Modern Genetics Flashcards

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1
Q

What is a genome?

A

All of an organism’s DNA

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2
Q

What are transcription factors?

A

Proteins which bind to DNA.

They bind to specific base sequences

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3
Q

What are promoter sequences?

A

Found upstream of the gene they act on

Enable the binding of RNA polymerase and therefore promote transcription

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4
Q

What are enhancer sequences?

A

Regulate DNA activity by changing chromatin structure (make it more or less open to RNA polymerase)
Open = active gene expression | Closed = gene inactivity - transcription factors either stimulate or prevent transcription of the gene

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5
Q

What is DNA methylation?

A

Addition of a methyl group to CpG on DNA

Prevents transcription and affects histone structure to make more/less DNA accessible to RNA polymerase

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6
Q

What is RNA splicing?

A

Post-transcriptional modification of mRNA

RNA splicing explains how eukaryotes produce more proteins than they have genes

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7
Q

Describe the process of RNA splicing.

A

Gene is transcribed which results in pre-mRNA
All introns and some exons are removed
Remaining genes are joined by spliceosomes

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8
Q

What can gene expression be changed by?

A

Epigenetic modification

; non-coding RNA, histone modification and DNA methylation

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9
Q

What is the importance of epigenetic modification?

A

To ensure cell differentiation

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10
Q

Define epigenetics.

A

Heritable and reversible modifications to the DNA that do not involve changes to the nucleotide sequence

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11
Q

Describe the first part of histone modification.

A

Acetylation - addition of an acetyl group which activates chromatin and allows transcription

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12
Q

Describe the second part of histone modification.

A

Methylation - addition of a methyl group, causes activation/inactivation of chromatin based on position of the lysine

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13
Q

How does RNA splicing result in different products from a single gene?

A

The same exons can be joined a variety of ways to produce several different versions of mature functional RNA.

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14
Q

What are stem cells?

A

Undifferentiated cells which have the ability to differentiate into many different cell types

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15
Q

What are the different types of stem cells?

A

Multipotent
Pluripotent
Totipotent

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16
Q

What are multipotent cells?

A

Cells which can give rise to multiple types of cells

17
Q

What are pluripotent cells?

A

Cells which can give rise to many types of specialised cells but NOT placental cells

18
Q

What are totipotent cells?

A

Cells which can give rise to all types of specialised cells INCLUDING placental cells

19
Q

Where are totipotent cells found?

A

For a limited time in a mammalian zygote

20
Q

Where are pluripotent, multi potent and uni potent cells found?

A

Mature (somatic) mammals

21
Q

What are pluripotent cells used for?

A

Treating human disorders by replacing damaged tissue

22
Q

What are some examples of stem cells?

A

Embryonic stem cells, adult stem cells, fused cells

23
Q

What are the benefits for stem cells?

A

Save many lives

Improve quality of life

24
Q

What are the ethical issues with stem cells?

A

Embryos are killed in the process of stem cell extraction
Risk of infection when cells are transplanted
They could become cancerous

25
Q

What are induced pluripotent stem cells?

A

Adult stem cells that have been reprogrammed to become pluripotent again

26
Q

Describe the formation of induced pluripotent stem cells

A

Fibroblasts taken from skin samples
Viruses introduce 4 genes for transcription factors
Cells behave like embryonic stem cells

27
Q

How can recombinant DNA be produced?

A

Isolation of gene
Complementary sticky ends
Recombinant DNA
Reincorporate plasmid

28
Q

Give examples of vectors.

A

Gene guns
Viruses
Liposome wrapping
Micro injection

29
Q

How do effective vectors behave?

A

Target right cells
Incorporate gene into host genome
Have no adverse side effects

30
Q

What do marker genes do?

A

Used to show where a foreign gene has been inserted

31
Q

How are marker genes used to identify recombinant cells?

A

Bacteria are transferred from a ‘master plate’ onto plates with antibiotics using sterile block
If they don’t grow, gene was inserted successfully and colonies are still on the ‘master plate’

32
Q

What are marker genes?

A

Fluorescence and antibiotic resistance combined with replica plating

33
Q

What are transgenic plants?

A

Plants which contain genetic material from an unrelated organism

34
Q

What are the benefits of genetic modification?

A

Herbicide resistance
Increased yield
Increased nutrient value

35
Q

Gives examples of GM plants and their benefits.

A

Soya beans

  • linoleic acid (polyunsaturated) is replaced by oleic acid (monounsaturated) which oxidises less easily so doesn’t go off as fast
  • healthier
36
Q

How can PCR samples be used to predict amino acid sequence?

A

Using gene sequencing

This determines possible links to genetically determined conditions