Biology Paper 1

Question 1

What is the main advantage of light microscopes?

Answer 1

Cheap to make and allow to see outlines of cells

Light microscopes have lower resolution compared to electron microscopes.

Question 2

What is a key feature of electron microscopes?

Answer 2

Allow for you to visualise finer details (organelles/subcellular structures) and have higher resolution

Electron microscopes are more expensive than light microscopes.

Question 3

What type of cells are eukaryotic cells?

Answer 3

Animal and Plant Cells

Eukaryotic cells contain a nucleus and other organelles.

Question 4

What is the function of the nucleus in animal cells?

Answer 4

Contains DNA

The nucleus is a key organelle in eukaryotic cells.

Question 5

What does the cell membrane do?

Answer 5

Semi-permeable, controls what enters and leaves the cell

It is essential for maintaining homeostasis.

Question 6

What is the primary function of mitochondria?

Answer 6

Site for respiration / Provides energy to the cell

Mitochondria are often referred to as the powerhouse of the cell.

Question 7

What are ribosomes responsible for?

Answer 7

Site for protein synthesis

Ribosomes can be found in both prokaryotic and eukaryotic cells.

Question 8

What is the composition of the plant cell wall?

Answer 8

Made of cellulose / Provides support and structure

The cell wall is a distinguishing feature of plant cells.

Question 9

What is the function of chloroplasts?

Answer 9

Site for photosynthesis (contain chlorophyll)

Chloroplasts are only found in plant cells.

Question 10

What is the role of the vacuole in plant cells?

Answer 10

Stores cell sap

It helps maintain turgor pressure within the cell.

Question 11

How many pairs of chromosomes do all human cells have?

Answer 11

23 pairs (diploid)

Gametes have just 23 chromosomes (haploid).

Question 12

What is mitosis?

Answer 12

Process by which new diploid cells are made for growth and repair

It results in two genetically identical diploid cells.

Question 13

What are the stages of the cell cycle?

Answer 13

1. Genetic material duplicates 2. Nuclear membrane dissolves 3. Chromosomes line up 4. Chromosomes pulled to opposite ends 5. Nucleus divides

This process also duplicates other organelles.

Question 14

Where is cell specialization found in animals?

Answer 14

Found in animal embryos

It allows for the development of different cell types.

Question 15

Where is cell specialization found in plants?

Answer 15

Found in plant meristems

Meristems are regions of growth in plants.

Question 16

Where in humans can cell specialization be found?

Answer 16

Found in bone marrow (can only specialise into blood cells)

Bone marrow is crucial for producing blood cells.

Question 17

What is diffusion?

Answer 17

Movement of particles from an area of high concentration to low concentration (down the concentration gradient)

It requires no energy.

Question 18

What is osmosis?

Answer 18

Diffusion of water across a semi-permeable membrane to balance concentration

Osmosis is critical for maintaining cell turgor.

Question 19

What is active transport?

Answer 19

Movement of particles from low concentration to high concentration via carrier proteins (up the concentration gradient)

Active transport requires energy.

Question 20

What is the hierarchy of biological organization?

Answer 20

Cell -> Tissue -> Organ -> Organ System

Example: Heart cell -> Heart tissue -> Heart -> Circulatory system.

Question 21

What is the function of teeth in the digestive system?

Answer 21

Break down food mechanically

Saliva contains amylase to aid in digestion.

Question 22

What is the role of the stomach in digestion?

Answer 22

Contains hydrochloric acid and enzymes that chemically break down food

It is a crucial organ for digestion.

Question 23

What does the liver produce?

Answer 23

Bile, which emulsifies lipids to form droplets

Bile increases the surface area for lipid digestion.

Question 24

What does the pancreas secrete?

Answer 24

Amylase, which breaks down starch into glucose in the small intestine

This is essential for carbohydrate digestion.

Question 25

What is the function of the large intestine?

Answer 25

Water is absorbed into the bloodstream ## Footnote This process is important for hydration.

Question 26

What is the role of the small intestine?

Answer 26

Nutrients like glucose are absorbed into the bloodstream by the villi ## Footnote The small intestine has a large surface area for absorption.

Question 27

What are enzymes?

Answer 27

Special proteins that act as biological catalysts ## Footnote They often break down molecules into shorter ones.

Question 28

What do carbohydrases do?

Answer 28

Break down carbohydrates into simple sugars (e.g., amylase breaks down starch into glucose) ## Footnote They are a type of enzyme.

Question 29

What do proteases do?

Answer 29

Break down proteins into amino acids ## Footnote Proteases are important for protein digestion.

Question 30

What do lipases do?

Answer 30

Break down lipids into glycerol & fatty acids ## Footnote Lipases are crucial for fat digestion.

Question 31

Why are enzymes specific?

Answer 31

Only break down substrates that fit their active site ## Footnote This specificity is key to their function.

Question 32

What happens to enzyme activity as temperature increases?

Answer 32

Activity increases until the enzyme denatures ## Footnote Denaturation changes the shape of the active site.

Question 33

How does pH affect enzyme activity?

Answer 33

Enzyme activity is affected by too high or too low pH ## Footnote Each enzyme has an optimum pH range.

Question 34

What is the procedure for an enzyme practical using amylase?

Answer 34

Mix amylase with starch, remove drops every 10 seconds, add to iodine, record time for no starch detection ## Footnote This helps determine the optimal conditions for enzyme activity.

