Yr 9 + Yr 10 Biology Content

Cells

Examples of Eukaryotic cells: Animal cell, plant cell
Example of Prokaryotic cell: Bacterial cell
What controls the cell’s activity? Nucleus
Where do chemical reactions take place in the cell? Cytoplasm
What controls what moves in and out of the cell? Cell membrane
Where does aerobic respiration take place? Mitochondria
Where does protein synthesis take place? Ribosomes
What is a plant cell wall made of? Cellulose
Where does photosynthesis take place? Chloroplasts
What chemical makes plants green? Chlorophyll
What part of a plant cell contains cell sap? Vacuole
What type of cells don’t have a nucleus but DNA in a loop? Prokaryotic cells (e.g., bacteria)
What is a circular piece of DNA in bacteria called? Plasmid
Specialised cell with many mitochondria? Muscle cell
How is a root hair cell specialised? Large surface area for water and mineral absorption
Formula for magnification? Image size ÷ Actual size
1 mm equals how many micrometres? 1000 µm
Which microscope has higher magnification and resolution? Electron microscope
Plant and animal cells are examples of? Eukaryotic cells
920000 in standard form = 9.2 × 10⁵
0.00025 in standard form = 2.5 × 10⁻⁴
What is a tissue? Group of similar cells working together
What is an organ? A group of tissues working together
3 features of gills, alveoli, villi: Large surface area, thin walls, good blood supply

Classification & Adaptations

Organisms in extreme conditions: Extremophiles
Animals that hunt prey: Predators
Animals that eat plants: Herbivores
Animals compete for: Food, mates, territory
Plants compete for: Light, water, minerals, space
Grouping similar organisms: Classification
Linnaeus’s system called: Binomial nomenclature
Woese’s three domains: Bacteria, Archaea, Eukarya
Linnaeus groups:

Kingdom
Phylum
Class
Order
Family
Genus
Species

3 abiotic factors: Light, temperature, moisture
3 biotic factors: Predators, disease, competition
Adaptations may be: Structural, behavioural, functional

Photosynthesis

What makes plants green? Chlorophyll
Equation for photosynthesis: Carbon dioxide + Water → Glucose + Oxygen
Symbol equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Limiting factors: Light, CO₂, temperature
Plants use glucose for: Respiration, cellulose, making fats, proteins, storage (starch)
Photosynthesis occurs in: Palisade mesophyll cells
CO₂ enters leaf through: Stomata
What controls stomata size? Guard cells
Water/mineral movement: Transpiration
Sugar movement: Translocation
Xylem features: Hollow tubes, lignified walls, one-way flow
Phloem features: Living cells, companion cells, two-way transport

Transport in Cells

High to low concentration movement: Diffusion
Concentration difference: Concentration gradient
Example of diffusion: Oxygen into blood
Osmosis: Movement of water through a semi-permeable membrane
Same solute concentration: Isotonic
More concentrated solution: Hypertonic
More dilute solution: Hypotonic
Movement against gradient: Active transport
Active vs passive: Requires energy, uses carrier proteins

Stem Cells & Mitosis

Mitosis produces: Identical cells
Chromosomes are found in: Nucleus
Chromosomes made of: DNA
Before division, DNA: Replicates
Mitosis used for: Growth, repair, asexual reproduction
Undifferentiated cells: Stem cells
Adult stem cells found in: Bone marrow
Can become any cell: Embryonic stem cells
Faulty division leads to: Cancer
Localised tumour: Benign
Spreading tumour: Malignant
Cancer-causing agents: Carcinogens
Stem cell therapy risks: Infection, rejection, cancer
Differentiation occurs: (a) Early in animals, (b) Throughout life in plants

Enzymes & Digestion

Carbohydrates made of: Sugars (e.g., glucose)
Lipids made of: Fatty acids and glycerol
Proteins made of: Amino acids
Enzymes do what? Speed up reactions
Substrate fits into: Active site
Enzymes affected by: Temperature, pH
If not right conditions: Enzyme denatures
Molecule fitting into enzyme: Substrate
Test for starch: Iodine
Starch colour change: Orange-brown → Blue-black
Test for sugars: Benedict’s
Sugar colour change: Blue → Brick red
Before colour change: Heat the mixture
Test for lipids: Sudan III or ethanol test
Lipids present: Red layer or cloudy emulsion
Test for proteins: Biuret
Protein colour change: Blue → Purple
Stomach acid function: Kills bacteria, helps digestion
Bile made in: Liver
Bile function: Emulsifies fats, neutralises acid
Small intestine: Digestion and absorption
Large intestine: Absorbs water
Saliva enzyme: Amylase
Stomach enzyme: Protease (pepsin)
Pancreas enzymes: Amylase, protease, lipase
Small intestine enzymes: Amylase, protease, lipase
Mouth to stomach tube: Oesophagus

