5th Form Definitions and Key Concepts

Question 1

digestion

Answer 1

the breakdown of large, insoluble molecules into smaller, more soluble ones

Question 2

adrenaline

Answer 2

a hormone produced by the adrenal glands in response to fear or stress. increases heart rate and boosts the delivery of blood to the muscles, flight or fight response

Question 3

memory cell

Answer 3

a lymphocyte that can recognise a pathogen previously encountered, either from vaccination or infection, and can be produce specific antibodies for that pathogen

Question 4

vaccination

Answer 4

the introduction of dead or inactive forms of a pathogen (antigens) into the body to stimulate the production of antibodies specific to that pathogen by white blood cells. it will make the response quicker

Question 5

antidiuretic hormone (ADH)

Answer 5

a hormone produced by the pituitary gland that increases the reabsorption of water in the collecting duct of the kidney

Question 6

auxins

Answer 6

plant hormones that control cell elongation and plant growth

Question 7

central nervous system (CNS)

Answer 7

the bran and spinal cord which coordinates the response of effectors

Question 8

coordination centres

Answer 8

areas of the body like the brain, spinal cord and pancreas that recieve and process information from receptors

Question 9

effectors

Answer 9

muscles or glands which bring about responses

Question 10

eye

Answer 10

a sense organ containing photoreceptors in the retina sensitive to light intensity (rods) and colour (cones)

Question 11

geo/gravitropism

Answer 11

a plants directional growth in response to gravity controlled by auxin

Question 12

homeostasis

Answer 12

maintenance of a stable internal environment in the body

Question 13

insulin

Answer 13

a hormone secreted by the pancreas when blood glucose concentration is too high, reducing blood glucose concentrations by increasing the uptake of glucose from the blood into the liver

Question 14

nerves

Answer 14

cells that link the CNS to sense organs, sensory neurones connecting receptors to the CNS, relay neurones connecting sensory neurones to motor neurones in the CNS and motor neurones which connect to effectors

Question 15

neurotransmitters

Answer 15

chemicals that are released at synapses

Question 16

oestrogen

Answer 16

a female sex hormone released by the ovaries and stimulates the growth of the uterus lining whilst inhibiting the release of FSH

Question 17

phototropism

Answer 17

a plants directional growth in response to light

Question 18

receptors

Answer 18

cells that detect a stimulus (photoreceptors, thermoreceptors)

Question 19

reflex arc

Answer 19

a rapid and automatic response to a stimulus. pathway of neurones: stimulus -> receptor -> sensory neurone -> relay neurone -> motor neurone -> effector -> response

Question 20

stimulus

Answer 20

a change in an organisms internal or external environment that can be detected by receptors

Question 21

sweating

Answer 21

secretion of sweat onto the surface of the skin by sweat glands. the evaporation of the water in sweat removes the heat energy from the skin, cooling the body down by removing that heat

Question 22

synapse

Answer 22

a junction between two nerve cells where neurotransmitters are released to diffuse across

Question 23

target organ

Answer 23

the organ which a hormone acts upon to produce an effect

Question 24

testosterone

Answer 24

the main male reproductive hormone, produced by the testes, stimulating sperm production and secondary sexual characteristics

Question 25

vasoconstriction

Answer 25

constriction of blood vessels near the surface of the skin to reduce blood flow near the surface of the skin and therefore reducing the amount of heat that is radiated from the skin

Question 26

vasodilation

Answer 26

the dilation of blood vessels near the surface of the skin and increasing the amount of blood flowing near the surface of the skin and so increasing the amount of heat that is radiated from the skin

Question 27

anticodon

Answer 27

part of tRNA that is complementary to a codon on mRNA

Question 28

codon

Answer 28

sequence of 3 bases on mRNA which corresponds to a specific amino acid

Question 29

complementary base pairing

Answer 29

adenine (A) - thymine (T) cytosine (C) - guanine (G)

Question 30

diploid

Answer 30

an organism with a full set of chromosomes (almost every body cell except for gametes). diploid human cells contain 46 chromosomes

