:

Animal, Plant, Fungus, Prokaryote, Protist

Viruses

Characteristics of Viruses:
- Have a central core of RNA or DNA surrounded by a protein coat.
- No nucleus, cytoplasm, or organelles (cell structure).
- Do not feed, excrete, or grow.
- Virus particles are NOT cells.
- Reproduce by using the cells of a living organism, taking over the host cell.

Dichotomous Keys

Used to identify organisms based on a series of choices between two contrasting features.
The term “Dichotomous” means “2 branches.”

Animal

Multicellular organisms
No cell wall or chloroplasts
Divided into vertebrates and arthropods

Vertebrates:

CLASS	MAIN FEATURES	EXAMPLES
MAMMALS	– FUR/HAIR ON SKIN	HORSE, DOG, SQUIRREL, HUMAN
	– HAVE A PLACENTA
	– YOUNG FEED ON MILK FROM MAMMARY GLANDS
	– EXTERNAL EARS (PINNA) VISIBLE
	– ENDOTHERMIC
BIRDS	– SKIN COVERED IN FEATHERS	PARROT, BLUE TIT, EAGLE
	– HAVE 2 LEGS AND 2 WINGS INSTEAD OF FORELIMBS
	– LAY EGGS WITH HARD SHELLS ON LAND
	– HAVE A BEAK
	– ENDOTHERMIC
REPTILES	– DRY, FIXED SCALES ON SKIN	SNAKE, TURTLE, IGUANA
	– LAY EGGS WITH RUBBERY SHELLS ON LAND
AMPHIBIANS	– SMOOTH, MOIST SKIN	FROG, TOAD, NEWT
	– ADULTS USUALLY LIVE ON LAND (SO HAVE LUNGS), LARVAE LIVE IN WATER (SO HAVE GILLS)
	– LAY EGGS WITHOUT SHELLS IN WATER
FISH	– LOOSE, WET SCALES ON SKIN	FLOUNDER, GROUPER
	– GILLS TO BREATHE
	– LAY EGGS WITHOUT SHELLS IN WATER

Arthropods:

CLASS	MAIN FEATURES	EXAMPLES
MYRIAPODS	– BODY CONSISTS OF MANY SEGMENTS	CENTIPEDE
	– EACH SEGMENT CONTAINS AT LEAST 1 PAIR OF JOINTED LEGS
	– 1 PAIR OF ANTENNAE
INSECTS	– 3 PART BODY – HEAD, THORAX AND ABDOMEN	BUTTERFLY
	– 3 PAIRS OF JOINTED LEGS
	– 2 PAIRS OF WINGS (1 OR BOTH PAIRS MAY BE VESTIGIAL – MEANING NON-FUNCTIONAL AND UNDEVELOPED)
	– 1 PAIR OF ANTENNAE
ARACHNIDS	– 2 PART BODY – CEPHALOTHORAX AND ABDOMEN	SPIDER
	– 4 PAIRS OF JOINTED LEGS
	– NO ANTENNAE
CRUSTACEANS	– MORE THAN 4 PAIRS OF JOINTED LEGS	CRAB
	– CHALKY EXOSKELETON FORMED FROM CALCIUM
	– BREATHE THROUGH GILLS
	– 2 PAIRS OF ANTENNAE

Plant

Multicellular
Cell wall made up of cellulose
Contains chloroplasts with chlorophyll
Can make their own food
Divided into ferns & flowering plants

Ferns

Land plants
Vascular plants – meaning it has xylem & phloem
Undergoes sexual reproduction
Produces gametes (sex cells) without seeds
So the zygote directly becomes the fern plant
Fern plants have sporangia, which makes spores

Flowering Plants

Divided into monocotyledon & dicotyledon

Feature	Monocotyledon	Dicotyledon
Leaf Shape	Long & narrow	Broad
Leaf Veins	Parallel	Branching
Cotyledon	One	Two
Grouping of Flowers	Threes	Fives

Fungus

Made up of thread-like hyphae, rather than cells
Many nuclei are distributed throughout the cytoplasm in their hyphae
Example: Yeast & Mushrooms

Prokaryote

Unicellular
Includes bacteria and algae
Chromosomes not organized into a nucleus
Each bacterial cell contains a single chromosome, consisting of circular DNA strands

Protist

Unicellular
Chromosomes enclosed in a nuclear membrane to form a nucleus
Example: Amoeba

Chapter 2: Organization of the Organism

Eukaryotic Cells

Have a nucleus
Membrane-bound organelles

Cell Structures in Both Animal and Plant Cells

Cell Membrane: Selective control of what goes into and out of the cell
Nucleus: Carries genetic material
Cytoplasm: Jelly-like substance where all chemical reactions take place
Ribosomes: Site of protein synthesis
Mitochondria: Site of aerobic respiration
- High metabolism cells need lots of mitochondria to release energy

Cell Structure in Plants Only

Cell Wall: Structural support for plants
Chloroplasts: Site of photosynthesis in plants
Central Permanent Vacuole:
- Stores/isolates harmful materials, stores small nutrients
- Maintains water balance in the cell
- Provides structural support by applying turgor pressure
- Some animal cells can have vacuoles, but they are not central and most likely temporary

Cell Structure in Bacterial Cells

Cell Wall
Cell Membrane
Cytoplasm
Ribosomes
Circular DNA: DNA not in the nucleus, outside in the cytoplasm and is in a loop
Plasmids: Little rings of DNA that contain extra DNA
Flagella: Helps them move around

Specialized Cells & Adaptations

Neurons (Nerve Cells)

Conduction of impulses
Long to reach different parts of the body
Extensions and branches connect with other nerve cells
Axon is a fatty sheath that insulates the cell and speeds up nerve impulses

Ciliated Cells

Allow movement of mucus in the trachea and bronchi

Root Hair Cells

Increases surface area to maximize absorption
Walls are thin
No chloroplasts needed

Red Blood Cells

Transport oxygen in the blood
Biconcave shape for increased surface area and flexibility
Contains hemoglobin, which joins with oxygen to transport it
Contains no nucleus to increase oxygen capacity

Sperm:

Head contains haploid nucleus with genetic information.
- Acrosome contains digestive enzymes to penetrate the egg.
Mid-piece has lots of mitochondria for swimming and fertilization.
Tail allows the cell to swim.

