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127 terms

genetical

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t/f while hybrids are usually uniform in F1, they tend to revert to parental phenotypes in F2
true
white and purple flowers are repeatedly crossed, with sexes alternating in color. (sometimes male purple, sometimes male white). Hybrids are always purple, this proves that?
both male and female contribute equally to genetics
a pair of crosses that reverse the sexes associated with a genotype
reciprocal cross
mendels first law of equal segregation
determinants separate when gametes are formed and reassociated randomly into zygotes upon fertilization
mendels second law of segregation
segreation of alleles in TWO DIFFERENT genes is independent of each other
Theory stating that substances present in women and semen directed the development of adult organism
Theory of Epigenesis
theory stating that Substances blended together to yield unique individual with traits from both parents
blending inheritance theory
theory stating that Particles, called gemmules, were collected from all parts of body and became concentrated in germ cells
pangenesis
mendels 5 theories
1-alleles of the same gene are separate
2-Each adult pea has 2 determinants for each character
3- gametes only have 1 determinant for each character
4-Each determinant segregates equally into gametes
5-Union of 2 gametes occurs randomly
probability formula
number of times event occurs/number of trials
breeding cross between P generation (parental generation) organisms that differ in two traits.
dihybrid cross
how to determine probability of independent events occurring together?
find probability of each event and multiply those probabilities
how to determine probability of mutually exclusive events
sum probabilities of each individual event
an offspring with parents exhibiting different expressions of the same trait
hybrid
phenotype of hybrid is intermediate between homozygous parents; neither trait is fully dominant
incomplete dominance
technique used to separate two alleles
gel electrophoresis
F1 hybrids show traits of both parents
co dominance
recessive allele controls expression of other genes WHEN HOMOZYGOUS
recessive epistasis
complementation study expemplefied?
there are 2 genes responsible for pigment formation. either recessive combo makes pigmentation. showed recessive epistasis
many genes are responsible for one trait
polygenic inheritance
genes w/ the same function
duplicate genes
more than 2 alleles for a single gene
multiple alleles
a gene with multiple functions
pleiotropic gene
in the coat color gene study in mice, a yellow coat could not be obtained, seemingly disproving mendels predicted ratio. in the end, what was responsible?
the homozygous combo for yellow was lethal
percentage of individuals with a genotype that exhibit a particular phenotype
penetrance
the extent to which a phenotype is expressed in an individual
expressivity
3 things high powered microscopes/special stains revealed
eukaryotic cells contained nuclei, which contained chromosomes, nuclei in egg and sperm were same size w/ size difference due to cytoplasm, nuclei likely contained genetic info,
t/f number of nuclei differ for every cell in an organism
false, number of nuclei constant
t/f number of nuclei in cells are the same in each species
false, number of nuclei vary by species
part of chromosome strand that connects it sister strand/where microtubules attach
centromere aka kinetochore
ends of chromosome strand
telomere
a replicated chromosome consists of how many strands
2
protein DNA complex that composes chromatids
chromatin fibers
t/f eukaryotic dna is both short and circular
false
DNA would around nucleosomes composed of?
histone proteins
6 phases of mitosis
inter, pro, prometa, meta, ana, telo
longest mitotic phase, centrosome divides and products migrate to polar ends of nucleus
interphase
3 phases of interphase
g1, s, g2
spindles form, sister chromatids join at centromeres and chromosomes condense
prophase
nuclear membrane fragments/chromosomes migrate middle of spindle
prometaphase
microtubules attach to chromosomes at kinetochore, chromosomes line up on equatorial plate
metaphase
chromatids separate and migrate to poles
anaphase
2 phases, nuclear membrane reforms, chromosomes decondense, cleavage furrow
telophase and cytokinesis
egg/sperm cells contain how many chromosomes, adults?
2,4
2 purposes of meiosis
segregates 1 copy of each chromosome into a gamete and mixes genes creating genetically diverse individuals.
5 phases of meiosis
prophase I, prometaphase I, meta I, anaphase I, telo I
meiosis phase in which chromatin condense and synapses align chromosomes
prophase I
2 phases in which parental chromosomes break and rejoin at chiasma
prophase I/prometaphase I
phase in which homologous pairs line up on equatorial plate
metaphase I
phase in which homologous pairs separate
anaphase I
phase of cleavage/formation of diploids
telophase I
t/f during meiosis parent chromosomes are bound together as a pair
false, bound as tetrad during meiosis
mobile junction of 4 strands of DNA that facilitate homologous recombination
holiday junction
t/f genetic diversity is a 2ndary result of recombination. Without it, chromosomes cannot fully separate
true
separation of chromaTIDS happens in meiosis 1 or 2
meiosis 2
precursors to sperm/egg? haploid/diploid?
