Brainscape's Knowledge GenomeTM

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


See full index

a level biology > UNIT 8 - Gene expression, Mutations and Gene technology > Flashcards

UNIT 8 - Gene expression, Mutations and Gene technology Flashcards

1
Q

what is a mutation

A

a change in the DNA base sequence

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

what is a substitution mutation

A

are when a base on the code is copied incorrectly and is substituted for another.

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

what is a deletion mutation

A

when a base is removed from the sequence causing a frame shift in the sequence to the left

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

what is an addition/insertion mutation

A

extra base is inserted in the sequence that has a similar effect to a base deletion that causes a frame shift to the right

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

what is a duplication mutation

A

One or more base is repeated, and it produces a frame shift to the right

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

what is an inversion mutation

A

a group of bases become separated from the DNA rotate and go back in causing it to be reversed and therefore effecting the amino acid that is sequenced for

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

what is a translocation mutation

A

a group of bases is moved from one location to another within the chromosome to a different chromosome

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

what is a mutagenic agent and an example

A

Mutagens are outside factors that can increase the mutation rate
e.g. gamma rays, alpha and beta particles

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

how do mutagenic agent increase the mutation rate

A
  1. They can act as a base which can be substituted for a base during DNA replication
  2. alter base sequence by deleting alternate bases
  3. changing the DNA structure like UV radiation causing adjacent bases that we dont want
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is an hereditary mutation

A

If a gamete containing a mutation is fertilised it will be present in the new foetus

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

what is a benefit of mutations

A

increases genetic diversity necessary for survival

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

what are stem cells

A

unspecialised cells that can make a new copy of itself or become specialised

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

what genes are permanently expressed

A

enzymes involved in respiration , transcription and translation

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

what is cell speciation

A

The process by which a cell develops into a specialised cell suited to its role by genes being expressed and it is irreversible

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

what does totipotency mean and where are they found

A

has the ability to give rise to all types of cells

normally fertilised egg

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

what is pluripotency and where are they found

A

Can still specialise to become anybody cells but lose the ability to make up the placenta

found in a mature embryo from the IVF process

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

what is multipotency and where are they found

A

Found in adults and can differentiate into a limited number of specialised cells

Bone marrow can become any type of blood cell

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

what is unipotency and where is it found

A

Can only differentiate into a single type of cell

Made in adult tissue

19
Q

what are induced pluripotent cells and why are they made

A

made to express a series of transcriptional factors normally associated with pluripotent stem cells and these cause the adult body cell to express the genes and divide indefinately and become a stem cell

20
Q

what are the uses of pluripotent stem cells

A

can be used to regrow tissues that have been damaged like burns and ones affected by parkinsons

21
Q

what is a transcription factor

A

something that controls the transcription of genes

22
Q

where are transcription factors found

A

they are proteins in the cytoplasm

23
Q

how do transcription factors work

A

they move into the nucleus and attach themselces to the DNA by the promotor region of a specific base sequence near their target zone

24
Q

what are activator

A

increase the rate of transcription as they help RNA polymerase bind to the promoter region

25
Q

what are repressors

A

inhibit or slow the rate of transcription and they bind to the promoter region and prevent RNA polymerase from binding

26
Q

outline how Oestrogen has an effect on gene transcription

A
  1. oestrogen is lipid soluble and can diffuse through phospholipid membrane and diffuse into the ctyloplasm
  2. oestrogen binds to an oestrogen receptor on a transcription factor forming a complex and changing the shape of the transcription factor
  3. transcription factor diffuses through the nuclear pore and gets to the DNA in the nucleus where it binds to a promotor region on a specific base sequence and this stimulates transcription of the gene
27
Q

what is epigenetics and how is it influenced

A

inheritable changes in gene function without changes to the base sequence of DNA

-the environment can influence gene expression without changing the base sequence e.g. diet, stress

28
Q

what is the epigenome

A

Epigenome is all the chemical modifications to all histone proteins and DNA in an organism

29
Q

how do epigenetic markers work

A
  1. attach or remove chemical groups and this alters how easilt transcription enzymes and other proteins interact with the DNA
30
Q

what happens to epigenetic markers between generations

A

Most epigenetic markers are removed between generations after fertilisation however some are passed on to the offspring

31
Q

what is epigenetic silencing

A

when the histone DNA complex is too condensed to be transcribed

32
Q

what happens when the association of histones with DNA is strong

A

the complex is more condensed and accessible by transcription factors which cannot initiate production of mRNA so the gene is switched off.

33
Q

what happens when the association of histones with DNA is weak

A

the complex is less condensed so this means the DNA is accessible by transcription factors to make mRNA so the gene can be expressed/ switched on

34
Q

outline what methylation is and what it does

A

methylation is the addition of a methyl group to a cytosine base of DNA and this changed the structure of DNA making it hard for transcriptional machinery to interact with the gene and therefore the gene isnt expressed and this can cause genes to be switched off

35
Q

what is epigentic silencing

A

when a histone DNA complex is too condensed to be transcribed

36
Q

outline what acetylation is and what it does

A

acetylatino is a process of transferring an acetyl group to a molecule from acetyle CoA and when histones are acetylation the chromatin is less condensed so the transcriptional machinery can access DNA allowing transcription

37
Q

what are the two genes that affect cancer

A

tumour supressor gene

protooncogene

38
Q

what are 3 things that help us treat disease with epigenetic therapy

A

use drugs to inhibit enzymes involved in acetylation of histones or DNA methylation

epigentics diagnostic testing helping us detect disease early

use drugs to inhibit enzymes and reactivate genes that have been silenced

39
Q

how does RNA interference work

A
  1. enzyme cuts large double stranded molecules into smaller sections called interfering RNA by hydrolysis (siRNA)
  2. one of the two strands combines with an enzyme using energy from ATP to separate the two strands
  3. the siRNA molecule guides the enzyme to mRNA by pairing up its complimentary bases
  4. the enzyme associated with the siRNA cuts the mRNA into smaller sections and this means it is no longer capable of being translated into a polypeptide chain and the gene will not be expressed
  5. the fragments are then broken down into RNA nucleotides by enzymes
40
Q

what does miRNA do in RNA interference

A
  1. enzyme cuts large strand of double stranded RNA into smaller pieces
  2. one of the two strand combines with an enzyme to form a complex
  3. the miRNA guides the enzyme to the mRNA where it binds by complementary base pairing and prevents translation
41
Q

where does RNA interference occur

A

cytoplasm

42
Q

how can siRNA be used it treat cancer

A

siRNA can be used to target oncognes that have been expressed or unregulated reducing the number of proteins produced that can lead to cancer or maintain cancerous growth

43
Q

how can siRNA be used to treat viruses

A

signals for the degradation of viral genetic material stopping the virus from using the hosts cellular machinery to replicate itself

a level biology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions