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Biology Revision Year 2 > Control of Gene Expression > Flashcards

Control of Gene Expression Flashcards

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1
Q

define mutation

A

a change to the nucleotide sequence of DNA

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2
Q

what does a Mutogenic Agent do?

A

increases the rate of mutation

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3
Q

What is a Base Analogue?

A

a chemical that can substitute for a normal nucleotide base —-> substition mutation

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4
Q

what does radiation cause?

A

change to the structur of DNA eg) UV

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5
Q

describe substitution

A

one base swapped for another one

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6
Q

describe addition, and what it causes

A

one base added this causes frame shift

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7
Q

describe deletion

A

one base is removed

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8
Q

decribe inversion and what it can cause

A

sequence of bases are reversed, can cause no change (degenerate) ,change a few, doesn’t cause frame shift

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9
Q

describe duplication

A

one or more bases are repeated

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10
Q

describe translocation

A

DNA is moved from one part of a genome to another part of a genome

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11
Q

what could be the impact of the alteration of one AA?

A

changes primary structure, changing H bonds, changing tertiary structure (could have negligable change)

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12
Q

what does change to many AA cause?

A

frame shift= change to primary/H bonds —> tertiary

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13
Q

describe stem cells

A

capable of diffferentiating into specialised cells, can divide for the organisms lifetime (no apoptosis)

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14
Q

what is a totipotent stem cell?

A

can differentiate into any specialised cell, found in early mammalian embryos

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15
Q

describe a pluripotent cell

A

can differentiate into many types of cells, but cannot make placental cells

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16
Q

describe a multipotent stem cell

A

can differentiate into a few types of specialised cells

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17
Q

describe a unipotent stem cell

A

stem cells that can differentiate into one type of cell

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18
Q

what happens when a cell becomes specialised?

A

conditions inside the cell control which genes are expressed (eg) transcription factors) cells become irreversibly specialised

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19
Q

How can we obtain induced pluripotent stem cells (iPS)

A

use a modified virus as a vector, virus inserts transcription factors from pluripotent —-> unipotent, transcription factors are expressed

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20
Q

how can we obtain embryonic stem cells?

A

IVF embryos, pluripotent stem cells are removed after a few days, pluripotent cells can differentiate into all types of body cell

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21
Q

how can we obtain Adult Stem Cells?

A

taken by consenting adults in an operation (eg) bone marrow) Adult stem cells are multipotent

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22
Q

how can bone marrow be used in medicine?

A

contain multipotent stem cells, can differentiate into WBCs and RBCs, donor bone marrow can be used to treat leukemia

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23
Q

how can stem cell grown organs be used in medicine?

A

no donor required, use iPS cells, no rejection

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24
Q

what are the advantages of stem cells in medicine?

A

improve quality of life, prevent suffering, save lives

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25
Q

what are the disadvantages of stem cells in medicine? (how can some of these be combatted)

A

embryos could develop into a foetus, fertalised —> right to life ( use an unfertalised egg that has been triggered to multiply, or develop iPS cells)

26
Q

define transcription factor

A

proteins that control the rate of transcription by switching genes on and off

27
Q

define promotor region

A

short sequence of DNA at the start of the gene that the ribosome attaches to

28
Q

decribe the process of a transcription factor

A

TF moves from the cytoplasm to the nucleus, binds to the promotor region, activate/ repress transcription by helping/ preventing RNA ploymerase binding to DNA

29
Q

describe using the example of oestrogen how transcription factors can be controlled

A

steriod hormone, binds to receptor, foring oestrogen - oestrogen receptor complex, alters shape to make transcription factor

30
Q

define cancer

A

uncontrolled cell division resulting in a tumour

31
Q

what is the role of a tumour suppressor gene?

A

make genes which slow down mitosis or trigger apoptosis

32
Q

what may result from a mutation of a tumour suppressor gene?

A

a non functional protein

33
Q

what is the role of a proto-oncogene?

A

speed up mitosis

34
Q

what is a proto-oncogene called if it mutates?

A

oncogene

35
Q

how does mutation of a proto -oncogene cause cancer?

A

oncogene can be over expressed, over increasing the rate of mitosis, resulting in a tumour

36
Q

define epigenetics

A

changes to gene expression caused by the environment (without changing the base sequence of DNA)

37
Q

can epigenetics be inherited?

A

yes

38
Q

how does epigenetics control gene expression?

A

by preventing transcription

39
Q

Methylation?

A

More Methylation —-> Terminates Transcription

40
Q

describe methylation

A

methyl group attaches to cytosine (CpG site) and prevents transcription, methylated CpG sites prevent transcription enzymes

41
Q

Acetylation?

A

Less Acetylation —–> Terminates Transcription

42
Q

describe acetylation

A

acetyl group make histones space out, and DNA less tightly coiled, allows transcription enzymes to attach

43
Q

How does RNA interferance control gene expression?

A

prevents translation

44
Q

describe siRNA

A

short, double stranded

45
Q

describe how siRNA prevents translation

A

combines with protein to form siRNA - protein complex, becomes single stranded, unpaired bases are complementary to target mRNA, siRNA protein complex breaks down mRNA, preventing translation

46
Q

what is formed when microRNA joins with protein?

A

microRNA-protein complex

47
Q

how does microRNA prevent translation?

A

binds to mRNA by complementary base pairing, prevents translation by stooping the ribosome attaching

48
Q

Describe hypermethylation

A

affects tumour suppressor genes (think why), proteins are not transcribed, leading to uncontrolled cell division (cancer)

49
Q

describe hypomethylation

A

affects proto-oncogenes (think why?), more proteins are transcribed, leading to uncontrolles cell division

50
Q

how can we uses mitosis to identify a tumour?

A

more cells dividing

51
Q

how can we use nuclei to identify a tumour?

A

appear large, irregular, multiple per cell

52
Q

how can we use the shape of cells to identify a tumour?

A

irregular appearance

53
Q

how would the arrangement of cells in a tumour appear?

A

disorganised

54
Q

what is a benign tumour?

A

non cancerous

55
Q

describe a benign tumour

A

slow growing, harmless, can become malignant

56
Q

what is a malignant tumour?

A

cancerous

57
Q

describe a malignant tumour

A

fast growing, harmful, can spread

58
Q

what hormone may cause breast cancer?

A

oestrogen

59
Q

how may oestrogen cause cancer?

A

oestrogen- oestrogen receptor complex acts as a transcription factor to increase rate of cell division, increasing cell divisin increases risk of mutations, leading to cancer

60
Q

why has the chain termination method of gene sequencing been replaced with high throughpat pyrosequencing?

A

automated, faster, cheaper

61
Q

why is it easier to sequence the genome of simple organisms such as prokaryotes?

A

few regulatory genes, little non coding DNA

62
Q

how is the genome project used?

A

understand evolutionary relatedness (phylogeny), medicine applications such as finding antigens for vaccines

Biology Revision Year 2 (13 decks)

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