Palisade Mesophyll Cells

Allow for photosynthesis to occur
Column shape to maximize sunlight absorption and fit many in a small layer
Contains many chloroplasts to maximize photosynthesis

Egg Cells:

Egg Cell has lots of cytoplasm for nutrients and growth of the embryo.
Cell membrane changes after fertilization so that no more sperm can enter.

Levels of Organization:

Cell
Basic functional and structural unit in living organisms.

Tissue
Groups of cells of similar structure working on the same function.

Organ
Made from different tissues to perform a specific function.

Organ System
Groups of organs with related functions working together to perform functions.

Note:

- Cells in the body need to divide to allow for growth and repair.
- New cells are produced through the division of existing cells.

Size of Specimens

Word and Chemical Equations

Word equation:

Glucose + Oxygen → Carbon dioxide + Water

Balanced Chemical equation:

$C_{6} H_{12} O_{6} + 6 O_{2} \to 6 {CO}_{2} + 6 H_{2} O$

Chapter 3: Movement into and out of Cells

Diffusion

Key Concepts of Diffusion

Net movement of particles from a region of higher concentration to a region of lower concentration as a result of random movement.
Occurs in both plants and animals, allowing substances to diffuse in and out of cell membranes.
Energy for diffusion comes from kinetic energy, which arises from the random movement of particles.
Diffusion occurs down the concentration gradient, with particles trying to spread evenly in all spaces.

Importance of Diffusion

In Animals:

Gas Exchange: Oxygen (O₂) and Carbon Dioxide (CO₂) exchange is carried out by diffusion.
Absorption of Dissolved Food Material: Carried out by diffusion.

In Plants:

Photosynthesis: CO₂ and O₂ diffuse during photosynthesis.
Dissolved Salts: Diffuse through root hair cells.

Factors that Influence the Rate of Diffusion

Surface Area:
- A larger surface area of the exchange membrane allows particles to diffuse faster.
Temperature:
- Increasing temperature increases kinetic energy, making particles move faster, thus increasing the rate of diffusion.
Concentration Gradient:
- The steeper the gradient (big difference from high to low), the faster the diffusion.
Distance:
- The thinner the exchange membrane, the easier it is for particles to go through it, making diffusion faster.

Osmosis

Key Concepts of Osmosis

Net movement of water molecules from high water potential (dilute) to lower water potential (concentrated) through a partially permeable membrane.
Dilute solution has more water potential, and concentrated solution has less water potential.
Occurs in both plant and animal cells.
Water moves in and out of the cell membrane.

Plant Cells in Different Solutions

If a plant cell is placed in distilled water (purified water), water molecules move from distilled water into plant cells. The cell swells up and becomes turgid. It won’t burst because of the cell wall, which is elastic. The vacuole exerts turgor pressure on the elastic cell wall.
If a plant cell is in a salt solution with low water potential, water moves from the cell to the solution, and the cell becomes plasmolyzed.

Animal Cells in Different Solutions

If an animal cell is in water, excess water enters the cell by osmosis, and if water isn’t expelled, the cell will burst. This is called haemolysis.
If an animal cell is in a salt solution, water from the cytoplasm osmoses out, and the cell becomes shrinked (crenated).

Hypertonic: More sugars and salt than blood.
Isotonic: Similar amount of sugars and salts to blood.
Hypotonic: Less sugars and salts than blood.

Importance of Osmosis

Plants gain water through osmosis from soil to roots.
If plant cell vacuoles aren’t full, the cell will become flaccid, and all the cells in the leaf will become flaccid, making the leaf droop and the plant wilt.
Plants need water to stay firm in a turgid state.
Cells in the animal body are surrounded by fluid that has the same concentration as the liquid inside cells (tissue fluid: liquid outside cells).

Active Transport

Key Concepts of Active Transport

The movement of particles through the cell membrane from a lower concentration to a higher concentration using energy acquired from respiration.
Carrier proteins pick up specific molecules and take them through the cell membrane against the concentration gradient.
Substance combines with the carrier molecule, and using energy from respiration, carriers are given the kinetic energy needed to change and move the substance through the membrane.

Importance of Active Transport

Uptake of glucose by epithelial cells in the villi of small intestines and by kidney tubules in the nephrons.
Uptake of ions from soil water by root hair cells in plants.

Chapter 4: Biological Molecules

Carbohydrates

Elements: Carbon, Oxygen, and Hydrogen.
Structure: Long chains of simple sugars.
Glucose: A simple sugar (Monosaccharide).
Formation: When lots of glucose join together, starch, glycogen, or cellulose can form depending on structure; these are polysaccharides.

Examples:

Cellulose
Starch
Glycogen

Proteins

Elements: All contain Carbon, Oxygen, Hydrogen, and Nitrogen. Some contain small amounts of other elements like sulfur.
Structure: Long chains of amino acids.
Amino Acids: 20 different amino acids.
Basic Structure: Same for all proteins, but the ‘R’ group is different for each one.
Diversity: Amino acids can be arranged in many different patterns, resulting in lots of differing proteins.

Examples:

Amino Acids
Peptide
Protein
General amino acid structure

Fats

Elements: Carbon, Oxygen, and Hydrogen.
Composition: Most fats (lipids) in the body are made up of triglycerides.
Basic Unit: 1 glycerol molecule chemically bonded with 3 fatty acid chains.
Types: Lipids are divided into fats (solid at RTP) and oils (liquid at RTP)

Structure of DNA Molecule

Deoxyribo Nucleic Acid (DNA):
- Molecule contains the instruction for growth and development of all organisms.
Structure:
- Consists of two strands of DNA wound around each other in what is called a double helix.
- The individual units inside DNA are called nucleotides.

Base Pairing:
- There are 4 different bases: Adenine (A), Cytosine (C), Thymine (T), and Guanine (G).
- Bases always pair in the same way:
  - Adenine always with Thymine (A-T)
  - Cytosine always with Guanine (C-G)

Iodine Solution Test for Starch

Procedure:
- Add drops of iodine solution (orange-brown at the start) to the food sample.
Positive Test:
- Iodine color changes to blue-black.
Negative Test:
- No color change.

Benedict’s Solution Test for Reducing Sugars

Procedure:
- Add Benedict’s solution (blue color at the start) to the sample solution in the test tube.
- Heat at 60-70°C in a water bath for 5 minutes.
Positive Test:
- Observe the color change to orange or brick red.
Negative Test:
- Solution remains blue-green or yellow-green.

Biuret Test for Proteins

Procedure:
- Add drops of biuret solution (blue at the start) to the food sample.
Positive Test:
- Color changes to violet/purple.
Negative Test:
- Solution remains denim-blue.

