AQA GCSE Biology Paper 2
What is homeostasis?==The maintenance of a constant internal environment.
What is a stimulus?==A change in your environment than requires a response. e.g Light, sound,
touch, pressure, pain, chemical or temperature.
What do the receptors do?==Detect the stimulus or change in environment.
What happens after the receptors?==Receptors send messages to the CNS via the sensory
neurone.
What makes up the central nervous system?==The brain or spinal cord
What is an effector?==Muscles or glands that bring about a response.
What do the muscles and glands do in response to stimuli?==Muscles contract and glands secrete
chemical substances(hormones).
What is a sensory neurone?==A neurone that carry information from the receptors to the CNS.
What is a relay neurone?==Neurones that carry impulses from the sensory neurone to the motor
neurone.
What is a motor neurone?==Neurones that carry information from the CNS to the effectors.
What is the nervous system?==It is a system that allows you to react to your surroundings.
How do signals travel across a synapse?==The chemical or neurotransmitter diffuses across the
synapse and binds to a complementary receptor on the neurone (postsynaptic). This causes an
electrical impulse to travel down the next neurone.
What is a synapse?==A gap between two neurones.
What is the thermoregulatory centre of the brain?==Near the hypothalamus, monitors the
temperature of blood.
Describe the stages in a reflex arc.==Stimulus->Receptor->sensory neurone->CNS (relay
neurone) -> motor neurone -> effector -> response
Name responses that reduce body temperature.==Hairs lie flat, sweat and blood vessels get
wider(vasodilation)
What happens during vasodilation?==The blood vessels supplying the skin dilate (widen). This
helps to transfer energy to the environment.
Name responses that increase body temperature.==Hairs stand up, no sweat, shivering and blood
vessels constrict(vasoconstriction)
What happens during vasoconstriction?==The blood vessels supplying the skin constrict to close
off the skins blood supply.
What is the body's core temp?==37 degrees Celsius
What are hormones?==Chemical messengers that travel in the blood to target organs.
Compare and Contrast the endocrine (hormone) system and the nervous system.==Nervous is
faster acting than the endocrine system.
Hormones have longer lasting effects compared to electrical impulses. Nerves act on a very
specific area whereas hormones act more general.
What does the thyroid gland do?==Produces thyroxine which is involved in regulating
metabolism.
,What do the adrenal glands do?==Produce adrenaline which is used to prepare the body for fight
or flight.
What is the role of the pancreas?==Produces glucagon and insulin which are involved in
regulating glucose levels in the blood.
Name the hormone that is released if blood sugar is too high.==Insulin
What does insulin do?==It makes the liver convert glucose into glycogen. This causes blood
glucose levels to decrease.
Name the hormone that is released if blood sugar is too low.==Glucagon
What does glucagon do? HINT GLU-COSE-GONE==It makes the liver convert glycogen to
glucose. This causes the blood glucose level to increase.
What is type I diabetes?==When the pancreas produces little or no insulin.
What is type II diabetes?==When a person becomes resistant to their own insulin. Being
overweight can increase your chances of type II diabetes.
How can type I diabetes be treated?==Insulin injections, limiting intake of foods rich is simple
carbohydrates e.g. sugars and regular exercise.
How can type II diabetes be treated?==It can be controlled by eating a carbohydrate controlled
diet and getting regular exercise.
What is the role of the kidneys.==Kidneys make urine by taking unwanted waste products out of
your blood. They are involved in selective reabsorption.
Name three things that are re-absorbed by the kidneys into the blood.==Glucose, water and ions.
Name three things that are removed from the body in the urine.==Urea, water and ions.
What is deamination?==Proteins (excess amino acids) cannot be stored by the body. Excess
amino acids are converted to fats and carbohydrates. This occurs in the liver.
What is produced as a waste product of deamination?==Ammonia is produced as a waste
product. Ammonia is toxic so it is converted into urea in the liver.
What hormone controls the amount of water absorbed by the kidneys?==ADH
What happens when the concentration of water in the blood is too low. I.e. the Blood is MORE
concentrated.==Receptors in the hypothalamus detects the water content is too low. The
coordinator in the brain receives the information and coordinates a response. The pituitary gland
produces MORE (Anti-diuretic hormone) ADH, which makes the kidney tubule MORE
permeable. This means that MORE water is reabsorbed into the bloodstream. The kidneys
produce a small volume of concentrated urine.
