aaa Flashcards

Question

in vivo

Answer 1

inside a living organism dna fragment placed in plasmid (vector) - carries the DNA fragment into host cell restriction endonuclease - DNA fragment has sticky ends - same cuts plasmid so complimentary = joins by h bonds DNA ligase binds nucleotides on fragment and plasmid - catalyses formation of phosphodiester bonds recombinant plasmid forms promoter and terminator need to be added

Answer 2

inserting into bacterium - cell membrane plasmid - polar, hydrophilic and negatively charged add calcium ions - positively charged - takes plasmid closer to membrane heat shock - holes in membrane

Answer 3

polymerase chain reaction - denaturation - 95C - high heat to break H-bonds in DNA fragment and make DNA template strand single stranded - annealing - cooling to allow primers join to complimentary bases at end of each strand by H bonds - polymerisation - temp increases - all DNA nucleotides bind to exposed template and thermostable DNA polymerase join them by phosphodiester bonds

Answer 4

short single stranded piece of DNA complimentary to a specific gene sequece DNA hybridisation - when DNA probe attaches to complimentary DNA sequence labelling probes - radioactive or fluorescent

Answer 5

1. produce copies of labelled DNA probes - pcr 2. heat up sample - H-bonds break - DNA strands seperate 3. add DNA probes and cool mixture - H-bonds form 4. wash DNA sample with ethanol solution 5. check if hybridisation has occurred

Answer 6

variable number of tandem repeats - VNTRs - repetitive non-coding DNA sequences directly next to each other 1. collect DNA sample 2. PCR to amplify DNA 3. restriction enzymes to produce VNTR DNA fragments 4. VNTR fragments separated by gel electrophoresis 5. add alkali to separate VNTRS to single strands 6. add complimentary DNA probes to identify VNTRs 7. compare patterns

Answer 7

finding nucleotide sequence for gene or whole genome human genome project - 2003 proteome - set of proteins in organisms we have non-coding DNA and regulatory proteins so hard to find proteome

Answer 8

- to separate molecules of DNA, RNA or proteins DNA and RNA - mass = length AA - mass = R group or number of aa or charge DNA negative charge due to phosphate group DNA fragments loaded into get at top electrodes connected -ve at top and +ve at bottom DNA move from negative to positive short = fast stain gel to visualise DNA

Answer 9

addition - one or more DNA nucleotide added = frameshift or addition of aa duplication - one or more bases duplicated = frameshift or addition of aa inversion - set of nucleotides separate from a DNA sequence and rejoin in inverse order translocation - set of nucleotides separate from sequence in one chromosome and attach to a different chromosome - changes gene expression

Answer 10

replacement of non-functional allele with functional allele - for monogenic diseases somatic gene therapy - introducing good allele to body cells - own symptoms cured but gametes contain bad allele germ-line gene therapy - good allele introduced to gamete - illegal

Answer 11

proteins that move from cytoplasm of eukaryotic cell to nucleus to stimulate or inhibit transcription each transcription factor has a complimentary binding to particular base sequence in DNA - can be active or inactive - important for induced pluripotent - altering unipotent cells to enable translation of additional genes

Answer 12

heritable changes in gene function without genes to the base sequence DNA-histone complex - tight = gene hidden to transcription hard to take place as transcription factors and DNA polymerase cannot reach epigenome - chemical tags - attach to DNA and histones - determines shape - added or removed by environmental factors acetylation - increase - stimulation methylation - descrease - stimulation

Answer 13

target enzymes as both acetylation and methylation involve enzymes responsible for adding or removing chemical tag eg inhibit the enzyme responsible for adding methyl groups must ONLY target disease cell

Answer 14

RNA interference - translation inhibition by RNA microRNA - miRNA - binds to protein complex in cytoplasm - RNA-induced silencing complex - then binds to complementary base pairs on mRNA - prevents translation by preventing ribosome from attaching or enzyme destroys mRNA SiRNA - cell naturally produces short double stranded RNA - one strand complimentary to mRNA - enzyme called DICER cuts into shorter fragments - siRNA - same as miRNA

Answer 15

code for proteins that slow or prevent cell division code for proteins that repair mistakes in DNA code for proteins that tell abnormal cells to die mutation deletion mutation - changes aa sequence - protein cannot function correctly proto-congenes - stimulate cell division oncogene - mutated proto-oncogene

Answer 16

oestrogen - hormone produces by ovary and fat cells in breast tissue passes through cell surface membrane and initiates transcription by binding to receptor on transcription factor - changes 3 str to comp with DNA - initiates transcription menopause - fat cells increase oestrogen production

Answer 17

stimulates B cells in islets of Langerhans in the pancreas - these release insulin into the blood insulin binds to insulin receptor proteins on cell surface membrane of liver and muscle cells - insulin receptor 3str change - series of reactions vesicles containing glucose carrier proteins move and added to membrane - exocytosis - glucose transported into cell from blood - facilitated diffusion - enzyme glycogen synthase activated by phosphorylation - glycogenesis insulin no longer binds with receptor - cell membrane loses glucose carrier and enzyme inactive B cells stop secreting insulin

