Genetics Test 2 Flashcards

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0
Q

Social sex determination

A

Many fish undergo sex reversal, depends on the mating system

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1
Q

Temperature dependent sex determination (TSD)

A

Controls sex determination in reptiles, crocodiles most turtles and some lizards: incubation temperature of egg drying embryonic development determines sex

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2
Q

Modifications at chromosome level

A

Phenotype variations (often substantial) result from changes of individual genes

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3
Q

Chromosome level mutations and aberrations

A

Total number of chromosomes vary, deletions, duplications, rearrangements

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4
Q

Aneuploidy

A

Organism gains or loses one or more chromosomes but not the entire set

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5
Q

Euploidy

A

Complete haploid sets of chromosomes beyond two are present (polyploidy more than 2, triploidy 3)

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6
Q

Nondisjunction

A

Gives rise to chromosome variation when paired homologs fail to disjoin during segregation (meisosis 1 or 2)

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7
Q

Monosomy

A

Loss of one chromosome producing 2n-1 complement, although a copy remains if one copy is lethal the organism is not viable

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8
Q

Haploinsufficiency

A

When one copy is not sufficient for an organism to survive

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9
Q

Trisomy

A

2n+1 chromosomes, addition produces more viable organisms, trisomes for autosomes are often lethal, plant trisomes are viable but the phenotype is altered

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10
Q

Trivalent

A

Three copies of chromosome are synapsed

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11
Q

Bivalent and univalent

A

Prior to first Miotic division, one bivalent and one univalent (an unpaired chromosome) may be present instead of a trivalent

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12
Q

Down syndrome

A

Trisomy of chromosome 21, has 12-14 defining characteristics (of which those affected experience 6-8)

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13
Q

Down syndrome critical region (DSCR)

A

Critical region of chromosome 21, genes in this region are dosage sensitive, responsible for many phenotypic associated syndromes

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14
Q

Origin of extra 21st chromosome

A

Nondisjunction of chromosome 21 during meiosis, homologs do not disjoin in anaphase 1 or 2, leads to n+1 gametes, ovum is source of 95% of trisomy cases, risk increases rapidly with maternal age

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15
Q

Diagnostic testing

A

Amniocentesis or chorionic villus (CVS) fetal cells are obtained from amniotic fluid or chorionic of placenta OR NIPGD fetal cells and DNA obtained from maternal circulation

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16
Q

Trisomics

A

Often found in spontaneously aborted fetuses

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17
Q

Polyploidy

A

More than two multiples of haploid chromosomes found

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18
Q

Autopolyploidy

A

Addition of one or more sets of chromosomes identical to haploid complement of same species

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19
Q

Allopolyploidy

A

Combination of chromosome sets from different species as consequence of hybridization

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20
Q

Allotetraploid

A

Polyploid contains equivalent of four haploid genomes derived from separate species

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21
Q

Amphidiploid

A

Allotetraploid with full diploid genome of each parent species

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22
Q

Endopolyploidy

A

Condition where any certain cells in diploid organism are polyploid, set of chromosomes replicates repeatedly without nuclear division

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23
Q

Chromosome rearrangements

A

Deletions, duplications, inversions, nonreciprocal trans locations, reciprocal trans locations

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24
Q

Alteration of chromosomes

A

Deletions and duplications (total amount of chromosomes changes)/inversions and translocations (same but rearranged)

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25
Q

Deletions

A

Missing region of chromosome

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26
Q

Completion loop

A

Synapsis between chromosome with large intercalary deletion and normal complete homolog, requires unparallel region of of normal homologous to loop out of linear structure into deletion or compensation loop

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27
Q

Cri-du-chat

A

Deletions of small terminal portion of chromosome 5p, segmented deletion, infants exhibit anatomical malformations

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28
Q

Duplication

A

Replicated segment of chromosome, single locus is present more than once in genome, can produce compensation loop, arise from unequal crossing over between synapsed chromosomes during meiosis

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29
Q

Gene redundancy

A

Ex. rRNA, multiple copies of genes encode for ribosomal RNA genes

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30
Q

Gene amplification

A

Another mechanism that increases rRNA, oocytes store nutrients including ribosomes, used by embryo in early development for rRNA synthesis

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31
Q

Gene duplication

A

Hypothesized to be major source of new genes, hypothesis supported by discovery of genes with substantial amount of DNA sequence in common, but distinct gene product

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32
Q

Copy number variants (CNVs)

A

Represent quantitative differences in number of large DNA sequences, found in coding and noncoding regions of genome, play crucial role in expression of traits

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33
Q

Inversion

A

Rearrangement of linear gene sequence, no loss of genetic information, segment of chromosome turned 180° within chromosome, requires two breaks in chromosomes and reinsertion inverted segment, may arise from chromosomal looping

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34
Q

Types of inversions

A

Paracentric (does not change the length of the two arms of the chromosome, centromere NOT part of inverted segment
Pericentric (centromere IS part of inverted segment)

