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Grade 12 Biology > Unit 5 > Flashcards

Unit 5 Flashcards

1
Q

Deoxyribonucleic acid (DNA)

A

A double-stranded polymer of nucleotides (each consisting of a deoxyribose sugar, a phosphate, and four nitrogenous bases) that carries the genetic information of an organism.

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2
Q

Bacteriophage

A

Any bacteria-infecting virus

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3
Q

Isotope

A

Différent atoms of the same element containing the same number of protons but a different number of neutrons

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4
Q

Radioisotopes

A

Unstable isotopes that decay spontaneously by emitting radiation

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5
Q

Deoxyribose sugar

A

Sugar molecule containing five carbons that has lost the -OH (hydroxyl group) on its 2’ (2 prime) carbon

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6
Q

Phosphate group

A

Group of four oxygen atoms surrounding a central phosphorus atom found in the backbone of DNA

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7
Q

Nitrogenous base

A

An alkaline, cyclic molecule containing nitrogen

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8
Q

Nucleotides

A

Molecules that consist of a five-carbon sugar (deoxyribose or ribose) with a nitrogenous base attached to their 1’ carbon and a phosphate group attached to their 5’ carbon

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9
Q

Antiparallel

A

Parallel but running in opposite directions; the 5’ end of one strand of DNA aligns with the 3’ end of the other strand in a double helix.

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10
Q

Complementary base pairing

A

Pairing of the nitrogenous base of one strand of DNA with the nitrogenous base of another strand; adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).

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11
Q

Glycosyl bond

A

A bond between a sugar and another organic molecule by way of an intervening nitrogen or oxygen atom

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12
Q

Friedrich Miescher

A
  • Late 1860s
  • Isolated nonprotein substance from nucleus of cells; named this substance nuclein
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13
Q

Frederick Griffith

A
  • 1920s
  • experimented using mice and two different strains of pneumococcus bacteria (virulent and nonvirulent); observed that when heat-treated virulent pneumococcus was mixed with nonvirulent pneumococcus and was injected into healthy mice dealt resulted
  • Discovered the process of transformation
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14
Q

Joachim Hammerling

A
  • 1930s
  • experimented using green alga Acetabularia; observed that regeneration of new appendages was driven by the nucleus-containing “foot” of the alga
  • hypothesized that hereditary information is stored in the nucleus
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15
Q

Oswald Avery, Maclyn McCarty, and Colin MacLeod

A
  • 1944
  • demonstrated that DNA was the transforming principle of pneumococcus bacteria
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16
Q

Erwin Chargaff

A
  • 1949
  • discovered that in the DNA of numerous organisms the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to that of cytosine.
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17
Q

Alfred Hershey and Martha Chase

A
  • 1952
  • used radioactively labeled viruses, infected bacterial cells; observed that the infected bacterial cells contained radioactivity originating from DNA of the virus
  • suggested that DNA is hereditary material
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18
Q

Rosalind Franklin

A
  • 1953
  • produced an X-ray diffraction pattern of DNA that suggested it was in the shape of a double helix
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19
Q

James Watson and Francis Crick

A
  • 1953
  • deduced the structure of DNA using information from the work of Chargraff, Franklin, and Maurice Wilkins
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20
Q

Mitosis

A

Division of the nucleus of a eukaryotic cell into two daughter nuclei with identical sets of chromosomes.

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21
Q

Cytokinesis

A

Division of cytoplasm and organelles of a cell into two daughter cells.

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22
Q

Template

A

A single-stranded DNA sequence that acts as the guiding pattern for producing a complementary DNA strand.

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23
Q

Semiconservative

A

Process of replication in which each DNA molecule is composed of one parent strand and one newly synthesized strand.

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24
Q

DNA helicase

A

The enzyme that unwinds double-helical DNA by disrupting hydrogen bonds.

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25
Q

anneal

A

the pairing of complementary strands of DNA through hydrogen bonding

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26
Q

single-stranded binding proteins (SSBs)

A

a protein that keeps separated strands of DNA apart

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27
Q

DNA gyrase

A

the bacterial enzyme that relieves the tension produced by the unwihding of DNA during replication

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28
Q

replication fork

A

the region whers the enzymes replicating a DNA molecule are bound to untwisted, single-stranded DNA

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29
Q

replication bubble

A

the region where two replication forks are in close proximity to each other, producing a bubble in the replicating
DNA

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30
Q

DNA polymerase III

A

the enzyme responsible for synthesizing complementary strands of DNA during DNA replication

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31
Q

deoxyribonucleoside
triphosphates

A

molecules composed of a deoxyribese bonded to three phosphate groups and a nitrogenous base

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32
Q

RNA (ribonucleic acid) primer

A

a sequence of 10060 RNA bases that is annealed to a region of single-stranded DNA for the purpose of initiating DNA replication

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33
Q

primase

A

the enzyme that builds
RNA primers

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34
Q

leading strand

A

the new strand of DNA that is Synthesized continuously during DNA replication

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35
Q

lagging strand

A

the new strand of DNA that is synthesized in short fragments, which are later joined together

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36
Q

Okazaki fragments

A

short fragments of DNA that are a result of the synthesis of the lagging strand during DNA replication

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37
Q

DNA polymerase I

A

an enzyme that removes RNA primers and replaces them with the appropriate deoxyri-bonucleotides during DNA replication

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38
Q

DNA ligase

A

the enzyme that joins
DNA fragments together by catalyzing the formation of a bond between the 3’ hydroxyl group and a 5’phoshate group on the sugar-phospate backbones

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39
Q

exonuclease

A

an enzyme that cuts outnucleolides at the end of a DNA strand

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40
Q

genes

A

a sequence of nucleotides in DNA that performs a specific function such as coding for a particular protein

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41
Q

proteins

A

complex molecules composed of one or more polypeptide chains made of amino acids and folded into specific three-dimensional shapes that determine protein function

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42
Q

amino acid

A

the monomer unit of a polypeptide chain that is composed of a carboxylic acid, an amino group, and a side group that differentiates it from other amino acids

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43
Q

transcription

A

the process in which
DNA is used as a template for the production of complementary messenger RNA molecules

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44
Q

translation

A

the process by which a ribosome assembles amino acids in a specific sequence to synthesize a specific polypeptide coded by messenger RNA

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45
Q

messenger RNA (mRNA)

A

the end product of transcription of a gene, mRNA is translated by ribosomes into protein

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46
Q

transfer RNA (tRNA)

A

a form of RNA that is responsible for delivering amino acids to the ribosomes during the process of translation

47
Q

ribosomal RNA (rRNA)

A

a form of RNA that binds with ribosomal protein to form ribosomes

48
Q

RNA polymerase

A

enzyme that transcribes DNA into complementary mRNA

49
Q

codon

A

sequence of three bases in
DNA or complementary mRNA that serves as a code for a particular amino acid

50
Q

start codon

A

specific codon (AUG) that signals to the ribosome that the translation commences at that point

51
Q

stop codons

A

specific codons that signal the end of translation to a ribosome

52
Q

upstream

A

region of DNA adjacent to the start of a gene

53
Q

promoter

A

sequence of DNA that binds RNA polymerase upstream of a gene

54
Q

template strand

A

the strand of DNA that the RNA polymerase uses as a guide to build complementary mRNA

55
Q

coding strand

A

the strand of DNA that is not used for transcription and is identical in sequence to mRNA, except it contains uracil instead of thymine

56
Q

terminator sequence

A

sequence of bases at the end of a gene that signals the RNA polymerase to stop transcribing

57
Q

primary transcript

A

mRNA that has to be modified before exiting the nucleus in eukaryotic cells

58
Q

5’ cap

A

7-methyl guanosine added to the start of an primary transcript to protect it from digestion in the cytoplasm and to bind it to the ribosome as part of the initiation of translation

59
Q

poly-A polymerase

A

enzyme responsible for adding a string of adenine bases to the end of mRNA to protect it from degradation later on

60
Q

poly-A tail

A

a string of 200 to 300 adenine base pairs at the end of an mRNA transcript

61
Q

exons

A

segments of DNA that code for part of a specific protein

62
Q

introns

A

noncoding region of a gene

63
Q

spliceosomes

A

particles made of RNA and protein that cut introns from mRNA primary transcript and joins together the remaining coding exon regions

64
Q

mRNA transcript

A

mRNA that has been modified for exit out of the nucleus and into the cytoplasm

65
Q

reading frame

A

one of three possible phases in which to read the bases of a gene in groups of three

66
Q

anticodon

A

group of three complementary bases on tRNA that recognizes and pairs with a codon on the mRNA

67
Q

aminoacyl-tRNA

A

a tRNA molecule with its corresponding amino acid attached to its acceptor site at the 3’ end.

