5th Form Definitions and Key Concepts Flashcards
digestion
the breakdown of large, insoluble molecules into smaller, more soluble ones
adrenaline
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
memory cell
a lymphocyte that can recognise a pathogen previously encountered, either from vaccination or infection, and can be produce specific antibodies for that pathogen
vaccination
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
antidiuretic hormone (ADH)
a hormone produced by the pituitary gland that increases the reabsorption of water in the collecting duct of the kidney
auxins
plant hormones that control cell elongation and plant growth
central nervous system (CNS)
the bran and spinal cord which coordinates the response of effectors
coordination centres
areas of the body like the brain, spinal cord and pancreas that recieve and process information from receptors
effectors
muscles or glands which bring about responses
eye
a sense organ containing photoreceptors in the retina sensitive to light intensity (rods) and colour (cones)
geo/gravitropism
a plants directional growth in response to gravity controlled by auxin
homeostasis
maintenance of a stable internal environment in the body
insulin
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
nerves
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
neurotransmitters
chemicals that are released at synapses
oestrogen
a female sex hormone released by the ovaries and stimulates the growth of the uterus lining whilst inhibiting the release of FSH
phototropism
a plants directional growth in response to light
receptors
cells that detect a stimulus (photoreceptors, thermoreceptors)
reflex arc
a rapid and automatic response to a stimulus. pathway of neurones: stimulus -> receptor -> sensory neurone -> relay neurone -> motor neurone -> effector -> response
stimulus
a change in an organisms internal or external environment that can be detected by receptors
sweating
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
synapse
a junction between two nerve cells where neurotransmitters are released to diffuse across
target organ
the organ which a hormone acts upon to produce an effect
testosterone
the main male reproductive hormone, produced by the testes, stimulating sperm production and secondary sexual characteristics
vasoconstriction
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
vasodilation
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
anticodon
part of tRNA that is complementary to a codon on mRNA
codon
sequence of 3 bases on mRNA which corresponds to a specific amino acid
complementary base pairing
adenine (A) - thymine (T)
cytosine (C) - guanine (G)
diploid
an organism with a full set of chromosomes (almost every body cell except for gametes). diploid human cells contain 46 chromosomes
mRNA
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)
protein synthesis
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
RNA
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
transcription
- 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
translation
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
tRNA
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
genetically modified (GM) crops
- 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
insulin
- 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
ligase
an enzyme used to join pieces of DNA together - this can be used when inserting the human insulin gene into a bacterial plasmid
plasmids
loops of DNA found in the cytoplasm of prokaryotic cells and can be used as vectors to transfer recombinant DNA into host cells
recombinant DNA
new DNA created from joining the genetic material of two or more different organisms
restriction enzymes
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
transgenic
process where genetic material is transferred from one species to another
vector
a structure responsible for transferring DNA into a cell, examples being plasmids and viruses such as bacteriophages
cloning
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
diploid nucleus
a nucleus that contains two sets of each chromosome - its inserted into an enucleated egg cell during cloning
explants
small samples from a parent plant that are used for micro propagation
micro propagation
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
tissue culture
a method of growing living cells/tissue in a medium to produce cloned plants
