Brainscape's Knowledge GenomeTM

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


See full index

Biology > Topic 8A: Mutations + Gene Expression > Flashcards

Topic 8A: Mutations + Gene Expression Flashcards

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

Mutation =

A

Any change to base sequence

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

Type of mutation: Substitution

A

One or more bases are swapped

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

Type of mutation: Deletion

A

one or more bases removed

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

Type of mutation: Addition

A

one or more bases added

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

Type of mutation: Duplication

A

one or more bases repeated

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

Type of mutation: Inversion

A

a sequence of bases are reversed

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

Type of mutation: Translocation

A

sequence of bases is moved from one location in the genome to another (can be movement within or between chromosomes)

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

Hereditary mutation

A

when gamete containing genetic disorder or type cancer is fertilised and present in new fetus

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

Mutagenic Agents =

A

increases rate of mutation

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

Examples of mutagenic agents

A

Ultraviolet radiation, ionising radiation and some chemicals and viruses

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

3 ways mutagenic agents increases rate mutations

A
  1. Acting as a base
  2. Altering bases
  3. Changing structure of DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Mutagenic agent: acting as a base

A

chemicals called Base Analogs can substitute for a base during DNA replication, = substitution mutation

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

Mutagenic agent: Altering bases

A

some chemicals can delete or alter bases

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

Mutagenic agent: Changing the structure of DNA

A

some types of radiation can change the structure of DNA which causes problems during DNA replication

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

Acquired mutations =

A

mutations that occur in individual cells after fertilisation (adulthood)

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

Uncontrolled cell division caused by

A

mutations in genes that control the rate of cell division

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

Tumours =

A

mass of abnormal cells

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

2 types of gene that control cell division

A
  1. tumour suppressor genes

2. proto-oncogenes

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

When tumour suppressor genes act normally =

A

slow cell division by producing proteins that stop cells dividing or cause self destruct

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

When mutation occurs in tumour suppressor gene

A

becomes inactivated - protein isn’t produced. Cells divide uncontrollably = tumour

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

When proto-oncogene acts normally

A

stimulate cell division by producing proteins that make cells divide

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

When mutation occurs in proto-oncogene

A

gene becomes overactive- stimulates cells divide uncontrollably = tumour

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

Mutated proto- oncogene called

A

oncogene

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

Malignant tumours =

A

cancerous - grow rapidly and invade and destroy surrounding tissues
cells can break off tumour and spread to other parts of the body in bloodstream or lymphatic system

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

Benign tumours =

A

not cancerous - grow slower and covered by fibrous tissue that stop cells invading other tissues
Harmless but can cause blockages and put pressure on organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

6 differences between tumour cells and normal cells

A
  1. irregular shape
  2. nuclues larger + darker (sometimes more than 1)
  3. dont produce all proteins needed to function
  4. different antigens on surface
  5. dont respond to growth regulating processes
  6. divide by mitosis more often
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Abnormal methylation of cancer- related genes can cause

A

tumour growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Methylation =

A

adding a methyl group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Methylation of DNA is an important method of

A

regulating gene expression - can control if gene transcribed and translated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Hypermethylation =

A

too much methylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Hypomethylation =

A

too little methylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

When tumour suppressor genes are hypermethylated

A

genes are not transcribed - so proteins they produce to slow cell division aren’t made

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Hypomethylation of proto -oncogenes

A

causes them to act as oncogenes increasing the production of the proteins that encourage cell division uncontrollably

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Increased exposure to oestrogen increases

A

woman’s risk to devloping breast cancer

and menstaration earlier or menopause later

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Oestrogen can stimulate

A

certain breast cancer cells to divide and replicate- increases chance of mutations and therefore chances of cancerous cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Problem with oestrogen stimulating cancerous cells

A

increases the formation of tumours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

impact of oestrogen on the DNA of certain breat cells

A

can introduce mutations directly into the DNA -increasing chances of cancerous cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Forms of risk factors:

A

genetic and environmental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Genetic factors =

A

some cancers linked w/ specific inherited alleles

-if that allele inherited you most likely have get that cancer but not always

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Environmental factors =

A

exposure to radiation, lifestyle choices (like smoking + alcohol + high fat diet) linked to increased chance of come cancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Why data on varaitions difficult to interpret

A

some characteristics can be affected by many different genes (polygenic) and many environmental factors - difficult to know which has the greatest effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

cancer caused by

A

mutations in proto-oncogenes and tumour suppressor genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

how knowing exactly how a cancer works helps in 3 forms of prevention

A

1- possible to screen for mutation in person’s DNA
2- preventative steps e.g. mastecomy ( removing of the breasts) or more frequent screenings - early detection
3- knowing more about a mutation= more scientific tests can be developed for more accurate diagnosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How knowing exactly how a cancer works helps in 3 forms of treatment and care

