Paper two

• 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 internal conditions does the body regulate?

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

  It sends signals to effectors to respond to changes
• 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?

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

  A pathway where signals bypass the brain
• 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 distance
• What is the effect of stimulants on reaction time?

  They can decrease reaction time
• How can you calculate reaction time from distance?

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

  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 and breathing rates
• What is the purpose of MRI scans?

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

  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 the function of the pupil?

  To change size based on light intensity
• What is the cornea?

  Transparent outer layer of the eye
• What do rods and cones in the retina do?

  Rods detect light intensity; cones detect color
• What is myopia?

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

  Longsightedness, can't focus on near objects
• How do glasses or contact lenses help vision?

  They converge or diverge light before entering eye
• What is thermoregulation?

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

  Sweat glands produce sweat, blood vessels dilate
• What happens when the body is too cold?

  Blood vessels constrict, muscles shiver
• 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 helps glucose enter cells for respiration
• What happens when blood glucose levels are too low?

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

  Condition where pancreas can't produce enough insulin
• What is type 2 diabetes?

  Condition where cells don't absorb glucose properly
• How do kidneys maintain water balance?

  By filtering blood and adjusting water reabsorption
• What is ADH?

  Antidiuretic hormone that regulates water reabsorption
• What is negative feedback?

  Body's response to return conditions to normal