A Level Biology: Homeostasis MCQs

Question 1

Insulin lowers blood glucose by

Accepted Answer

increasing glucose uptake by cells and glycogen synthesis

Answer

stimulating gluconeogenesis

Answer

stimulating glycogen breakdown

Answer

reducing glucose transporters

Question 2

Which substance is normally absent from the glomerular filtrate?

Accepted Answer

Plasma proteins

Answer

Sodium ions

Answer

Urea

Answer

Glucose

Question 3

ABA causes stomata to close in water stress by

Accepted Answer

causing K⁺ to leave guard cells so water follows

Answer

increasing photosynthesis

Answer

pumping water into guard cells

Answer

causing K⁺ to enter guard cells

Question 4

The inner wall of a guard cell is

Accepted Answer

thicker and less elastic than the outer wall

Answer

thinner than the outer wall

Answer

absent

Answer

made of suberin

Question 5

Urea is produced in the liver by

Accepted Answer

deamination of excess amino acids

Answer

ultrafiltration

Answer

hydrolysis of fats

Answer

breakdown of glucose

Question 6

Which component of the cascade does glucagon binding activate first?

Accepted Answer

A G-protein

Answer

cAMP

Answer

Protein kinase A

Answer

Glycogen phosphorylase

Question 7

Homeostasis is best described as

Accepted Answer

maintaining a constant internal environment

Answer

making hormones

Answer

producing urine

Answer

responding to external stimuli only

Question 8

In negative feedback,

Accepted Answer

a change triggers a response that reverses the change

Answer

a change is amplified

Answer

there is no set point

Answer

only hormones are involved

Question 9

Glucose test strips contain

Accepted Answer

glucose oxidase and peroxidase

Answer

amylase and maltase

Answer

insulin and glucagon

Answer

ADH and aquaporins

Question 10

In water stress, ABA is produced by

Accepted Answer

roots and leaves

Answer

flowers

Answer

guard cells only

Answer

xylem vessels

Question 11

Glucose is reabsorbed from the PCT by

Accepted Answer

cotransport with sodium ions

Answer

simple diffusion only

Answer

endocytosis

Answer

osmosis

Question 12

In the cell signalling cascade for glucagon, the second messenger is

Accepted Answer

cyclic AMP

Answer

glycogen

Answer

adenylyl cyclase

Answer

G-protein

Question 13

Stomata open when guard cells

Accepted Answer

take up K⁺ ions and water, becoming turgid

Answer

produce ABA

Answer

become flaccid

Answer

lose K⁺ ions and water

Question 14

ADH is released from the

Accepted Answer

posterior pituitary

Answer

pancreas

Answer

hypothalamus directly into urine

Answer

anterior pituitary

Question 15

Stomata must open to

Accepted Answer

let carbon dioxide in for photosynthesis

Answer

let oxygen in for respiration only

Answer

absorb light

Answer

stop transpiration

Question 16

Proton pumps in guard cell membranes

Accepted Answer

pump H⁺ out, leading to K⁺ entry

Answer

make ABA

Answer

pump water in

Answer

pump K⁺ out

Question 17

Which layer of the glomerulus/Bowman's capsule acts as the main filter?

Accepted Answer

Basement membrane

Answer

Proximal convoluted tubule

Answer

Podocytes

Answer

Endothelium

Question 18

In ABA signalling, the second messenger is

Accepted Answer

calcium ions

Answer

cyclic AMP

Answer

water

Answer

potassium ions

Question 19

Podocytes have

Accepted Answer

filtration slits between their foot processes

Answer

aquaporins

Answer

cilia

Answer

microvilli

Question 20

ADH increases water reabsorption by

Accepted Answer

causing aquaporins to be inserted into collecting duct membranes

Answer

closing aquaporins

Answer

increasing glomerular pressure

Answer

pumping water actively

Question 21

Osmoreceptors that detect blood water potential are in the

Accepted Answer

hypothalamus

Answer

adrenal gland

Answer

posterior pituitary

Answer

kidney

Question 22

The enzyme cascade in liver cells amplifies the signal because

Accepted Answer

each activated enzyme activates many molecules of the next enzyme

Answer

cAMP is a hormone

Answer

receptors are destroyed

Answer

glucagon is used up

Question 23

Stomata opening in the morning even in constant light shows

Accepted Answer

a daily (circadian) rhythm

Answer

a response to ABA

Answer

wilting

Answer

plasmolysis

Question 24

Glucagon is secreted by

Accepted Answer

α cells of the islets of Langerhans

Answer

the adrenal medulla

Answer

the liver

Answer

β cells

Question 25

The renal pelvis

Accepted Answer

collects urine and leads into the ureter

Answer

contains the loops of Henle

Answer

filters blood

Answer

makes ADH

A Level Biology: Homeostasis MCQs — Biology

1. Insulin lowers blood glucose by

2. Which substance is normally absent from the glomerular filtrate?

3. ABA causes stomata to close in water stress by

4. The inner wall of a guard cell is

5. Urea is produced in the liver by

6. Which component of the cascade does glucagon binding activate first?

7. Homeostasis is best described as

8. In negative feedback,

9. Glucose test strips contain

10. In water stress, ABA is produced by

11. Glucose is reabsorbed from the PCT by

12. In the cell signalling cascade for glucagon, the second messenger is

13. Stomata open when guard cells

14. ADH is released from the

15. Stomata must open to

16. Proton pumps in guard cell membranes

17. Which layer of the glomerulus/Bowman's capsule acts as the main filter?

18. In ABA signalling, the second messenger is

19. Podocytes have

20. ADH increases water reabsorption by

21. Osmoreceptors that detect blood water potential are in the

22. The enzyme cascade in liver cells amplifies the signal because

23. Stomata opening in the morning even in constant light shows

24. Glucagon is secreted by

25. The renal pelvis

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