A

1- treatment for cancer can be different for different mutations so can be useful for developing drugs to effectively target
2- some cancers need more aggressive treatments - so helps produce best treatment plan
3- genetic therapy used to treat cancers caused by mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Genetic therapy =

A

faulty alleles in person’s cells are replaced by working versions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Totiponent stem cells =

A

able to mature into any type of body cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Multicellular organisms made up from

A

many diff cell types that are specialised to their function

all have some form of stem cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

All specialised cells original come from

A

stem cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Stem cells =

A

unspecialised cells that can develop into other types of cells which then become specialised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Stem cells found in

A
  • the embryo (where they become specialised cells needed to form a fetus)
  • in some adult cells (where become specialised cells that need to be replaced)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Totipotent stem cells only present in

A

mammals in the first few cell divisions of an embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

After the first few cell divisions embryonic stem cells become

A

pluripotent- can still specialise into any cell in the body except the cells that make up the placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Stem cells in adult mammals are either

A

multipotent stem cells

unipotent stem cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Multipotent stem cells =

+ example

A

able to differentiate into a few different type of cell e.g. both red and white blood cells formed from multipotent stem cells found in the bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Unipotent stem cells =

+ example

A

can only differentiate into one type of cell e.g. only one type unipotent stem cell that can divide to produce epidermal skin cells - make up outer layer of your skin

56
Q

stem cells become specialised because

A

during development the only transcribe and translate part of their DNA

57
Q

Stem cells all contain the same

A

genes but not all are transcribed and translated (expressed)

58
Q

mRNA is only transcibed from

A

specific genes

59
Q

mRNA translated into

A

proteins that modify the cell - determine the cell structure + control cell processes (e.g. expression of some genes)

60
Q

Changes to cell due to proteins makes cells

A

specialised
changes are difficult to reverse
so once specialised cell stays specialised

61
Q

Red blood cells are produced from

A

a type of stem cell in the bone marrow- contains lots haemoglobin and no nucleus - to make more room for haemoglobin

62
Q

Red blood cells stem cells produce new cell in which

A

genes for haemoglobin production are expressed

and other genes which remove the nucleus are expressed too

63
Q

Cardiomyocytes =

A

heart muscle cells that make up alot of the tissue in our hearts
made from unipotent stem cells

64
Q

Recent research has found that our hearts have

A

regenerative capability

65
Q

When can the heart become damaged

A

by a heart attack or with old age

66
Q

Old or damaged cardiomyocytes can be replaced by

A

new cardiomyocytes derived from a small supply of unipotent stem cells in the heart

67
Q

The conflicting opinions around cardiomyocytes placements

A
  • Some believe process really slow + possible some cardiomyocytes are never replaced throughout a lifetime
  • others think occur very quickly so every cardiomyocytes in heart replaced several times in a lifetime
68
Q

Stem cells can be used to treat

A

human diseases

69
Q

Bone marrow transplants used

A

to replace faulty bone marrow in patients tat produce abnormal blood cells because the stem cells can become specialised to form any type of blood cell

70
Q

How stem cells in transplanted bone marrow works

A

they divide and specialise to produce healthy blood cells

71
Q

Bone marrow transplants have been successful in treating

A

leukaemia (a cancer of the blood or bone marrow) + lymphoma (cancer of the lymphatic system)

72
Q

Genetic disorders that stem cell therapies treat

A

sickle cell anaemia + severe combined immunodeficiency (SCID)

73
Q

People with SCID have

A

poorly functioning immune system as their white blood cells are defective so they can’t defend against infections (can’t identify + destroy microorganisms)

74
Q

Scientists are researching in using stem cell therapies in

A
  • spinal cord injuries - replace damaged nerve tissues
  • Heart disease + damage caused by heart attacks
  • Bladder conditions -stem cells could be used to grow whole bladders, which then implanted into patient
  • Respiratory diseases - donated windpipes can be stripped down to their simple collagen structure + covered w/ tissue generated by stem cells
  • organ transplants - organs can be grown from stem cells to provide new organs or ppl on donor waiting list
75
Q

Benefits on stem cells

A
  • can save many lives e.g. ppl on organ transplant list

- improve the quality of life for many ppl - stem cells could be used to replace damage cells in the eye for the blind

76
Q

Three main potential sources of human stem cells

A
  • Adult tissues
  • Embryos
  • in labs
77
Q

Adult stem cells obtained by

A

a simple operation w/ very little risk but quite uncomfortable

78
Q

Adult stem cells vs embryonic stem cells

A

Adult stem cells aren;t as flexible - can only specialise into a limited range of cells- not all body cell types (multipotent)

