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BIOL 3451 - Genetics Lecture > Exam 1 > Flashcards

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1

William Harvey (1578-1657)

theory of epigenesis

2

theory of epigenesis

structures are not initially present and develop over time

3

Schleiden and Schwann

cell theory, all living things are composed of cells

4

Charles Darwin

natural selection and descent with modification

5

Mendel

quantitative data to support his findings published in 1866

6

Mitosis stages

prophase, metaphase, anaphase, telophase

7

Meiosis differs from mitosis in that:

4 gametes that are haploid, not diploid

8

Diploid number

cell condition when two of each type of chromosome are present (2 "sets" of chromosomes)

9

alleles

Different forms of a gene

10

Avery, MacLeod, McCarty

found DNA is the carrier of genetic information

11

DNA structure

antiparallel, double helix, phosphate - sugar - base

12

Pyrimidines

thymine and cytosine

13

purines

Adenine and Guanine

14

Transcription

DNA to RNA

15

translation

The process by which mRNA is decoded and a protein is produced

16

Recombinant DNA

DNA produced by combining DNA from different sources

17

Reverse Genetics

discovering gene function from a genetic sequence

18

Gene knockout

made by disrupting the function of a gene

19

Chromatin

long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes

20

Peptidoglycan

makes up bacterial cell walls; sugars cross-linked by short polypeptides

21

Glycocalyx

The external surface of a plasma membrane that is important for cell-to-cell communication

22

Nucleoid

A dense region of DNA in a prokaryotic cell.

23

Centrioles

Cell organelle that aids in cell division in animal cells only, organizes spindle fibers

24

Homologous pairs

Chromosomes that each have a corresponding chromosome from the opposite-sex parent

25

Centromere

Area where the chromatids of a chromosome are attached

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somatic cells

Any cells in the body other than reproductive cells

27

Karyokinesis

division of a cell nucleus during mitosis.

28

Cytokinesis

Division of the cytoplasm during cell division

29

cell cycle checkpoints

control mechanisms which ensure proper division of the cell

30

cell cycle checkpoints

G1 G2 M

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Separase

enzyme that degrades cohesin

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shugoshin

Maintains centromere cohesion until meiosis II

33

Kinetochore

protein structure where microtubules attach during mitosis

34

Disjunction

the separation of homologous chromosome pairs

35

Meiosis I

Homologous chromosomes separate

36

Meiosis II

sister chromatids separate

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crossing over

the exchange of genetic material between homologous chromosomes during meiosis

38

Mendel model organism

peas

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monohybrid cross

A cross between individuals that involves one pair of contrasting traits

40

F1 generation

the first generation of offspring obtained from an experimental cross of two organisms

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F2 generation

Offspring resulting from the interbreeding of the hybrid F1 generation.

42

reciprocal cross

reverse the phenotypes of each parent relative to the initial cross

43

segregation

separation of alleles during gamete formation

44

Punnett square

diagram showing the gene combinations that might result from a genetic cross

45

test cross

Used to figure out if the genotype is heterozygous or homozygous dominant - cross between dominant phenotype and homozygous recessive

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dihybrid cross

A cross between two individuals, concentrating on two definable traits

47

Independent Assortment

genes assort independently during gametes formation

48

trihybrid cross

three pairs of contrasting traits crossed

49

Discontinuous variation

The pattern of variation for a trait whose phenotypes fall into two or more distinct classes

50

Continuous variation

A characteristic that changes gradually after a range of values ex. Height

51

chromosomal theory of inheritance

The idea that the genetic material in living organisms is contained in chromosomes.

52

Chi-squared test

a test of association that is used with nominal data in the form of frequencies - to see if the outlying numbers are due to random chance

53

null hypothesis

2 sets of data are not statistically different from each other

54

degrees of freedom

n-1

55

pedigree

A diagram that shows the occurrence of a genetic trait in several generations of a family.

56

pedigree conventions

circle - female square - male diamond - unknown sex

57

gene interaction

the idea that several genes influence a particular characteristic

58

Mutation

a random error in gene replication that leads to a change

59

Wild type allele

Traits prevailing in nature (the more common traits) - Not necessarily the dominant trait

60

loss of function mutation

Mutation that results in a gene product or protein having less or no function

61

gain of function mutation

Mutation that results in the gene product or protein having a new and abnormal function

62

dominant allele

An allele whose trait shows up in the organism when the allele is present

63

recessive allele

An allele that is masked when a dominant allele is present

64

Incomplete dominance

situation in which one allele is not completely dominant over another, pink

65

Tay-Sachs disease

neuron membranes do not develop properly, therefore cannot conduct impulses properly

66

threshold effect

normal phenotypic expression results if 50% or less of a gene is expressed

67

Codominance

A condition in which neither of two alleles of a gene is dominant or recessive - joint expression

68

multiple alleles

three or more forms of a gene that code for a single trait

69

Bombay phenotype

Homozygous recessive for a mutation which masks the genotype for blood groups

70

lethal alleles

Mutated genes that are capable of causing death

71

Dominant lethal allele

presence of one or more copy of the allele means death

72

Huntington's disease

caused by a dominant allele for a protein found in brain cells, heterozygous delayed until adulthood, progressive degeneration of nervous system dominant autosomal allele

73

Mutant Allele

The less-occurring trait, not necessarily recessive.