68
Q

A (acceptor) site

A

site in the ribosome where tRNA brings in an amino acid

69
Q

P (peptide) site

A

site in the ribosome where peptide bonds are formed between adjoining amino acids on a growing polypeptide chain

70
Q

release factor

A

a protein involved in the release of a finished polypeptide chain from the ribosome

71
Q

housekeeping genes

A

genes that are switched on all the time because they are needed for life functions vital to an organism

72
Q

transcription factors

A

proteins that switch on genes by binding to DNA and helping the RNA polymerase to bind

73
Q

gene regulation

A

the turning on or off of specific genes depending on the requirements of an organism

74
Q

lactose

A

a disaccharide that consists of the sugars glucose and galactose

75
Q

B(beta)-galactosidase

A

the enzyme responsible for the breakdown of lactose into its component sugars, glucose and galactose

76
Q

operon

A

a cluster of genes under the control of one promoter and one operator in prokaryotic cells; acts as a simple regulatory loop

77
Q

operator

A

regulatory sequences of
DNA to which a repressor protein binds

78
Q

lac operon

A

a cluster of genes under the control of one promoter and one operator; the genes collectively code for the enzymes and proteins required for a bacterial cell to use lactose as a nutrient

79
Q

Lac I protein

A

a repressor protein that binds to the lac operon operator, preventing RNA polymerase from transcribing the lac operon genes

80
Q

repressor protein

A

regulatory molecules that bind to an operator site and prevent the transcription of an operon

81
Q

signal molecule

A

a molecule that activates an activator protein or represses a repressor protein

82
Q

inducer

A

a molecule that binds to a repressor protein and causes a change in conformation, resulting in the repressor protein falling off the operator

83
Q

trp operon

A

a cluster of genes in a prokaryotic cell under the control of one promoter and one operator, the genes govern the synthesis of the necessary enzymes required to synthesize the amino acid tryptophan

84
Q

corepressor

A

a molecule (usually the product of an operon) that binds to a repressor to activate it

85
Q

mutations

A

changes in the DNA sequence that are inherited

86
Q

silent mutation

A

a mutation that does not result in a change in the amino acid coded for and, therefore, does not cause any phenotypic change

87
Q

missense mutation

A

a mutation that results in the single substitution of one amino acid in the resulting polypeptide

88
Q

nonsense mutation

A

a mutation that converts a codon for an amino acid into a termination codon

89
Q

substitution

A

the replacement of one base in a DNA sequence by another base

90
Q

deletion

A

the elimination of a base pair or group of base pairs from a
DNA sequence

91
Q

insertion

A

the placement of an extra nucleotide in a DNA sequence

92
Q

frameshift mutation

A

a mutation that causes the reading frame of codons to change, usually resulting in different amino acids being incorporated into the polypeptide

93
Q

point mutations

A

mutations at a specific base pair in the genome

94
Q

translocation

A

the transfer of a fragment of DNA from one site in the genome to another location

95
Q

transposable elements

A

segments of DNA that are replicated as a unit from one location to another on chromosomal DNA

96
Q

inversion

A

the reversal of a segment of DNA within a chromosome

97
Q

spontaneous mutations

A

mutations occurring without chemical change or radiation but as a result of errors made in DNA replication

98
Q

mutagenic agents

A

agents that can cause a mutation

99
Q

induced mutations

A

mutations caused by a chemical agent or radiation

100
Q

coupled transcription-translation

A

a phenomenon in which ribosomes of bacteria start translating an mRNA molecule that is still being transcribed

101
Q

endosymbiotic

A

physical and chemical contact between one species and another species living within its body, which is beneficial to at least one of the species

102
Q

fission

A

asexual reproduction typical of bacteria in which the cell divides into two daughter cells

103
Q

nucleomorph

A

tiny nucleus containing genomic material found within a eukaryotic endosymbiotic structure originally believed to be derived from primitive red alga

104
Q

chromatin

A

complex of DNA and histone proteins located in the nucleus of eukaryotes

105
Q

histones

A

positively charged proteins that bind to negatively charged DNA in chromosomes

106
Q

nucleosome

A

a complex of eight histones enveloped by coiled DNA

107
Q

supercoiling

A

DNA folded into a higher level of coiling than is already present in nucleosomes

108
Q

variable number tandem repeats (VNTRs)

A

repetitive sequences of
DNA that vary among individuals;
also known as microsatellites

109
Q

telomeres

A

long sequences of repetitive, noncoding DNA on the end of chromosomes

110
Q

centromeres

A

constricted region of chromosome that holds two replicated chromosome strands together

111
Q

pseudogenes

A

DNA sequences that are homologous with known genes but are never transcribed

112
Q

LINEs

A

repeated DNA sequences
of 5000 to 7000 base pairs in length that alternate with lengths of DNA sequences found in the genomes of higher organisms

113
Q

SINEs

A

repeated DNA sequences of 300 base pairs in length that alternate with lengths of DNA sequences found in the genomes of higher organisms

Grade 12 Biology (5 decks)

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