What happens when the concentration of water in the blood is too high. I.e. the Blood is
dilute/LESS concentrated.==Receptors in the hypothalamus detects the water content is too high.
The coordinator in the brain receives the information and coordinates a response. The pituitary
gland produced LESS ADH, which makes the kidney tubule LESS permeable. This means that
LESS water is reabsorbed into the bloodstream. The kidneys produce a large volume of dilute
urine.
How does a dialysis machine work?==In a dialysis machine the patients blood flows between a
partially permeable membrane surrounded by dialysis fluid. The dialysis fluid contains the same
concentration of dissolved ions and glucose as healthy blood. This means they won't be lost from
the blood during dialysis. Only wastes such as urea and excess ions and waters diffuse across the
barrier.
What is the purpose of the partially permeable membrane in the dialysis machine.==To only
allow small soluble molecules (e.g. urea, water and ions) to move into the dialysis fluid, not large
molecules like proteins.
, What are the advantages and disadvantages of a kidney transplant over dialysis?==Kidney
transplants are a cure, but they can be rejected. Patients are treated with immunosuppressants.
People are not always on the donor list, relatives have to agree to the donation. Transplants are
cheaper than dialysis to the NHS. Long waiting lists for transplants. Patients have to spend 3-4
hours a day, 3 x a week which can have a negative impact on their quality of life.
What are the four stages of the menstrual cycle?==1) Menstruation-the uterus lining breaks down
2) The uterus lining builds up again
3) Ovulation-Around day 14 a egg is released from an ovary.
4) The wall is maintained for about 14 days until day 28. If the egg has not been fertilised and
implanted into the uterus lining it breaks down.
What is the role of FSH (Follicle stimulating hormone) in the menstrual cycle?==Made in the
pituitary gland.
Causes a egg to mature in one of the ovaries in a structure called a follicle.
Stimulates the ovaries to produce oestrogen.
What is the role of oestrogen in the menstrual cycle?==Produced by the ovaries. Causes the
lining of the uterus to grow. Stimulates the release of LH (which causes ovulation) and inhibits
the release of FSH.
What is the role of LH (Luteinising hormone) in the menstrual cycle?==Produced in the pituitary
gland.
Stimulates the release of an egg (ovulation) at day 14.
What is the role of progesterone in the menstrual cycle?==Produced by the ovary by the remains
of the follicle. Maintains the lining of the uterus. When the level of progesterone falls the lining
of the uterus breaks down. Inhibits the release of LH and FSH.
Where is testosterone produced?==In the testes.
How does the contraception pill work?==Contains oestrogen and progesterone. Taking oestrogen
every day prevents the release of an egg by inhibiting FSH. Progesterone reduces fertility by
stimulating the production of thick sticky mucus at the cervix preventing the sperm getting to the
egg.
What are the side effects of the pill?==Headaches and nausea. Still contract STIs.
What is the contraceptive patch?==Contains same hormones as the pill. Patch is stuck under the
skin (5cm x 5cm). Each patch lasts a week.
What is the contraceptive implant/injection?==Implant is inserted under the skin. Releases
progesterone. Can last for 3 years. Injection lasts less time 2-3 months.
What is an intrauterine device?==Is a T shaped device that is inserted into the uterus to kill
sperm and prevent implantation of the fertilised egg.
Name three barrier methods, non hormonal methods of contraception.==Male and female
condom, diaphragm, spermicide
What is the diaphragm?==A plastic cup that fits over the cervix (opening to the womb) to form a
barrier.
How does spermicide work?==It kills or disables the sperm.
Name a permanent ways to avoid pregnancy.==Abstinence (not having sex), sterilisation which
is having Fallopian tubes or sperm duct cut.
How does IVF work to help infertile couples?==FSH and LH are given to a woman to help eggs
mature and release. Eggs are then collected from a woman's ovaries. The eggs are fertilised in a
lab with the man's sperm. The fertilised eggs are grown into embryos in an incubator. The 1-2
embryos are then transferred to the woman's uterus to increase chance of pregancy.
