Exam 1 Flashcards
(127 cards)
1
Q
William Harvey (1578-1657)
A
theory of epigenesis
2
Q
theory of epigenesis
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structures are not initially present and develop over time
3
Q
Schleiden and Schwann
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cell theory, all living things are composed of cells
4
Q
Charles Darwin
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natural selection and descent with modification
5
Q
Mendel
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quantitative data to support his findings published in 1866
6
Q
Mitosis stages
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prophase, metaphase, anaphase, telophase
7
Q
Meiosis differs from mitosis in that:
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4 gametes that are haploid, not diploid
8
Q
Diploid number
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cell condition when two of each type of chromosome are present (2 “sets” of chromosomes)
9
Q
alleles
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Different forms of a gene
10
Q
Avery, MacLeod, McCarty
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found DNA is the carrier of genetic information
11
Q
DNA structure
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antiparallel, double helix, phosphate - sugar - base
12
Q
Pyrimidines
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thymine and cytosine
13
Q
purines
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Adenine and Guanine
14
Q
Transcription
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DNA to RNA
15
Q
translation
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The process by which mRNA is decoded and a protein is produced
16
Q
Recombinant DNA
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DNA produced by combining DNA from different sources
17
Q
Reverse Genetics
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discovering gene function from a genetic sequence
18
Q
Gene knockout
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made by disrupting the function of a gene
19
Q
Chromatin
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long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes
20
Q
Peptidoglycan
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makes up bacterial cell walls; sugars cross-linked by short polypeptides
21
Q
Glycocalyx
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The external surface of a plasma membrane that is important for cell-to-cell communication
22
Q
Nucleoid
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A dense region of DNA in a prokaryotic cell.
23
Q
Centrioles
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Cell organelle that aids in cell division in animal cells only, organizes spindle fibers
24
Q
Homologous pairs
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Chromosomes that each have a corresponding chromosome from the opposite-sex parent
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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
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Karyokinesis
division of a cell nucleus during mitosis.
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Cytokinesis
Division of the cytoplasm during cell division
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cell cycle checkpoints
control mechanisms which ensure proper division of the cell
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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
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Kinetochore
protein structure where microtubules attach during mitosis
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Disjunction
the separation of homologous chromosome pairs
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Meiosis I
Homologous chromosomes separate
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Meiosis II
sister chromatids separate
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crossing over
the exchange of genetic material between homologous chromosomes during meiosis
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Mendel model organism
peas
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monohybrid cross
A cross between individuals that involves one pair of contrasting traits
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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.
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reciprocal cross
reverse the phenotypes of each parent relative to the initial cross
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segregation
separation of alleles during gamete formation
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Punnett square
diagram showing the gene combinations that might result from a genetic cross
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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
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Independent Assortment
genes assort independently during gametes formation
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trihybrid cross
three pairs of contrasting traits crossed
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Discontinuous variation
The pattern of variation for a trait whose phenotypes fall into two or more distinct classes
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Continuous variation
A characteristic that changes gradually after a range of values ex. Height
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chromosomal theory of inheritance
The idea that the genetic material in living organisms is contained in chromosomes.
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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
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null hypothesis
2 sets of data are not statistically different from each other
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degrees of freedom
n-1
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pedigree
A diagram that shows the occurrence of a genetic trait in several generations of a family.
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pedigree conventions
circle - female square - male diamond - unknown sex
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gene interaction
the idea that several genes influence a particular characteristic
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Mutation
a random error in gene replication that leads to a change
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Wild type allele
Traits prevailing in nature (the more common traits) - Not necessarily the dominant trait
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loss of function mutation
Mutation that results in a gene product or protein having less or no function
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gain of function mutation
Mutation that results in the gene product or protein having a new and abnormal function
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dominant allele
An allele whose trait shows up in the organism when the allele is present
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recessive allele
An allele that is masked when a dominant allele is present
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Incomplete dominance
situation in which one allele is not completely dominant over another, pink
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Tay-Sachs disease
neuron membranes do not develop properly, therefore cannot conduct impulses properly
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threshold effect
normal phenotypic expression results if 50% or less of a gene is expressed
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Codominance
A condition in which neither of two alleles of a gene is dominant or recessive - joint expression
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multiple alleles
three or more forms of a gene that code for a single trait
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Bombay phenotype
Homozygous recessive for a mutation which masks the genotype for blood groups
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lethal alleles
Mutated genes that are capable of causing death
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Dominant lethal allele
presence of one or more copy of the allele means death
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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
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Mutant Allele
The less-occurring trait, not necessarily recessive.