Ethanol Emulsion Test for Fats and Oils

Procedure:
- Mix the food sample with 2 cm³ of ethanol and shake.
- Ethanol (clear & colorless at the start) is added to an equal volume of cold water.
Positive Test:
- A cloudy emulsion forms.
Negative Test:
- Solution remains clear/colorless.

DCPIP Test for Vitamin C

Procedure:
- Add 1 cm³ of DCPIP solution (blue at the start) to the test tube.
- Add a small amount of the food sample (as a solution).
Positive Test:
- Blue dye disappears.
Negative Test:
- No change to blue color.

Chapter 5: Enzymes

Catalyst:

A substance that increases the rate of a chemical reaction without being changed by the reaction.

Enzyme:

A protein that functions as a biological catalyst.
Enzymes can be used multiple times without change, and only small amounts are needed to speed up the metabolic reactions.

Why Are Enzymes Important?

They maintain reaction speeds of all metabolic reactions at a rate that can sustain life.
For example, if digestive enzymes didn’t exist, it would take around 2-3 weeks to digest a meal; with enzymes, it takes 4 hours.

Common Enzymes Found in Our Body:

Enzyme Name	Site of Production	Site of Action	Substrate Digested	End Product
Amylase	Salivary glands, Pancreas	Mouth, Duodenum	Starch	Maltose, Glucose
Protease	Stomach, Pancreas, Small Intestines	Stomach, Duodenum	Protein	Amino acids
Lipase	Pancreas, Mouth, Stomach	Duodenum	Fats	Fatty acids, Glycerol

How Do Enzymes Work?

Substrate: Substance on which the enzyme acts upon.
Product: The molecules produced after the reaction.
Enzyme-Substrate Complex: A temporarily formed complex when the enzyme combines with the substrate.

Steps:

Enzymes and substrates randomly move about in a solution.
When an enzyme and its complementary substrate randomly collide—with the substrate fitting into the active site of the enzyme—an enzyme-substrate complex is formed, and the reaction occurs.
Product(s) is formed from the substrate(s) and released from the active site.

Key Points:

Anabolic: Synthesis of larger molecules.
Catabolic: Breakdown of smaller molecules.

How Are Enzymes Affected by Temperature?

Enzymes are proteins and have a specific shape, held in place by bonds.
This is important for the active site’s shape, as it ensures the substrate can fit and the reaction can occur.
Enzymes work best at optimum temperature.
- For human body enzymes, this is 37°C.
Heating an enzyme beyond its optimum temperature can lead to denaturation.
- This means the enzyme will break bonds and lose its shape.
- The substrate won’t fit into the active site, and the denaturation is irreversible.
Increasing temperature:
- Increases molecular movement, leading to more collisions with the substrate.
- Provides more energy for the reaction.
Low temperatures don’t denature enzymes; they just work slower.

Investigating Enzyme Actions

Investigating the Effect of Temperature on Amylase

Investigating the Effect of pH Level on Amylase

Chapter 6: Plant Nutrition

Photosynthesis

Definition: The process in which plants synthesize carbohydrates from raw materials using light energy.
Raw Materials: Water and Carbon Dioxide.
End Products: Glucose and Oxygen.

Equations:

Word Equation: Carbon dioxide + Water → Glucose + Oxygen
Balanced Chemical Equation:
The light energy is converted into chemical energy in the bonds holding the atoms in the glucose molecules together.

Chlorophyll

Definition: Chlorophyll is a green pigment found in chloroplasts within plant cells.
Function:
- It gives plants their green color.
- Transfers energy from light into chemical energy for the synthesis of carbohydrates.
- Chlorophyll is essential for photosynthesis to occur.

Minerals in Plants

Importance: Photosynthesis produces carbohydrates, but plants also need to make biological molecules like proteins, lipids, and nucleic acids.
Sources:
- Carbs contain carbon, hydrogen, and oxygen, but proteins, for example, also contain nitrogen.
- Chlorophyll contains nitrogen and magnesium.
- Plants absorb these elements from the soil through their roots.

Key Minerals:

Nitrogen:
- Required to make amino acids for protein synthesis.
- Lack of nitrogen causes stunted growth and yellow leaves.
Magnesium:
- Needed to make chlorophyll.
- Lack of magnesium leads to yellowing between leaf veins (chlorosis).

Use and Storage of Carbohydrates

Storage: Carbohydrates produced by photosynthesis can be:
- Converted to starch and stored.
- Converted to cellulose to build cell walls.
- Used for respiration to provide energy.
- Converted to sucrose for transport in the plant.
- Used as nectar to attract pollinators.
- Converted to lipids for energy storage in seeds.

Limiting Factors of Photosynthesis

Definition: A limiting factor is something present in the environment in short supply that restricts life processes.
Explanation:
- Plants do not have unlimited raw materials, so the rate of photosynthesis is limited by the lowest available factor.
- Key Limiting Factors:
  - Temperature
  - Light Intensity
  - Carbon Dioxide Concentration

Additional Information:

Water is generally not a limiting factor because the amount needed is smaller than the amount transpired, so there’s usually enough for photosynthesis.

TEMPERATURE

LIGHT INTENSITY

CARBON DIOXIDE CONCENTRATION

Leaf Structure and Adaptations for Photosynthesis

Key Concepts:

Cross-Section and Cells of a Leaf:
- A cross-section of the leaf shows how different layers are structured to facilitate photosynthesis.

Photosynthesizing cells obtain CO₂ from the atmosphere through air spaces around the spongy mesophyll and leaf mesophyll cells, which contain chloroplasts.

Structure and Description of Leaf Components

Structure	Description
Wax Cuticle	Protective layer on top of the leaf; prevents water from evaporating.
Upper Epidermis	Thin and transparent to allow light to enter the palisade mesophyll layer underneath it.
Palisade Mesophyll	Column-shaped cells tightly packed with chloroplasts to absorb more light, maximizing photosynthesis.
Spongy Mesophyll	Contains internal air spaces that increase the surface area to volume ratio for the diffusion of gases (mainly carbon dioxide).
Lower Epidermis	Contains guard cells and stomata.
Guard Cell	Absorbs and loses water to open and close the stomata to allow carbon dioxide to diffuse in, and oxygen to diffuse out.
Stomata	Where gas exchange takes place; opens during the day, closes during the night. Evaporation of water also takes place from here. In most plants, found in much greater concentration on the underside of the leaf to reduce water loss.
Vascular Bundle	Contains xylem and phloem to transport substances to and from the leaf.
Xylem	Transports water into the leaf for mesophyll cells to use in photosynthesis and for transpiration from stomata.
Phloem	Transports sucrose and amino acids around the plant.