79
Q

Embryonic stem cells obtained from

A

embryos at an early stage of development

80
Q

Embryonic stem cells:

embryos created in lab using

A

vitro fertilisation (IVF)- eggs cells fertilised by sperm outside the womb

81
Q

Embryonic stem cells:

Once embryo 4/5 days old

A

stem cells removed and rest of embryo destroyed

82
Q

How many times can embryonic stem cells divide

A

unlimited number of times + develop into all types of body cells (pluripotent)

83
Q

iPS Cells =

A

induced pluripotent stem cells

84
Q

iPS cells created in

A

labs

process = “reprogramming” specialised adult body cells so they become pluripotent

85
Q

iPS Cells:

what happens when adult cells are reprogrammed

A

they are made to express a series of transcription factor that are normally associated w/ pluripotent stem cells.
Transcription factor causes adult body cell to express genes that are associated with pluripotency

86
Q

iPS Cells:

how transcription factor introduced to adult cells

A

by infecting them with specially- modified virus
virus has the gene coding for the transcription factor w/in its DNA
when virus infects the adult cell the genes are passed in to the adult cell’s DNA - then able to produce the transcription factors

87
Q

Research being done around iPS cells

A

to see how similar they actually are to true pluripotent embryonic stem cells before can be utilised properly

88
Q

Ethical issues around using embryonic stem cells

A

1- destruction of embryo that could be a fetus in the womb

2- at moment fertilisation an individual has right of life- wrong to destroy

89
Q

Why people object less eggs that aren’t fertilised by sperm cell but artificially activated

A

cells couldn’t survive past a few days + wouldn’t produce a fetus in a womb

90
Q

pros and cons of only using adult stem cells

A

production doesn’t destroy an embryo

but can’t develop into all the specialised cell types that embryonic stem cells can

91
Q

Pros of induced pluripotent stem cells

A
  • have the potential to be as flexible as embryonic stem cells but from adult tissue
  • cells could be made from patient’s own cells - genetically identical so used to grow new tissue or organ that body wouldn’t reject
92
Q

Transcription =

A

when gene is copied from DNA into messenger RNA using enzyme RNA polymerase

93
Q

All cells in an organism carry the same

A

genes (DNA) but the structure + function of different cells varies cause not all expressed

94
Q

Transcription of genes controlled by

A

protein molecules called transcription factors

95
Q

How transcription factors work

A
  • move from cytoplasm to nucleus
  • in nucleus they bind to specific DNA sites near start of target genes (genes they control expression of)
  • control expression by controlling rate of transcription
96
Q

2 forms of transcription factors

A

Activators - stimulate or increase the rate of transcription
Repressors - inhibit or decrease rate of transcription
both either help or prevent RNA polymerase from binding

97
Q

Oestrogen =

+ how it affect transcription

A

a steroid hormone that can bind to transcription factor called an oestrogen receptor forming oestrogen- oestrogen receptor complex

98
Q

What happens when oestrogen- oestrogen receptor complex formed

A

complex moves from the cytoplasm into the nucleus where it binds to specific DNA sites near the start of target gene - can be activator or repressor depending on type cell and target gene

99
Q

In eukaryotics gene expression affected by

A

RNA interference (RNAi)

100
Q

RNAi =

A

small, double standed, non coding RNA molecules that stop mRNA from target genes from being translated into proteins

101
Q

Molecules involved in RNAi =

A

small interfering RNA (siRNA)

microRNA (miRNA)

102
Q

How siRNA in eukaryotes and miRNA in plants work

5 steps

A
  1. Once mRNA has been transcribed it leaves the nucleus for the cytoplasm
  2. in cytoplasm double stranded siRNA associates w/ several proteins + unwinds
  3. single strand binds to target mRNA- bases of siRNA complementary to target mRNA
  4. proteins associated with siRNA cut the mRNA into fragments so no longer can be translated
  5. fragments move into a processing body - contains tools to degrade them
103
Q

2 difference between miRNA and siRNA

A
  1. in mammals miRNA not fully complementary to target mRNA - less specifc than siRNA so may target more than 1 mRNA molecule
  2. miRNA protein complex physically blocks the translation of target mRNA
104
Q

How miRNA works

A
  1. it associates with proteins + binds to target mRNA in the cytoplasm
  2. miRNA- protein complex physically blocks the translation of target mRNA
  3. mRNA moved into processing body where either stored or degraded
    if stored it can be returned + translated at another time)
105
Q

