3 Flashcards

Question

what is a multipotent cell

Answer 1

can divide to replicte itself and produce different types of cells in one type of tissue - adult stem cells

Answer 2

-leftover embryos for IVF are 'living', 'killing unborn child' -can be seen as 'playing God'

Answer 3

stem cells are totipotent meaning they can be used in a wide range of therapies the source of embryonic stem cells has to be regulated ethical issues surrounding the destruction of embryos to obtain stem cells need for research establishment to be regulated

Answer 4

homologous pairs have same genes but diff alleles

Answer 5

each zygote formed from different gametes- random fertilisation each gamete contains different combination of alleles this is due to indpendent assortment and crossing voer during meiosis

Answer 6

a mutation of a gene located on a x or y chromosme therefore disorder is more likely in one gender than another

Answer 7

conversion cannot occur between some sections of x and y chromosomes as not homologous pairs

Answer 8

In meiosis homologous chromosomes are separated from each other as well as spindle fibres pulling the sister chromatid apart to opposite ends of the cell so sister chromatid containing copies of the same cells separated from each other

Answer 9

cells are not totipotent therefore some genes have already be acitavted and deactivated will not be able to specialise

Answer 10

stem cells being {totipotent / pluripotent} ; continously divide to give rise to {differentiated / specialised} cells and these can replace damaged cells

Answer 11

1. fertilised egg allowed to {grow for a few days/divide several times / eq} ; 2. reference to a {blastocyst/ blastula / hollow ball of cells / eq} ; 3. cells in inner cell mass are {pluripotent /harvested} ; 4. procedure for extraction of cells / eq ; 5. ref to source of fertilised egg e.g. spare embryo after IVF ;

Answer 12

1. cord blood /umbilical cord / placenta ; 2. {fertilised egg / zygote / eq} / blastocyst / (early) embryo ; 3. detail of site within blastocyst 4. bone marrow / eq ; 5. {brain / connective / skin / liver} cells / eq ; 6. addition of adult nucleus to enucleated egg cell

Answer 13

1. halves the chromosome number / eq ; 2. to produce a haploid nucleus / eq ; 3. so that at fertilisation the {fullcomplement / diploid number / eq} of chromosomes is restored / eq ; 4. allows genetic variation (in gametes) / eq 5. through independent assortment / eq ; 6. through crossing over / eq ;

Answer 14

1. cells have same genotype 2. no rejection / avoids immune response 3. idea of no disease transmission ;

Answer 15

both involve vesicles both involve the release of enzymes through exocytosis acrosome causes digestion of zona pellucida and cortical causes thickening of zona

Answer 16

independent assortment gives rise to different combinations of paternal and maternal chromosomes crossing over involves exchange of sections of non sister chromatid of homologous pairs resulting in new combinations of alleles

Answer 17

The position of a gene on a chromosome

Answer 18

x chromosome carries genes not present on the y chromosome meaning males only have 1 allele of some genes and if only one allele then that allele will be expressed

Answer 19

DNA is wrapped around histone proteins and both the DNA anf histones have chem markers attached to their surface- make up the epigenome- influence the trancription of genes in the cell

Answer 20

attachment of methyl groups to DNA of a gene prevents transcription to mRNA by stopping RNA polymerase binding- winds DNA tighter

Answer 21

in cells of partocular type of tissue, all genes for specific funtion are active but all genses specific to other tissues are switched off During DNA replication the epigentic markers are copied so when a cell of a tissue divides if forms other cells with same fucntion

Answer 22

used to see acitve genes in specialised cells isolate mRNA from basic cell and specialised cell Reverse transcriptase transcribes specialised cell's mRNA to complementary DNA mRNA is digested before cDNA is hybridized with basic cell 's mRNA any mRNA that is alos produced in the differentiayed cell will combine with cDNA to form double strands- left over unpaird bases show acitve genes

Answer 23

group of genes under the same regulatory mechanisms and are all trancibed as a single unit found in groups of prokaryotic cells can turn specific genes on and off

