Unit 1 Flashcards

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1
Q

What are eukaryotes?

A

Cells which have a membrane bound nucleus which stores genetic material.

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2
Q

What are the cells of eukaryotes?

A

Animals, plants, and fungi.

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3
Q

What are prokaryotes? Give examples of what they do/don’t have.

A

Cells which do not have membrane bound organelles.

They do not have mitochondria or the nucleus.

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4
Q

What cells are prokaryotes?

A

Bacteria.

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5
Q

Structures which both the eukaryotes and prokaryotes have?

A

Cell membrane, cytoplasm, cell wall.

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6
Q

What are codons?

A

The series of base triplets which make up RNA.

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7
Q

What are nucleotides consisted of?

A

A base, a deoxyribose sugar, and a phosphate group.

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8
Q

Give full names of A, T, C, and G.

A

Adenine, thymine, cytosine, and guanine.

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9
Q

What holds the nucleotides together?

A

Strong chemical bonds.

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10
Q

State the numbers on the dna strand, starting with the top left, then top right, bottom left, then bottom right.

A

5’, 3’, 3’, 5’.

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11
Q

What is meant by anti-parallel?

A

When two strands are side by side, but are going in opposite directions.

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12
Q

What is PCR? What does it stand for?

A

Polymerase chain reaction.

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13
Q

What is PCR? Give def.

A

PCR is the method to make multiple copies of a target DNA sequence.

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14
Q

What is required to carry out PCR?

A

Buffer, template DNA, primers, nucleotides, DNA polymerase.

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15
Q

What’s the use of PCR? What can/does it do?

A

Can be used to diagnose early malignant diseases, like leukaemia or aids.

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16
Q

Give the steps of PCR.

A
  • DNA molecule is denatured, which will break hydrogen bonds.
  • DNA is left to cool, primers bind themselves to target strands.
  • DNA is then reheated, so primers can extend.
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17
Q

What is gene expression? Give def.

A

Gene expression is when specific genes are activated to produce a required protein.

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18
Q

What processes make up gene expression?

A

Transcription and translation of DNA sequences.

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19
Q

What is transcription?

A

The first step in protein synthesis.

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20
Q

Where does transcription start and end?

A

Starts at the promoter, ends at the terminator.

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21
Q

What are introns?

A

Non-coding regions.

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22
Q

What are exons?

A

Coding regions.

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23
Q

What types of RNA are involved with gene expression?

A

mRNA, tRNA, rRNA

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24
Q

What enzyme is required during transcription?

A

RNA polymerase.

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25
Q

Where does transcription occur?

A

In the nucleus.

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26
Q

What is cellular differentiation? Give def.

A

Differentiation is the process in which unspecialised cells become specialised to perform a specific function.

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27
Q

What happens during differentiation? Give steps.

A
  • Many essential genes remain switched on.
  • Some genes for specific characteristics are switched on.
  • Unnecessary genes are switched off.
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28
Q

Give examples of differentiation.

A

Sperm: have tails to allow them to swim.

Red blood cells: have increased surface area to be able to carry more oxygen.

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29
Q

What is the cost of differentiation? What does this mean?

A

Cells which are specialised often cannot make copies of themselves. This results the storage of stem cells so the body can replenish these cells whenever needed.

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30
Q

What are meristems?

A

Meristems are regions of unspecialised cells in plants, which are capable of cell division (growth). These unspecialised cells also have the ability to become any specialised cell.

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31
Q

what process is responsible for growth in plant cells?

A

Mitosis, elongation, division.

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32
Q

Where are meristems?

A

At the tip of the roots and shoots.

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33
Q

What are stem cells?

A

Cells which can constantly undergo cell division, and can become any cell.

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34
Q

What are the two types of stem cells?

A
  • Embryonic stem cells (found in embryos)

- Adult (tissue) stem cells (found in children and adults)

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35
Q

What do embryonic stem cells do?

A

They can differentiate into all cell types and make up an organism, important for growth.

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36
Q

What do adult stem cells do?

A

To replenish differentiated cells that need to be replaced and give rise to a more limited range of cell types (multipotent).

37
Q

Describe potential therapeutic uses for stem cells.

A

Used to repair damaged or diseased organs, helps transplants and skin grafts for burns.

Also been used to find out how disease happens, and how to treat it.

38
Q

What’s a genome?

A

A genome of an organism is its’ hereditary information encoded in its’ DNA.

39
Q

What is the genome made of?

A

The genome is made out of genes that code for proteins, and other non-coding DNA sequences.

40
Q

Most of the genome is consisted of non-coding regions. How true is this?

A

It is true for eukaryotic cells.

41
Q

Functions of non-coding regions?

A
  • Regulating transcription
  • Transcription of RNA
  • No known function.
42
Q

What are mutations? What happens?

A

Mutations are changes is the DNA. This results in either no proteins being made, or a different protein being made.

43
Q

What are single gene/point mutations?

A

The alternation of a DNA sequence.

44
Q

What are chromosome structure mutations?

A

When mutations affect the structure of one or two chromosomes.

45
Q

What are the 3 types of single gene/point mutation?

A
  • Substitution.
  • Insertion.
  • Deletion.
46
Q

What happens during substitution?

