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module 6 > 6.1.1 cellular control > Flashcards

6.1.1 cellular control Flashcards

1
Q

acetylation/phosphorylation

A

the addition of acetyl/phosphate groups, to make them more negative so that the DNA can coil less tightly, and transcription can take place

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2
Q

methylation

A

the addition of methyl groups to make the histones more hydrophobic so that they can bind more tightly to eachother, preventing transcription

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3
Q

epigenetics

A

used to describe the control of gene expression by the modification of DNA

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4
Q

operon

A

group of genes that are under the same regulatory mechanism and are expressed at the same time

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5
Q

are operons prokaryotic or eukaryotic

A

prokaryotic

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6
Q

lac operon

A

group of 3 genes, lacZ, lacY and lacA, involved in the metabolism of lactose - structural genes

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7
Q

enzymes that the lac operon codes for

A

B galactosidase, lactose permease and transacetylase

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8
Q

regulatory gene of the lac operon

A

lacI, codes for the repressor protein which prevents the transcription of the structural genes in the absence of lactose

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9
Q

lac operon when lactose is absent

A

regulatory gene codes for the repressor protein
attaches to operator site
blocks the promoter site
this means RNA pol cannot attach
structural genes are not transcribed

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10
Q

when lactose is present

A

a little bit of lactose enters the cell by diffusion
attaches to the repressor protein
this changes the shape of the protein, so cannot attach to operator
RNA pol can attach to promoter
structural genes are transcribed
so enzymes are made

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11
Q

post transcriptional control

A

splicing

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12
Q

splicing process

A

pre- mRNA (introns and exons) is then changes when introns are removed and exons are joined, forming mature mRNA
a cap is added on 5’ end and a tail is added on 3’ end for stabilising

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13
Q

spliceosomes

A

the enzymes involved in splicing, can join the exons in a variety of ways, producing several versions of functional mRNA

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14
Q

factors that regulate when translation starts and stops

A
  • how long the mRNA lasts in the cytoplasm
  • inhibitory factors
  • initiation factors
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15
Q

post translational control

A

addition of non protein groups
folding into final shape
activation of proteins by cAMP

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16
Q

cAMP

A

cyclic AMP, can change the 3D shape of a protein, activating the active

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17
Q

activation of PKA

A
  1. PKA is an enzyme with 4 subunits
  2. when cAMP isnt bound the 4 units are bound together and inactive
  3. when cAMP binds, it causes a change in the enzymes 3d shape, releasing the active subunits, activating the enzymes
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18
Q

morphogenesis

A

the regulation of the pattern of anatomical development

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19
Q

homeobox genes

A

group of genes which all contain a homeobox

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20
Q

homeobox

A

section of DNA 180 base pairs long coding for a protein which is 60 amino acids long (a homeodomain)

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21
Q

homeodomain

A

60 amino acids long, and binds to DNA, and switches other genes on and off

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22
Q

hox genes

A

a group of homeobox genes that are only present in animals, responsible for the correct positioning of body parts

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23
Q

amount of hox genes in humans

A

39

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24
Q

how body plans are represented

A

cross sections through the organism showing the fundamental arrangement of tissue layers

25
Q

somites

A

the segments in embryo that allow individual vertebrae to be developed, directed by hox genes

26
Q

radial symmetry

A

seen in diploblastic animals like jellyfish, no left or right, just top and bottom

27
Q

bilateral symmetry

A

seen in most animals means that organisms have both a left and right side and a head and a tail

28
Q

asymmetry

A

seen in sponges which have no lines of symmetry

29
Q

apoptosis

A

programmed cell death

30
Q

how apoptosis shapes body parts

A

removes unwanted cells and tissues

31
Q

what regulates mitosis and apoptosis?

A

hox genes

32
Q

factors affecting the expression of regulatory genes

A

environment, internal and external
stress and drugs etc

33
Q

mutation

A

change in the sequence of bases in DNA or RNA

34
Q

substitution mutation

A

mutation in which a single nucleotide changes the codon in which it occurs

35
Q

degenerate code

A

multiple codons encode a single amino acid

36
Q

nonsense mutation

A

a mutation that changes an amino acid codon to one of the 3 stop codons, resulting in a shorter and non functional protein

37
Q

missense mutation

A

a base pair substitution that results in a codon that codes for a different amino acid

38
Q

insertion mutation

A

a mutation in which one or more nucleotides are added to a gene

39
Q

deletion mutation

A

a mutation in which one or more pairs are removed from a gene

40
Q

frameshift

A

mutation that causes the reading frame of mRNA codons to shift (insertion or deletion)

41
Q

no effect mutation

A

there is no effect on the phenotype of an organism because the normally functioning proteins are still synthesised

42
Q

damaging effect mutation

A

phenotype of an organism is affected in a negative way because proteins are no longer synthesised, which can interfere with essential processes

43
Q

beneficial effects of mutations

A

mutations often produce proteins with new or altered functions that can be useful to organism in changing environments

44
Q

mutagens

A

physical and chemical agents that interact with DNA to cause mutations

45
Q

physical mutagens

A

radiation x rays, UV light (break one or both DNA strands)

46
Q

chemical mutagens

A

deaminating agents - chemically alter bases in DNA changing the base sequence

47
Q

biological mutagens

A

viruses, base analogs, alkylating agents

48
Q

chromosome mutation - deletion

A

due to breakage, a piece of chromsome is lost

49
Q

chromsome mutation - inversion

A

a chromosome rearragement in which a segment of chromosome is reversed end to end

50
Q

chromosome mutation - translocation

A

a section of one chromosome breaks off and joins another non-homologous chromosome

51
Q

housekeeping genes

A

the genes that code for enzymes present in metabolic reactions that are always required

52
Q

tissue specific genes

A

the genes that code for protein based hormones which are only required a certain times to carry out short lived responses

53
Q

the different levels of gene regulation

A

transcriptional, post transcriptional, translational, post translational

54
Q

heterochromatin

A

tightly wound DNA, where RNA pol cannot access the genes

55
Q

euchromatin

A

loosely wound DNA where RNA polymerase can access the genes

56
Q

suggest reasons why fruit flies are chosen for research into genes controlling development of body plan

A
  • fewer public concerns over ethics of using flies
  • low cost
  • rapid reproduction rate
  • fruit fly genetics is understood well
57
Q

why would mice be used in research of body plans? why not?

A
  • low cost
  • similar to humans
  • however more ethical concerns
58
Q
A

module 6 (6 decks)

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