Genetics Test 2 Flashcards
0
Q
Social sex determination
A
Many fish undergo sex reversal, depends on the mating system
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
2
Q
Modifications at chromosome level
A
Phenotype variations (often substantial) result from changes of individual genes
3
Q
Chromosome level mutations and aberrations
A
Total number of chromosomes vary, deletions, duplications, rearrangements
4
Q
Aneuploidy
A
Organism gains or loses one or more chromosomes but not the entire set
5
Q
Euploidy
A
Complete haploid sets of chromosomes beyond two are present (polyploidy more than 2, triploidy 3)
6
Q
Nondisjunction
A
Gives rise to chromosome variation when paired homologs fail to disjoin during segregation (meisosis 1 or 2)
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
8
Q
Haploinsufficiency
A
When one copy is not sufficient for an organism to survive
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
10
Q
Trivalent
A
Three copies of chromosome are synapsed
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
12
Q
Down syndrome
A
Trisomy of chromosome 21, has 12-14 defining characteristics (of which those affected experience 6-8)
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
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
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
16
Q
Trisomics
A
Often found in spontaneously aborted fetuses
17
Q
Polyploidy
A
More than two multiples of haploid chromosomes found
18
Q
Autopolyploidy
A
Addition of one or more sets of chromosomes identical to haploid complement of same species
19
Q
Allopolyploidy
A
Combination of chromosome sets from different species as consequence of hybridization
20
Q
Allotetraploid
A
Polyploid contains equivalent of four haploid genomes derived from separate species
21
Q
Amphidiploid
A
Allotetraploid with full diploid genome of each parent species
22
Q
Endopolyploidy
A
Condition where any certain cells in diploid organism are polyploid, set of chromosomes replicates repeatedly without nuclear division
23
Q
Chromosome rearrangements
A
Deletions, duplications, inversions, nonreciprocal trans locations, reciprocal trans locations
24
Alteration of chromosomes
Deletions and duplications (total amount of chromosomes changes)/inversions and translocations (same but rearranged)
25
Deletions
Missing region of chromosome
26
Completion loop
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
27
Cri-du-chat
Deletions of small terminal portion of chromosome 5p, segmented deletion, infants exhibit anatomical malformations
28
Duplication
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
29
Gene redundancy
Ex. rRNA, multiple copies of genes encode for ribosomal RNA genes
30
Gene amplification
Another mechanism that increases rRNA, oocytes store nutrients including ribosomes, used by embryo in early development for rRNA synthesis
31
Gene duplication
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
32
Copy number variants (CNVs)
Represent quantitative differences in number of large DNA sequences, found in coding and noncoding regions of genome, play crucial role in expression of traits
33
Inversion
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
34
Types of inversions
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)
35
Inversion loop
Inverted and noninverted chromosomes in meiosis paired only if they form inversion loop
36
Translocation
Movement of chromosomal segment to new location in genome
37
Reciprocal translation
Involved exchange of segments between two nonhomologous chromosomes, genetic mutation is lot or gained, has unusual synapsis configuration during meiosis
38
Segregation patterns
Alternate segregation (pattern at first meiotic division, complete set of genetic information) adjacent segregation (leads to gametes containing duplications and deficiencies)
39
Robertsonian translocation
Involves breaks at extreme ends of the short arms of two nonhomologous chromosomes, small segments are lost, large submetacentric chromosome produced
40
Fragile sites
More susceptible to chromosome breakers when cultured in a sense of folic acid or other chemicals, sites imdicate regions of non-rightly coiled chromatin
41
Fragile X syndrome (Martin bell syndrome)
Folate sensitive site on X chromosome exhibits FXS, most common form of inherited mental retardation; dominant trait
42
Semi conservative DNA replication
Each replicated DNA molecule consists of one old strand and one new strand
43
Conservative DNA replication
Two newly synthesized strands come together, original helix is conserved
44
Dispersive DNA replication
Parental strands are dispersed into two new double helices
45
Meselson and Stahl
Provided strong evidence that DNA is semiconservative in prokaryotes
46
Taylor-Woods-Hughes
DNA replication is semiconservative in eukaryotes
47
Audiography
Pinpoints location of radioisotope in cells, results: presence of dark grains identifies location of newly synthesized DNA
48
Origin of replication (ORI)
Where DNA replication begins
49
Replication fork
Where the helix is unwound at the site of replication
50
Bidirectional
The fact that DNA replication goes both ways aka there are two replication forks
51
Replicon
Length of DNA replicated
52
DNA synthesis in bacteria involves _____ polymerase as well as other enzymes
5
53
Polymerase only add to the ______ end
3'
54
Polymerase III
Holoenzyme contains core enzyme complexes made up of subunits (polymerase, exonuclease, core assembly), different parts do different things
55
Holoenzyme
Active form of polymerase III
56
Unwinding
An issue during replication if not done properly
57
Coiling
It's imperative to reduce increased coiling during DNA replication, generated during unwinding
58
Primer
DNA requires a primer to initiate replication
59
Lagging strand
The second strand of DNA replicated that requires a more complex process and creates Okazaki fragments
60
RNA primers
Must be removed for replication
61
Gap filling DNA
Must be joined to the adjacent strand during replication
62
Proofreading
Issue in DNA replication because it doesn't occur
63
The condition that exists when an organism gains or loses one or more chromosomes but not a complete haploid set is known as
Aneuploidy
64
A condition in which chromosome count is altered by the addition of loss of an entire 1n chromosome set?