Identifying Leaf Structures in a Dicotyledonous Plant

Key Structures:
- Chloroplasts
- Cuticle
- Guard cells
- Stomata
- Upper & Lower Epidermis
- Palisade Mesophyll
- Spongy Mesophyll
- Air spaces
- Vascular bundles (Xylem & Phloem)

Leaf Under Micrograph =>

Investigating the Need for Chlorophyll, Light & CO₂

Chlorophyll:

Experiment:
- Leaves can’t be tested for glucose as it’s quickly used, but starch is a reliable indicator.
- Starch is stored in chloroplasts where photosynthesis occurs.
- In the experiment, ethanol is flammable, so it’s best to use an electric water bath.

Light:

Experiment:
- The same experiment as above can be used. The plant needs to be destarched for 24 hours prior to the experiment, and the leaf can be covered with foil and placed in sunlight.
- The leaf can then be tested for starch with iodine, and this will prove that light is necessary for photosynthesis and the production of starch.

Carbon Dioxide:

Experiment:
- One plant is placed in sodium hydroxide to absorb carbon dioxide from the surrounding air.
- Another plant is placed in a jar with a beaker of water, which won’t absorb carbon dioxide.

Investigating the Rate of Photosynthesis

Method:
- Plants used are usually Elodea or Cabomba—seaweed!
- As photosynthesis occurs, oxygen will release into water, and bubbles per minute can be counted to record the rate.
- A more accurate experiment would measure the volume of the oxygen.
This Practical Can Be Used To:

Investigate the effect of changing light intensity.

Investigate the effect of changing temperature.

Investigate the effect of changing carbon dioxide concentration.

Investigating Gas Exchange

Concept:
- Plants are photosynthesizing at a faster rate than respiring during the day, so the net intake of carbon dioxide is found, and the net output of oxygen is observed.

Investigation:

We can investigate the effect of light on the net gas exchange using a pH indicator like hydrogen carbonate indicator.
Carbon dioxide is an acidic gas when in water.

Concentration of Carbon Dioxide and Color of Hydrogen Carbonate Indicator in Relation to Plant Conditions

Concentration of Carbon Dioxide	Color of Hydrogen Carbonate Indicator	Conditions in Plant
Highest	Yellow █	More respiration > Photosynthesis → Lower pH (More Acidic)
Higher	Orange █	More respiration > Photosynthesis → Lower pH (More Acidic)
Atmospheric Level	Red █	Photosynthesis = Respiration
Lower	Magenta █	More photosynthesis > Respiration → Higher pH (More Alkaline)
Lowest	Purple █	More photosynthesis > Respiration → Higher pH (More Alkaline)

Chapter 7: Human Nutrition

Diets and Deficiencies

Balanced Diet:
- A balanced diet needs a proper amount of carbohydrates, protein, lipids, vitamins, minerals, dietary fiber, and also water!

Food Pyramid:
- The balanced diet includes a variety of foods represented in the food pyramid.

Food Types, Functions, and Sources

Food Type	Function	Sources
Carbohydrate	Source of energy	Bread, cereals, pasta, rice, potatoes
Protein	Growth and repair	Meat, fish, eggs, pulses, nuts
Lipid	Insulation and energy storage	Butter, oil, nuts
Dietary Fibre	Provides bulk (roughage) for the intestine to push food through it	Vegetables, whole grains
Vitamins	Needed in small quantities to maintain health	Fruits and vegetables
Minerals	Needed in small quantities to maintain health	Fruits and vegetables, meats, dairy products
Water	Needed for chemical reactions to take place in cells	Water, juice, milk, fruits and vegetables

Factors Affecting Dietary Needs

Factor	Dietary Needs
Age	The amount of energy that young people need increases towards adulthood as this energy is needed for growth. Children need a higher proportion of protein in their diet than adults as this is required for growth. Energy needs of adults decrease as they age.
Activity Levels	The more active, the more energy required for movement as muscles are contracting more and respiring faster.
Pregnancy	During pregnancy, energy requirements increase as energy is needed to support the growth of the developing foetus, as well as the larger mass that the mother needs to carry around. Extra calcium and iron are also needed in the diet to help build the bones, teeth, and blood of the fetus.
Breastfeeding	Energy requirements increase and extra calcium is still needed to make high-quality breast milk.

Vitamins and Minerals: Functions and Sources

Vitamin/Mineral	Function	Sources
Vitamin C	Forms an essential part of collagen protein, which makes up skin, hair, gums, and bones. Deficiency causes scurvy.	Citrus fruit, strawberries, green vegetables
Vitamin D	Helps the body to absorb calcium and is required for strong bones and teeth.	Oily fish, eggs, liver, dairy products, also made naturally by the body in sunlight
Calcium	Needed for strong teeth and bones and involved in the clotting of blood. Deficiency can lead to osteoporosis later in life.	Milk, cheese, eggs
Iron	Needed to make hemoglobin, the pigment in red blood cells that transports oxygen.	Red meat, liver, leafy green vegetables like spinach

Scurvy:

Cause: Vitamin C deficiency.
Details: Lack of vitamin C for 3 months in the diet.
Symptoms:
- Anemia
- Tooth loss
- Exhaustion
- Gum ulceration
  
  Additional Info:
- Scurvy was commonly seen in sailors between the 15th and 17th centuries.
- Long sea journeys led to no source of fresh fruits.
- Scurvy can be treated with oral or intravenous (injected) vitamin C.

Rickets:

Cause: Vitamin D deficiency.
Details: Vitamin D is needed to absorb calcium into the body, and calcium is a key component for bones and teeth.
Symptoms:
- Bone pain
- Lack of bone growth
- Soft, weak bones (deformities)
Additional Info:
- Vitamin D comes from sunlight exposure and is also found in foods like fish, eggs, and butter.
- Prevention of rickets includes consuming foods rich in calcium and vitamin D; vitamin D supplements can also be prescribed.

Digestive System

Processes:
- Ingestion: Taking in substances like food & water.
- Digestion: The breakdown of food.
- Absorption: Movement of nutrients from the intestines into the blood.
- Egestion: Removal of undigested food in the form of feces.
- Assimilation: Uptake and use of nutrients by the cell.