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35
Q

Inversion loop

A

Inverted and noninverted chromosomes in meiosis paired only if they form inversion loop

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36
Q

Translocation

A

Movement of chromosomal segment to new location in genome

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37
Q

Reciprocal translation

A

Involved exchange of segments between two nonhomologous chromosomes, genetic mutation is lot or gained, has unusual synapsis configuration during meiosis

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38
Q

Segregation patterns

A

Alternate segregation (pattern at first meiotic division, complete set of genetic information) adjacent segregation (leads to gametes containing duplications and deficiencies)

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39
Q

Robertsonian translocation

A

Involves breaks at extreme ends of the short arms of two nonhomologous chromosomes, small segments are lost, large submetacentric chromosome produced

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40
Q

Fragile sites

A

More susceptible to chromosome breakers when cultured in a sense of folic acid or other chemicals, sites imdicate regions of non-rightly coiled chromatin

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41
Q

Fragile X syndrome (Martin bell syndrome)

A

Folate sensitive site on X chromosome exhibits FXS, most common form of inherited mental retardation; dominant trait

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42
Q

Semi conservative DNA replication

A

Each replicated DNA molecule consists of one old strand and one new strand

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43
Q

Conservative DNA replication

A

Two newly synthesized strands come together, original helix is conserved

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44
Q

Dispersive DNA replication

A

Parental strands are dispersed into two new double helices

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45
Q

Meselson and Stahl

A

Provided strong evidence that DNA is semiconservative in prokaryotes

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46
Q

Taylor-Woods-Hughes

A

DNA replication is semiconservative in eukaryotes

47
Q

Audiography

A

Pinpoints location of radioisotope in cells, results: presence of dark grains identifies location of newly synthesized DNA

48
Q

Origin of replication (ORI)

A

Where DNA replication begins

49
Q

Replication fork

A

Where the helix is unwound at the site of replication

50
Q

Bidirectional

A

The fact that DNA replication goes both ways aka there are two replication forks

51
Q

Replicon

A

Length of DNA replicated

52
Q

DNA synthesis in bacteria involves _____ polymerase as well as other enzymes

A

5

53
Q

Polymerase only add to the ______ end

A

3’

54
Q

Polymerase III

A

Holoenzyme contains core enzyme complexes made up of subunits (polymerase, exonuclease, core assembly), different parts do different things

55
Q

Holoenzyme

A

Active form of polymerase III

56
Q

Unwinding

A

An issue during replication if not done properly

57
Q

Coiling

A

It’s imperative to reduce increased coiling during DNA replication, generated during unwinding

58
Q

Primer

A

DNA requires a primer to initiate replication

59
Q

Lagging strand

A

The second strand of DNA replicated that requires a more complex process and creates Okazaki fragments

60
Q

RNA primers

A

Must be removed for replication

61
Q

Gap filling DNA

A

Must be joined to the adjacent strand during replication

62
Q

Proofreading

A

Issue in DNA replication because it doesn’t occur

63
Q

The condition that exists when an organism gains or loses one or more chromosomes but not a complete haploid set is known as

A

Aneuploidy

64
Q

A condition in which chromosome count is altered by the addition of loss of an entire 1n chromosome set?

A

Euploidy

65
Q

Nondisjunction is viewed as a major cause of aneuploidy (true or false)

A

True

66
Q

Assume that a species has a diploid chromosome number of 24, the term applied to an individual with 25 chromosomes would be triploid (true or false)

A

False, 2n+1 is trisomy

67
Q

Although the most frequent form of Down’s syndrome are caused by a random error, nondisjunction of chromosome 21, Down syndrome occasionally runs in families. The cause of this form of familial Down syndrome is _________

A

A translocation between chromosome 21 and another chromosome

68
Q

Which is not a form of chromosomal aberration: duplication, deletion, point mutation, deviation in #chromosomes, rearrangements

A

Point mutation

69
Q

I’m angiosperms the unique event known as double fertilization results in a ____________ zygote and a ____________ endosperm nuclei

A

Diploid;triploid

70
Q

The phenomenon where having a single copy of a chromosome is not sufficient for an organism to survive

A

Haploinsufficiency

71
Q

Which kingdom is knwon for being particularly flexible in regards to viability in the face of varied chromosome numbers?

A

Plantae

72
Q

This term refers to the hybrid condition of having 2 complete diploid genomes; one from each parent species

A

Amphiploid

73
Q

Mitochondrial mutations are passed equally to offspring by both male and females (true or false)

A

False only females

74
Q

What term is applied when two genes fail to assert independently, that is they tend to segregate together during gamete formation

A

Linkage

75
Q

One explanation for organelle inheritance is that_________

A

Mitochondria and chloroplasts have DNA that is subject to mutation

76
Q

Which of the following organelles are involved in the general category of organelle heredity?

