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 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 maintain balance
• What does the CNS consist of?

  Brain and spinal cord
• What does the PNS consist of?

  Nerves throughout the rest of the body
• What is a receptor?

  A structure that detects changes due to stimuli
• What happens when a stimulus is detected?

  An electrical signal travels to the spine
• What is the synapse?

  The gap between neurons
• How does a reflex arc work?

  It bypasses the brain for a faster response
• What are effectors?

  Muscles or glands that respond to signals
• How can reaction times be investigated?

  By dropping a ruler and measuring distance
• What is the mean average in reaction time experiments?

  The average distance caught over multiple trials
• How can an independent variable affect reaction time?

  By introducing stimulants or depressants
• What is the formula for calculating reaction time?

  $t =$$\frac{d}{0.5a}$
• 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 rate
• What are MRI scans used for?

  To see brain activity safely
• 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 the pupil's function?

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

  The transparent outer layer of the eye
• What are rods and cones in the retina?

  Cells that respond to light intensity and color
• What is myopia?

  Shortsightedness, can't focus on distant 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 the eye
• What is thermoregulation?

  Control of internal temperature by the body
• 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 that secrete hormones
• What is the main gland in the endocrine system?

  The pituitary gland
• What does the pancreas produce?

  Insulin to regulate blood glucose levels
• What happens when blood glucose levels are too high?

  The pancreas secretes insulin to lower levels
• What happens when blood glucose levels are too low?

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

  When the pancreas can't produce enough insulin
• What is type 2 diabetes?

  When cells no longer absorb glucose effectively