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Grade 12 Biology > Molecular Genetics > Flashcards

Molecular Genetics Flashcards

1
Q

What 3 things do genes have to be capable of doing?

A

carry information from one generation to the next, put information that they carry to work to produce traits of the organism and copy the gene to replicate every time a cell divides

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2
Q

What is a chromosome made of?

A

Half nucleic acid and half protein

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3
Q

What did James Watson and Francis Crick discover?

A

The model for the structure of a DNA molecule

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4
Q

What are the small units of DNA?

A

nucleotides

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5
Q

What do nucleotides consist of?

A

a phosphate group, a 5-carbon sugar and a nitrogen base

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6
Q

What is the 5-carbon sugar called?

A

deoxyribose

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7
Q

What are the 4 bases found in DNA?

A

Adenine, Guanine, Thymine and Cytosine

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8
Q

What is a purine and which bases are purines?

A

a double ringed structure, guanine and adenine

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9
Q

What is a pyrimidine and which bases are pyrimidines?

A

a single ringed structure, cytosine and thymine

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10
Q

What is the backbone of DNA made of?

A

Alternating sugar and phosphate groups

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11
Q

What did Erwin Chargaff discover (Chargaffs rule)?

A

the amount of the base pairs are equal in any sample of DNA

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12
Q

What process did Rosalind Franklin use?

A

x-ray diffraction

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13
Q

What did Rosalind Franklin discover?

A

DNA is twisted around each other in a shape known as a helix, 2 strands, nitrogen bases were at the center of the molecule

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14
Q

What bond is used to bind the 2 sides of the DNA strand?

A

weak hydrogen bonds

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15
Q

Which base pairs have 2 hydrogen bonds?

A

Adenine and Thymine

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16
Q

Which base pairs have 3 hydrogen bonds?

A

Guanine and Cytosine

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17
Q

What is a chromosome composed of?

A

DNA and proteins

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18
Q

What is DNA wrapped around?

A

Histones

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19
Q

What is a nucleosome?

A

The beadlike structure formed from DNA and histones

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20
Q

What are the differences between DNA and RNA?

A
  • RNA is single stranded and DNA is double stranded
  • The sugar in RNA is called ribose and the sugar in DNA is called deoxyribose
  • In RNA, uracil binds with adenine, in DNA thymine binds with adenine
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21
Q

What does semiconservative replication mean?

A

separating the 2 parent strands and building a new, complimentary replacement strand for each

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22
Q

What does antiparallel mean?

A

The 2 DNA strands run in opposite directions of each other due to bonding arrangements which allow the molecule to be stable

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23
Q

What should be attached to the sugar on one end of a DNA strand?

A

a hydroxyl of the 3’ carbon

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24
Q

What should be attached to the last sugar on the other end of the DNA strand?

A

a phosphate attached to the 5’ carbon

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25
Q

What does DNA polymerase 1 do?

A

Removes RNA primers

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26
Q

What does DNA polymerase 2 do?

A

Catalyzes the repair of mistake nucleotide pairs

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27
Q

What does DNA polymerase 3 do?

A

Builds new strands of DNA during replication

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28
Q

What is the template strand?

A

The DNA strand that directs the synthesis of the complementary strand

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29
Q

What is the lagging strand?

A

The new DNA strand synthesized in fragments

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30
Q

What is the leading strand?

A

The new DNA strand that is synthesized continuously

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31
Q

What does ligase do?

A

pairs the complementary strands of DNA due to the phosphodiester bonds

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32
Q

What does primase do?

A

Builds the RNA primers

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33
Q

What does topoisomerase do?

A

Relieves tension in DNA while the 2 parent strands are separating

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34
Q

What does helicase do?

A

Unwinds the DNA strands and separates them

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35
Q

What is a replication fork?

A

It keeps the separated strands of DNA apart

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36
Q

What are okazaki fragments?

A

Shot lengths of DNA produced during the synthesis of the lagging strand

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37
Q

What is a single stranded binding protein?

A

The area where DNA polymerase is bound to unwound DNA, prevents parent DNA strands from rejoining to each other once they have separated

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38
Q

What is anneling?

A

links the sugars and phosphates together

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39
Q

What is a replication origin?

A

a starting point on the DNA where helicase attaches on and starts separating the parent strands

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40
Q

In what direction is a DNA strand synthesized?

A

5’ to 3’ direction

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41
Q

In what direction is DNA read from?

A

3’ to 5’ direction

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42
Q

Why is DNA repair necessary?

A

Diseases like cancer can result from non-functioning DNA

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43
Q

What is eukaryotic DNA organization?

A

DNA wrapped around histones

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44
Q

What is prokaryotic DNA organization?

A

one chromosome that is commonly circular

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45
Q

What is DNA polymerases starting point?

A

a primer

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46
Q

What happens at the end of the lagging strand?

A

the primer is removed and the new DNA polymerase has no where to go, the section is lost on both strands as it cannot synthesize the end piece of DNA

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47
Q

What can happen after many losses of DNA and the shortening of the chromosomes?

