Brainscape's Knowledge GenomeTM

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


See full index

BIO > Gene expression > Flashcards

Gene expression Flashcards

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

What is a genetic mutation?

A
  • Alteration in a base in a base sequence
  • Occurs during DNA replication during interphase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Explain the effect of genetic mutation

A
  • Change in the base sequence = change in the amino acid sequence = modified 3’
  • Bonds form in different places = different shape = non-functioning protein
  • Can also result in cancer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Examples of mutagenic agents

A
  • Radiation: Alpha/Beta/Gamma/X-ray can damage and disrupt DNA structure
  • Carcinogen: Tobacco smoke/ Mustard gas/ Peroxide chemicals that can interfere with DNA structure + transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How many types of genetic mutations?

A

6 types:
1) Addition
2) Deletion
3) Substitution
4) Inversion
5) Duplication
6) Translocation

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

Describe addition mutation

A
  • Extra base added
  • Causes frameshift to right
  • Altered codons = code for multiple different amino acids = different amino acid sequence = non-functional protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe deletion mutation

A
  • Deletion of a base
  • Causes frameshift to left
  • Altered codons = code for different amino acid sequence = non-functional protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe substitution mutation

A
  • 1 base swapped for another
  • Number of bases stays same = no frameshift = only 1 codon changes
  • Genetic code = degenerate = 1 codon could still code for same amino = no impact to protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe inversion mutation

A
  • Section of bases detach from DNA sequence but when re-attaching = inverted = code read back to front
  • Can cause different amino to be coded for that region
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe translocation

A
  • Section of bases detaches from 1 chromosome and attaches to another chromosome
  • Causes significant difference on gene expression = phenotype change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a stem cell?

A

Undifferentiated cells that can continually divide and become specialized

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

Describe a totipotent cells

A
  • Divide and produce any type of body cell
  • During development these cells only translate only 1 part of their DNA = specialization
  • Occur for a limited time in early embryo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe pluripotent cells

A
  • Divide and produce ALMOST any body cell
  • Found in embryo a few days after fertilization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Uses of pluripotent cells

A
  • Used in research to potentially use in treating human disorders
  • Could be used to regrow damaged cells e.g. burnt skin, beta cells for diabetes, neurons in Parkinson’s
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Issues with pluripotent cells

A
  • Treatment with stem cells can continue dividing causing uncontrollable growth = create tumor
  • Ethical: If it is ok to make a therapeutic clone of yourself + make embryo for stem cells then to destroy it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe multipotent cells

A
  • Divide and produce into limited number of cells e.g. all blood cells
  • Found in mature mammal cells e.g. bone marrow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe unipotent cells

A
  • Divide and produce only 1 type of cell
  • Found in mature mammal cells e.g. skin cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Sources of stem cells

A

1) Embryos: For a limited time post fertilization = pluripotent
2) Umbilical cord blood: Like adult stem cells = multipotent
3) Placenta: Limited types of specialized cells = multipotent
4) Adult stem cells: Can repair within certain tissue + organs = multipotent/unipotent

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

Explain induced pluripotent stem cells

A
  • Altering adult unipotent stem cells to make them in the state of pluripotency
  • This is done using transcriptional factors
  • Similar to embryonic cells without the ethical issue of destroying embryos
19
Q

What is epigenetics?

A
  • Heritable change in gene function without changing DNA base sequence
  • Changes caused by environment
20
Q

Factors that effect epigenetics

A
  • Diet/Stress/Toxins
  • Can add chemical tags to DNA which controls gene expression
21
Q

What is the epigenome?

A

Single layer of chemical tags on DNA which impacts the shape of the DNA-histone complex

22
Q

How does the epigenome effect gene expression?

A
  • If DNA tightly wound = won’t be expressed
  • If DNA unwound = will be expressed
  • Tightly wound = transcription factors cannot bind = changes from the environment to epigenome = inhibits transcription
23
Q

Explain methylation of DNA

A
  • Increase = tightening = inhibits transcription
  • Methyl group attaches to cytosine
  • Prevents transcriptional factors from binding
24
Q

Explain acetylation of DNA

A
  • Decrease = tightening = inhibits transcription
  • Acetyl groups attach/detach from histone proteins
  • Makes DNA + histone more strongly associated = harder for transcriptional factors to bind
25
Q

Explain how mutations effects tumor suppressor genes

A
  • Mutation = don’t produce proteins to slow down cell division = division continues
  • Mutated cells not identified and destroyed
  • Causes BRCA1/BRCA2 linked to breast cancer
26
Q

Explain how abnormal methylation effects tumor suppressor genes

A
  • Hypermethylation: Increased number of methyl groups = tightens = inhibits transcription = gene inactivated
  • Hypomethylation: Reduces number of methyl groups = causes oncogenes that control mitosis = permanently turned on = continuous cell division
27
Q

Function of transcriptional factors

A
  • Stimulate/inhibit transcription of target genes
  • Turn on/off genes so only certain proteins are produced in particular cells
  • This causes cells to become specialized
28
Q

Explain how transcriptional factors affect transcription in protein synthesis

A
  • Once activated transcriptional factor proteins move into the nucleus
  • Bind to different base sequences that they are complementary to
  • Binding = enables RNA polymerase binding = transcription starts = mRNA made
29
Q

Explain how estrogen initiates transcription

A
  • It is a steroid hormone that binds to the receptor site on the transcriptional factor
  • This causes a change in shape/ 3’ = TF now complementary and able to bind to DNA = initiates transcription
30
Q

Describe RNA interference

A
  • Translation of mRNA is inhibited
  • Transcribed mRNA is destroyed before it can be translated into a polypeptide by siRNA
31
Q

Describe how siRNA works

A

-Enzyme cuts mRNA into siRNA
- 1 strand of siRNA combines with an enzyme
- The siRNA/enzyme complex binds to complementary bases on another mRNA
- Binding = cutting up of mRNA = cannot be translated

32
Q

What is cancer?

A
  • Mutation occurs in genes that are involved in mitosis
  • Mutation = non-functioning protein = unregulated mitosis = uncontrollable cell division = tumor
33
Q

Describe benign tumors

A
  • Non-cancerous
  • Can grow large but at a slow rate
  • Produce adhesive molecules that stick them together to a particular tissue
  • Surrounded by capsule = compact = easier to remove by surgery
  • Impact is localized = not life-threatening depending on location
34
Q

Describe malignant tumors

A
  • Cancerous
  • Grow large and rapidly as the cell nucleus grows and becomes unspecialized again
    -Don’t produce adhesive molecules = metastasis = tumor breaks off and spreads
  • No surrounding capsule = grows into surrounding tissue = develops it’s own blood supply
  • Threat of spread = life-threatening so treatment required is extensive and can reoccur
35
Q

What causes tumor development?

A

1) Mutated oncogenes
2) Mutated tumor suppressor genes
3) Abnormal methylation
4) Increased estrogen concentration

36
Q

Explain how a mutation in oncogenes causes tumor development

A
  • Proto-oncogene: Code for protein that initiates DNA replication/mitosis
  • Mutated proto-oncogene = oncogene = permanently activated = uncontrollable cell division = tumor
37
Q

Explain how a mutation in tumor suppressor genes causes tumor development

A
  • Tumor suppressor genes: Code for proteins that slow down cell division + cell death if there is copying errors
  • Mutated gene = protein not produced = uncontrollable cell division + mutated cells not identified and destroyed = tumor
38
Q

Explain how abnormal methylation causes tumor development

A
  • Hypermethylation of tumor suppressor gene: Increases methyl groups = tightening = inactivates gene = turned off = protein not produced = cell division continues = tumor
  • Hypomethylation of oncogene: Decrease methyl group = loosening = gene permanently switched on = cell division continues = tumor
39
Q

Explain how increased estrogen concentrations cause tumor development

A
  • Estrogen is produced in fat cells in breast tissue post menopause
  • Estrogen can interfere with the genes in the cell cycle = tumor
  • Tumor can cause production of even more estrogen + attract WBC = increased tumor size
40
Q

What is a genome?

A

Entire genetic material of an organism in the nucleus of a cell

41
Q

What is genetic sequencing?

A

Working out the DNA base sequence for all the DNA in a cell

42
Q

Describe genome sequencing

A
  • HGP took 13 years to complete in 2003
  • Methods for sequencing are continuously being improved and updated
  • Now an automated process
43
Q

Describe genome sequencing for simpler organisms

A
  • DNA doesn’t contain introns = genome can be used to sequence proteins = derive proteome
  • Useful to identify potential antigens for vaccines
44
Q

Describe genome sequencing for complex organisms

A
  • DNA has introns and regulatory genes = genome cannot easily be translated into proteome

BIO (20 decks)

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