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Recessive Lethal Allele
sufficient for survival
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gene interaction
the idea that several genes influence a particular characteristic
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Epistasis
interaction between alleles in which one allele hides the effects of another allele
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hereditary deafness
the mutation that interrupts many of the steps of ear development
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Dominant Epistasis
- when dominance at one allele can overshadow other genes
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Complementation Analysis
screens the number of individual mutations resulting in the same phenotype, and can predict the total number of genes determining a trait
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Complementation Group
all mutations present in a single gene
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Pleiotropy
The ability of a single gene to have multiple effects.
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Marfan syndrome
autosomal dominant; pleiotropic; tall, weak heart
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porphyria Variegata
autosomal disorder of toxic buildup of porphyrins in the body
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X linked genes
Genes found on the X chromosome.
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color blindness
a variety of disorders marked by the inability to distinguish some or all colors, X chromosome-linked
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Duchenne Muscular Dystrophy
a form of muscular dystrophy that weakens and progressively destroys muscle tissue, lethal x linked recessive disorder
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sex-limited inheritance
expression of the specific phenotype is absolutely limited to one sex
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sex influenced trait
an autosomal trait that is influenced by the presence of male or female sex hormones
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Phenotypic expression
influenced by the environment and by genes
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Penetrance
percentage of expression of the mutant genotype in a population
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Expressivity
the degree to which a particular genotype is expressed in the phenotype
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position effect
Dependence of the expression of a gene on the gene's location in the genome
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temperature-sensitive mutations
Phenotypic expression is partially determined by the surrounding temperature
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nutritional mutation
phenotype expressed or not based on nutrition
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Phenylketonuria
A birth defect that causes an amino acid called phenylalanine to build up in the body.
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Galactosemia
absence of a necessary enzyme that breaks down fatty galactose
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Lesch-Nyhan Syndrome
x linked recessive, purine salvage enzyme defect, normal for about 6 months and then dies
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genetic anticipation
symptoms appear at an earlier age and with more severity across generations
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genomic imprinting
One parent imprints (inactivates) the gene during transmission to offspring
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Prader-Willi Syndrome
the paternal segment is deleted
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Angelman Syndrome
Clinical features with molecular genetic testing and/or cytogenetic analysis, the maternal segment is deleted
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DNA methylation
chemical modification of parts of the genome may prevent gene expression
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complete linkage
linkage without crossing over
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linkage
the tendency of genes on a chromosome to be inherited together
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crossing over
non-sister chromatids exchanging DNA segment
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Linkage ratio
the complete linkage between 2 genes due to close proximity
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linkage group
Genes located together on the same chromosome
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chiasmata
X-shaped regions where crossing-over occurred.
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Sturtevant
realized that genes could be linked and came up with the first genetic map of chromosomes
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map units
unit of distance between genes. 1 = 1% recombination frequency.
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single crossover
Leads to half recombinant, half non-recombinant
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Double crossover
double exchanges of genetic material, used to determine the distance between three linked genes and genes must be heterozygous for 2 alleles
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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
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Interference
inhibition of further crossing over events, inhibited by another crossing over event nearby and reduces the expected number of multiple crossovers
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coefficient of coincidence
the ratio of observed double crossovers to expected double crossovers
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Complete interference
no double crossovers
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Positive interference
fewer double crossovers than expected
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negative interference
more double crossovers than expected
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somatic cell hybridization
assigning human genes to their respective chromosomes
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heterokaryon
a cell composed of different nuclear types (i.e. multiple nuclei) in a common cytoplasm
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synkaryon
heterokaryon where nuclei are fused
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synteny testing
presence or absence of each chromosome with the presence or absence of each gene product
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DNA marker
a unique DNA sequence linked to a trait or disease
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Restriction Fragment Length Polymorphisms (RFLPs)
polymorphic sites generated when specific DNA sequences are recognized and cut by restrictive enzymes
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Microsatellites
Non-coding stretches of DNA that are highly repetitive and have a high mutation rate
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single nucleotide polymorphism
variation in a DNA sequence occurring when a single nucleotide in a genome is altered.
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Cystic fibrosis
A disease that affects the mucous glands throughout the body