74

Recessive Lethal Allele

sufficient for survival

75

gene interaction

the idea that several genes influence a particular characteristic

76

Epistasis

interaction between alleles in which one allele hides the effects of another allele

77

hereditary deafness

the mutation that interrupts many of the steps of ear development

78

Dominant Epistasis

- when dominance at one allele can overshadow other genes

79

Complementation Analysis

screens the number of individual mutations resulting in the same phenotype, and can predict the total number of genes determining a trait

80

Complementation Group

all mutations present in a single gene

81

Pleiotropy

The ability of a single gene to have multiple effects.

82

Marfan syndrome

autosomal dominant; pleiotropic; tall, weak heart

83

porphyria Variegata

autosomal disorder of toxic buildup of porphyrins in the body

84

X linked genes

Genes found on the X chromosome.

85

color blindness

a variety of disorders marked by the inability to distinguish some or all colors, X chromosome-linked

86

Duchenne Muscular Dystrophy

a form of muscular dystrophy that weakens and progressively destroys muscle tissue, lethal x linked recessive disorder

87

sex-limited inheritance

expression of the specific phenotype is absolutely limited to one sex

88

sex influenced trait

an autosomal trait that is influenced by the presence of male or female sex hormones

89

Phenotypic expression

influenced by the environment and by genes

90

Penetrance

percentage of expression of the mutant genotype in a population

91

Expressivity

the degree to which a particular genotype is expressed in the phenotype

92

position effect

Dependence of the expression of a gene on the gene's location in the genome

93

temperature-sensitive mutations

Phenotypic expression is partially determined by the surrounding temperature

94

nutritional mutation

phenotype expressed or not based on nutrition

95

Phenylketonuria

A birth defect that causes an amino acid called phenylalanine to build up in the body.

96

Galactosemia

absence of a necessary enzyme that breaks down fatty galactose

97

Lesch-Nyhan Syndrome

x linked recessive, purine salvage enzyme defect, normal for about 6 months and then dies

98

genetic anticipation

symptoms appear at an earlier age and with more severity across generations

99

genomic imprinting

One parent imprints (inactivates) the gene during transmission to offspring

100

Prader-Willi Syndrome

the paternal segment is deleted

101

Angelman Syndrome

Clinical features with molecular genetic testing and/or cytogenetic analysis, the maternal segment is deleted

102

DNA methylation

chemical modification of parts of the genome may prevent gene expression

103

complete linkage

linkage without crossing over

104

linkage

the tendency of genes on a chromosome to be inherited together

105

crossing over

non-sister chromatids exchanging DNA segment

106

Linkage ratio

the complete linkage between 2 genes due to close proximity

107

linkage group

Genes located together on the same chromosome

108

chiasmata

X-shaped regions where crossing-over occurred.

109

Sturtevant

realized that genes could be linked and came up with the first genetic map of chromosomes

110

map units

unit of distance between genes. 1 = 1% recombination frequency.

111

single crossover

Leads to half recombinant, half non-recombinant

112

Double crossover

double exchanges of genetic material, used to determine the distance between three linked genes and genes must be heterozygous for 2 alleles

113

three-point mapping

the parent must be heterozygous for all 3 genes phenotype class must reflect the genotype of gametes parents sufficient number of offspring must be produced for a represented sample

114

Interference

inhibition of further crossing over events, inhibited by another crossing over event nearby and reduces the expected number of multiple crossovers

115

coefficient of coincidence

the ratio of observed double crossovers to expected double crossovers

116

Complete interference

no double crossovers

117

Positive interference

fewer double crossovers than expected

118

negative interference

more double crossovers than expected

119

somatic cell hybridization

assigning human genes to their respective chromosomes

120

heterokaryon

a cell composed of different nuclear types (i.e. multiple nuclei) in a common cytoplasm

121

synkaryon

heterokaryon where nuclei are fused

122

synteny testing

presence or absence of each chromosome with the presence or absence of each gene product

123

DNA marker

a unique DNA sequence linked to a trait or disease

124

Restriction Fragment Length Polymorphisms (RFLPs)

polymorphic sites generated when specific DNA sequences are recognized and cut by restrictive enzymes

125

Microsatellites

Non-coding stretches of DNA that are highly repetitive and have a high mutation rate

126

single nucleotide polymorphism

variation in a DNA sequence occurring when a single nucleotide in a genome is altered.

127

Cystic fibrosis

A disease that affects the mucous glands throughout the body