AQA, GCSE, combined science, BIOLOGY, paper 2

Pregunta	Respuesta
What is meant my the term 'homeostasis'?	maintaining a stable internal environment in response to changes in external and internal conditions.
What two types of communication is involved in 'homeostasis'?	nervous and hormonal communication.
What are the three automatic controls in 'negative feedback'?	1. receptor 2. coordination centre 3. effector
What is the role of the 'receptor'?	detects a stimulus
What is the role of the 'coordination centre'?	receives and processes the information then organises a response.
What is the role of the 'effector'?	produces a response, which counteracts the change and restores the optimum level
What does 'CNS' stand for?	the central nervous system.
Where is the 'CNS' located in the body?	the brain and the spinal chord.
How is information passed through the 'CNS'?	through neurons as electrical impulses.
What are the 5 stages to the 'CNS'?	stimulus, receptor, coordinator, effector, response.
What is a synapse?	the connection between two neurons is called a synapse.
How is the nerve signal transferred?	transferred by chemicals which diffuse through the gap.
What is a 'reflex'?	a rapid, automatic response to certain stimulus that don't involve the brain.
What is the passage of information in a reflex called?	the reflex arc.
What are the 6 stages to the reflex arc?	1. reflex arc goes through the spinal chord. 2. stimulus is detected by the receptor. 3. impulses travel along the sensory neurons. 4. impulses passed along a relay neuron. 5. impulses travel along a motor neuron. 6. when impulse reaches the muscle it contracts.
What are hormones?	are chemical messengers sent int the in blood.
What is the endocrine system?	where hormones are produced and secreted into the blood.
What are the 6 different glands in the body?	pituitary glands, thyroid, adrenal gland, ovaries, testes, pancreas.
What is the pituitary gland?	produces all the hormones the the body - 'master gland'.
What is the thyroid gland?	produces 'thyroixine' for the rate of metabolism.
What is the role of the 'adrenal gland'?	produces adrenaline.
What is the use of the ovary glands?	produce 'oestrogen' - menstrual cycle.
What is the role of the 'testes gland'?	produces 'testosterone' - controls sperm production.
What is the role of the pancreas in the endocrine system?	produces 'insulin' - regulate glucose levels.
What are the main differences between 'nerves' and 'hormones'?	nerves: very fast action, act for a short time, act on a very precise area. hormones: slower action, act for longer time, act in a general way.
What controls blood glucose concentration?	pancreas.
if blood glucose concentration is to high what does the pancreas secrete into the blood?	insulin.
Where is excess glucose stored?	GLUCOGEN is stored in the liver and muscle cells.
What is secreted into the blood is the blood glucose level is too high?	insulin.
What is secreted into the blood if glucose concentartion is too low?	glucagon.
What are the reproductive hormones in a female?	ovaries - oestrogen.
What is the male reproductive hormones?	testes - testosterone.
What are the primary characteristics?	ones you are born with.
What are secondary characteristics?	ones you have after puberty.
What is FSH?	follicle stimulating hormone - causes maturation of an eff in the ovary.
What is LH?	Luteinising hormones - stu=imulates the release of the egg.
What is oestrogen?	causes the uterus lining to grow.
What is progesterone?	maintains the lining of the uterus.
What is the barrier method of contraception?	condoms and diaphragm - prevent the sperm reaching the egg.
What is the surgical method of contraception.	surgically sterilising man: sperm ducts are cuts ans ties. female: oviducts are cute (permanent).
What is the chemical method of contraception?	spermicides kill or disable sperms.
What is the IUD method on contraception?	intrauterine device - inserted into the uterus, to kill sperm ans stop implantation.
What is the hormone based contraception?	mixed pills, contraceptive implant, contraceptive patch.
What is the role of the mixed pills in contraception?	contains low doses of oestrogen and progesterone (stops FSH) - no eggs mature.
What is the role of the contraceptive implant in contraception?	progesterone under the skin released slowly.
What is the role of the contraceptive patch in contraception?	contains progesterone and oestrogen - shot into the arm .
What is IVF?	in vitro fertility. involves giving FSH and LH to stimulate the maturation of several eggs. (test tube baby)
What is a gamete?	a sex cell.
What fuses together in animals?	sperm and egg cells.
What fuses together on plants?	pollen and egg cells in flowering plants.
What type of reproduction allows for variation in offspring?	sexual reproduction.
What type of cell division takes place in the formation of gametes?	meiosis.
How many parent cells does asexual reproduction involve?	1.
What type of cell division takes place in asexual reproduction?	mitosis.
What is the main difference between mitosis and meiosis.	mitosis - genetically identical offspring. meiosis - allows variation in offspring.
What is DNA?	genetic material of a cell.
What are chromosomes?	2 strands of DNA forming a double helix.
What is a genome?	the entire genetic material of an organism.
What is a gene?	segment of DNA (physical & characteristics of an organism).
What is an allele?	form of a gene - dominant (B), and recessive (b).
What is meant by the term homozygous?	pair of matching alleles (BB or bb).
What is meant by the term Hetrozygous?	pair of genes - dominant and recessive (Bb)
What is meant by the term Genotype?	set of genes in our DNA - genetic makeup of our characteristics.
What is meant by the term Phenotype?	the physical appearance (blue eyes, black hair).

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