What is homeostasis?==The maintenance of a constant internal environment.
What is a stimulus?==A change in your environment than requires a response. e.g Light, sound,
touch, pressure, pain, chemical or temperature.
What do the receptors do?==Detect the stimulus or change in environment.
What happens after the receptors?==Receptors send messages to the CNS via the sensory
neurone.
What makes up the central nervous system?==The brain or spinal cord
What is an effector?==Muscles or glands that bring about a response.
What do the muscles and glands do in response to stimuli?==Muscles contract and glands secrete
chemical substances(hormones).
What is a sensory neurone?==A neurone that carry information from the receptors to the CNS.
What is a relay neurone?==Neurones that carry impulses from the sensory neurone to the motor
neurone.
What is a motor neurone?==Neurones that carry information from the CNS to the effectors.
What is the nervous system?==It is a system that allows you to react to your surroundings.
How do signals travel across a synapse?==The chemical or neurotransmitter diffuses across the
synapse and binds to a complementary receptor on the neurone (postsynaptic). This causes an
electrical impulse to travel down the next neurone.
What is a synapse?==A gap between two neurones.
What is the thermoregulatory centre of the brain?==Near the hypothalamus, monitors the
temperature of blood.
Describe the stages in a reflex arc.==Stimulus->Receptor->sensory neurone->CNS (relay
neurone) -> motor neurone -> effector -> response
Name responses that reduce body temperature.==Hairs lie flat, sweat and blood vessels get
wider(vasodilation)
What happens during vasodilation?==The blood vessels supplying the skin dilate (widen). This
helps to transfer energy to the environment.
Name responses that increase body temperature.==Hairs stand up, no sweat, shivering and blood
vessels constrict(vasoconstriction)
What happens during vasoconstriction?==The blood vessels supplying the skin constrict to close
off the skins blood supply.
What is the body's core temp?==37 degrees Celsius
What are hormones?==Chemical messengers that travel in the blood to target organs.
Compare and Contrast the endocrine (hormone) system and the nervous system.==Nervous is
faster acting than the endocrine system.
Hormones have longer lasting effects compared to electrical impulses. Nerves act on a very
specific area whereas hormones act more general.
What does the thyroid gland do?==Produces thyroxine which is involved in regulating
metabolism.
,What do the adrenal glands do?==Produce adrenaline which is used to prepare the body for fight
or flight.
What is the role of the pancreas?==Produces glucagon and insulin which are involved in
regulating glucose levels in the blood.
Name the hormone that is released if blood sugar is too high.==Insulin
What does insulin do?==It makes the liver convert glucose into glycogen. This causes blood
glucose levels to decrease.
Name the hormone that is released if blood sugar is too low.==Glucagon
What does glucagon do? HINT GLU-COSE-GONE==It makes the liver convert glycogen to
glucose. This causes the blood glucose level to increase.
What is type I diabetes?==When the pancreas produces little or no insulin.
What is type II diabetes?==When a person becomes resistant to their own insulin. Being
overweight can increase your chances of type II diabetes.
How can type I diabetes be treated?==Insulin injections, limiting intake of foods rich is simple
carbohydrates e.g. sugars and regular exercise.
How can type II diabetes be treated?==It can be controlled by eating a carbohydrate controlled
diet and getting regular exercise.
What is the role of the kidneys.==Kidneys make urine by taking unwanted waste products out of
your blood. They are involved in selective reabsorption.
Name three things that are re-absorbed by the kidneys into the blood.==Glucose, water and ions.
Name three things that are removed from the body in the urine.==Urea, water and ions.
What is deamination?==Proteins (excess amino acids) cannot be stored by the body. Excess
amino acids are converted to fats and carbohydrates. This occurs in the liver.
What is produced as a waste product of deamination?==Ammonia is produced as a waste
product. Ammonia is toxic so it is converted into urea in the liver.
What hormone controls the amount of water absorbed by the kidneys?==ADH
What happens when the concentration of water in the blood is too low. I.e. the Blood is MORE
concentrated.==Receptors in the hypothalamus detects the water content is too low. The
coordinator in the brain receives the information and coordinates a response. The pituitary gland
produces MORE (Anti-diuretic hormone) ADH, which makes the kidney tubule MORE
permeable. This means that MORE water is reabsorbed into the bloodstream. The kidneys
produce a small volume of concentrated urine.
