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Mr Dewhurst- Cellular control Flashcards

1
Q

what is a codon

A

3 nucleotide bases on mRNA that codes for an amino acid

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2
Q

what is meant by degenerate

A

more codons than amino acids so multiple combinations code for same amino acid

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3
Q

what is meant by non-overlapping

A

code 3 bases at a time

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4
Q

what’s meant by universal code

A

everyone has same amino acids so evidence we have common ancestor from start of life

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5
Q

what happens when a stop codon is reached

A

produces shorter proteins as transcriptions stops

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6
Q

what is a mutation

A

change in base sequence

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7
Q

what is meant by substitution

A

one base is changed which might them change the amino acid meaning the 3D shape may change

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8
Q

what is an example of a health condition caused by substitution

A

sickle cell anaemia- A swapped for T in gene of haemoglobin - red blood cell changes shape

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9
Q

what is meant by nonsense substitution

A

base swapping causes stop codon which means protein is shorter and won’t function properly

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10
Q

what is meant by missense substitution

A

amino acid changes which changes function and shape

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11
Q

what is meant by silent substitution

A

change in base makes no difference to amino acid it has coded for

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12
Q

what is the mutation of insertion

A

extra base added messing up whole sequence - pushes along one

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13
Q

what is deletion

A

base removed which effects every codon after deletion

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14
Q

what is the frame shift

A

caused by insertion and deletion- shifts back/forth causing every codon to change and the protein changes

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15
Q

what is meant by the neutral effect of mutation

A

proteins function normally because protein is till synthesised and the phenotype is unchanged

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16
Q

what is the harmful effect of mutation

A

protein is not synthesised or not functional- phenotype negatively effected

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17
Q

what is the beneficial effect of mutation

A

slight change to amino acid - but change may be beneficial or protein may carry out desirable functions- rare

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18
Q

what are 4 causes of mutation

A

radiation/ X-rays
chemical in cigarette smoke
chemicals in caffeine
UV light

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19
Q

what are some health disorders caused by mutations

A

cystic fibrosis- deletion
cancer- protooncogenes changed- uncontrolled cell division
huntingtins

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20
Q

what are transcription factors

A

proteins that move in from cytoplasm and bind with DNA to attatch RNA polymerases to DNA
mostly inactive and activated by hormones
some are only present at a certain stage of development

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21
Q

what do transcription factors do

A

attatch to the promoter so RNA polymerase can bind and transcribe gene

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22
Q

what happens when a transcription factor is bound to an inhibitor

A

stops transcription as prevents it binding to the promoter as it changes its shape

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23
Q

what happens when oestrogen is bound to transcription factor

A

releases inhibitor so it can bind to promoter

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24
Q

what is an operon

A

section of DNA that contains a cluster of genes transcribed together as well as control elements and regulatory gene

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25
what is the lac operon
in bacteria - E.coli only produces enzymes to respire ;lactose when it is present
26
outline how the lac operon turns genes off
the regulatory gene codes for a repressor protein which attaches to the operator, blocking the promoter where RNA polymerase attaches so transcription cannot occur
27
outline how lac operon turns genes on
when lactose is present it binds to the repressor changing its shape preventing it from binding to operator, this means that the RNA polymerase can bind to promoter and transcription can take place of structural genes that produce enzymes for lactose utilization
28
What is meant by control of gene expression at posttranscriptional level
Editing primary mRNA by removing introns to form mature mRNA
29
What is an intron
Section of gene that doesn’t code for amino acid
30
What are exons
Section of gene that codes for amino acids
31
What happens to exons and introns when a gene is transcribed
Only exons are left , introns are removed
32
What is splicing of pre-mRNA
In pre-mRNA of eukaryotic cells the introns are removed and functional exons are joined together - splicing
33
What are snRNPs “snurp”
Small nuclear ribonucleases that make spliceosome
34
What is a spliceosome
Loops introns to excise it (cut)
35
What happens after intron is cut out of pre-mRNA
Loop of intron that has no function , snRNPs , mature mRNA that leaves nucleus into cytoplasm for next stage of protein synthesis
36
37
What does beta galactosidase do
Hydrolyses glycosidic bonds between lactose
38
39
What is lactose permase
Inserted into cell surface membrane to make it more permeable to lactose
40
what is meant by post transcriptional level
protein activation or inhibition by cyclic AMP
41
what are the 5 process on how a protein is inhibited/activated
hormone binds to complementary receptor activates G protein activates adenyl cyclase/ inhibits catalyses ATP- cAMP phosphorylates protein kinases which triggers response to target cells ( enzymes, ion channels etc)
42
how is protein formation inhibited
a different hormone binds to different receptor
43
why are fruit flies good to study body plans of
small, easy to keep, short life cycle, not really unethical
44
how do scientists know what the genes are responsible for
scientists change genes to see effect to know what they are responsible for
45
what are hox genes
class of homeobox genes in animals to position body parts and code for homeodomain proteins
46
what is special about hox genes
position on chromosome is position on organism
47
homeobox genes
highly conserved regions, control arrangement of body parts
48
what's meant by homeobox genes being highly conserved
don't differ a lot - if there is a mutation the organism will die and not pass gene on
49
what is the homeobox sequence
sequence of bases found within genes in regulating anatomical development in plants and animals
50
what are homeodomain proteins
transcription factors to activate or repress genes that regulate mitosis, apoptosis (kill cells), cell cycle
51
whats the phrase in terms of homeobox genes and hox genes
every hox gene is a homeobox gene but not every homeobox is a hox gene
52
what is pax 6
homeobox gene that has mutated that can cause blindness
53
what is thalidomide
provided for morning sickness, affected behaviour of homeobox gene at critical stage in embryonic development -cause limbs to not grow but can be used to prevent tumours developing
54
what happens at G1 phase
cell increases in size, preps for replication, organelles replicate
55
what happens at G1 checkpoint
checks cell size, nutrients, growth factors and DNA damage
56
what is the s phase
DNA synthesis
57
what happens at G2 phase
cell increases in size, source of energy for mitosis
58
what is the G2 checkpoint
makes sure replicated DNA isn't faulty
59
what is the G0 phase
taken out if DNA is damaged or if cell has been differentiated
60
what is the metaphase (spindle assembly checkpoint)
ensures chromosomes attach to spindle fibres
61
what is apoptosis
programmed cell death series of biochemical events leading to an orderly and tidy cell death
62
how many cells apoptosis a day
50-70 million but the rate of dying must balance with cells produced by mitosis not enough- formation of tumours too much- loss and degeneration
63
how is apoptosis controlled
hox genes regulate mitosis and apoptosis expression is regulated by stimuli and different stressors
64
what is the internal influence on apoptosis
damage to DNA is detected in the cell cycle genes expressed that causes cell cycle to pause, triggers apoptosis release of hormones
65
what is the external influence of apoptosis
change in light intensity, temperature pathogen attack lack of nutrients, drugs
66
what is day 48 of apoptosis
mitosis and differentiation create bulk of tissue
67
what is day 51 and 56 of apoptosis
apoptosis refines parts by removing unwanted structures
68
outline the process of apoptosis
normal cell, cell starts to bleb and nucleus disintegrates, cell fragments are produced with intact plasma membranes containing organelles which are then ingested and digested by phagocytic cells
69
what happens to the resources within the cells that are destroyed
released into blood stream to be reused

Biology (22 decks)

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