A

Mitochondria and chloroplasts

77
Q

What is the name of a form of extrachromosomal inheritance that is due to transmission of symbiotic or parasitic microorganisms

A

Infectious heredity

78
Q

Linkage (viewed from results of typical crosses) always occurs when two loci are on the same chromosome (true or false)

A

False

79
Q

This theory explains both an origin of extra nuclear inheritance and the origin of eukaryotic life?

A

Endosymbiosis

80
Q

What relatively recent scientific advancement has made mapping by linkage or classical genetic mapping approaches virtually obsolete

A

The genome sequence of a species

81
Q

Forms of inheritance that do not follow typical Mendelian patterns and that appear to be more influences by the parent contributing the most cytoplasm to the embryo are grouped under the general heading of ___________

A

Extrachromosomal inheritance

82
Q

If two gene loci are on nonhomologous chromosomes, genes at these loci are expected to as sort independently. (True or false)

A

True

83
Q

It is safe to say that a maternal effect is caused by the genotype, not the phenotype, of the parent producing the egg. (True or false)

A

True

84
Q

Genetic material

A

Information contained in genes that gets passed onto new generation, source of variability

85
Q

To serve as genetic material a molecule must be able to

A

Replicate, store information, express information, allow variation by mutation

86
Q

Central dogma

A

DNA to RNA to protein

DNA makes RNA (transcription) which makes proteins (translation)

87
Q

Protein as genetic material

A

Until 1994, genetics favored proteins as genetic material since proteins were diverse and abundant in cells

88
Q

Tetranucleic hypothesis

A

DNA contains equal amounts of four nucleotides, postulated identifies groups and repeats of four components was basis for DNA structure

89
Q

Evidence favoring DNA

A

Avery Macleod McCarty, first direct experiment proof that DNA is biomolecule responsible for heredity

90
Q

Griffith transformation experiment

A

Provided foundation for Avery Macleod and McCarty, showed avirulent strains could be transformed to virulent

91
Q

Hershey and chase

A

Demonstrated that DNA, not protein, is the genetic material using radioisotopes, demonstrated that DNA enters bacterial cell during infection and directs viral reproduction

92
Q

Transfection

A

Infection by only viral nucleic acid, proves conclusively that viral DNA alone contains all necessary information for production of mature viruses

93
Q

Indirect evidence of DNA as genetic material

A

Distribution of DNA, mutagenesis: UV light mutates genetic material at 260 nm

94
Q

Direct evidence

A

Recombinant DNA technology, eukaryotic DNA now functional in bacterial cell, trans gene animals

95
Q

RNA genetic material

A

Ribose sugar, some viruses have RNA core

96
Q

Nucleotides

A

DNA is a nucleic acid, binary blocks of nucleic acid, the building blocks of DNA, contain nitrogenous base, pentode sugar, phosphate group

97
Q

Nitrogenous bases

A

Purines adenine and guanine

Pyrimidines cytosine thymine uracil

98
Q

Structure of DNA

A

Watson and crick model, double helix, two antiparallel strands connected by base pairing, stacked nitrogenous base

99
Q

Analytical techniques

A

Absorption of UV light, denaturation and renaturation of nucleic acids, molecular hybridization, reassociation kinetics, electrophoresis of nucleic acids

100
Q

Absorption of UV light

A

Strong at 254-260nm due to interaction between UV light and ring systems of the bases, used in localization isolation and characterization

101
Q

Molecular hybridization

A

Denaturation and renaturation of nuclear acids are the basis for molecular hybridization

102
Q

Reassociation kinetics

A

Analyses rate of reassociation if complementary single DNA strands

103
Q

Electrophoresis

A

Separated DNA and RNA fragments by size, smaller fragments migrate through gel at faster rate than the large fragments

104
Q

DNA bases

A

Adenine, guanine, cytosine and thymine

105
Q

RNA bases

A

Adenine uracil cytosine guanine

106
Q

Nucleoside

A

Contains nitrogenous base and pentose sugar

107
Q

Nucleotide

A

Nucleoside with a phosphate group

108
Q

Monophosphates

A

A nucleotide

109
Q

Diphosphates

A

Nucleotide with the addition of two phosphate groups

110
Q

Triphosphate

A

Nucleotide with the addition of three phosphate groups, serve as precursor molecule during nucleic acid synthesis

111
Q

Phosphodiester bonds

A

How nucleotides are linked between phosphate group at c-5’ position and oh group on c-3’ position

112
Q

Chargaff

A

Proposed base composition of adenine equal to thymine and cytosine equal to guanine

113
Q

PCR

A

A way to denature DNA using heat

114
Q

FISH fluorescent in situ hybridization

A

Usually fluorescent proves to monitor hybridization

115
Q

Probes

A

Nucleic acid that will hybridize ONLY with specific chromosomal areas

116
Q

Agarose gel

A

Pour us matrix restricts migration of larger molecules more than it restricts smaller ones