Master GCSE Biology

Questions:

1. Knowledge Recall (1-2 marks)

Q1. Define homeostasis and explain why it is essential for multicellular organisms. (2 marks)

2. Application of Knowledge (2-3 marks)

Q2. Describe the role of receptors in the nervous system and explain how they detect specific stimuli. (3 marks)

3. Extended Response (3-4 marks)

Q3. Explain how the reflex arc helps maintain homeostasis. Discuss the importance of each component of the reflex arc. (4 marks)

4. Knowledge Recall (1-2 marks)

Q4. Define the terms hormones and endocrine system. (2 marks)

5. Application of Knowledge (2-3 marks)

Q5. Describe the role of insulin and glucagon in regulating blood glucose levels. (3 marks)

6. Extended Response (3-4 marks)

Q6. Discuss the factors that can affect the release of ADH and explain how ADH helps maintain water balance in the body. (4 marks)

7. Knowledge Recall (1-2 marks)

Q7. Define auxins and gibberellins. (2 marks)

8. Application of Knowledge (2-3 marks)

Q8. Describe how auxins promote cell elongation and explain the importance of gibberellins in plant growth. (3 marks)

9. Extended Response (3-4 marks)

Q9. Explain how adrenaline prepares the body for a "fight-or-flight" response. (4 marks)

10. Knowledge Recall (1-2 marks)

Q10. Define thyroxine and explain its role in the human body. (2 marks)

Mark Schemes:

1. MS1:

- (1 mark) Homeostasis is the maintenance of a constant internal environment despite changes in the external environment

- (1 mark) It is essential for multicellular organisms to survive and function properly

2. MS2:

- (1 mark) Receptors detect specific stimuli from the environment

- (1 mark) Each receptor is shaped to fit a particular stimulus

- (1 mark) When the stimulus binds to the receptor, it triggers a change in the receptor

3. MS3:

- (1 mark) Stimulus detected by receptor

- (1 mark) Sensory neurone carries the stimulus to CNS

- (1 mark) CNS processes the stimulus and sends a motor response

- (1 mark) Motor neurone carries the response to the effector

- (1 mark) Effector carries out the response

4. MS4:

- (1 mark) Hormones are chemical messengers that travel in the blood

- (1 mark) Endocrine system is the network of glands that produce hormones

5. MS5:

- (1 mark) Insulin is a hormone that lowers blood glucose levels by increasing glucose uptake into cells

- (1 mark) Glucagon is a hormone that raises blood glucose levels by stimulating the breakdown of glycogen to glucose

- (1 mark) Insulin and glucagon work together to maintain blood glucose homeostasis

6. MS6:

- (1 mark) ADH is released when blood osmolarity increases

- (1 mark) ADH targets the kidneys and increases water reabsorption

- (1 mark) This leads to decreased urine output and increased blood volume

- (1 mark) Factors affecting ADH release include the hypothalamus, the osmoreceptors in the brain, and the adrenal glands

7. MS7:

- (1 mark) Auxins are plant hormones that promote cell elongation

- (1 mark) Gibberellins are plant hormones that promote stem elongation and seed germination

8. MS8:

- (1 mark) Auxins promote cell elongation by stimulating the proton pump in the cell membrane

- (1 mark) The proton pump creates an acidic environment that weakens the cell wall

- (1 mark) Gibberellins promote stem elongation by stimulating cell division and elongation

9. MS9:

- (1 mark) Adrenaline is a hormone that prepares the body for a "fight-or-flight" response

- (1 mark) Adrenaline increases heart rate and blood pressure

- (1 mark) Adrenaline increases blood flow to muscles and the brain

- (1 mark) Adrenaline dilates the airways

10. MS10:

- (1 mark) Thyroxine is a hormone that increases metabolic rate

- (1 mark) Thyroxine helps regulate growth and development