Revision

Question 1

What are the 6 main nutrients the body needs?

Answer 1

Carbohydrates, Proteins, Fats, Vitamins, Minerals, Water.

Question 2

What is the function of carbohydrates?

Answer 2

They are the body’s primary source of energy.

Question 3

What do proteins do in the body?

Answer 3

They help in growth and repair.

Question 4

What are fats used for?

Answer 4

Energy storage, hormone production, and cell growth.

Question 5

Name the two types of vitamins.

Answer 5

Water-soluble (e.g., Vitamin C, B), Fat-soluble (e.g., A, D, E, K).

Question 6

Why are minerals important?

Answer 6

They support physiological functions, e.g., calcium for bones.

Question 7

What is water’s main role in the body?

Answer 7

Transports nutrients and regulates temperature.

Question 8

How do you test for starch and what colour does it turn if starch is present?

Answer 8

Use iodine; it turns blue-black if starch is present.

Question 9

How do you test for glucose and what colour does it turn if glucose is present?

Answer 9

Use Benedict’s solution and heat; it turns brick-red if glucose is present.

Question 10

How do you test for protein and what colour does it turn if protein is present?

Answer 10

Use biuret solution; it turns purple if protein is present.

Question 11

How do you test for fats?

Answer 11

Use ethanol; a milky white emulsion forms if fat is present.

Question 12

What is the role of the small intestine?

Answer 12

Absorbs nutrients using villi and microvilli.

Question 13

What are enzymes?

Answer 13

Biological catalysts that speed up reactions like digestion.

Question 14

Where is amylase produced and what does it break down?

Answer 14

Mouth & pancreas; breaks starch into glucose.

Question 15

What enzyme breaks down proteins?

Answer 15

Protease.

Question 16

What enzyme breaks down fats?

Answer 16

Lipase.

Question 17

What is Ohm’s Law?

Answer 17

V = I x R (Voltage = Current × Resistance)

Question 18

In a series circuit, how is current distributed?

Answer 18

It is the same everywhere.

Question 19

In a parallel circuit, how is voltage shared?

Answer 19

Each branch gets full voltage.

Question 20

What happens when you add a lamp in series?

Answer 20

Resistance increases; lamps get dimmer.

Question 21

What happens when you add a cell in parallel?

Answer 21

Voltage stays the same, but cells last longer.

Question 22

What is the human range of hearing?

Answer 22

20 Hz to 20,000 Hz.

Question 23

What does pitch depend on?

Answer 23

Frequency of the wave.

Question 24

What does loudness depend on?

Answer 24

Amplitude of the wave.

Question 25

How many electrons fit in the first 3 shells?

Answer 25

1st = 2, 2nd = 8, 3rd = 8.

Question 26

What charge does an atom have if it loses electrons?

Answer 26

Positive ion (cation).

Question 27

What charge does an atom have if it gains electrons?

Answer 27

Negative ion (anion).

Question 28

What is ionic bonding?

Answer 28

Transfer of electrons from metal to non-metal.

Question 29

What is covalent bonding?

Answer 29

Sharing of electrons between non-metals.

Question 30

Example of covalent compound?

Answer 30

Water (H₂O), Ammonia (NH₃).

Question 31

What is the formula for density?

Answer 31

density = mass/volume

Question 32

How to find volume of irregular object?

Answer 32

Use a displacement method with a measuring cylinder.

Question 33

How do you separate soluble salts?

Answer 33

Dissolve, filter, evaporate, and crystallise.

Question 34

What is filtration used for?

Answer 34

To separate insoluble solids from liquids.

Question 35

Which metals are more reactive?

Answer 35

Potassium > Sodium > Calcium > Magnesium > Zinc > Iron > Copper.

Question 36

What does magnesium do in plants?

Answer 36

Makes chlorophyll.

Question 37

What happens if a plant lacks nitrates?

Answer 37

Poor growth and yellow leaves.

Question 38

What does xylem carry?

Answer 38

Water and minerals (up only).

Question 39

What does phloem carry?

Answer 39

Sugar (in both directions — up and down).

Question 40

What is osmosis?

Answer 40

Movement of water from high to low water concentration through a semi-permeable membrane

Question 41

What are CFCs?

Answer 41

Gases that damage the ozone layer.

Question 42

What’s the issue with CO₂ increase?

Answer 42

Global warming and climate change.

Question 43

What is DNA?

Answer 43

Molecule that stores genetic instructions.

Question 44

What are chromosomes?

Answer 44

Tightly coiled DNA seen during cell division (humans have 46).

Question 45

What is a gene?

Answer 45

A segment of DNA that codes for a trait.

Question 46

What is a zygote?

Answer 46

Single cell formed after fertilisation.

Question 47

What is the difference between embryo and fetus?

Answer 47

Embryo: up to 8 weeks. Fetus: after 8 weeks.

Question 48

Why is maternal health important?

Answer 48

Affects fetal development — poor diet or smoking can harm the baby.

Question 49

What causes variation?

Answer 49

Mutations and genetic recombination.

Question 49

What is natural selection?

Answer 49

The process where traits that help survival are passed on.