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Genetics Flashcards

1
Q

Define mutations

A

Change in structure of DNA in which new phenotypes are formed. This can make them better or less adapted to survival

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2
Q

What is the base pair rule?

A

Adenine to Thymine and Cytosine to Guanine

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3
Q

What are chromosomes made up of?

A

60% protein and 40% DNA

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4
Q

Where is RNA made?

A

Nucleus

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5
Q

What is the chemical nature of enzymes?

A

Protein

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6
Q

What is the name of the backbone in double stranded DNA?

A

Phosphate-sugar backbone

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7
Q

What type of sugar is present in DNA?

A

Deoxyribose

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8
Q

How many types of DNA are there?

A

One

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9
Q

Give an example of a chromosome mutation

A

Down’s syndrome

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10
Q

What are the names of the different types of RNA?

A

rRNA - ribosmal
mRNA - messenger
tRNA - transfer

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11
Q

How are mistakes made in genes?

A

By a mutation in replication

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12
Q

Give some examples of a gene mutation

A

*Albinism
* Cystic fibrosis
* Sickle cell anaemia

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13
Q

What is your reasons for blending the mixture for three seconds in your experiment to isolate DNA from a plant tissue?

A
  • Breaks down cell walls
    *Max. three seconds so DNA doesn’t break down
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14
Q

What two nucleotides are pyrimidines?

A

Thymine and cytosine

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15
Q

Give a characteristic of mutant alleles in a population

A
  • Random occurence
  • Low frequency
  • Disadvantageous
  • Advantageous
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16
Q

Give some examples of disorders that arise from mutations (+diagram)

A
  • Sickle cell anaemia
  • Cystic fibrosis
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17
Q

Define species

A

Group of organisms that can interbreed and produce fertile offspring

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18
Q

Draw a diagram to show DNA replication

A

See notes

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19
Q

What is your reason for using protease in your experiment to isolate DNA from a plant tissue?

A

Breaks down histone proteins that surround DNA

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20
Q

Define start codon

A

3 bases that code for the signal to start transcription

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21
Q

What is your reason for adding ice cold ethanol in your experiment to isolate DNA from a plant tissue?

A

DNA precipitates so it is visible

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22
Q

Give an example of a coding structure

A

Base sequences

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23
Q

Where is RNA found?

A

Nucleus and cytoplasm

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24
Q

Explain how transcription occurs

A
  • Double helix unwinds at a certain site of the gene that is to form a protein
  • Bases (RNA nucleotides) attach to their exposed DNA bases (DNA is acting like a template)
  • RNA bases join together using the enzyme RNA polymerase (catalyses the reaction) to make mRNA
  • mRNA moves into the cytoplasm
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25
Q

Draw a diagram to show double stranded DNA

A

See notes

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26
Q

Describe some applications of DNA profiling

A
  • Finding the parent of a child: Comparing the DNA of a child to that of a potential parent
  • Crime scene forensics: By comparing the DNA at a crime scene with a possible suspect/victim
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27
Q

Define transcription

A

mRNA is formed using a single strand of DNA (DNA acts like a template) in the nucleus using RNA polymerase (enzyme).

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28
Q

Explain the steps of DNA replication

A
  • DNA unwinds
  • Enzyme (helicase) breaks bond between bases
  • Free nucleotides from the cytoplasm move into the nucleus and join with their complimentary exposed bases on the DNA
  • DNA polymerase binds the nucleotides together
  • DNA rewinds (half old/half new strand) - 2 copies of DNA
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29
Q

Where does transcription occur?

A

Nucleus

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30
Q

Where is RNA found in the cell and no DNA?

A

Cytosol and ribosome

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31
Q

What is the reason for chopping the fruit in your experiment to isolate DNA from a plant tissue?

A

Increased surface area and breaks down cell walls

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32
Q

Define coding DNA

A

Carries code to produce a protein

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33
Q

Define gene

A

A short section of DNA that codes for a protein

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34
Q

Explain how translation occurs

A
  • mRNA attaches to a ribosome (made of rRNA)
  • tRNA in the cytoplasm bring an amino acid to the ribosome and bind to mRNA
  • Matching codons on mRNA bond with anti-codons on the tRNA until they reach a stop codon
  • Amino acids join in the right order to make a protein (by peptide bonds )
  • Proteins form a functional shape by folding (globular)
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35
Q

How many hydrogen are there between each base pair

A

A(2)T and C(3)G

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36
Q

Describe the experiment to isolate DNA from a plant tissue (+diagram)

A
  • Add washing up liquid and salt to a graduated cylinder and stir
  • Add chopped onion to a beaker. Pour in the salt washing up liquid and stir
  • Stand the beaker in a water bath at 60 degrees celsius for 15 minutes
  • Cool the mixture by standing the beaker in an ice bath for 5 minutes
  • Blend the mixture for no more than 3 seconds
  • Filter the blended mixture through coffee filter paper
  • Add 2-3 drops of protease enzyme to onion extract
  • Very carefully, pour ice cold ethanol onto the surface of the onion extract
  • DNA forms at the interface of the ethanol and extract
  • Draw the DNA out of the solution by wrapping it around a glass rod
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37
Q

Give some examples of a mutagen

A
  • Radiation - x-rays
  • UV rays
  • Chemicals - smoking cigarettes, asbestos
  • Biological agents: Viruses, bacteria
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38
Q

Define genetic code

A

Sequence of bases that code for a protein

39
Q

Explain the different types of RNA

A
  • mRNA - messenger - carries the code to make a protein
  • rRNA - ribosomal - makes the ribosome
  • tRNa - transfer - carries an amino acid to the ribosome
40
Q

Define amino acid codon

A

Codes for an amino acid

41
Q

Where does DNA replication occur?