Euploidy
65
Nondisjunction is viewed as a major cause of aneuploidy (true or false)
True
66
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)
False, 2n+1 is trisomy
67
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 translocation between chromosome 21 and another chromosome
68
Which is not a form of chromosomal aberration: duplication, deletion, point mutation, deviation in #chromosomes, rearrangements
Point mutation
69
I'm angiosperms the unique event known as double fertilization results in a ____________ zygote and a ____________ endosperm nuclei
Diploid;triploid
70
The phenomenon where having a single copy of a chromosome is not sufficient for an organism to survive
Haploinsufficiency
71
Which kingdom is knwon for being particularly flexible in regards to viability in the face of varied chromosome numbers?
Plantae
72
This term refers to the hybrid condition of having 2 complete diploid genomes; one from each parent species
Amphiploid
73
Mitochondrial mutations are passed equally to offspring by both male and females (true or false)
False only females
74
What term is applied when two genes fail to assert independently, that is they tend to segregate together during gamete formation
Linkage
75
One explanation for organelle inheritance is that_________
Mitochondria and chloroplasts have DNA that is subject to mutation
76
Which of the following organelles are involved in the general category of organelle heredity?
Mitochondria and chloroplasts
77
What is the name of a form of extrachromosomal inheritance that is due to transmission of symbiotic or parasitic microorganisms
Infectious heredity
78
Linkage (viewed from results of typical crosses) always occurs when two loci are on the same chromosome (true or false)
False
79
This theory explains both an origin of extra nuclear inheritance and the origin of eukaryotic life?
Endosymbiosis
80
What relatively recent scientific advancement has made mapping by linkage or classical genetic mapping approaches virtually obsolete
The genome sequence of a species
81
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 ___________
Extrachromosomal inheritance
82
If two gene loci are on nonhomologous chromosomes, genes at these loci are expected to as sort independently. (True or false)
True
83
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)
True
84
Genetic material
Information contained in genes that gets passed onto new generation, source of variability
85
To serve as genetic material a molecule must be able to
Replicate, store information, express information, allow variation by mutation
86
Central dogma
DNA to RNA to protein
| DNA makes RNA (transcription) which makes proteins (translation)
87
Protein as genetic material
Until 1994, genetics favored proteins as genetic material since proteins were diverse and abundant in cells
88
Tetranucleic hypothesis
DNA contains equal amounts of four nucleotides, postulated identifies groups and repeats of four components was basis for DNA structure
89
Evidence favoring DNA
Avery Macleod McCarty, first direct experiment proof that DNA is biomolecule responsible for heredity
90
Griffith transformation experiment
Provided foundation for Avery Macleod and McCarty, showed avirulent strains could be transformed to virulent
91
Hershey and chase
Demonstrated that DNA, not protein, is the genetic material using radioisotopes, demonstrated that DNA enters bacterial cell during infection and directs viral reproduction
92
Transfection
Infection by only viral nucleic acid, proves conclusively that viral DNA alone contains all necessary information for production of mature viruses
93
Indirect evidence of DNA as genetic material
Distribution of DNA, mutagenesis: UV light mutates genetic material at 260 nm
94
Direct evidence
Recombinant DNA technology, eukaryotic DNA now functional in bacterial cell, trans gene animals
95
RNA genetic material
Ribose sugar, some viruses have RNA core
96
Nucleotides
DNA is a nucleic acid, binary blocks of nucleic acid, the building blocks of DNA, contain nitrogenous base, pentode sugar, phosphate group
97
Nitrogenous bases
Purines adenine and guanine
Pyrimidines cytosine thymine uracil
98
Structure of DNA
Watson and crick model, double helix, two antiparallel strands connected by base pairing, stacked nitrogenous base
99
Analytical techniques
Absorption of UV light, denaturation and renaturation of nucleic acids, molecular hybridization, reassociation kinetics, electrophoresis of nucleic acids
100
Absorption of UV light
Strong at 254-260nm due to interaction between UV light and ring systems of the bases, used in localization isolation and characterization
101
Molecular hybridization
Denaturation and renaturation of nuclear acids are the basis for molecular hybridization
102
Reassociation kinetics
Analyses rate of reassociation if complementary single DNA strands
103
Electrophoresis
Separated DNA and RNA fragments by size, smaller fragments migrate through gel at faster rate than the large fragments
104
DNA bases
Adenine, guanine, cytosine and thymine
105
RNA bases
Adenine uracil cytosine guanine
106
Nucleoside
Contains nitrogenous base and pentose sugar
107
Nucleotide
Nucleoside with a phosphate group
108
Monophosphates
A nucleotide
109
Diphosphates
Nucleotide with the addition of two phosphate groups
110
Triphosphate
Nucleotide with the addition of three phosphate groups, serve as precursor molecule during nucleic acid synthesis
111
Phosphodiester bonds
How nucleotides are linked between phosphate group at c-5' position and oh group on c-3' position
112
Chargaff
Proposed base composition of adenine equal to thymine and cytosine equal to guanine
113
PCR
A way to denature DNA using heat
114
FISH fluorescent in situ hybridization
Usually fluorescent proves to monitor hybridization
115
Probes
Nucleic acid that will hybridize ONLY with specific chromosomal areas
116
Agarose gel
Pour us matrix restricts migration of larger molecules more than it restricts smaller ones