What happens when the concentration of water in the blood is too high. I.e. the Blood is
dilute/LESS concentrated.==Receptors in the hypothalamus detects the water content is too high.
The coordinator in the brain receives the information and coordinates a response. The pituitary
gland produced LESS ADH, which makes the kidney tubule LESS permeable. This means that
LESS water is reabsorbed into the bloodstream. The kidneys produce a large volume of dilute
urine.
How does a dialysis machine work?==In a dialysis machine the patients blood flows between a
partially permeable membrane surrounded by dialysis fluid. The dialysis fluid contains the same
concentration of dissolved ions and glucose as healthy blood. This means they won't be lost from
the blood during dialysis. Only wastes such as urea and excess ions and waters diffuse across the
barrier.
What is the purpose of the partially permeable membrane in the dialysis machine.==To only
allow small soluble molecules (e.g. urea, water and ions) to move into the dialysis fluid, not large
molecules like proteins.
, What are the advantages and disadvantages of a kidney transplant over dialysis?==Kidney
transplants are a cure, but they can be rejected. Patients are treated with immunosuppressants.
People are not always on the donor list, relatives have to agree to the donation. Transplants are
cheaper than dialysis to the NHS. Long waiting lists for transplants. Patients have to spend 3-4
hours a day, 3 x a week which can have a negative impact on their quality of life.
What are the four stages of the menstrual cycle?==1) Menstruation-the uterus lining breaks down
2) The uterus lining builds up again
3) Ovulation-Around day 14 a egg is released from an ovary.
4) The wall is maintained for about 14 days until day 28. If the egg has not been fertilised and
implanted into the uterus lining it breaks down.
What is the role of FSH (Follicle stimulating hormone) in the menstrual cycle?==Made in the
pituitary gland.
Causes a egg to mature in one of the ovaries in a structure called a follicle.
Stimulates the ovaries to produce oestrogen.
What is the role of oestrogen in the menstrual cycle?==Produced by the ovaries. Causes the
lining of the uterus to grow. Stimulates the release of LH (which causes ovulation) and inhibits
the release of FSH.
What is the role of LH (Luteinising hormone) in the menstrual cycle?==Produced in the pituitary
gland.
Stimulates the release of an egg (ovulation) at day 14.
What is the role of progesterone in the menstrual cycle?==Produced by the ovary by the remains
of the follicle. Maintains the lining of the uterus. When the level of progesterone falls the lining
of the uterus breaks down. Inhibits the release of LH and FSH.
Where is testosterone produced?==In the testes.
How does the contraception pill work?==Contains oestrogen and progesterone. Taking oestrogen
every day prevents the release of an egg by inhibiting FSH. Progesterone reduces fertility by
stimulating the production of thick sticky mucus at the cervix preventing the sperm getting to the
egg.
What are the side effects of the pill?==Headaches and nausea. Still contract STIs.
What is the contraceptive patch?==Contains same hormones as the pill. Patch is stuck under the
skin (5cm x 5cm). Each patch lasts a week.
What is the contraceptive implant/injection?==Implant is inserted under the skin. Releases
progesterone. Can last for 3 years. Injection lasts less time 2-3 months.
What is an intrauterine device?==Is a T shaped device that is inserted into the uterus to kill
sperm and prevent implantation of the fertilised egg.
Name three barrier methods, non hormonal methods of contraception.==Male and female
condom, diaphragm, spermicide
What is the diaphragm?==A plastic cup that fits over the cervix (opening to the womb) to form a
barrier.
How does spermicide work?==It kills or disables the sperm.
Name a permanent ways to avoid pregnancy.==Abstinence (not having sex), sterilisation which
is having Fallopian tubes or sperm duct cut.
How does IVF work to help infertile couples?==FSH and LH are given to a woman to help eggs
mature and release. Eggs are then collected from a woman's ovaries. The eggs are fertilised in a
lab with the man's sperm. The fertilised eggs are grown into embryos in an incubator. The 1-2
embryos are then transferred to the woman's uterus to increase chance of pregancy.
