Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology A Level > Topic 8 > Flashcards

Topic 8 Flashcards

1
Q

Gene mutation

A

change in base sequence of DNA
occurs during DNA replication
includes addition, deletion, substitution, inversion, duplication and translocation of bases

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

Mutagenic agents

A

chemical or radiation that increases mutation rate

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

Addition mutation

A

One extra base is added to the DNA sequence
causes all subsequent codons to be altered (frameshift)

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

Deletion mutation

A

One base is deleted in the DNA sequence.
causes all subsequent codons to be altered (frameshift)

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

Substitution mutation

A

One base in the DNA sequence is changed
no frameshift
only one codon changes
may have no impact due to degenerate genetic code

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

Frameshift

A

A change in all the codons after the point of mutation
each base shifts left or right one position

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

Inversion mutation

A

A section of bases detach from the DNA sequence and re-join inverted
results in different amino acids being coded for in this region

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

Duplication mutation

A

One base is duplicated at least once in the sequence
causes a frameshift to the right

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

Translocation of bases mutation

A

A section of bases on one chromosome detaches and attaches to a different chromosome

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

Non-functioning protein

A

a protein with a different primary and tertiary structure therefore the shape is changed it cannot carry out its function

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

Benign tumour

A

a mass of cells as a result of uncontrolled cell division
can be benign or malignant
non-cancerous tumour
grows large but at a slow rate
produce adhesive and are surrounded by a capsule so they cannot spread

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

Malignant tumour

A

Malignant tumours that form due to uncontrolled cell division
cancer cells breaking off from the tumour
spreading to form secondary tumours in different tissues or organs

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

Oncogene

A

a mutated version of a proto-oncogene
results in constant initiation of DNA replication and mitotic cell division
causes tumour formation

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

Tumour suppressor genes

A

genes that produce proteins to slow down cell division and cause cell death if DNA copying errors are detected

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

Epigenetics

A

the heritable change in gene function without changing the DNA base sequence caused by changes in the environment
can inhibit transcription

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

Hypermethylation

A

an increased number of methyl groups attached to a gene results in the gene being deactivated
results in cancer if happens to a tumour suppressor gene
inhibits transcription

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

Methylation of DNA

A

methyl groups attach to the cytosine base on DNA prevents transcriptional factors from binding
condenses the DNA-histone complex

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

How can oestrogen increase the risk of breast cancer?

A

Oestrogen is a steroid hormone it binds to a receptor site on a transcriptional factor causing a change in shape so it can bind to the DNA to initiate transcription
can result in uncontrolled cell division

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

Stem cell

A

undifferentiated cells that can continually divide and become specialised

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

Totipotent stem cell

A

occur for a limited time in early mammalian embryos
can differentiate into almost any body cell

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

Pluripotent stem cell

A

occur in embryos
can differentiate into almost any body cell
But not placenta cells

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

Multipotent stem cell

A

can differentiate into a limited number of cells
found in mature mammals bone marrow

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

What is a unipotent stem cell?

A

Stem cell that can differentiate into one type of cell

found in mature mammals

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

What is an induced pluripotent stem cell?