Answer 24

bacteria generally uses glucose as an energy source however when glucose is not avalibale bacteria can use lactose as an energy source but requires specific proteins produced by lactose operon

Answer 25

regulatory gene coding for repressor protein that prevents transcription of structural genes. Always turned on. section of DNA where RNAp olymerase binds to begin trancription section where repressor protein binds codes for B-galactosidase which catalyses hydrolysis of lactose to glucose and galactose. codes for membrane carrier protein lactose permease, which tensports lactose into bacterial cells

Answer 26

repressor protein binds to operator section preventing binding of RNA polymerase to the promoter region stopping tranciption of Lac operon- Lac Y and Z

Answer 27

stucture and function of each cell is depednent on the proteins it synthesises

Answer 28

attach to histone and losen DNA making tranciprion easier

Answer 29

presence of lactose induces transcription of structural genes, allowing B-galactosidase a lactose permease lactose acts as inducer by binding to repressor protein or denaturing it. repressor protein is not able to bind to operator region RNA polymerase able to bird to promoter and begin transcription -lac operon is only expressed when inducer molecule is present to preserve energy.

Answer 30

recognition proteins one cell surface membrane that help cells recognise other cells like them and stick to them- extends from membrane and binds to complemnetary protenins on adjaxcent cells

Answer 31

a group of tissues working together to carry out one function

Answer 32

charecteristics of an organism which result from interaction of the genes of the organism and the environment

Answer 33

genetically determined and caused by monogenic inheritance where alleles are on the same locus has definite specific categories 2 or more categories with no intermediate values qualitative differences between phenotypes phenotypes that fall into discrete groups with no overlap

Answer 34

each locus is responsible for a different heritable feature

Answer 35

environment= diet genes for height but may not reach full potential due to malnutirtion

Answer 36

genes is uncoiled regions of DNA can be transcribed into mRNA- RNA polymerase binds to a section ofDNA adjacent to the gnee-the promoter region gene remains switched off until enzyme attaches to promoter region- attachment of a regulatory protein usally required to start transcription transcription of a gene can be prevented by protein repressor molecules attaching to DNA of promotor region- blocking attachment site- can attach to regulatory protein preventing it from attaching

Answer 37

•different stimuli activate different genes (chemical) •active genes are transcribed to mRNA °mRNA translated & produced to proteins for specific cell °proteins determine functions of cell °different genes activated result in different cell types

Answer 38

a group of specilaised cells working together to carry out one function

Answer 39

no definite categories , continuous range of values ↳ quantitative differences between phenotypes presented as bell curve, most are at mean value a few at extremes affected by geneotype and environment - e.g. height- human can be any height within the human range controlled by genes at many loci - polygenic inheritance

Answer 40

conditions where several genetic factors and one or more environmental factors

Answer 41

made by cells called melanocytes activated by melanocytes stimulating hormone (MSH) binding to cell surface receptors which are triggered by UVA rays- melanocytes place melanin into organelles called melanosomes. melansomes are transferred to nearby skin and hair cells collecting around nucleus & protecting DNA from sun damage UV increases the amont of MSH and MSH receptors

Answer 42

signal proteins- produced by the mRNA of master genes switch on the genes responsible for producing the proteins needed for specilaisation of cells in each segment

Answer 43

occurs when the rate of cell multiplication is faster than rate of cell death- growth of a tumour caused by damage to DNA- can be reuslt of UV, radiation, asbestos, chems such as carcinogens, DNA mutation, abnormal methylation of genes in cancer cells can lead to activation or deactivation in genes involved in cell cycle

Answer 44

code 4 protein that stimulate the transition from 1 stage in the cell cycle to the next- dna mutation or epigenetic changes can lead to the cell cycle being continously activated

Answer 45

produces supressor protein that stops the cell cycle- DNA mutation or epigenetic changes means there is no break in the cell cycle

