rest of paper 2 Flashcards
1
Q
Alterations to tumour suppressor genes can lead to the development of tumours:
A
- increased methylation of tumour suppressor genes
- tumour suppressor genes are not transcribed
- results in uncontrollable division
2
Q
What is meant by epigenetics:
A
- heritable changes in gene function
- without changes to the base sequence of DNA
3
Q
Oestrogen binds with…
Methyl groups bind with…
Acetyl groups bind with…
A
protein
DNA
Protein
4
Q
How increased methylation can lead to cancer:
A
- methyl groups added to a tumour suppressor gene
- transcription of tumour suppressor genes is inhibited
- leading to uncontrolled cell division
5
Q
one way benign tumours differ from malignant:
A
- cells of benign tumours cannot spread to other parts of the body
6
Q
How methylation of tumour suppressor genes can lead to cancer:
A
- methylation prevents transcription
- protein not produced that prevents cell division
- no control of mitosis
7
Q
How could you stimulate gene expression:
A
- transcription factor
- binds to DNA
- stimulates RNA polymerase
8
Q
How recombinant DNA is inserted into plasmids:
A
- restriction endonuclease cuts plasmids
- ligase joins sticky ends
9
Q
Two features of data that helps to ensure validity of conclusions:
A
- large sample size
- control present for comparison
10
Q
Describe the role of two names types of enzymes used to insert DNA fragments into plasmids:
A
- restriction endonuclease: cuts plasmids
- ligase: joins DNA to plasmid
11
Q
Suggest two features of the structure of different proteins that enable them to be separated by electrophoresis:
A
- mass of amino acids
- charge
12
Q
Explain the role of reverse transcriptase in RT-PCR:
A
- produces cDNA using mRNA
13
Q
Role of DNA ploymerase in RT-PCR:
A
- joins nucleotides to produce DNA
14
Q
Why use gene machine:
A
- faster to use gene machine than all the enzyme-catalysed reactions
15
Q
How to insert copies of gene into plasmids:
A
- cut the plasmid with restriction endonuclease
- so both have sticky ends
- add ligase to join sticky ends
16
Q
Process of genetic testing using DNA sample:
A
- use of PCR to amplify
- cut using restriction endonuclease
- separate using electrophoresis
- addition of DNA probes and binding
- mutations identified by fluorescence
17
Q
Suggest how transcription factors can reprogramme cells to form iPS cells:
A
- attach to promoter region
- stimulate RNA polymerase
18
Q
Equation to find the frequency of an allele, if the frequency of the other is already known:
A
- p +q = 1
p = dominant
q = recessive
19
Q
Hard-Weinberg equation:
A
p^2 + 2pq + q^2 = 1
p^2 = the frequency of the homozygous dominant
2pq = the frequency of the heterozygous genotype
q^2 = the frequency of the homozygous recessive genotypes
20
Q
How digesting insects can be beneficial in low nutrient soil:
A
- digestion of proteins
- provides amino acids
- Breakdown of DNA
- provides nucleotides
21
Q
how would you estimate the size of a population in a small marsh:
A
- use a grid
- random number generator to obtain co ordinates
- count number in section
- large sample and calculate average
22
Q
reasons why sterilised soil is needed for practicals:
A
- kills pathogens
- kills competitors
- kills pests
23
Q
why soil contained recommended conc, of fertiliser for practicals:
A
- fertiliser is a controlled variable
- affects crop growth
- may affect water potential of soil
24
Q
How is a colour seen at different wavelengths:
A
- colour vision involves cones
- each photoreceptor absorbs different wavelengths
25
Three features of the PCT that allows rapid absorption:
- microvilli provides a large surface area
- many channel proteins for facilitated diffusion
- many carrier proteins for active transport
26
Two parts of a nephron where receptors are found:
- collecting duct
- distal convoluted tubule
27
receptors may bind to specific hormone because:
- specific tertiary structure
- structures are complementary
28
Location of receptors that detect a decrease in blood pressure:
- aorta
29
How release of ADH will affect blood pressure:
- ADH increases reabsorption of water
- increases volume of blood and pressure increases
30
Community definition:
- population of different species
31
Carrying capacity:
- ecosystem supports a certain size of population of a species
32
Two reasons for conserving rain forests:
- for biodiversity
- source of medicine
- reduces climate change
33
Reasons for low efficiency of energy transfer from secondary consumers to tertiary consumers:
- heat loss from respiration
- not all food eaten
- excretion
34
Describe how short tandem repeats could be removed from a sample of DNA:
- restriction endonuclease
- cuts DNA at restriction/recognition sites
35
Importance of knowing the short base sequence either side of STRs during PCR:
- for primers
- produces a complementary base sequence
36
two features of STRs which enable them to be separated by electrophoresis:
- mass
- charge
37
role of ATP in muscle contraction:
- to break actinomyosin bridges
- to bend myosin heads
- for active transport of calcium ions
38
How delayed insertion of a gene can lead to offspring who are not transgenic:
- cell division has occurred before gene added
- gametes do not receive gene
39
Why different primers are required when detecting different RNA viruses:
- base sequences differ
- different complementary primers required
40
Use of a radioactive labelled DNA probe to identify a gene:
- extract DNA and using restriction endonuclease
- separate fragments using electrophoresis
- treat DNA to form single strands
- the probe will bind to the gene
41
Suggest how the production of ‘antisense’ SUT1 mRNA in type A plants
would reduce the expression of the SUT1 gene:
- antisense mRNA is complementary to sense mRNA
- antisense mRNA would bind to sense mRNA
- ribosomes would not be able to bind
- preventing translation
42
DNA probe:
- short single strand of DNA
- with bases complementary with DNA
43
how DNA is separated into smaller fragments:
- restriction endonuclease
- breaks phosphodoester bonds
- at recognition sites
44
PCR
- in vitro
45
Why the number of people expressing an allele would rapidly increase in the population once selection for this condition had been established:
- dominant allele
- expressed when only one allele is present
46
glycogen role in skeletal msucles:
- to be hydrolysed to glucose
- to provide ATP
47
effect of low pH on muscle contractions:
- low pH changes shape of calcium ion receptors
- fewer calcium ions binds to tropomyosin
- fewer tropomyosin molecules move away
- fewer binding sites on actin revealed
- fewer myosin heads can bind
48
role of ATP in myofibril contraction:
- allows binding of myosin to actin
- provides energy to move myosin head
49
Longer loop of Henle:
- increase in sodium concentration in medulla
- therefore water potential gradient maintained, so more water reabsorbed
50
effect in collecting duct of ADH:
- concentration rises because duct loses water by osmosis
- ADH increases permeability to water by osmosis
51
plants producing more chlorophyll would grow faster because
- have faster production of ATP and reduced NADP
- faster light independent reaction
- so more energy for growth
52
Two features of a calorimeter that would enable a valid measurement of the total heat energy released:
- stirrer distributes heat
- insulation reduces loss of heat
53
Why some falling light in natural ecosystems is not used in photosynthesis:
- light is reflected
- light misses chlorophyll
- light is wrong wavelength
54
Why a respirometer is left for 10 minutes at the end of the experiment:
- equilibrium reached
- allow for expansion in apparatus
- allow respiration rate of seeds to stabilise
55
how to maintain a unidirectional flow of blood:
- pressure in left atrium is higher than in ventricle, causing valve to open
- pressure in left ventricle is higher than in atrium, causing valve to open
56
How hydrophobic molecules can pass through cell membrane:
- lipid soluble
- diffuse through phospholipid bilayer
57
when you use a calorimeter you need to:
- use a known volume of solution
- record absorbance using a calorimeter
- plot concentration of solution against absorbance
58
how inhibiting adenylate cyclase may help to lower the blood glucose
concentration:
- less ATP converted to cAMP
- less kinase activated
- less glycogen converted to glucose