Heart & Health

Circulatory system job: Transport substances
Double circulation: Blood goes to lungs and body
Arteries carry blood: Away from heart
Veins carry blood: To the heart
Top heart chambers: Atria
Bottom chambers: Ventricles
Heart valves function: Prevent backflow
Pulmonary artery goes to: Lungs
Aorta goes to: Body
Returns blood from body: Vena cava
Returns blood from lungs: Pulmonary vein
Supplies heart muscle: Coronary arteries
Heart rate controlled by: Pacemaker cells
Artificial pacemakers: Control heartbeat
Capillaries function: Exchange substances
Capillaries adapted by: Thin walls, close to cells
Blocked arteries opened by: Stents
Liquid blood part: Plasma
Red cells contain: Haemoglobin
Forms clots: Platelets
Large lumen vessels: Veins
Thick muscular walls: Arteries
Prevent rejection: Immunosuppressants
Drug downside: Increased infection risk
Non-infectious diseases: Non-communicable
Disease risk factors: Risk factors

Immunity

Microbes making you ill: Pathogens
Microbes hiding in cells: Viruses
White blood cells can:
a. Engulf pathogens
b. Produce antibodies
c. Produce antitoxins
Antibiotics kill: Bacteria
Vaccine contains: Dead/inactive pathogen
Vaccines produce: Antibodies/memory cells
Most people vaccinated: Herd immunity
Antibiotic-resistant bacteria: MRSA
Resistance develops by: Mutation + natural selection
Grow microbes in: Petri dish
In dish: Agar jelly
Measles & HIV: Viruses
Cholera & TB: Bacteria
Malaria vector: Mosquito
Malaria pathogen type: Protist
Stomach defence: Hydrochloric acid
Respiratory defence: Mucus and cilia
Double blind trial: Patient & doctor don’t know
Inactive drug: Placebo
Plant virus example: TMV (Tobacco Mosaic Virus)
Plant fungus: Rose black spot
Plant physical defences: Waxy cuticle, cell wall, bark
Mechanical defences: Thorns, mimicry
Chemical defences: Poisons, antibacterial chemicals
Drug testing stage 1: Lab testing (cells/tissues)
Stage 2: Animal testing
Stage 3: Human clinical trials
Combined with lymphocytes: Tumour cells
Called: Hybridoma

Pathogens & Diseases

(a) Measles – Virus, airborne droplets, fever + rash
(b) HIV – Virus, sexual contact/blood, immune damage
(c) TMV – Virus, contact between plants, discoloured leaves
(d) Salmonella – Bacteria, food, vomiting + diarrhoea
(e) Gonorrhoea – Bacteria, sexual contact, discharge + pain
(f) Rose black spot – Fungus, spores, black leaf spots
(g) Malaria – Protist, mosquito, fever + chills

Breathing & Respiration

Diaphragm when breathing in: Contracts and flattens
Ribs when breathing in: Move up and out
Thorax volume: Increases
Chest pressure: Decreases
Air sacs called: Alveoli
Alveoli adaptations: Thin walls, moist, large surface area
Windpipe called: Trachea
Lung tubes: Bronchi and bronchioles
Respiration is: Exothermic
Respiration equation: Glucose + Oxygen → CO₂ + Water + Energy
We need energy for:
a. Movement
b. Keeping warm
c. Active transport
d. Cell division
Low oxygen respiration: Anaerobic
Waste product: Lactic acid
After exercise: To remove lactic acid
Repay oxygen debt by: Breathing deeply
Plants/microbes anaerobic: Ethanol + CO₂
Yeast anaerobic respiration: Fermentation
Fermentation use: Alcohol & bread-making
All cell reactions called: Metabolism