Answer 46

faulty BRCA 7- gene predisposes individual to breast cancer ↳ produces protein repairing DNA ↳ makes individuals more susceptible to cancer

Answer 47

GR gene (receptor protein binding to glucocorticoid) may be repressed by epigenome-due to poor grooming a ticking habits ↳ glucocorticoid is present in bloodstream causing increased anxiety levels in mice -GR gene is turned off if mother does not groom offspring , making lower GR stress receptors and high glucocorticoid levels

Answer 48

smoking- carcinogens in fags pose chemical risk , tar lodges in bronchi causes DNA damage surrounding epithelial cells -UV light: ionising radiation causes increased DNA mutation -low antioxidant diet : destroy cancer-causing fee radicals that damages DNA -Viral infection : hepatitis causes liver cancer ,HPV causes cervical cancer. Virus containsoncogene which interferes with cell cycle refutation

Answer 49

a charecteristic showing continuos variation caused by multiple genes at different loci

Answer 50

embryonic stem cells are totipotent and can be used in a wide range of therapies source of embryonic stem cells has to be regulated ethical issues due to the destruction of embryos to retrieve embryonic stem cells research establishment to be regulated

Answer 51

cells are not totipotent some genes have already been activated and deactivated will not be able to specialize into tissue cells

Answer 52

genes activated and deactivated by methylation and acetylation therefore same genes will be activated in daughter cell

Answer 53

breaksdown middle lamella allowing cells to be seperated and producing a thin layer

Answer 54

makes chromosomes visible so stages of mitosis can be identified

Answer 55

height affected by environment as well as genotype as well as being polygenic inheritance therefore offspring can inherit a mixture of alleles from both parents that increases height. Environmental factors can be higher protein diet and better healthcare. Parents could of also not reached their genetic potential due to lower protein and calcium diet

Answer 56

DNA methylation deactivates genes affecting enzyme production and mtabolism

Answer 57

bone marrow , blastocyst, skin, placenta

Answer 58

decide on max age of embryo allowed for research setting or considering {ethical / legal} aspects / judging what is acceptable / follow acode of practice ; checking that source of stem cells is acceptable stopping of cloning (of humans) / eq ;

Answer 59

height affected by genotype and environment hieght proudct of polgenic inhertiance menaing a mixture of alleles from parents responisble for hieght environmntal factors- hugher protien diet and better helathcare

Answer 60

Transcription factors bind to promoter regions on DNA meaning no genes switched off as RNA polymerase now able bind to genes that were previously deactivated , mRNA produced and protein translated an folded. That allow cells to divide / undifferentiate /unspecialise as all genes are switched on

Answer 61

working near a Bunsen burner to provide a convetion current • sterilising work surfaces • sterilising equipment with heat • limiting time containers are open

Answer 62

• to allow bacteria to multiply • without encouraging pathogenic organisms

Answer 63

boiling the culture medium before use { ‘flaming’ / disinfecting } of the instruments keeping lids off for the minimum time working in { updraught of a flame / a flow hood } disinfecting the bench (before or after working) autoclaving used plates

Answer 64

Cut a 5mm sample of the root tip using a scalpel. Transfer root tip to sample tubes containing HCl and leave for 5 minutes-break up middle lamella creating a single layer of cells Transfer to watch glass containing cold distilled water. Leave for 5 minutes. Dry root tips on filter paper. Place tip on a microscope slide. Macerate with a needle to spread the cells out. This makes the chromosomes visible and will therefore show which cells are undergoing mitosis. Add a drop of toluidine blue to the slide and leave to stain for 2 minutes- taken up by sample- dying the cells so stages of mitosis can be viewed Lower the cover slip down carefully onto the slide. Make sure there are no air bubbles in the slide which may distort the image, and that the coverslip doesn’t slide sideways which could damage the chromosomes. Wrap in a paper towel and gently ‘squash’ the slide. Place under a microscope and set the objective lens on the lowest magnification, then use the coarse adjustment knob to move the lens down to just above the slide. Use the fine adjustment knob to carefully re-adjust the focus until the image is clear (can use a higher magnification if needed).