Structures and Functions in the Digestive System

Structure	Function
Mouth / Salivary Glands	The mouth is where mechanical digestion takes place. – Teeth chew food to break it into smaller pieces and increase its surface area to volume ratio. – Amylase enzymes in saliva start digesting starch into maltose. – The food is shaped into a bolus (ball) by the tongue and lubricated in saliva so it can be swallowed easily.
Oesophagus	Tube that connects the mouth to the stomach. Where the food bolus goes after being swallowed. Wave-like contractions will take place to push the food bolus down without relying on gravity.
Stomach	Food is mechanically digested by churning actions while protease enzymes start to chemically digest proteins. Hydrochloric acid is present to kill bacteria in food and provide the optimum pH for protease enzymes to work.
Small Intestine	The first section is called the duodenum and is where the food coming out of the stomach finishes being digested by enzymes produced here and also secreted from the pancreas. The pH of the small intestine is slightly alkaline – around pH 8-9. The second section is called the ileum and is where absorption of digested food molecules takes place. The ileum is long and lined with villi to increase the surface area over which absorption can take place.

Additional Structures and Functions in the Digestive System

Structure	Function
Large Intestine	Water is absorbed from remaining material in the colon to produce feces. Feces is stored in the rectum and removed through the anus.
Pancreas	Produces all three types of digestive enzyme: amylase, protease, and lipase. Secretes enzymes in an alkaline fluid into the duodenum for digestion to raise pH of fluid coming out of the stomach.
Liver	Produces bile to emulsify fats (break large droplets into smaller droplets) – an example of mechanical digestion. Amino acids not used to make proteins are broken down here (deamination), which produces urea.
Gall Bladder	Stores bile to release into the duodenum as required.

Physical Digestion

Breakdown of food into smaller pieces without chemical change to the food molecules.
This process increases the surface area of food to make it easier for enzymes to digest in chemical digestion.

Teeth

Teeth are used for chewing, which increases the surface area of the food, so it is more exposed to saliva and other digestive juices, allowing food to be broken down quicker.
Different teeth have different functions, e.g., canines to rip/tear food, incisors to bite and cut, and premolars/molars to chew the food.

Stomach

The stomach lining contains muscles that contract to physically squeeze and mix the food with strong digestive juices that are present, which is also known as stomach churning.
Food is digested within the stomach for several hours.

Bile

The liver produces bile; bile is stored in the gallbladder.
Bile is alkaline; it neutralizes hydrochloric acid from the stomach. This needs to happen because enzymes in the small intestine have an alkaline pH level.
Bile breaks large fat droplets into smaller droplets. This process is emulsification, which increases the surface area of fat, allowing lipase to chemically break down lipids.
Emulsification doesn’t chemically change the substance; it simply makes it smaller, which is still part of physical/mechanical digestion.

Chemical Digestion

Breakdown of food into smaller molecules that can be absorbed and used by the body.

Enzymes in Digestion

Amylase

Produced in the mouth and pancreas, then secreted into the duodenum.
Amylase digests starch into smaller sugars.
- It digests starch to maltose, and maltase digests maltose to glucose within the enzyme maltase.

Proteases

Produced in the pancreas and secreted in the stomach and duodenum.
Protease digests protein into amino acids.
- Protein is digested in the stomach, where it breaks down in acidic conditions.
- Protein is also digested in the pancreas and secreted into the duodenum, where it breaks down protein in alkaline conditions.

Lipases

Lipase enzymes are produced in the pancreas and secreted into the duodenum.
They digest lipids into fatty acids and glycerol.

Hydrochloric Acid

The stomach produces a lot of fluids, and this is known as gastric juice.
Hydrochloric acid is one of these fluids.
The acid kills bacteria and provides the acidic pH for enzymes to work in the stomach.
- Low pH denatures enzymes in bacterial cells, making the cell unable to carry out any cell reactions to maintain life.
- Example: Pepsin has a pH of 2.
Hydrochloric acid ensures the condition in the stomach is within the optimum pH, allowing enzymes like pepsin to work at the fastest rate.

Absorption

Absorption is the movement of digested food molecules from the digestive system into the blood (glucose and amino acids) and lymph (fatty acids and glycerol).
Nutrients are absorbed in the small intestines.
Water is absorbed in both the small and large intestines (colon), but most absorption (80%) happens in the small intestines.

Adaptation of Small Intestines

The ileum is long and highly folded and has a surface with millions of villi, so it’s adapted for absorption.
These adaptations massively increase the surface area of the ileum, allowing absorption to happen more quickly and efficiently.
Microvilli on the surface of villi increase the surface area even more.
The wall of villi is small, allowing for fast diffusion; it is one cell thick.
The ileum is well supplied with a network of blood capillaries that are used to transport glucose and amino acids away from the small intestines.
Lacteal runs through the center of the villus to transport fatty acids and glycerol away from the small intestines into the lymph.

Chapter 8: Transport in Plants

Plants contain two types of transport vessels:
- These vessels are arranged throughout root, stem, and leaves and are called vascular bundles.

Xylem

Transports water and materials from the roots to the stem and leaves.

Phloem

Transports food materials (mainly sucrose & amino acids) made by the plant through photosynthesizing leaves and transports them to non-photosynthesizing regions in roots and stems.

Function

Transport tissue for water and dissolved mineral ions.

Adaptations

Thick walls with lignin.
No cell contents.
Cells joined end to end with no cross walls forming a long continuous tube.

Example of Xylem and Phloem

Roots: Xylem always inside, phloem always outside.
Stems: Vascular bundle.
Leaves: Internal stem structure.

Root Hair Cells

Root hairs are single-celled extensions of epidermis cells in the roots.
They grow between soil particles and absorb water and minerals from the soil.
Water enters root hair cells by osmosis.
This happens because the soil has a higher water potential than the cytoplasm in root hair cells, so water osmoses into the cell.
Root hair cells have an increased surface area for the absorption of water by osmosis and mineral ions by active transport.

Investigating Water Movement in Plants:
- Pathway can be investigated by placing a plant (like celery) into a beaker of water with colored water (food dye).
- After a few hours, you can see the leaves of the celery turning into the color of the water, proving water is taken up.
- If a cross-section is cut, only certain areas of the stalk are stained with color; these are the xylem vessels.

Investigating Water Movement in Plants:
- Pathway can be investigated by placing a plant (like celery) into a beaker of water with colored water (food dye).
- After a few hours, you can see the leaves of the celery turning into the color of the water, proving water is taken up.
- If a cross-section is cut, only certain areas of the stalk are stained with color; these are the xylem vessels.