42
Q

Who identified DNA?

A

Watson and Crick

43
Q

What are the two base pairs present in DNA?

A

A-T and C-G

44
Q

What are the base pairs present in RNA?

A

A-U and C-G (Uracil instead of Thymine)

45
Q

What is your reason for using coffee filter paper in your experiment to isolate DNA from a plant tissue?

A

Bigger pores for DNA to pass through

46
Q

Define triplet/codon

A

Sequence of three bases on DNA/RNA which code for an amino acid/start/stop

47
Q

Draw a diagram to show a nucleotide with a purine base

48
Q

How do mutations occur?

A

When DNA fails to replicate properly or proteins can’t be made

49
Q

What is the name of the sugar present is RNA?

50
Q

Define complementary in the context of DNA structure

A

Two bases joined together by hydrogen bonds. Purine with a pyrimidine

51
Q

What two nucleotides are purines?

A

Adenine and guanine

52
Q

Define mutagen

A

Agent that causes mutations

53
Q

Why is DNA replication important?

A
  • So mitosis can occur
  • Make identical cells
54
Q

How much of DNA is non-coding

55
Q

Define genetic screening

A

DNA is tested for a presence or absence of a particular gene or an altered gene.

56
Q

Define allele

A

Alternate form of a gene

57
Q

Where does translation occur?

A

Cytoplasm - ribosome

58
Q

Define exons

A

Coding genes

59
Q

What is the reason for adding washing up liquid in your experiment to isolate DNA from a plant tissue?

A

It breaks down the cell and nuclear membranes

60
Q

Where is DNA found?

61
Q

Define stop codon

A

3 bases that code for the signal to finish transcription of a gene

62
Q

What is your reason for passing your mixture through a filter in your experiment to isolate DNA from a plant tissue?

A

Separates out DNA and proteins

63
Q

What is the reason for adding salt in your experiment to isolate DNA from a plant tissue?

A

To clump DNA

64
Q

Give examples of non-coding structures

A

Sugar and phosphate

65
Q

What shape is RNA?

A

Single stranded

66
Q

What are DNA nucleotides made up of?

A

Phosphate, 5C deoxyribose sugar and a nitrogenous base

67
Q

What is the overall shape of DNA?

A

Double helix - parallel double stranded

68
Q

Define gene

A

Section of DNA that codes for a protein

69
Q

Describe the two types of mutations

A

Gene mutation: Effects on a small section of DNA
Chromosomes mutation: Large section of DNA/extra chromosome

70
Q

What does DNA stand for?

A

Deoxyribonucleic acid

71
Q

What is your reason for using a glass rod in your experiment to isolate DNA from a plant tissue?

A

To gently lift out the DNA

72
Q

Define introns

A

Non-coding genes

73
Q

When does DNA replication occur?

A

Interphase

74
Q

Draw a diagram to show a nucleotide with a pyrimidine base

75
Q

What is the enzyme in DNA?

A

DNA polymerase

76
Q

What does the enzyme in DNA do if mutations occur?

A

Repair mutations

77
Q

Define non coding DNA

A

Does not carry the code to produce a protein

78
Q

What is your reason for putting your mixture in an ice bath in your experiment to isolate DNA from a plant tissue?

A

Prevents remaining enzymes destroying DNA

79
Q

What is the term used to describe abnormal or altered DNA?

80
Q

What is a ribosome made of?

A

rRNA and protein

81
Q

How are DNA profiles prepared?

A
  • DNA is released (same as experiment)
  • DNA is cut into fragments using a restriction enzyme
  • Fragments are separated according to size (gel electrophoresis)
82
Q

Define phenotype

A

Physical appearance

83
Q

Define gene expression

A

The precise way that information in the genetic code in a gene is decoded to the cell and used to make a protein

84
Q

Define nucleotide

A

Subunit of DNA

85
Q

What is the reason for putting your mixture in a water bath at 60 degrees celsius in your experiment to isolate DNA from a plant tissue?

A

Denatures enzymes that would usually break down DNA

86
Q

Define DNA profile

A

Making a unique pattern of bands from the DNA of a person - this can be used to tell different people apart by using their DNA

87
Q

Define variation

A

Differences among a species

88
Q

How is genetic variation caused?

A
  • Sexual reproduction
  • Mutations
  • Environmental changes
89
Q

Define acquired variations

A

Not passed on from generations

90
Q

Define inherited variation

A

Passed on from parents to offspring (using genes)

91
Q

Define evolution

A

Inheritable change within a population in response to change in the environment by natural selection over time

92
Q

Name the two scientists involved in evolution

A

Darwin and Wallace

93
Q

Describe the theory of evolution by natural selection

A
  • High reproductive rates (or overbreeding)
  • Competition (or struggle for survival
  • Better adapted to survive (Survival of the fittest)
  • The survivors reproduce (or breed)
  • Others die out
  • The genes of the most succesful are passed on
  • Organisms with beneficial characteristics will dominate
94
Q

What evidence is there of evolution?

A
  • Fossils
  • Comparative anatomy
  • Comparative embryology

Biology (12 decks)

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