Answer 65

Calibrate the eyepiece graticule by placing both on the stage and lining up the divisions of the stage micrometer (which have a known length) with the divisions of the eyepiece graticule (for which the length is unknown) to calculate the length of one division of the graticule. Cut transverse sections of the plant stem (on the white tile using a razor, wet to reduce friction) as thinly as possible. Select the thinnest sections. Place one section on a microscope slide. Draw a line in wax crayon from top to bottom of the slide either side of the specimen to prevent the dye from spreading. Add a few drops of concentrated phloroglucinol and lower the cover slip down carefully onto the slide. Make sure there are no air bubbles in the slide which may distort the image. Place under a microscope and set the objective lens on the lowest magnification, then use the coarse adjustment knob to move the lens down to just above the slide. Use the fine adjustment knob to carefully re-adjust the focus until the image is clear (can use a higher magnification if needed). Observe and draw the stem. Measure the size of the stem diameter and vascular bundle using the calibrated eyepiece graticule

Answer 66

length and width of each fibre should be around the same length for even comparison, the mass used for each fibre should be the same.

Answer 67

Cut all the fibres to the same length and width Attach each end of the fibre to a clamp stand and add masses in the middle. Continue until the fibre snaps and record the mass with which the fibre snaps. Repeat with all fibres force/cross sectional area of fibre= tensil strength- micrometre and eye piece gratica to measure width

Answer 68

Surfaces should be wiped down with an antibacterial cleaner before and after the experiment Keep the Petri dish close to the Bunsen burner so convection currents draw microbes away from the culture Flame the neck of any bottles to prevent bacteria entering the vessel and flame equipment to sterilise Keep all vessels containing bacteria open for the minimum amount of time. Keep all windows and doors closed to limit air currents.

Answer 69

Same concentration of plant material used Type and amount of bacteria used – E.coli will be used as the bacteria and it will be evenly spread across an agar medium Volume of plant material used for each disc – 0.1 cm³ can be used per sterile paper disc each time Contamination of culture – aseptic techniques and sterile equipment used to avoid contamination of bacteria culture Temperature of cultures – all Petri dishes should be incubated overnight at the same temperature pH of medium – an agar jelly will be used in each case with a consistent, neutral pH

Answer 70

Crush 3 g of garlic with a pestle & mortar and use a measuring cylinder to add 10 cm³ of denatured alcohol to the mixture. Shake the mixture occasionally for 10 minutes. Repeat step 1 but this time using 3g of the mint plant material. Pipette 0.1 cm³ of the garlic extract solution onto 4 of the sterile paper discs. Allow each disc to dry. Repeat this process for the mint extract solution. Label the other Petri dishes for garlic, mint and control solutions – include the date. Use the sterile forceps to place all 4 discs of each type of extract onto their corresponding Petri dish. Close each dish and seal with hazard tape. Make sure that a small gap is left so that oxygen can enter and there is no build-up of anaerobic bacteria.Leave the cultures to incubate overnight. Open each Petri dish and use a ruler to work out the zone of inhibition for each paper disc.

Answer 71

reduces conc of substance, antimicorbiral pectaical to determine most effective concentration

Answer 72

{mutation / change in base sequence} of a gene for {check point protein / cell cycle (control) protein} (1) no check point (1) activating oncogenes / deactivating tumour suppressor genes (1) cell {cycle / division} is no longer inhibited / shortening the cell cycle

Answer 73

1. { identical / monozygotic twins } are genetically identical / eq ; 2. derived from one egg and one sperm /one { zygote / embryo / eq } / eq ; 3. (so any phenotypic ) difference is due to { nurture / environmental } / eq ; 4. {non-identical twins / dizygotic twins} are genetically different ; 5. (any phenotype) that is different when the environment is the same is likely to be { nature / genetic / eq }

3 Flashcards

(97 cards)