Translocation

The soluble products of photosynthesis are sugars (mainly sucrose) and amino acids.
These are transported around the plants in the phloem tubes, which are made up of living cells (xylem tubes are made of dead cells).
The cells are joined end to end and contain holes in the end cell walls (sieve plates) that allow easy flow of substances from one cell to another.
The transport of sucrose and amino acids in the phloem, from regions of production to regions of storage or use, is called translocation.
Transport in the phloem goes in many different directions depending on development, but usually for dissolved foods, it’s always source to sink (where it’s stored or used).
- During winter, when the plant has no leaves, phloem transports dissolved sucrose and amino acids from storage organs to other parts to be used for respiration in the plant.
- During the growth period (Spring), storage organs (roots) would be the source, and growing areas of the plant would be the sinks.
- After the plant has grown (Summer), leaves will photosynthesize, so they are the source, and roots become sinks – the roots store sucrose as starch until it’s needed again.

TISSUE	WHAT IS MOVED	PROCESS	DIRECTION OF FLOW	CELLS
XYLEM	WATER AND MINERAL IONS	TRANSPIRATION STREAM	ONE WAY FROM ROOTS TO LEAVES	DEAD
PHLOEM	SUCROSE AND AMINO ACIDS	TRANSLOCATION	IN ALL DIRECTIONS	LIVING

Transpiration

Water travels up xylem from roots to the leaves to replace water that is lost by transpiration.
Transpiration is the loss of water vapour from leaves by evaporation of water from the surface of spongy mesophyll, followed by diffusion of water vapour through stomata.
Xylem is adapted in ways such as:
- Lignin that kills cells in the cell wall.
- Dead cells become hollow tubes and form a continuous tube for water and minerals.
- Lignin strengthens the plant to help it withstand the pressure of water movement.
Movement in xylem only takes place in one direction, from roots to leaves (phloem goes in different directions).

Transpiration

Water travels up xylem from roots to the leaves to replace water that is lost by transpiration.
Transpiration is the loss of water vapour from leaves by evaporation of water from the surface of spongy mesophyll, followed by diffusion of water vapour through stomata.
Xylem is adapted in ways such as:
- Lignin that kills cells in the cell wall.
- Dead cells become hollow tubes and form a continuous tube for water and minerals.
- Lignin strengthens the plant to help it withstand the pressure of water movement.
Movement in xylem only takes place in one direction, from roots to leaves (phloem goes in different directions).

Transpiration Functions:

Transport mineral ions
Provide water to keep cells turgid
Provide water for photosynthesis
Keeping leaves cool (evaporative cooling)

Investigate the Effect of Temperature & Wind Speed on Transpiration Rate

In the experiment, shoot is underwater to prevent air from entering the xylem.
Remove the capillary tube to let an air bubble form and place the tube back in water.
The further the bubble travels in the same time period, the faster transpiration is occurring.

Factor	Condition	Effect on the Rate of Transpiration (More/Less)
Wind Speed	High	More – Good airflow removes water vapour from the air surrounding the leaf, which sets up a concentration gradient between the leaf and the air, increasing water loss.
Humidity	High	Less – Humidity is a measure of moisture (water vapour) in the air; when the air is saturated with water vapour, the concentration gradient is weaker, so less water is lost.
Temperature	High	More – At higher temperatures, particles have more kinetic energy, so transpiration occurs at a faster rate as water molecules evaporate from mesophyll and diffuse away faster than at lower temperatures.

Experimental Setup for Testing the Effect of Light Intensity:

Temperature:
- Temperature ↑ → Transpiration ↑
Wind Speed:
- Wind speed ↑ → Transpiration ↑

Wilting

If more water evaporates from the leaves than that is available in the soil to move to roots by osmosis, wilting will occur.
This is when cells are not full of water, so strength of the cell wall can’t support the plant, and it starts to collapse.

Wilting Plant | Healthy Plant

Transpiration Stream

Water molecules are attracted to each other by cohesion – continuous columns of water.
Water moves through xylem in a continuous transpiration stream from root to leaves via the stem.
Transpiration produces a tension or ‘pull’ on water in xylem by the leaves.
As water is held by cohesive forces, so water is pulled up through the plant.
If the rate of transpiration from the leaves increases, water is pulled up the xylem leaves quicker.

Water Vapour Loss

Evaporation takes place from surfaces of spongy mesophyll cells.
The many interconnecting air spaces between cells and stomata create large surface area.
Evaporation can rapidly happen when stomata are open.

Chapter 9 : Transport in Animals

Circulatory System:

The circulatory system is a system of blood vessels with a pump and valves to ensure one-way flow.

Fish have two chambered hearts and a single circulation. For every one circuit of the body, the blood passes through the heart once.

Mammals have a four-chambered heart, and double circulation, the blood passes through the heart twice. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs (pulmonary circulation). The left side of the heart receives oxygenated blood from the lungs and pumps it to the body (systematic circulation).

Advantages of Double Circulation

Blood traveling through the small capillaries in the lungs loses a lot of pressure that was given to it by the pumping of the heart, meaning it can’t travel fast.
By returning blood to the heart after going through the lungs, its pressure can be raised again before sending it to the body, meaning the cells can be supplied with oxygen and glucose they need for respiration faster and more frequently.

Blood Vessels

Arteries

Carry blood away from the heart at high pressure.
Carry oxygenated blood (except pulmonary artery).
Thick muscular walls containing elastic fibers, narrow lumen to maintain high pressure, and they have a fast flow of blood.

Veins

Carry blood at low pressure towards the heart and carry deoxygenated blood (except for pulmonary vein).
Have thin walls and large lumen, they also contain valves to prevent backflow due to low pressure, and the speed of blood flow is slow.

Capillaries

Carry blood at low pressure within tissues and carry both oxygenated and deoxygenated blood, the walls are only one cell thick so substances can diffuse in and out easily and walls are leaky so blood plasma can leak out to form tissue fluid surrounding cells.

Blood is carried away from the heart to organs in arteries, these narrow arterioles and then capillaries as they pass through the organ, and capillaries widen to venules and finally veins as they move from the organs, veins carry blood back to the heart.

Organ	Towards Organ	Away from Organ
Heart	Vena cava, Pulmonary vein	Aorta, Pulmonary artery
Lung	Pulmonary artery	Pulmonary vein
Kidney	Renal artery	Renal vein
Liver	Hepatic artery	Hepatic vein
Hepatic portal vein sends deoxygenated blood from gut to liver.

