AQA GCSE Biology Paper 2 questions and solutions

AQA GCSE Biology Paper 2 questions and solutions


What is homeostasis? - answersThe maintenance of a constant internal environment.
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What is a stimulus? - answersA change in your environment than requires a response. e.g Light, sound, touch, pressure
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pain, chemical or temperature.
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What do the receptors do? - answersDetect the stimulus or change in environment.
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What happens after the receptors? - answersReceptors send messages to the CNS via the sensory neurone.
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What makes up the central nervous system? - answersThe brain or spinal cord
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What is an effector? - answersMuscles or glands that bring about a response.
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What do the muscles and glands do in response to stimuli? - answersMuscles contract and glands secrete chemical
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substances(hormones).
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What is a sensory neurone? - answersA neurone that carry information from the receptors to the CNS.
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What is a relay neurone? - answersNeurones that carry impulses from the sensory neurone to the motor neurone.
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What is a motor neurone? - answersNeurones that carry information from the CNS to the effectors.
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What is the nervous system? - answersIt is a system that allows you to react to your surroundings.
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How do signals travel across a synapse? - answersThe chemical or neurotransmitter diffuses across the synapse and
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binds to a complementary receptor on the neurone (postsynaptic). This causes an electrical impulse to travel down the
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next neurone.
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What is a synapse? - answersA gap between two neurones.
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What is the thermoregulatory centre of the brain? - answersNear the hypothalamus, monitors the temperature of blood.
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Describe the stages in a reflex arc. - answersStimulus->Receptor->sensory neurone->CNS (relay neurone) -> motor
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neurone -> effector -> response
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Name responses that reduce body temperature. - answersHairs lie flat, sweat and blood vessels get wider(vasodilation
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What happens during vasodilation? - answersThe blood vessels supplying the skin dilate (widen). This helps to transfer
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energy to the environment.
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Name responses that increase body temperature. - answersHairs stand up, no sweat, shivering and blood vessels
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constrict(vasoconstriction)
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,What happens during vasoconstriction? - answersThe blood vessels supplying the skin constrict to close off the skins
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blood supply.
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What is the body's core temp? - answers37 degrees Celsius
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What are hormones? - answersChemical messengers that travel in the blood to target organs.
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Compare and Contrast the endocrine (hormone) system and the nervous system. - answersNervous is faster acting tha
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the endocrine system.
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Hormones have longer lasting effects compared to electrical impulses. Nerves act on a very specific area whereas
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hormones act more general.
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What does the thyroid gland do? - answersProduces thyroxine which is involved in regulating metabolism.
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What do the adrenal glands do? - answersProduce adrenaline which is used to prepare the body for fight or flight.
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What is the role of the pancreas? - answersProduces glucagon and insulin which are involved in regulating glucose leve
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in the blood.
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Name the hormone that is released if blood sugar is too high. - answersInsulin
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What does insulin do? - answersIt makes the liver convert glucose into glycogen. This causes blood glucose levels to
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decrease.
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Name the hormone that is released if blood sugar is too low. - answersGlucagon
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What does glucagon do? HINT GLU-COSE-GONE - answersIt makes the liver convert glycogen to glucose. This cause
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the blood glucose level to increase.
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What is type I diabetes? - answersWhen the pancreas produces little or no insulin.
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What is type II diabetes? - answersWhen a person becomes resistant to their own insulin. Being overweight can increas
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your chances of type II diabetes.
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How can type I diabetes be treated? - answersInsulin injections, limiting intake of foods rich is simple carbohydrates e.g.
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sugars and regular exercise.
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How can type II diabetes be treated? - answersIt can be controlled by eating a carbohydrate controlled diet and getting
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regular exercise.
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What is the role of the kidneys. - answersKidneys make urine by taking unwanted waste products out of your blood. They
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are involved in selective reabsorption.
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Name three things that are re-absorbed by the kidneys into the blood. - answersGlucose, water and ions.
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Name three things that are removed from the body in the urine. - answersUrea, water and ions.
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What is deamination? - answersProteins (excess amino acids) cannot be stored by the body. Excess amino acids are
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converted to fats and carbohydrates. This occurs in the liver.
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,What is produced as a waste product of deamination? - answersAmmonia is produced as a waste product. Ammonia is
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toxic so it is converted into urea in the liver.
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What hormone controls the amount of water absorbed by the kidneys? - answersADH
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What happens when the concentration of water in the blood is too low. I.e. the Blood is MORE concentrated. -
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answersReceptors in the hypothalamus detects the water content is too low. The coordinator in the brain receives the
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information and coordinates a response. The pituitary gland produces MORE (Anti-diuretic hormone) ADH, which mak
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the kidney tubule MORE permeable. This means that MORE water is reabsorbed into the bloodstream. The kidneys
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produce a small volume of concentrated urine.
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What happens when the concentration of water in the blood is too high. I.e. the Blood is dilute/LESS concentrated. -
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answersReceptors in the hypothalamus detects the water content is too high. The coordinator in the brain receives the
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information and coordinates a response. The pituitary gland produced LESS ADH, which makes the kidney tubule LESS
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permeable. This means that LESS water is reabsorbed into the bloodstream. The kidneys produce a large volume of dilu
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urine.
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How does a dialysis machine work? - answersIn a dialysis machine the patients blood flows between a partially permeab
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membrane surrounded by dialysis fluid. The dialysis fluid contains the same concentration of dissolved ions and glucos
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as healthy blood. This means they won't be lost from the blood during dialysis. Only wastes such as urea and excess ions
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and waters diffuse across the barrier.
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What is the purpose of the partially permeable membrane in the dialysis machine. - answersTo only allow small soluble
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molecules (e.g. urea, water and ions) to move into the dialysis fluid, not large molecules like proteins.
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What are the advantages and disadvantages of a kidney transplant over dialysis? - answersKidney transplants are a cu
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but they can be rejected. Patients are treated with immunosuppressants. People are not always on the donor list, relativ
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have to agree to the donation. Transplants are cheaper than dialysis to the NHS. Long waiting lists for transplants. Patie
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have to spend 3-4 hours a day, 3 x a week which can have a negative impact on their quality of life.
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What are the four stages of the menstrual cycle? - answers1) Menstruation-the uterus lining breaks down
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2) The uterus lining builds up again
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3) Ovulation-Around day 14 a egg is released from an ovary.
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4) The wall is maintained for about 14 days until day 28. If the egg has not been fertilised and implanted into the uterus linin
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it breaks down.
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What is the role of FSH (Follicle stimulating hormone) in the menstrual cycle? - answersMade in the pituitary gland.
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Causes a egg to mature in one of the ovaries in a structure called a follicle. ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




Stimulates the ovaries to produce oestrogen. ro ro ro ro ro




What is the role of oestrogen in the menstrual cycle? - answersProduced by the ovaries. Causes the lining of the uterus to
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grow. Stimulates the release of LH (which causes ovulation) and inhibits the release of FSH.
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What is the role of LH (Luteinising hormone) in the menstrual cycle? - answersProduced in the pituitary gland.
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Stimulates the release of an egg (ovulation) at day 14. ro ro ro ro ro ro ro ro ro




What is the role of progesterone in the menstrual cycle? - answersProduced by the ovary by the remains of the follicle.
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Maintains the lining of the uterus. When the level of progesterone falls the lining of the uterus breaks down. Inhibits the
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release of LH and FSH.
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Where is testosterone produced? - answersIn the testes. ro ro ro ro ro ro ro




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