Question 35

What contains genetic material to survive and reproduce in prokaryotic cells?

Answer 35

Loose DNA strand ## Footnote The loose DNA strand is essential for the cell's survival and reproduction.

Question 36

What are plasmids in prokaryotic cells?

Answer 36

Extra DNA (e.g antibiotic resistance) ## Footnote Plasmids can carry genes that confer advantages, such as antibiotic resistance.

Question 37

What structure propels bacteria cells?

Answer 37

Flagella ## Footnote Flagella are whip-like structures that enable motility in bacteria.

Question 38

Which organelles do bacteria cells NOT have?

Answer 38

* Mitochondria * Nucleus * Chloroplasts ## Footnote These organelles are characteristic of eukaryotic cells, not prokaryotic cells.

Question 39

What are the four chambers of the heart?

Answer 39

Right atrium, right ventricle, left atrium, left ventricle

Question 40

What does the right side of the heart do?

Answer 40

Receives deoxygenated blood, pumps it to lungs

Question 41

What does the left side of the heart do?

Answer 41

Receives oxygenated blood, pumps it to body

Question 42

What are arteries and their main characteristics?

Answer 42

Carry blood away from the heart, thick walls

Question 43

What are veins and their main characteristics?

Answer 43

Carry blood to the heart, valves prevent backflow

Question 44

What are capillaries?

Answer 44

Tiny blood vessels for exchange of substances

Question 45

What is the function of red blood cells?

Answer 45

Carry oxygen, no nucleus, contain haemoglobin

Question 46

What is the role of white blood cells?

Answer 46

Fight infection

Question 47

What do platelets do?

Answer 47

Help blood clot

Question 48

What is plasma?

Answer 48

Liquid part of blood, carries everything (CO2, urea, hormones)

Question 49

Define communicable diseases.

Answer 49

Caused by pathogens, can spread (e.g., flu)

Question 50

Define non-communicable diseases.

Answer 50

Cannot spread (e.g., cancer, diabetes)

Question 51

What are some risk factors for diseases?

Answer 51

Smoking, alcohol, poor diet, lack of exercise

Question 52

What is the function of xylem in plants?

Answer 52

Transports water, one-way, made of dead cells

Question 53

What is the function of phloem in plants?

Answer 53

Transports sugars (glucose), two-way, made of living cells

Question 54

What are stomata?

Answer 54

Pores for gas exchange, controlled by guard cells

Question 55

What are the types of pathogens?

Answer 55

* Bacteria * Viruses * Fungi * Protists

Question 56

How do bacteria spread disease?

Answer 56

Release toxins (e.g., salmonella)

Question 57

How do viruses spread disease?

Answer 57

Replicate inside cells, burst them (e.g., measles, HIV)

Question 58

How do fungi spread disease?

Answer 58

Spread by spores (e.g., athlete’s foot)

Question 59

How do protists spread disease?

Answer 59

Often carried by vectors (e.g., malaria)

Question 60

What are the ways diseases can spread?

Answer 60

* Air (coughs, sneezes) * Water (dirty water) * Direct contact (touching contaminated surfaces or people)

Question 61

What is the role of skin in body defenses?

Answer 61

Physical barrier

Question 62

What do mucus and hairs do in body defenses?

Answer 62

Trap particles

Question 63

What is the function of stomach acid?

Answer 63

Kills bacteria

Question 64

What is phagocytosis?

Answer 64

Engulf and destroy pathogens

Question 65

What is antibody production?

Answer 65

Specific to each pathogen

Question 66

What are antitoxins?

Answer 66

Neutralise toxins from bacteria

Question 67

What is vaccination?

Answer 67

Introduces small amounts of dead/inactive pathogens

Question 68

What do white blood cells do after vaccination?

Answer 68

Make memory cells

Question 69

What is the next response after vaccination?

Answer 69

Fast immune response

Question 70

What do antibiotics do?

Answer 70

Kill bacteria (e.g., penicillin), not viruses

Question 71

What are the stages of drug development?

Answer 71

* Preclinical (cells, animals) * Clinical trials (humans)

Question 72

What is double-blind testing?

Answer 72

Neither participants nor researchers know who receives treatment

Question 73

What is a placebo?

Answer 73

Fake drug used in trials to compare effects

Question 74

What is the photosynthesis equation?

Answer 74

Carbon dioxide + water → glucose + oxygen

Question 75

Where does photosynthesis occur?

Answer 75

In chloroplasts

Question 76

What are the uses of glucose in plants?

Answer 76

* Respiration * Making cellulose (cell walls) * Making amino acids (need nitrates from soil) * Stored as starch * Stored as oils/fats

Question 77

What are the limiting factors of photosynthesis?

Answer 77

* Light intensity * Carbon dioxide * Temperature

Question 78

What is aerobic respiration?

Answer 78

Glucose + oxygen → carbon dioxide + water (+ energy)

Question 79

Where does aerobic respiration occur?

Answer 79

In mitochondria

Question 80

What is anaerobic respiration in animals?

Answer 80

Glucose → lactic acid (+ little energy)

Question 81

What causes muscle fatigue?

Answer 81

Lactic acid from anaerobic respiration

Question 82

What is oxygen debt?

Answer 82

Extra oxygen needed to break down lactic acid

Question 83

What is anaerobic respiration in yeast?

Answer 83

Glucose → ethanol + carbon dioxide

Question 84

What is fermentation used for?

Answer 84

In bread and alcohol production