primary spermatocyte/oocyte, diploid
theory saying genes are located on chromosomes
chromosome theory of inheritance
haploid sperm/egg zygote or gamete
gamete
zygote haploid or diploid
diploid
the PHENOTYPIC expression of an allele related to the chromosomal sex of the individual
sex linkage
in contrast to sex linkage, alleles on autosomes have?
equal inheritance probability for males/females
t/f genes are named after the first mutant (rare phenotype, not necessarily recessive) allele, not the wild type
true
t/f in fruit flies, sex determined by combination of xy or xx chromosome
false, determined by number of x chromosomes
sex determining region of Y chromosome
SRY gene
3 facts of y chromosome
low in # of genes, heterochromatic/highly condensed, SRY gene activated in 7th week of pregnancy
t/f by default humans are male
false, female
having only 1 copy of a chromosome
hemizygous (males only)
term for inactive x chromosome
barr body
each x chromosome has an x-inactivation center where what is located
XIST
high or low levels of XIST inactivate x chromosome
high
inactive x chromosome is heterochromatic, meaning?
highly condensed
t/f human females have twice the amount of X chromosome genes
false, one is randomly deactivated
t/f drosophilia females have same amount of X chromosome genes as males
false, they have twice the amount
phenotype expressed only in one sex
sex limited trait
sex determines whether an allele is dominant or recessive
sex-influenced trait
tendency of certain alleles to be inherited together
gene linkage
phenomena that is exception to mendels law of independent assortment
gene linkage
2 things proved in morgans experiment
genes could be inherited as blocks (linked), alleles could be exchanged in meiosis via recombination
breakage of chromosome, separation of genes and exhcnage of genes between chromatids
recombination
the distance on the genetic map of a chromosome is the average number of?
crossovers between them
place of a gene on a chromosome
locus
genes or segregating alleles
markers
mutations are used to?
mark/follow a gene
test used to determine if observations are due to chance or are significant
chi square
low p values indicate that observations are significant or change?
significant
% chance unlinked genes have of recombination due to independent assortment
50%
max recombination frequency for genes to be considered linked
50%
occurrence of a first cross over interferes with formation of a second one
positive interference
positive interference affects
double crossovers
t/f orientation of junction plays a small role determining type of recombination
false, orientation plays critical role in type of recombination
fertilized egg aka
zygote
bacteria can grow on minimal medium
prototrophic
bacteria can't grow on minimal medium
auxotrophic
mutations in genes encoding the enzymes in a pathway for synthesis of any nutrient leads to?
auxotrophy
encode enzymes that catalyze DNA movement (Transposition)
insertion elements
antibiotic resistance genes
transposons
method to quickly xfer colonies from one plate to another in which og plate pressed on piece of velvet. other plates are pressed against velvet.
replica plating
3 ways bacteria exchange genetic info
transformation, conjugation, transduction
recipient cell acquires genes from free DNA in environment
transformation
DNA is xferred from a bacteria donor cell to recipient cell by cell-cell-contact
conjugation
bacterial dna is xferred from one bacteria to another by phage particle
transduction
DNA that allows bacteria to create a sex pilus for conjugation
F factor
bring bacterial cells together so they can exchange genetic info
pili
hayes experiment showed that?
transfer of DNA between bacteria during conjugation was directional
bacterial conjugation is not true sexual reproduction bc?
in sexual reproduction, both partners contribute equally genetic info.
can F-, F+ or Hfr initiate conjugation
F+
Which of 3 bacteria types yields a low frequency xfer/only contains partial info for F factor
Hfr
t/f gene transfer starts with origin of F factor and ends w/ fertility genes.
true
theory that genes control protein structure
one gene one enzyme theory
3 parts of dna
phosphate, 5 carbon sugar, nitrogenous base
experiment that proved DNA is genetic material/not protein
hershey chase (phage xferred the phosphorus in DNA, not the sulfur in amino acids
4 dna bases
ATGC
purine bases
A(skip)G
pyrimidine bases
T(skip)C
t/f dna strads are anti parallel
true
AT/GC # bonds
2/3 respectively
t/f hydrogen bonding between bases releases before covalent bond of sugar phosphate backbone
true
first level of DNA compaction
supercoiling
number of twists in supercoiled dna as compared to relaxed dna
linkage number
enyzyme that regulates supercoiling
topoisomerase/DNA grase
is DNA pos or negatively charged
neg
are histones pos or neg charged
pos
contransduction freq formula
(1-d/2)cubed
hold chromosome in x shape
scaffold structures
5 part eukaryote chromosome structure
double helix, supercoiling, nucleosomes, chromatin fibers, chromosomes
2 part prokaryote chromosome structure
double hilix, supercoiling
shape of eukaryote coiling
solenoidal