Biology

Question 1

What are the 7 life processes in MRS GREN?

Answer 1

Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition

Question 2

What are the five kingdoms of living organisms?

Answer 2

Animals, Plants, Fungi, Protoctists, Prokaryotes (Bacteria)

Question 3

Are viruses living organisms?

Answer 3

No — they cannot carry out life processes on their own and need a host to reproduce.

Question 4

Two features of animal cells

Answer 4

No cell wall; store carbohydrates as glycogen

Question 5

Two features of plant cells

Answer 5

Have a cell wall and chloroplasts; store carbohydrates as starch

Question 6

How do fungi feed?

Answer 6

By saprotrophic nutrition (secreting enzymes externally and absorbing nutrients)

Question 7

What are protoctists?

Answer 7

Single-celled organisms with features of either animals or plants (e.g. Amoeba, Chlorella)

Question 8

Define prokaryotic cell

Answer 8

A cell with no nucleus and no membrane-bound organelles (e.g. bacteria)

Question 9

Define eukaryotic cell

Answer 9

A cell that has a nucleus and membrane-bound organelles

Question 10

How are prokaryotic cells different from eukaryotic cells?

Answer 10

Prokaryotes, like bacteria, lack a nucleus and membrane-bound organelles and their DNA is in a loop. While eukaryotes, such as plants and animals, possess a nucleus and various organelles enclosed by membranes.

Question 11

Levels of organisation (smallest to largest)

Answer 11

Organelle → Cell → Tissue → Organ → Organ system → Organism

Question 12

What is a tissue?

Answer 12

A group of similar cells performing a specific function

Question 13

Function of the nucleus

Answer 13

Contains genetic material and controls cell activity

Question 14

Function of the cytoplasm

Answer 14

Where most chemical reactions take place

Question 15

Function of the cell membrane

Answer 15

Controls what enters and leaves the cell

Question 16

Function of the mitochondria

Answer 16

Site of aerobic respiration

Question 17

Function of the ribosomes

Answer 17

Site of protein synthesis

Question 18

3 structures found only in plant cells

Answer 18

Cell wall, chloroplasts, large central vacuole

Question 19

Define diffusion

Answer 19

Movement of particles from high to low concentration

Question 20

Define osmosis

Answer 20

Movement of water from high to low water potential through a partially permeable membrane

Question 21

Define active transport

Answer 21

Movement of particles against a concentration gradient using energy (ATP)

Question 22

Where does active transport occur in humans?

Answer 22

In the small intestine to absorb glucose into the blood

Question 23

What are the 3 types of blood vessels?

Answer 23

Arteries, veins, capillaries

Question 24

Function of red blood cells

Answer 24

Transport oxygen using haemoglobin

Question 25

Function of white blood cells

Answer 25

Defend the body against infection (e.g. by engulfing or producing antibodies)

Question 26

Function of platelets

Answer 26

Help blood clot and stop bleeding

Question 27

What does plasma carry?

Answer 27

CO₂, urea, hormones, nutrients, antibodies, heat

Question 28

What prevents backflow of blood in veins?

Answer 28

Valves

Question 29

What elements are in carbohydrates?

Answer 29

Carbon, hydrogen, oxygen

Question 30

What are carbohydrates made from?

Answer 30

Simple sugars (e.g. glucose)

Question 31

What is the function of carbohydrates?

Answer 31

providing energy, storing energy

Question 32

What elements are in proteins?

Answer 32

Carbon, hydrogen, oxygen, nitrogen (sometimes sulfur)

Question 33

What are proteins made from?

Answer 33

Amino acids

Question 34

What is the function of proteins?

Answer 34

Growth, repair, enzymes, hormones, antibodies

Question 35

What elements are in lipids?

Answer 35

Carbon, hydrogen, oxygen

Question 36

What are lipids made from?

Answer 36

Fatty acids and glycerol

Question 37

What are the functions of lipids?

Answer 37

Energy storage, insulation, protection, part of cell membranes

Question 38

What is the test for starch?

Answer 38

Iodine – turns blue-black

Question 39

What is the test for glucose?

Answer 39

Benedict's solution – turns brick red when heated

Question 40

What is the test for protein?

Answer 40

Biuret solution – turns purple

Question 41

What is the test for lipids?

Answer 41

Ethanol emulsion test – white milky layer forms

Question 42

What is an enzyme?

Answer 42

A biological catalyst that speeds up chemical reactions without being used up

Question 43

What is the ‘lock and key’ model?

Answer 43

The enzyme (lock) is specific to the substrate (key); only the right substrate fits

Question 44

What affects enzyme activity?

Answer 44

Temperature and pH

Question 45

What happens to enzymes at high temperatures?

Answer 45

They denature – active site changes shape

Question 46

What is the optimum temperature for human enzymes?

Answer 46

Around 37°C

Question 47

What is the optimum pH for most enzymes in the small intestine?

Answer 47

Slightly alkaline (around pH 8)

Question 48

What does amylase do?

Answer 48

Breaks down starch into maltose

Question 49

Where is amylase produced?

Answer 49

Salivary glands, pancreas, small intestine

Question 50

What does protease do?

Answer 50

Breaks down proteins into amino acids

Question 51

Where is protease produced?

Answer 51

Stomach (pepsin), pancreas, small intestine

Question 52

What does lipase do?

Answer 52

Breaks down lipids into fatty acids and glycerol

Question 53

Where is lipase produced?

Answer 53

Pancreas and small intestine

Question 54

What does bile do?

Answer 54

Neutralises stomach acid and emulsifies fats

Question 55

Why is fat emulsification important?

Answer 55

Increases surface area for lipase to act faster

Question 56

What is the word equation for photosynthesis?

Answer 56

Carbon dioxide + water → glucose + oxygen (with light and chlorophyll)

Question 57

Where does photosynthesis happen?

Answer 57

In the chloroplasts of plant cells

Question 58

What does chlorophyll do?

Answer 58

Absorbs light energy for photosynthesis

Question 59

What are the limiting factors of photosynthesis?

Answer 59

Light intensity, CO₂ concentration, temperature

Question 60

What do plants use glucose for?

Answer 60

Respiration, making cellulose, making proteins, storing as starch

Question 61

What mineral is needed for making chlorophyll?

Answer 61

Magnesium

Question 62

What happens if a plant lacks magnesium?

Answer 62

Yellow leaves (chlorosis)

Question 63

What mineral is needed to make proteins?

Answer 63

Nitrates

Question 64

What gases are exchanged in leaves?

Answer 64

Oxygen and carbon dioxide

Question 65

When do plants photosynthesise?

Answer 65

During the day (light required)

Question 66

When do plants respire?

Answer 66

All the time (day and night)

Question 67

What is the function of stomata?

Answer 67

Allow gas exchange and control water loss

Question 68

What controls the opening and closing of stomata?

Answer 68

Guard cells

Question 69

How are leaves adapted for gas exchange?

Answer 69

Large surface area, thin, air spaces, stomata on the underside