Arterioles and Venules

As arteries divide more as they get further from the heart and they get narrower and narrower, vessels that connect artery to capillaries are called arterioles.
Veins also get narrower and narrow vessels that connect capillaries to veins are called venules.

Blood

Components of Blood:

Component	Structure
Red Blood Cells	Biconcave discs containing no nucleus but plenty of the protein haemoglobin.
White Blood Cells	Large cells containing a big nucleus; different types have slightly different structures and functions.
Platelets	Fragments of cells.
Plasma	Straw-colored liquid.

RBC:
Transport oxygen for respiration & oxygen is carried in the form of oxyhaemoglobin.

WBC:
Defend the body against infections by pathogens by carrying out phagocytosis and antibody production.

Platelets:
Help blood clot.

Plasma:
Transport carbon dioxide, nutrients, urea, mineral ions, hormones, and heat energy.

IDENTIFYING RED 8 WHITE BLOOD CELLS.

BLOOD CLOTTING

Platelets are fragments of cells which are involved in blood clotting and forming scabs where the skin has been cut or punctured.

Blood clotting prevents continued/a lot of blood loss when wounded. Scab formation seals the wound and prevents the entry of microorganisms that cause infections. The scab remains in place till the new skin grows under it.

Platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin and form an insoluble mesh across the wound, trapping RBC and forming a clot.
The clot dries out and develops into a scab to protect the wound against bacteria that may enter.

TYPES OF WHITE BLOOD CELLS

WBC is part of the body’s immune system and there are two main types of WBC: phagocytes and lymphocytes.

PHAGOCYTES
Carry out phagocytosis by engulfing & digesting pathogens.

Phagocytes have sensitive surfaces that can detect chemicals produced by pathogenic cells. When the phagocyte comes in contact with the pathogen, they engulf it and release digestive enzymes to digest it. Phagocytes can be identified under a microscope by their multilobed nucleus and granular cytoplasm.

LYMPHOCYTES

Produce antibodies to destroy pathogenic cells and antitoxins to neutralize toxins released by pathogens.

They can be identified under a microscope by a large round nucleus which takes up nearly the whole cell and clear non-granular cytoplasm.

Heart

Blood is pumped towards the heart veins and away from the heart in arteries. The two sides of the heart are separated by a muscle wall called septum. The heart is made of muscle tissue, which is supplied with blood by coronary arteries.

Ventricles are thicker than atria as they pump blood out, so they need to generate higher pressure. The left ventricle has a thicker muscle wall than the right as it needs to pump blood to the whole body, but the right only pumps blood to the lungs. The septum separates left and right to prevent mixing of oxygenated and deoxygenated blood.

Valves prevent backflow of blood. There are two sets of valves:

Atrioventricular valves: Separate atrium and ventricles.
- Right side is tricuspid.
- Left side is bicuspid valve.
Valves open when the atria contract and close when the ventricles contract.

Semilunar valves prevent backflow from the artery to the ventricles from the right ventricle to the lungs (pulmonary valve) and left to body (aortic valve). These two arteries are the only two that contain valves. These valves open when the ventricle contracts and shut when relaxed.

Deoxygenated blood from the body flows into the right atrium via the vena cava. As the right atrium is filled, it contracts, and blood is pushed through the tricuspid valve into the right ventricle. The walls of the ventricle contract, and blood travels to the lungs after passing the pulmonary valve. Oxygenated blood returns to the left atrium through the pulmonary vein, then passes through the bicuspid valve into the left ventricle. The left ventricle pushes blood into the aorta, and then it is transported all over the body. The aortic valve (semilunar) prevents backflow.

Effect of physical activity on heart:

Heart activity can be monitored using an ECG (Electrocardiogram), measuring the pulse rate, or listening to the sound of valves opening and closing using a stethoscope.

Heart rate is measured in beats per minute (bpm). Increased physical activity results in increased heart and breathing rate. This is to ensure sufficient blood is taken to muscles with nutrients and oxygen. Waste products need to also be removed faster, and also the oxygen debt needs to be repaid. The heart beats faster to ensure extra oxygen is still being delivered, and lactic acid build-up is being broken down.

Coronary Heart Disease

Muscle cells need their own blood supply. This is supplied by the coronary arteries. If one of these arteries is partially or completely blocked by fatty deposits called ‘plaques’ (caused by cholesterol), the arteries aren’t elastic, so they can’t accommodate blood being forced, leading to Coronary Heart Disease.

Partial blockage: restricted blood flow results in severe chest pains called angina.

Complete blockage: cells in the area can’t respire, the heart won’t contract, leading to a heart attack.

To reduce the risk of CHD:

Quit smoking
Diet – reducing animal fat will reduce cholesterol levels & help weight loss
Exercise regularly

Risk factors for Coronary Heart Disease

FACTOR	EXPLANATION
POOR DIET	Eating more saturated fat increases cholesterol levels, increasing the chance of the buildup of fatty plaques
STRESS	When under stress, hormones produced can increase blood pressure, increasing the chance of a blockage in the coronary arteries
SMOKING	Nicotine in cigarettes will cause blood vessels to become narrower, increasing blood pressure which will cause the buildup of fat globules. If this occurs in the coronary artery, this will cause coronary heart disease
GENETIC PREDISPOSITION	Studies show that people with a history of coronary heart disease in their family are more likely to develop it themselves, suggesting it partly has a genetic basis
AGE	The risk of developing coronary heart disease increases as you get older
GENDER	Males are more likely to develop coronary heart disease than females

Chapter 10: Diseases and Immunity

Pathogens and Barriers

Pathogen: Disease-causing organism.
Pathogens are passed from one host to another so they cause transmissible diseases. They can be passed by:

Direct Contact – direct from one host to another via body fluids (blood/semen) e.g. HIV.
Indirect Contact – the pathogen leaves the host and is carried in some other way to others.

Method of Transmission	Examples of Diseases Spread in This Way
Droplets in Air	Common Cold, Influenza
Food or Water	Cholera, Typhoid, Dysentery
Touching Contaminated Surfaces	Athlete’s Foot, Salmonella (can be transmitted on the feet of flies who land on food that is then eaten)
Insect Bites	Malaria, Dengue Fever

3 main body defences:

Mechanical barriers – Structures that make it difficult for pathogens to enter:
- Skin: Covers all parts of the body.
- Nose hair: Makes it difficult for pathogens to enter lungs.
Chemical barriers – Substances that are produced to trap or kill pathogens:
- Stomach acid: Contains hydrochloric acid to kill any pathogens.
- Mucus: Pathogen gets trapped and removed.
Cells – White blood cells work to prevent pathogen replication:
- Phagocytosis: Engulf and digest pathogens.
- Production of antibodies: Clump pathogens and release chemicals to signal that these cells must be destroyed.