A

when a nucleotide is replaced by another.

47
Q

What happens during insertion?

A

when one or more nucleotides are inserted into a DNA sequence.

48
Q

What happens in deletion?

A

When one or more nucleotides are deleted from a DNA sequence.

49
Q

What is the result of substitution?

A

Affects one codon. Affects them by either; missense, nonsense, or splice-mutations.

50
Q

What is the result of insertion and deletion?

A

Frame-shift mutations.

51
Q

What happens during missense in substition?

A

Changes the codon, causes a different amino acid to be produced. Results in the amino acid shape changing, but may not have any major effects.

52
Q

What happens during nonsense in substitution?

A

Causes stop codon to be produced, results in shorter protein being made. Short protein means it cannot function, or its function is affected.

53
Q

What happens during splice-site in substitution?

A

Affects splice-sites (boundaries between exons and introns), can prevents splicing at the site. Results in very different protein to be made.

54
Q

What is frame-shift mutation? Which single gene/point mutation does this apply to?

A

Occurs in deletion and insertion. This result in the codon being shifted by one codon, which causes it to be read differently. This results in a completely different protein being made and is usually non-functional.

55
Q

What is vertical gene transfer? Give def.

A

When genes are transferred from parent to offspring.

56
Q

What is horizontal gene transfer? Give def.

A

When genes are transferred between each other in the same generation.

57
Q

In what cells does vertical gene transfer occur?

A

Eukaryotic cells.

58
Q

In what cells does horizontal gene transfer occur?

A

Prokaryotic cells.

59
Q

What are the 4 types of chromosome structure mutations?

A
  • deletion
  • translocation
  • inversion
  • duplication
60
Q

What happens during deletion in chromosome structure mutation?

A

Where a section of a chromosome is removed.

61
Q

What happens during translocation in chromosome structure mutation?

A

Where a section of a chromosome is added to another chromosome, that is not its homologous partner.

62
Q

What happens during inversion in chromosome structure mutation?

A

Where a section of chromosome is reversed.

63
Q

What happens during duplication in chromosome structure mutation?

A

When a section of chromosome is added from its homologous partner.

64
Q

When chromosome mutations happen, are they deadly?

A

Yes, they are often lethal as they change the chromosome structure.

65
Q

What are the types of selection?

A
  • stabilising
  • directional
  • disruptive
66
Q

What happens in stabilising selection? What does this result in?

A

When an intermediate (average) phenotype is favoured whilst an extreme phenotype is against.

This results in a reduction in genetic diversity.

67
Q

What happens in directional selection? What does this result in?

A

When one extreme phenotype is favoured.

Results in a progressive shift in population’s mean.

68
Q

What happens in disruptive selection? What does this result in?

A

When two or more extreme phenotypes are favoured for, at the expense of average phenotypes.

Results splitting group into two distinct groups.

69
Q

What is natural selection?

A

A random increase in the frequency of DNA sequences, which increase survival chances and are not random. Also known as survival of the fittest.

70
Q

What’s a species? Give def.

A

A species is a group of organisms which can interbreed to create fertile offspring.

71
Q

What are the 3 main stages which lead to the formation of a new species?

A
  • Isolation by barrier (geographical)
  • Mutation
  • Natural selection
72
Q

What is genomic sequencing?

A

Genomic sequencing is the process of figuring out DNA nucleotides or bases for an entire genome.

73
Q

What is genomics?

A

The study of genomes.

74
Q

What is bioinformatics?

A

The use of computer programs which can identify base sequences and (analyse them) look for other sequences familiar to genes.

75
Q

When is genomic sequencing used?

A
  • comparison of genomes from different species in research
  • personal genomics and/or health
  • Phylogenetics
76
Q

Sequencing can improve research, such as?

A
  • sequence of disease: causing organism can rule out accurate disease.
  • sequence of pest species can help identify risks and find a different method of control rather than pesticides.
  • sequences of model species can be used for medical research rather than using mammals.
77
Q

What is phylogenetics? Give def.

A

Phylogenetics is the process in which genetic sequencing can be used to work out the evolutionary relationships of different species/groups of organisms.

78
Q

which gene transfer allows a faster evolution?

A

Horizontal.

79
Q

what do molecular clocks measure?

A

it measures the mutations in a dna sequence over time.

Or; it measures the changes in a genome over time.

80
Q

What is comparative genomics?

A

Comparative genomics is the comparison of genomic features in different/same organisms.

81
Q

What is allopatric speciation caused by?

A

a geographical barrier.

82
Q

What is sympatric speciation caused by?

A

Ecological or behavioural barrier.

83
Q

what can phylogenetics be used to work out?

A

lineage and sequence divergence

84
Q

what is lineage?

A

the exact sequence which can be traced back through ancestor populations.

85
Q

what is sequence divergence?

A

how and when lineages diverged from common ancestry.

86
Q

What does mutant mean?

A

When the change in genotype affects the phenotype.

87
Q

Process in which many proteins can be made from a single gene?

A
  • Alternative splicing

- Post translational modification

88
Q

Difference between RNA splicing and Alternative splicing?

A

RNA splicing - when only exons are in the final mature transcript.

Alternative splicing - when exons and introns are included in the final mature transcript.