Answer 18

a cells - islets of langerhans - release protein hormone glucagon into blood - binds with glucagon receptor proteins on cell surface membrane of liver and muscles - changes 3str - activates enzyme adenylate cyclase adenylate cyclase converts ATP to cAMP - secondary messenger causing reactions involving kinase enzyme to activate other enzymes in cell - hydrolysis of glycogen to glucose - glycogenolysis - glucose synthesised from non-carbohydrate sources eg fatty acids - gluneogenesis - more glucose - transport proteins introduced so glucose can leave cell into blood glucagon no longer binds to receptor, membrane loses glucose carrier proteins, enzymes inactive a cells stop secreting glucagon

Answer 19

sarcomere - section inside myofibril made up of a vertical stack of atleast 4 thin and 1 thick m line - middle of sarcomere - thick z line - mid point between m lines - thin I band - where only thin A band - thick and thin H zone - only thick

Answer 20

neuromuscular function nerve impulse passes from motor neurone to muscle fibre - triggers depolarisation - spreads across whole muscle fibre - depolarisation reaches sacroplasmic endoreticulum - wrapped around muscle fibre’s myofibrils 3. depolarisation causes sacroplasmic reticulum to release calcium ions into myofibrils

Answer 21

thin filament - wrapped with tropomyosin protein chain - binding sites under - specific for myosin heads calcium ions - tropomyosin changes shape exposing binding sites actomyosin bridge

Answer 22

active site on myosin head - ATP hydrolysis ATPase

Answer 23

- calcium ions trigger tropomyosin to move away from binding site - actinomyosin bridge forms - ADP and Pi released from myosin head - power stroke - ATP molecule binds to myosin - bridge broke - ATP hydrolysis - starting position reading to bind again

Answer 24

two or more genes are on the same autosomal chromosome

Answer 25

interaction of different loci on the gene one gene locus affects the other gene - can mask or suppress expression recessive - 9:3:4 dominant - 12:3:1

Answer 26

used to estimate the frequency of alleles in a population - see whether change in allele frequency is occurring in population over time - assumed no mutation - large population - no selection p + q = 1.0 p^2 + 2pq + q^2 = 1 p = frequency of dominant allele q = frequency of recessive allele p^2 = frequency of AA 2pq = frequency of Aa q^2 = frequency of aa

Answer 27

area previously devoid of life - colonised by community of organisms colonised by pioneer species - as organisms die, they decompose by microorganisms - makes environment less harsh - more suitable for complex organisms richer in mineral over time - larger plants climax community - final stage - self-sustaining stable community

Answer 28

previously colonised area has been cleared eg forest fire - soil layer already present

Answer 29

1. Totipotent - can form any type of cells in the body plus extra embryonic cells. 2. Pluripotent - these cells can form any cell type in the body, however cannot form extra embryonic cells. They are also found in the early stages of an embryo. These are often used in replacing damaged tissues in human disorders. 3. Multipotent - can differentiate into other cells types but are more limited e.g. the cells in the bone marrow and umbilical cord. 4. Unipotent - these cells can only differentiate into one type of cell.

Answer 30

sensory neurones - osmoreceptors monitor water potential if water potential decrease - nerve impulse - sensory neurones to posterior pituitary gland - release antidiuretic hormones which causes kidneys to reabsorb more water

Answer 31

ADH binds to receptor proteins in the cell surface membranes of the collecting duct cells aquaporins are phosphorylated - activates them vesicles move towards luminal membranes of collecting duct cells vesicles fuse with luminal membranes water moves through aquaporins down water potential gradient

Answer 32

Within the Bowman’s capsule of each nephron is a structure known as the glomerulus Each glomerulus is supplied with blood by an afferent arteriole (which carries blood from the renal artery) The capillaries of the glomerulus rejoin to form an efferent arteriole Blood then flows from the efferent arteriole into a network of capillaries that run closely alongside the rest of the nephron Blood from these capillaries eventually flows into the renal vein

Answer 33

arterioles branch off renal artery to nephron - form glomerulus inside bowman’s capsule capillaries get narrower - increases pressure of blood which forces smaller molecules out of the capillaries into the bowman’s capsule - filtrate blood passes through glomerular capillaries - holes in endothelial cells and gaps between podocytes allow substances dissolved in blood plasma to pass into bowman’s capsule - aa, water, glucose

Answer 34

due to differences in water potential between plasma in glomerular capillaries and filtrate in bowman’s capsule

Answer 35

only substances body needs - most reabsorption in proximal convoluted tubule - microvilli, many co-transporter proteins, mitochondria - sodium-potassium pumps use ATP from mitochondria to pump sodium ions out of proximal convoluted epithelial cells into blood - sodium ions move passively down concentration gradient from filtrate to epithelial cells - protein co-transporter molecules in membrane which also bring glucose and aa into cell - transport proteins in basal membrane allow solutes to diffuse down conc gradient from epithelial cells into blood

Answer 36

- filtrates goes through loop on henle - salts reabsorbed by diffusions - water follows by osmosis - after necessary reabsorption - filtrate leaves nephron

aaa Flashcards

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