A

Stem cell produced from adult somatic cells
using protein transcriptional factors
Turns on all genes which were switched off to make it specialised therefore regaining state of pluripotency
overcomes ethical issues of using embryonic stem cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is a transcriptional factor?
Proteins that can bind to different base sequences on DNA to initiate transcription of genes
26
What is RNA interference (RNAi)?
Inhibition of the translation of mRNA by small interfering RNA (siRNA) siRNA destroys mRNA molecules to prevent translation An enzyme breaks a long double stranded rna into siRNA One of the two strands of siRNA joins with an enzyme siRNA inside navigates the enzyme to a mRNA and binds to complimentary bases and now the enzyme breaks down mRNA into smaller fragments and these cannot be translated Therefore gene not expressed
27
What is a vector?
A DNA molecule used as a carrier of isolated DNA fragment e.g. plasmids/viruses
28
What is acetylation of histones?
Process where decreased acetylation inhibits transcription by making histones more positive and attracting the negative phosphate group on DNA Decreased acetylation forms heterochromatin Increased acetylation forms chromatin
29
What is recombinant DNA technology?
Combining different organisms' DNA to manipulate and alter genes for industrial processes and medical treatment
30
What are sequencing projects?
Reading the full genome of organisms to screen DNA for potential medical problems
31
How can you create a DNA fragment?
By using a gene machine, reverse transcription with reverse transcriptase, or restriction endonucleases
32
What is reverse transcriptase?
An enzyme that makes cDNA single-stranded copies of DNA from mRNA
33
What is a restriction endonuclease?
Enzymes that cut up DNA to create fragments by cutting at specific recognition/restriction sequences
34
What is in vivo cloning?
Creating DNA fragments using bacteria and restriction endonuclease enzymes
35
What is in vitro cloning?
Using PCR to create a large number of copies of a DNA fragment
36
What are the uses of PCR?
Widely used in gene technology for forensics, genotyping, cloning, paternity tests, and microarrays
37
What is gel electrophoresis?
Separation of DNA samples using an electrical voltage to separate different lengths of DNA VNTRs
38
Why does DNA move in gel electrophoresis?
DNA is negatively charged and moves towards the positive end of the gel; shorter DNA pieces move faster and further
39
What is genetic screening?
Testing DNA to identify the presence of alleles that can cause/increase the risk of developing a disease
40
What is genetic counselling?
Type of social work giving people advice following the screening of disease-causing alleles
41
What is cDNA?
Complementary, single-stranded DNA strands created by reverse transcriptase
42
What are the advantages of using the gene machine?
Very quick, accurate, and can create intron-free DNA
43
What are the advantages of using reverse transcription?
Create intron-free cDNA
44
What are the advantages of using restriction endonucleases?
Create sticky ends on DNA to enable DNA fragments to join with complementary base pairs
45
What are oligonucleotides?
Short DNA molecules used in gene machines to create DNA fragments
46
What are sticky ends?
Exposed staggered ends of bases created by restriction endonuclease enzymes
47
What is a palindromic sequence?
Sequences of bases that read the same forwards as they do backwards
48
What is a blunt end?
When a restriction endonuclease cuts the DNA double-strand in the same position without overhang of bases
49
What are the two methods to amplify DNA?
In vivo and in vitro (PCR)
50
What is a promoter region?
A sequence of DNA that is the binding site for RNA polymerase to enable transcription to occur
51
What is a terminator region?
Added at the end of the gene to cause RNA polymerase to detach and stop transcription
52
What is a plasmid?
A circular DNA molecule used as a vector in recombinant DNA technology
53
What is a recombinant plasmid?
A plasmid that has had foreign DNA inserted into it for cloning purposes
54
What happens when a restriction endonuclease cuts the DNA double-strand in the same position?
There is no overhang of bases ## Footnote Example sentence: The restriction endonuclease EcoRI cuts the DNA double-strand in the same position, resulting in no overhang of bases.
55
What is the Promoter region?
A sequence of DNA that is the binding site for RNA polymerase to enable transcription to occur ## Footnote Additional information: The promoter region plays a crucial role in initiating the transcription process.
56
What is the Terminator region?
A region added at the end of the gene that causes RNA polymerase to detach and stop transcription to ensure one gene is copied into mRNA at a time
57
What is a Plasmid?
A small loop of bacterial DNA that contains only a few genes ## Footnote Additional information: Plasmids are commonly used in genetic engineering for gene cloning purposes.
58
What is a Recombinant plasmid?
A small loop of bacterial DNA with the DNA from another organism inserted into it
59
What is Transformation?
The process of getting a plasmid to re-enter a bacterium, involving calcium ions and temperature shocking
60
How can transformed cells be identified?
Using marker genes such as antibiotic resistance genes, genes coding for fluorescent proteins, or enzymes
61
What is a DNA probe?
Short, single-stranded pieces of DNA labelled radioactively or fluorescently so that they can be identified
62
What is DNA hybridisation?
DNA is heated to separate the double helix into single strands, mixed with complementary sequences of single-stranded DNA, and then cooled for complementary strands to anneal
63
What are VNTRs?
Variable number tandem repeats sequences of bases in introns that are unique to each person
64
How can DNA samples be collected?
From blood, body cells, or hair follicles
65
How is DNA extracted from cells so that it can be examined?
Through cell fractionation and ultracentrifugation
66
How is DNA digested in genetic fingerprinting?
Restriction endonucleases are added to cut the DNA into smaller fragments, followed by the addition of enzymes that cut close to the target VNTRs
67
Why can the genome not be easily translated into the proteome in complex organisms?
Due to the presence of non-coding DNA and regulatory genes
68
What is the role of DNA ligase in making recombinant DNA?
DNA ligase is used to stick the DNA fragment to create recombinant DNA

Biology A Level (9 decks)

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