A

loss or damage of important genes

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48
Q

What is a telomere?

A

zones of repetitive, non-coding nucleotide sequences found at the end of eukaryotic chromosomes

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49
Q

How do telomeres work?

A

every time DNA replicates, part of the telomeres are lost and get shorter preventing the loss of the DNA

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50
Q

What happens to the telomeres after replication?

A

They are fully lost and no longer provide protection for the chromosome

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51
Q

What happens once enough replications have occurred?

A

Portions of DNA may be lost resulting in new cells losing their ability to function which can lead to hearing loss, slower cognitive function, slower reaction times

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52
Q

What is hayflicks limit?

A

the number of times a cell can divide (60)

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53
Q

What is a gene?

A

the coded DNA instructions that controls the production of specific proteins which includes enzymes, structural proteins and oxygen-carrying proteins

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54
Q

What are proteins?

A

the links between genotypes and phenotypes

55
Q

What do proteins determine?

A

traits in offspring

56
Q

What is gene expression?

A

the process where DNA directs the synthesis of proteins in 2 stages: transcription and translation

57
Q

What are proteins made of?

A

Amino acids

58
Q

What specifies an amino acid?

A

3 nucleotides in a sequence

59
Q

What is a triplet nucleotide called?

A

a codon

60
Q

What does each codon call for?

A

A specific amino acid

61
Q

What is a start codon?

A

a specific sequence of nucleotides that indicates where the proteins building instructions begins

62
Q

What is a stop codon?

A

they act a signal for the end of the protein chain

63
Q

Where are proteins made?

A

by the ribosomes in the cytoplasm

64
Q

How is a protein made?

A

the gene of the DNA is copied into RNA, the copy instructions are send to the ribosomes in the cytoplasm, RNA then carries the message from the DNA to the ribosomes, the RNA then tells the ribosomes which protein to make and how

65
Q

What does the mRNA do?

A

travels from the nucleus to the cytoplasm with instructions to make proteins

66
Q

What is the mRNA?

A

the messenger between the DNA in the nucleus and the ribose in the cytoplasm

67
Q

What is the structure of tRNA?

A

a anticodon at one end and an amino acid binding site at the other, bases of the anticodon are complementary to the mRNA codon

68
Q

What does the tRNA do?

A

reads the messages carried by the mRNA and gathers the amino acids for making proteins

69
Q

How does the tRNA work?

A

transfers amino acids from the cytoplasm pool of the amino acids to a ribosome, one end attaches to one amino acid and carries it to the ribosome

70
Q

What does rRNA do?

A

binds mRNA and tRNA to the ribosome and allows all components required for the synthesis of the proteins to be held together

71
Q

What does transcription do?

A

forms a strand of RNA from a strand of DNA

72
Q

Where does transcription occur?

A

in the nucleus

73
Q

What enzyme catalyzes transcription?

A

RNA polymerase

74
Q

What is the promotor region?

A

the DNA sequence where RNA polymerase attaches and initiates transcription

75
Q

What is the terminator region?

A

the DNA sequence that signals the end of transcription

76
Q

What are the steps of transcription?

A
  • RNA polymerase binds to the promotor site on the DNA molecule
  • RNA polymerase separates the DNA strands
  • New nucleotides are inserted base on pairing rules on the template DNA strand
  • As the RNA polymerase moves across the DNA molecule, hydrogen bonds between the 2 strands of DNA are reformed
  • A single stranded RNA molecule has been transcribed
77
Q

What are introns?

A

sequences of nitrogenous bases that are not involved in the making of proteins

78
Q

What needs to be cut out of RNA before RNA goes to the ribosomes?

A

introns

79
Q

What are exons?

A

sequences of nitrogenous bases that are involved in the making proteins

80
Q

When are introns and exons copied from DNA?

A

when mRNA is formed

81
Q

When do the introns get cut out of the RNA?

A

While the RNA is still in the nucleus

82
Q

What happens to the remaining exons in the RNA?

A

they get spliced together

83
Q

What is added to the final RNA molecule?

A

a cap and tail

84
Q

What does a cap and tail do?

A

helps identify the front and back end of the RNA and helps the ribosomes identify the front and back end of the instructions

85
Q

What do introns allow?

A

a single gene to code for more than one type of protein depending on which segments are exons and introns

86
Q

What is translation?

A

the synthesis of proteins

87
Q

What happens when each codon of the mRNA molecule moves through the ribosome?

A

the proper amino acid is brought into the ribosome by the tRNA

88
Q

What does the ribosome do in translation?

A

hitches the amino acid together with peptide bonds and polypeptides are made

89
Q

What are polypeptides?

A

a long chain or amino acids but not a functioning protein

90
Q

Where are polypeptides sent?

A

to the ER and the golgi apparatus where they modify and shape themselves into functioning proteins

91
Q

What happens if a codon is read incorrectly?