E. coli =

A

a bacterium that respires glucose but can use lactose if glucose not available

106
Q

Response of E.coli if lactose present

A

makes an enzyme (β- galactosidase) to digest

107
Q

Transcription factor that controls the production of the β- galactosidase enzyme

A

lac repressor

108
Q

Responses of the lac repressor if lactose present or not

A

Not - lac repressor binds to the DNA at the start of the gene- stopping transcription
Present- lactose binds to lac repressor - stopping it binding to the DNA so gene transcribed

109
Q

In eukaryotics epigentic control can determine

A

whether gene is switched on or off - whether gene transcribed or translated

110
Q

How epigentic control works

A

through attachment or removal of chmeical groups (aka epigenetic marks) to or from DNA or histone proteins

111
Q

Epigentic marks alter

A

how easily it is for enzymes + their proteins needed for transcription to interact w/ + transcribe the DNA
but don’t alter DNA base sequence

112
Q

Organisms inherit DNA base sequence from

A

their parents

113
Q

When are most epigenetic marks on DNA removed

A

between generations but some escape the removal process and are passed on to offspring

114
Q

Epigenetic changes to gene expression due to

A

its role in lots of normal cellular processes or changes in the environment

115
Q

2 forms of epigenetic control

A

methylation + acetylation

116
Q

Methylation process

A

Methyl group attached to the DNA coding for a gene - always at a CpG site
increased methyation changes the DNA structure so that the transcriptional machinery (enzymes, proteins etc) can’t interact with the gene so not expressed

117
Q

CpG site =

A

where cytosine and guanine base are next to each other in the DNA linked by phosphodiester bond

118
Q

Histones =

A

proteins that DNA wraps around to form chromatin, which make up chromosomes

119
Q

Process decreased acetylation of histones

A

when acetyl group removed from the histone
chromatin becomes highly condensed + genes in DNA can’t be transcribed because transcriptional machinery can’t physically access them

120
Q

HDAC enzymes =

A

histone deacetylase enzymes that are responsible for removing the acetyl groups

121
Q

Epigenetics can play a role in the development of what syndromes

A

Fragile X syndrome
Angleman’s syndrome
Prader - Willi syndrome
+ many others

122
Q

Fragile X syndrome =

A

a genetic disorder that can cause learning + behavioral difficulties as well as characteristic physical features

123
Q

Fragile X syndrome: caused by

A

a heritable duplication mutation in a gene on the X chromosome called FMR1 resulting in a short DNA sequence CGG being repeated more times than usual

124
Q

Fragile X syndrome:

impact of the repeating CGG sequence

A

lots more CpG sites in the genes than usual
More CpG sites = increased methylation of gene which switches it off
because gene switched off the protein that it codes for isn’t produced - causing symptoms of the disease

125
Q

Why are we able to develop drugs to counter the epigentic changes?

A

they are reversible

126
Q

Example of how drugs used stop DNA methylation

A

azzacitidine is used in chemotherapy for types of cancers that are caused by increased methylation of tumour supressor genes

127
Q

Example of how drugs used stop decreased acetylation

A

HDAC inhibitor drugs e.g. romidepsin inhibit the activity of histone deacetylase enzymes so genes can be transcribed

128
Q

Problem with developing drugs to counteract epigentic change

A

these changes take place normally in a lot of cells so important that drug is specific as possible to target dividing cells not normal body ones

129
Q

Phenotype =

A

a characteristic of an organism that’s a result of the organism’s genotype + the interaction of its geneotype with the environment

130
Q

2 examples of phenotypes being influenced by both genes + environment

A

overeating vs antioxidant levels in berries

131
Q

Overeating:

due to environmental factor

A

increased availability of food in developed countries

132
Q

Overeating:

due to genetic food factor

A

consumption increases brain dopamine levels in animals
once enough dopamine released people stop eating
research found ppl w/ one particular allele had 30% less dopamine receptor so more likely to overeat

133
Q

Antioxidant levels in berries:

due to genetics factor

A

scientists found that different berries produced by different species contained different levels of antioxidants

134
Q

Antioxidant levels in berries:

due to environmental factor

A

same species of berries grown in different environments produced very different levels of antioxidants

135
Q

What are twin studies

A

studies used to determine if a phenotype is due to environmental or genetic factors

136
Q

Why identical twins used for studies

A

they are genetically identical so any differences in phenotype must be due to environmental factors
if characteristic is very similar genetics is the larger influence
if characteristic very different environment is the larger influence

137
Q

Practicality of data from twin studies

A

large sample size (pairs of twins) so better for drawing a valid conclusion based on a small sample size - more representative of the population

Biology (5 decks)

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