Controlling Spread of Disease

Simplest way to prevent disease is to stop pathogens from spreading. This includes simple measures such as good hygiene, effective sanitation, and waste disposal to safely discard pathogens.

Measure to Prevent Spread	How It Works
Hygienic Food Preparation	– Keep food cold so bacteria and fungi reproduce more slowly – Prepare food hygienically to avoid contamination from pathogens by washing hands well with soap and cleaning work surfaces with products such as bleach to kill pathogens – Cook food well (long enough at high temperature) to kill bacteria and fungi – Cover food to prevent flies landing on it before eating – Use separate chopping boards/utensils for cutting uncooked meat – Wash hands after using the bathroom before handling food
Personal Hygiene	– Washing with soap removes substances which trap pathogens as well as pathogens themselves from the skin – Use tissues to catch sneezes and coughs – Dispose of used tissues as soon as possible as pathogens can still be alive – Wash hands after using the bathroom
Waste Disposal	– Waste food is a food source for flies that can act as vectors for transmissible diseases and so should be disposed of in a sealed container – Rubbish bins should be covered and removed to the landfill for disposal or burning regularly – All rubbish should be stored before collection away from human habitation
Sanitation	– Homes and public places should have plumbing and drains to safely remove faeces and waste which can carry pathogens – Raw sewage should be treated to remove solid waste and kill pathogens before being released into the environment

If a large amount of the population is vaccinated, it protects the entire population as there will be very few places for the pathogens to breed. This is called herd immunity.
If less people are vaccinated, it leaves the population at risk of mass infection, which increases the number of infections.
Herd immunity prevents epidemics/pandemics from occurring in populations.
Most children are vaccinated after birth to keep the vaccinated population high, which aims to eradicate diseases; an example would be smallpox.

Antigens and Antibodies

All cells have proteins and other substances projecting from the cell membrane; these are called antigens and are specific to that type of cell. Lymphocytes read antigens and recognize foreign antigens. They can then make antibodies, which have a complementary shape to the pathogen cell surface.

Antibodies attach to antigens and cause agglutination (clump together). This makes it harder for pathogenic cells to move, and simultaneously, chemicals are released by phagocytes to destroy pathogenic cells.

The initial response of lymphocytes encountering a pathogen and making antibodies takes a few days. After antibodies are made for the first time, memory cells are also made to retain instructions for antibodies. The next time, antibodies are made faster, and the person becomes immune. However, this won’t work for all pathogens as they can mutate and change antigens.

Vaccinations:

Vaccinations give protection against specific diseases and boost the body’s defense against infection. The level of population protection depends on the proportion of people vaccinated.
Vaccines introduce dead or altered forms of the disease which have specific antigens to our body.
In their weakened state, pathogens can’t cause illness but can provoke the immune system.
Lymphocytes produce complementary antibodies and memory cells are also created.
Since memory cells are produced, if live pathogen enters, body quickly responds and immunity is long-lasting.

Passive Immunity & Breastfeeding:

Passive immunity is a fast-acting, short-term defense against a pathogen by antibodies acquired from another individual.
Antibodies pass from mother to infant via breast milk, this is important because babies need to fight infections till they are older and stronger.
The body doesn’t make its own antibodies or memory cells in passive immunity.

Cholera

Cholera causes diarrhea

Loss of watery feces from the anus which may lead to death.
Severe diarrhea causes water & ion loss & it can be treated by oral rehydration therapy, which is a drink with a small amount of salt and sugar.
One infection that causes diarrhea is Vibrio Cholerae bacteria, which causes cholera.

Bacteria attaches to small intestines.
They produce a toxin.
Toxin stimulates intestine lining cells to release chloride ions.
Chloride builds in the lumen of small intestine & lowers water potential.
Water moves out of cells into lumen (osmosis).
Large amount of watery loss through watery feces.
Blood contains too little chloride ions & water.

Active Immunity:

Making antibodies and developing memory cells for future is active immunity.
Two ways in which active immune response happens:
- Body is infected by pathogens.
- Vaccination.
Active immunity is slow acting & provides long-lasting immunity.

Chapter 1: Characteristics and Classification

Movement

Respiration

Sensitivity

Growth

Reproduction

Excretion

Nutrition

Species

Binomial Naming System

Why Do We Classify Organisms?

How Do We Classify Organisms?

Hierarchical Classification

All living things have certain features in common, such as:

Whittaker’s Five Kingdom Scheme

Viruses

Characteristics of Viruses:

Dichotomous Keys

Animal

Vertebrates:

Arthropods:

Plant

Ferns

Flowering Plants

Fungus

Prokaryote

Protist

Chapter 2: Organization of the Organism

Eukaryotic Cells

Cell Structures in Both Animal and Plant Cells

Cell Structure in Plants Only

Cell Structure in Bacterial Cells

Specialized Cells & Adaptations

Neurons (Nerve Cells)

Ciliated Cells

Root Hair Cells

Red Blood Cells

Sperm:

Palisade Mesophyll Cells

Egg Cells:

Levels of Organization:

Note:

Size of Specimens

Word equation:

Balanced Chemical equation:

Chapter 3: Movement into and out of Cells

Diffusion

Key Concepts of Diffusion

Importance of Diffusion

Factors that Influence the Rate of Diffusion

Osmosis

Key Concepts of Osmosis

Plant Cells in Different Solutions

Animal Cells in Different Solutions

Importance of Osmosis

Active Transport

Key Concepts of Active Transport

Importance of Active Transport

Chapter 4: Biological Molecules

Carbohydrates

Examples:

Proteins

Examples:

Fats

Structure of DNA Molecule

Iodine Solution Test for Starch

Benedict’s Solution Test for Reducing Sugars

Biuret Test for Proteins

Ethanol Emulsion Test for Fats and Oils

DCPIP Test for Vitamin C

Chapter 5: Enzymes

Catalyst:

Enzyme:

Why Are Enzymes Important?

Common Enzymes Found in Our Body:

How Do Enzymes Work?

Steps:

Key Points:

How Are Enzymes Affected by Temperature?

Investigating Enzyme Actions