A

a polypeptide will be made by putting the wrong amino acids in order which makes it unlikely for the resulting protein to function

92
Q

What are subunits made of?

A

proteins in a RNA molecule called rRNA

93
Q

Where are subunits made?

A

in the nucleus

94
Q

What are the 3 tRNA binding sites?

A

E site, P site and A site

95
Q

What does the P site hold?

A

the rRNA carrying the growing polypeptide chain

96
Q

What does the A site hold?

A

the tRNA carrying the next amino acid for the polypeptide chain

97
Q

What happens at the E site?

A

where discharged tRNAs leave the ribosome from

98
Q

What are mutations?

A

mistakes in copying DNA, incorrect nitrogen bases, change in the genetic material of the cell

99
Q

What is a point mutation?

A

changes in one pair of a gene at a single point in the DNA sequence

100
Q

What is a base pair substitution?

A

one nitrogen base is changed to another

101
Q

What is a base pair insertion or deletion?

A

a nitrogen base is added or removed from the DNA sequence

102
Q

What is a frameshift mutation?

A

a insertion or deletion of a base that causes the bases to be shifted left or right for every codon that follows

103
Q

What does gene on mean?

A

cell is actively transcribing the DNA into mRNA, the mRNA is being translated to synthesize proteins, gene is being expressed

104
Q

what does gene off mean?

A

cell is not transcribing or translating DNA, gene is not expressed

105
Q

What is the taxonomy of prokaryotic gene regulation?

A

kingdom archaebacteria and eubacteria

106
Q

What is the genome size in prokaryotic gene regulation?

A

very small

107
Q

What is the DNA organization in prokaryotic gene regulation?

A

circular DNA

108
Q

What is the cellular hierarchy in prokaryotic gene regulation?

A

unicellular

109
Q

What is a Lac Operon?

A

insight into how a gene will work in the presence or absence of lactose sugar

110
Q

What is a operator?

A

location on a prokaryotic DNA where the operon is turned off or on

111
Q

what is a operon?

A

a group of prokaryotic genes which are transcribed together

112
Q

What happens when there is no lactose in prokaryotic gene regulation?

A

lac repressor binds tightly to the operator, it gets in RNA polymerases way which prevents transcription and turns the gene off

113
Q

What happens where there is lactose in prokaryotic gene regulation?

A

allolactose binds to the lac repressor and makes it let go of the operator, RNA polymerase can now transcribe the operon, transcription, translation and protein synthesis can occur

114
Q

What is the taxonomy in eukaryotic gene regulation?

A

Protista, plantae, animalia, fungi

115
Q

What is the genome size in eukaryotic gene regulation?

A

very large

116
Q

what is the DNA organization in eukaryotic gene regulation?

A

chromosomes

117
Q

What is the cellular hierarchy in eukaryotic gene regulation?

A

unicellular or multicellular

118
Q

What is the promotor/operator/binding site in eukaryotic gene regulation?

A

location on eukaryotic DNA where the transcription factor proteins bind

119
Q

What are transcription factor proteins?

A

proteins used during gene expression to turn genes on

120
Q

How do transcription factor proteins work?

A

they bind to the promotor of the DNA sequence which attacks the RNA polymerase to begin transcription

121
Q

What are activator proteins?

A

turns the gene on by signaling the mediator proteins to begin binding to assemble the transcription complex

122
Q

What are mediator proteins?

A

a bridge between the activator proteins and the TATA binding proteins

123
Q

What do TATA binding proteins do?

A

binds to the TATA box DNA sequence before the exon on the DNA strand and the RNA polymerase so they can begin transcription

124
Q

What is the transcription complex?

A

the assembly of all the proteins needed for transcription

125
Q

What is a TATA box?

A

a DNA sequence found in the promoter region of genes in the archaea and eukaryotes

126
Q

What do repressor proteins do?

A

turns the gene off by binding to the repressor site and to the RNA polymerase, keeping the other transcription factor proteins from binding

127
Q

What does CRISPR stand for?

A

clustered regularly interspaced short palindromic repeats

128
Q

What is CRISPR?

A

gene editing systems that can be programmed to target specific sequences of genetic code and to edit DNA at precise locations

129
Q

What do CAS proteins do?

A

they cut out a portion of the infecting agents DNA and inserts it into the CRISPR region of its own DNA

130
Q

What is the polymerase chain reactions (PCR)?

A

a lab technique for making millions of copies of a specific DNA region, done without the use of a cell or organism

131
Q

What are the 3 steps to the PCR?

A

Denaturing, annealing and extension

132
Q

What is denaturing?

A

heating the reaction to 95 degrees Celsius so the DNA strands separate to provide single-stranded templates

133
Q

What is annealing?

A

cooling the reaction to 50-55 degrees Celsius so that primers can bind to their complimentary sequences on the single-stranded template DNA

134
Q

What is Extension?

A

raising the temperature to 72 degrees Celsius 3 so DNA polymerase extends the primers, synthesizing new strands of DNA

Grade 12 Biology (3 decks)

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