Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Year 2 > 6.1.1- Cellular Control > Flashcards

6.1.1- Cellular Control Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

what is a mutation?

A

a change in the amount or arrangement of genetic material in a cell
-change in chromosome
-change in nucleotide sequence of a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are spontaneous mutations?

A

mutations caused by errors during DNA replication or gamete formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are inherited mutations?

A

mutations which are passed on to offspring through gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are induced mutations?

A

mutations caused by mutagens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are examples of mutagens?

A

-mustard gas
-radiation (UV light and X-rays)
-viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is a gene mutation?

A

the change in nucleotide base sequence which lead to changes in the gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are chromosome mutations?

A

changes in part of chromosome/chromosome number, which occurs during meiosis and are harmful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the 4 types of chromosome mutations and what occurs?

A

-deletion= section of chromosome breaks off
-duplication= sections duplicated
-translocation= section breaks off and joins another non-homologous chromosome
-inversion= section breaks off, is reversed and joins back onto chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the 3 point mutations and explain these?

A

-substitution= one nucleotide pair is replaced by another (missense, nonsense, silent)
-insertion= extra nucleotide base pairs are inserted into a length of dna
-deletion= nucleotide base pairs are deleted from a length of dna

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what do deletion and insertion lead to?

A

a frameshift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is a missense mutation?

A

a type of substitution, where the triplet code changes to a code for another amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is a nonsense mutation?

A

a type of substitution, where a triplet code for an amino acid changes to a code which instructs translation to stop.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is a silent mutation?

A

a type of substitution, where a triplet code changes to a different code for the same amino acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is a frameshift mutation?

A

where every triplet code after the point of insertion or deletion is altered, making a completely different protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is a neutral mutation?

A

mutations with no selective advantage or disadvantage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are beneficial mutations?

A

mutations which increase the chance of survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are harmful mutations?

A

mutations which decrease chances of survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is an example of a beneficial mutation?

A

the peppered moth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is an example of a harmful mutation?

A

sickle cell anaemia, mutation in the gene coding for haemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is transcriptional control?

A

when genes can be turned on or off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what two chemicals are involved in chromatin remodelling and what do they do?

A

-methyl= make the histones more hydrophobic so they pack more tightly to each other
-acetyl= reduces the positive charge of the histones, so they do not coil as tightly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is heterochromatin?

A

when the histones are tightly packed, so transcription is not possible as RNA polymerase cannot access genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is euchromatin?

A

when dna is loosely wound so transcription is possible, as RNA polymerase can access genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is a transcription factor?

A

proteins that bind to DNA and switch genes on or off by increasing/decreasing the rate of transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are activators?

A

transcription factors that increase the rate of transcription

26
Q

what are repressors?

A

transcription factors that decrease the rate of transcription

27
Q

what are inducible enzymes?

A

some enzymes are only synthesised in response to environmental changes

28
Q

what are the 3 inducible enzymes created in bacteria/e.coli that are present to metabolise lactose, and what do they do?

A

-lactose permease= transports lactose into cell
-B-galactosidase= catalyses hydrolysis of lactose into glucose/galactose
-transacetylase= adds acetyl groups to molecules

29
Q

what is a lac operon?

A

a length of DNA made up of structural genes, regulatory genes and control sites

30
Q

what are structural genes?

A

genes that code for proteins

31
Q

what are regulatory genes?

A

genes that code for regulatory proteins which are involved in switching transcription of the structural genes on or off

32
Q

what are control sites?

A

the sites where the regulatory protein binds to witch transcription of the structural gene on or off.

33
Q

what happens in the lac operon when lactose is absent?

A

1-regulator gene is transcribed and translated to make the repressor protein
-repressor protein binds to operator and blocks promotor
-rna polymerase cannot bind to promotor so structural genes cannot be transcribed
-enzymes are not made, as otherwise this would be a waste of energy.

34
Q

what happens in the lac operon when lactose is present?

A

1-lactose binds to repressor protein, which changes shape so no longer binds to the operator
2-rna polymerase binds to promotor so structural genes are transcribed
3-mrna from structural genes are translated
4-cells make the 3 enzymes

35
Q

what is the post-transcriptional level?

A

mRNA can be modified, which regulates translation and the types of proteins produced

36
Q

what is the translational level?

A

translation can be stopped or started

37
Q

what is the post-translational level?

A

proteins can be modified after synthesis which changes their function.

38
Q

what happens in the post-transcriptional level?

A

1- a cap (modified nucleotide) is added to the 5’ end and a tail (long chain of adenine nucletides) is added to the 3’ end. This stabilisers the mRNA and delays degradation in the cytoplasm
2- splicing occurs, where the rna is cut at specific points, the introns (non-coding dna) are removed and the exons (coding dna) are joined together
3- rna editing can occur in which some mRNA molecules can also be changed through base addition, deletion, or substitution , can synthsise different proteins with different functions from a single mRNA molecule or gene.

39
Q

what are the mechanisms of translational control?

A

1- degradation of mRNA
2- binding of inhibitory proteins to the mRNA preventing it from binding to ribosomes
3- activation of initiation factors which aid the binding of mRNA to ribosomes

40
Q

what is morphogenesis?

A

the regulation of the pattern of anatomical development.

41
Q

what are homeobox genes?

A

a group of regulatory genes that contain a homeobox, and code for transcription factors that regulate transcription

42
Q

what is a homeobox?

A

a section of dna that is 180 base pairs long and codes for a part of the protein that is made up of 60 amino acids

43
Q

what is the part of the protein that is coded by the homeobox?

A

homeodomain, that binds to dna and turns on or off genes

44
Q

why are the homeobox genes similar in plants, animal and fungi?

A

because they are highly conserved.

45
Q

why are the homeobox genes similar in plants, animal and fungi?

A

because they are highly conserved.

46
Q

what are hox genes?

A

one group of homeobox gene that are only present in animals

47
Q

what are hox genes responsible for?

A

the correct positioning of body parts

48
Q

in mammal bodies, where are hox genes found?

A

four clusters on different chromosome

49
Q

how many hox genes do humans have?

A

39

50
Q

how does hox genes aid in the correct position of body parts?

A

the genes are transcribed in a particular order during development?

51
Q

what is a good example of where hox genes aid in development?

A

fly development

52
Q

what are diploblastic animals?

A

animals that have 2 primary tissue layers

53
Q

what are triploblastic animals?

A

animals that have 3 primary tissue layers

54
Q

what are somites?

A

segments in an embryo that are directed by hox genes to develop in a certain way depending on their position in the sequence

55
Q

what is bilateral symmetry?

A

organisms have both a left and right side and a head and tail

56
Q

what is radial symmetry?

A

seen in diploblastic animals (eg- jellyfish), no left or right, only a top and bottom

57
Q

what is the role of mitosis in shaping organisms?

A

increase the number of cells leading to growth

58
Q

what is apoptosis?

A

programmed cell death

59
Q

what is the role of apoptosis in shaping organisms?

A

removes unwanted cells and tissue

60
Q

what are the 4 steps to apoptosis?

A

-hydrolytic enzymes from lysosome released inside cell break down the cytoskeleton
-cytoplasm becomes dense, blebs form on cell surface membrane
-nucleus fragments and cells break into vesicles
-phagocytes ingest the vesicles

61
Q

what is apoptosis controlled by?

A

cell signals

Biology Year 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions