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Gene Expression Flashcards

(93 cards)

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1
Q

Give examples of mutagenic agents

A

High energy ionising radiation

Chemicals

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2
Q

What type of gene mutations are possible

A 
Deletion
Substitution
Addition
Duplication
Inversion
Translocation
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3
Q

Describe the gene mutation Duplication

A

One or more bases are repeated

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4
Q

Describe the gene mutation inversión

A

Base sequence is spliced and reinserted in reverse order

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5
Q

Describe the gene mutation translocation

A

Base sequence removed from. One chromosome and reinserted into another

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6
Q

Describe the posible outcomes of the gene mutation deletion

A

Frame shift resulting in non functional DNA

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7
Q

Describe the posible outcomes of the gene mutation substitution

A

No effect due to degenerate code or in intron

Formation of stop codon or different Amino acid

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8
Q

Describe the posible outcomes of the gene mutation addition

A

Frame shift resulting in non functional DNA

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9
Q

Describe the posible outcomes of the gene mutation Duplication

A

Frame shift right resulting in non functional DNA if sequence multiplied is not a multiple of 3

Frame shift to the right

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10
Q

Describe the posible outcomes of the gene mutation inversión

A

Change to one Amino acid

Or no chnage due to degenerate code

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11
Q

Describe the posible outcomes of the gene mutation translocation

A

Frame shift resulting in non functional DNA

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12
Q

When do gene mutations occur

A

During DNA replication

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13
Q

Why is differentiation and specialisation important in cells

A

No one cell can provide the optimum conditions for every function

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14
Q

How does a zygote divide

A

By mitosis

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15
Q

How can a zygote produce all the body cells in a human

A

All cells contain the same genes but some are switched on or off to allow for a particular function

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16
Q

What occurs during differentiation

A

Certain genes are switched off or on

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17
Q

Why is specialisation more efficient than not having specialised cells

A

Conserve energy and resources that might go to waste in mechanisms unnecessary for a particular function

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18
Q

Define a stem cell

A

A cell that retains the ability to become specialised

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19
Q

Why are xylem and red blood cells unable to differentiate

A

They are so specialised that they don’t have a nucleus and so don’t have the genes that can be turned off or on for specialisation

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20
Q

What general properties do stem cells possess

A

Able to divide and renew themselves over a long period of time

Unspecialised

Can differentiate into other specialised cells

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21
Q

What are the main sources of stem cells

A

Bone marrow
Embryo
Umbilical cord blood
Placenta

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22
Q

How are stem cells classified

A

By their ability tot differentiate

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23
Q

Define totipotent stem cells and give example sof where they are found

A

Can differentiate into any cell

Early embryo

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24
Q

Define pluripotent stem cells and give example sof where they are found

A

Can differentiate into almost any cell

embryonic and fetal stem cells

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25
Define multipotent stem cells and give example sof where they are found
Can differentiate into a limited number of cells Adult stem cells and Umbilical cord blood
26
Define unipotent stem cells and give example sof where they are found
Can differentiate into one type of cell Adult tissue
27
Define the steps to forming a cardiomyocyte
Totipotent cell in Embryo Pluripotent cell Multipotent cell able to differentiate into any muscle cell Unipotent cell only able to differentiate into cardiomyocyte Cardiomyocyte
28
What do induced pluripotent cells derive from
Unipotent cells
29
How are induced pluripotent cells produced
Genes otherwise not expressed are expressed Induce transcriptional factor synthesis
30
What do ips cells prove
That all cells contain same genes
31
How are ips cells different to embryonic stem cells
Able to self renew and unlimited number of times
32
What is the advantage of ips cells
They can replace embryonic stem cells in research
33
What disease can be cured using heart cells produced from stem cells
Heart damage | Eg from heart attack
34
What disease can be cured using skeletal muscle cells produced from stem cells
Muscular dystrophy
35
What disease can be cured using beta cells produced from stem cells
Type 1 diabetes
36
What disease can be cured using nerve cells produced from stem cells
``` Parkinsons Ms Strokes Alzheimers Paralysis ```
37
What disease can be cured using blood cells produced from stem cells
Leukemia | Inherited blood diseases
38
What disease can be cured using skin cells produced from stem cells
Burns and wounds
39
What disease can be cured using bone cells produced from stem cells
Osteoporosis
40
What disease can be cured using cartilage cells produced from stem cells
Osteoarthritis
41
What disease can be cured using retina cells produced from stem cells
Macular degeneration
42
Pros of using embryonic stem cells
Saves a life of a human already suffering Embryos from ivf would go to waste anyways Laws against cloning provide protection against any exploitation
43
Cons of using embryonic stem cells
Every Embryo has the potential for life People undermine the respect for life Move towards reproductive cloning (research knowledge used in other countries with less restrictions) Embryos are not the only source of stem cells
44
How is gene expression controlled
Regulation of transcription and translation
45
Define transcriptional factor
Protein complex with different subunits that binds to DNA and stimulates transcription
46
Why does each gene have a different transcriptional factor associated with the stimulation of transcription
Each TF has a very specific shape that is only complementary to the promotor region of a specific DNA sequence
47
How do transcriptional factors stimulate transcription
By binding to the promotor region before a gene, attracting Co factors and stimulating transcription
48
Define promotor sequence
Base sequence before gene that TF binds to
49
Describe how inhibitor molecules work
Block DNA binding site preventing action of TF Competitive inhibition
50
How do steroid hormones stimulate transcription
Diffuse through bilayer Bind to TF and activate it TF changes shape so DNA binding site is comp to promotor region TF diffuses through nuclear pore into nucleus Binds to promote region and attracts cofactors Transcription is stimulated
51
Give an example of a steroid hormone.
Oestrogen
52
How can gene expression be reduced
Using small interfering RNA
53
Explain how small interfering RNA works
An enzyme cuts a large double stranded RNA into smaller sections One of the two strands combines with an enzyme which is activated using ATP SiRNA forms hydrogen bonds with the mRNA via comp base pairing Enzyme cuts mRNA into small sections No more translation of MRNA
54
Define epigentics
When environmental factors cause heritable changes in gene expression or function without changing the DNA base sequence
55
What environmental factor might affect the epigenome
Diet Exercise Light exposure Hormon levels
56
How do tags affect gene. Expression
Determine shape of DNA histone complex
57
How does the shape of a DNA histone complex affect transcription
Less condensed or compact = easier binding of transcriptional factors and RNA polymerase More transcription
58
How does acetyl action affect transcription
More acetyl groups = less condensed = more transcription Make histones less positive so repel DNA
59
What do acetyl groups attach to
Histones
60
How does methylation affect transcription
More methylation = more condensed = less transcription Methyl groups prevent binding of transcriptional factors and RNA polymerase. Attract proteins that condense DNA histones complexes by inducing deacetylation
61
What occurs to epigenetic tags in the early stages of Embryo development
Most tags are erased but some remain
62
What two genes play the largest role in cancer development
Tumor suppressor genes and protooncogenes
63
How can epigenetic therapy be used
Inhibit enzymes involved in methylation to reactivate genes to treat cancer Diagnostic tests to determine levels of methylation and acetylation
64
Why must epigenetic therapy be very targeted
Because normal cells will turn cancerous if also treated
65
How do malignant tumors differ from benign ones
They grow larger Cancerous Grow rapidly Have large dark nuclei due to more DNA Unspecialised cells as opposed to specialised ones No adhesion molecules produced so metastasis No dense tissue capsule so fingerlike projections extend into neighbouring tissue More likely to be lifethreatening Systemic affects not localised Must use radio or chemotherapy to remove not surgery More frequent reoccurances
66
Describe how metastasis occurs
Tumor enlarges and grown lymphatic vessels Tumor cells squeeze into blood and lymphatic vessels Tumor cells circulate in blood, adhere to blood vessel walls and squeeze into healthy tissue and metastasis Tumor cells circulate via lymph and metastasis within lymph Nodes
67
What ways can tumors circulate around the body
Blood lymph
68
How does one cell cause a tumor
Single cell mutates to have uncontrolled cell division Cell in lineage mutates again causing differences in appearance and growth
69
Define oncogene
Mutated proto oncogene causing genes that stimulate cell division to be permanently switched one
70
How can an oncogene lead to cancer
Permanently switch on receptor protein for growth factors so cell division occurs despite lack of growth factors May code for growth factor protein which is produced in excess amounts Lead to uncontrolled cell division
71
How do growth factors lead to gene transcription
Growth factor binds to cell receptor Causes transcriptional factor to be activated Transcriptional factor enters nucleus and Activates transcription
72
Define tumor suppressor gene
Gene to slow down cell division, repair mistakes in DNA and initiate apoptoisis
73
How can mutated tumor suppressor genes lead to cancer
Causes gene to be silenced Non functional growth factor protein produced Lead to uncontrolled cell division
74
Define hypermethylation
Over methylation
75
Define hypomethylation
Under methylation
76
How can hypermethylation lead to cancer
Hypermethylation of tumor suppressor gene in promotor region Gene is inactivated (DNA histone complexes more compact)
77
How does hypomethylation lead to cancer
Less methylation of oncogenes occurs DNA histone complexes are less compact so more transcription Uncontrolled cell growth
78
How is oestrogen produced in post. Menopausal women
Not produced in ovaries | More produced in fat cells of breast
79
Why is the risk of breast cancer higher in post menopausal women
More oestrogen produced by fat cells in breast Oestrogen causes activation of transcriptional factors If the transcriptional factor is complementary to a proto oncogene then tumor occurs So higher risk of tumor Tumor occurs = even more oestrogen produced White blood cells drawn to tumor so more oestrogen produced
80
What occurs during a genome project
DNA is mapped out Genes are mapped onto chromosomes
81
Define bio informatics
Science of celle ting and analysing complex biological data
82
How is DNA sequenced
Using whole genome shotgun sequnceing DNA is cut into smaller pieces so more easily sequenced Algorithms align overlapping segments to assemble entire genome
83
How has DNA sequnceing been used for medical advances
Single nucleotide polymorphisms detected and associated with certain diseases Medical screening for snps for early diagnosis and intervention
84
How has DNA sequnceing been used
Genome sequnceing Medical advances Identification of evolutionary links
85
Define proteome
All proteins coded for by genome
86
Define complete proteome
All proteins coded for in particular organism at certain time and conditions
87
Define cellular proteome
All proteins coded for in particular cell at certain time and condition
88
How can DNA technology be used in simple organisms
Genome exploited and use to help cure and provide knowledge about disease Genes from extreme files used to clean environment
89
Why is the determination of a simple organisms genome easy
No histones Only one piece of circular DNA No intorns
90
Why is the determination of a complex organisms genome hard
Intorns | Genes used in the control of other genes expression
91
What is the main dilemma when sequcing the human genome
Who's DNA should be used
92
How do tumor suppressor genes work
They code for a protein that activate apoptoisis or control mitosis
93
What affects do transcriptional factors have
Activate RNA polymerase

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