Paper 2

• What topics does the AQA biology paper 2 cover?

  Homeostasis, inheritance, variation, evolution, ecology
• What is homeostasis?

  Regulation of internal conditions despite external changes
• Why is homeostasis important?

  It allows crucial chemical reactions to occur optimally
• What three conditions does the body regulate?

  Blood glucose concentration, temperature, water levels
• How does the nervous system help maintain homeostasis?

  By sending signals to effectors based on stimuli
• What are the two main parts of the nervous system?

  CNS and PNS
• What does the CNS consist of?

  Brain and spinal cord
• What is the role of receptors in the nervous system?

  To detect changes due to stimuli
• What is a reflex arc?

  A pathway that bypasses the brain for quick responses
• What is the function of glands in the body?

  To produce specific chemicals as needed
• How can you investigate reaction times?

  By dropping a ruler and measuring the distance caught
• How can you introduce an independent variable in a reaction time experiment?

  By using a stimulant or depressant
• What is the formula to calculate reaction time from distance?

  $s =$$\frac{1}{2} a t^2$
• What are the three parts of the brain you need to know?

  Cerebral cortex, cerebellum, medulla oblongata
• What does the cerebral cortex control?

  Higher level functions like memory and speech
• What is the function of the cerebellum?

  Motor skills, movement, balance, coordination
• What does the medulla oblongata control?

  Unconscious actions like heart rate and breathing
• What is the purpose of MRI scans?

  To safely see brain activity
• What is accommodation in the eye?

  The ability to change lens shape for focus
• How does the eye focus on distant objects?

  Ciliary muscles relax, lens becomes thin
• How does the eye focus on near objects?

  Ciliary muscles contract, lens becomes thicker
• What is myopia?

  Shortsightedness
• What is hyperopia?

  Longsightedness
• How do glasses or contact lenses help vision?

  By converging or diverging light before entering the eye
• What is thermoregulation?

  Control of internal temperature by the body
• How does the body respond when too hot?

  Sweating and vasodilation occur
• What happens when the body is too cold?

  Shivering and vasoconstriction occur
• What is the endocrine system?

  A system of glands producing hormones
• What is the role of the pituitary gland?

  It produces hormones that stimulate other glands
• What hormone does the pancreas produce?

  Insulin
• What does insulin do?

  It lowers blood glucose levels
• What happens when blood glucose levels are too low?

  Pancreas produces glucagon to raise levels
• What is type 1 diabetes?

  Insufficient insulin production by the pancreas
• What is type 2 diabetes?

  Cells no longer absorb glucose effectively
• How do kidneys maintain water balance?

  By filtering blood and reabsorbing water
• What is ADH's role in water balance?

  It increases water reabsorption in kidneys
• What is negative feedback?

  A response that returns conditions to normal
• What happens if kidneys fail?

  Dialysis is required to filter blood
• What hormone is involved in menstruation?

  FSH (follicle stimulating hormone)
• What does FSH do in females?

  Causes an egg to mature in the ovary