Biology Paper 2

• What is homeostasis?

  Regulation of internal conditions despite external changes
• What is the role of receptors in the nervous system?

  They detect changes due to stimuli
• Why is homeostasis important for enzymes?

  It allows chemical reactions to occur at optimum rates
• What does the nervous system consist of?

  CNS and PNS
• How does an electrical signal travel in the nervous system?

  Through sensory and relay neurons
• What is a reflex arc?

  A pathway where signals bypass the brain
• How can you investigate reaction times?

  By dropping a ruler and measuring distance
• What do glands produce in the body?

  Specific chemicals needed by the body
• What is the formula to calculate reaction time from distance?

  $t =$$\sqrt{\frac{2d}{a}}$
• What does the cerebral cortex control?

  Higher level functions like memory and speech
• What are the three parts of the brain?

  Cerebral cortex, cerebellum, medulla oblongata
• What is the function of the cerebellum?

  Controls motor skills, movement, and balance
• What is MRI used for?

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

  Ability to change lens shape for focus
• What does the medulla oblongata control?

  Unconscious actions like heart rate
• 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 thick
• What is myopia?

  Shortsightedness, can't focus on far objects
• What is hyperopia?

  Longsightedness, can't focus on near objects
• How do glasses correct vision?

  By converging or diverging light before entry
• What is thermoregulation?

  Control of internal temperature by the brain
• What is vasodilation?

  Widening of blood vessels to increase heat loss
• What happens when the body is too hot?

  Sweat glands produce sweat to cool down
• What happens when the body is too cold?

  Vasoconstriction occurs to retain heat
• What is the endocrine system?

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

  Produces hormones in response to stimuli
• What hormone does the pancreas produce?

  Insulin
• What does glucagon do?

  Causes liver to convert glycogen to glucose
• What happens when blood glucose levels are too high?

  Pancreas secretes insulin to lower levels
• What is type 1 diabetes?

  Pancreas can't produce enough insulin
• What is type 2 diabetes?

  Cells no longer absorb glucose effectively
• What is dialysis?

  Machine that filters blood like kidneys
• What is negative feedback?

  Body responds to return things to normal
• What happens during menstruation?

  Eggs mature and uterine lining thickens
• What hormone causes egg maturation?

  Follicle stimulating hormone (FSH)
• What does luteinizing hormone (LH) do?

  Causes egg release from the ovary
• What does estrogen do during the menstrual cycle?

  Thickens uterine lining and inhibits FSH
• What are some contraception methods?

  Pills, injections, condoms, IUDs
• What is IVF?

  Fertilization of eggs in a lab
• What is the role of gibberellins in plants?

  Promotes seed germination and flowering