Question 31

mRNA

Answer 31

has a complementary sequence to a sequence of bases on DNA (gene). made up of codons (3 bases on mRNA), produced in the nucleus during transcription and travels to the ribosomes for translation (protein synthesis)

Question 32

protein synthesis

Answer 32

the formation of a sequence of amino acids and then a protein from a gene. involves transcription, the production of mRNA in the nucleus and translation, the production of the sequence of amino acids from mRNA forming a polypeptide chain (protein) in the ribosome

Question 33

RNA

Answer 33

a single stranded polymer of RNA nucleotides; adenine, uracil, cytosine and guanine, with it being the same as DNA but uracil replaces thymine. two main types, mRNA and tRNA

Question 34

transcription

Answer 34

- first stage of protein synthesis and happens in the nucleus, where DNA is unwound using DNA helicase, the bases on the gene are read using RNA polymerase - the complementary RNA nucleotide binds to the exposed base on DNA using the complementary base pairing rule (A-U, U-A, C-G, G-C) - RNA polymerase then joins the RNA nucleotides together and they detach from DNA forming a strand of mRNA which lives the nucleus

Question 35

translation

Answer 35

second phase of protein synthesis which occurs in the ribosome where mRNA is read by the ribosome and tRNA molecule with a complementary anticodon to the codon on mRNA moves to the ribosome, bringing with it a specific amino acid - this process continues with peptide bonds forming between the amino acids until a polypeptide (protein) is created

Question 36

tRNA

Answer 36

a form of RNA that is involved in translation. has a complementary anticodon to a codon on mRNA and brings a specific amino acid with it to the ribosome

Question 37

genetically modified (GM) crops

Answer 37

- crops that have had their genomes modified by inserting a desire gene from another organism to increase food population by having better yields and being resistant to pests - an example being golden rice where the gene that gives carrots their golden colour is added to rice to make it golden and more importantly a source of vitamin A

Question 38

insulin

Answer 38

- a hormone involved in the control of blood glucose concentration - type 1 diabetes cannot produce any/enough insulin so bacteria can be genetically engineered by inserting he human gene for insulin into the plasmid of a bacteria to mass produce human insulin which can be used by type 1 diabetes

Question 39

ligase

Answer 39

an enzyme used to join pieces of DNA together - this can be used when inserting the human insulin gene into a bacterial plasmid

Question 40

plasmids

Answer 40

loops of DNA found in the cytoplasm of prokaryotic cells and can be used as vectors to transfer recombinant DNA into host cells

Question 41

recombinant DNA

Answer 41

new DNA created from joining the genetic material of two or more different organisms

Question 42

restriction enzymes

Answer 42

enzymes that cut DNA at specific regions to isolate a gene from a chromosome e.g. restriction enzymes will be used to cut the human insulin gene out of a chromosome and the same restriction enzyme will be used to cut a section out of the plasmid to insert the insulin gene into

Question 43

transgenic

Answer 43

process where genetic material is transferred from one species to another

Question 44

vector

Answer 44

a structure responsible for transferring DNA into a cell, examples being plasmids and viruses such as bacteriophages

Question 45

cloning

Answer 45

the production of an organism, genetically identical to another, an example being dolly the sheep, where the sheep that dolly was cloned from had a cell removed and its nucleus was fused with an egg cell of another sheep which had its nucleus removed and this egg cell was embedded into the uterus of a sheep

Question 46

diploid nucleus

Answer 46

a nucleus that contains two sets of each chromosome - its inserted into an enucleated egg cell during cloning

Question 47

explants

Answer 47

small samples from a parent plant that are used for micro propagation

Question 48

micro propagation

Answer 48

the multiplication of plants using tissue culture methods and can be used to produce large numbers of plants that are all genetically identical to one another, all with the desirable characteristics that the parent plant had

Question 49

tissue culture

Answer 49

a method of growing living cells/tissue in a medium to produce cloned plants