paper 2 2

Question 2

What is homeostasis?

Answer 2

Regulation of internal conditions despite external changes.

Question 3

What systems regulate homeostasis?

Answer 3

Nervous system (CNS & PNS) and Endocrine system.

Question 4

What are the three main parts of the brain?

Answer 4

Cerebral cortex (thinking), Cerebellum (movement), Medulla oblongata (automatic functions).

Question 5

How does the eye focus light?

Answer 5

By adjusting the lens.

Question 6

What are the two types of light receptor cells in the eye?

Answer 6

Rods (low light vision) and Cones (color vision).

Question 7

What happens when the body is too hot?

Answer 7

Sweating and vasodilation (blood vessels widen).

Question 8

What happens when the body is too cold?

Answer 8

Shivering and vasoconstriction (blood vessels narrow).

Question 9

What is the role of the pituitary gland?

Answer 9

It secretes hormones to regulate body functions.

Question 10

What hormone regulates blood glucose levels?

Answer 10

Insulin (lowers glucose) and Glucagon (raises glucose).

Question 11

How do the kidneys regulate water balance?

Answer 11

By releasing ADH, which controls urine concentration.

Question 12

What do reproductive hormones control?

Answer 12

Egg maturation and uterine preparation.

Question 13

How does contraception work?

Answer 13

Prevents fertilization.

Question 14

What is IVF?

Answer 14

Lab fertilization of eggs; low success rate, risk of multiple births.

Question 15

What does adrenaline do?

Answer 15

Prepares the body for ‘fight or flight’.

Question 16

What does thyroxine do?

Answer 16

Regulates metabolism.

Question 17

What do plant hormones control?

Answer 17

Growth and phototropism (response to light).

Question 18

What does DNA do?

Answer 18

Encodes proteins.

Question 19

What can happen when DNA mutates?

Answer 19

It may cause dysfunctions or diseases.

Question 20

What is epigenetics?

Answer 20

The study of non-coding DNA affecting gene expression.

Question 21

What are dominant and recessive alleles?

Answer 21

Dominant alleles are always expressed; Recessive alleles are only expressed when both copies are recessive.

Question 22

What do Punnett squares predict?

Answer 22

Genetic inheritance patterns and sex determination.

Question 23

How does evolution work?

Answer 23

Random variations → Adaptations → Natural selection.

Question 24

What supports the theory of evolution?

Answer 24

Antibiotic-resistant bacteria.

Question 25

What is genetic modification?

Answer 25

Altering DNA to enhance traits.

Question 26

What do fossils show?

Answer 26

Insights into past life forms and evolution.

Question 27

How are plants cloned?

Answer 27

Using cuttings.

Question 28

How are animals cloned?

Answer 28

By nuclear transfer into egg cells.

Question 29

What are the three domains of life?

Answer 29

Archaea, Bacteria, Eukarya.

Question 30

What is ecology?

Answer 30

The study of how organisms interact in ecosystems.

Question 31

What affects ecosystems?

Answer 31

Abiotic factors (non-living, e.g., temperature) & Biotic factors (living, e.g., predators).

Question 32

Why is biodiversity important?

Answer 32

It ensures ecosystem stability.

Question 33

What threatens biodiversity?

Answer 33

Pollution, habitat destruction, and human activities.

Question 34

Why is biomass lost at each trophic level?

Answer 34

Due to respiration, waste, and incomplete consumption.

Question 35

What challenges food security?

Answer 35

Population growth, diet changes, climate change, farming costs, and geopolitical conflicts (e.g., Ukraine wheat supply).

Question 36

How can farming be more efficient?

Answer 36

Minimize biomass loss, maximize input efficiency.

Question 37

What is sustainable fishing?

Answer 37

Using nets that let juvenile fish escape to prevent overfishing.