somatic cells have __ chromosomes
46
chromatin is found in the
nucleus
reproductive cells have __ chromosomes
23
reproductive cells
germ cells
cells total hereditary endowment of DNA
genome
DNA is complexed with proteins called
histones
__ forms chromosomes
chromatin
length of cell cycle varies from
10-30 hours
G1
growth
S
replication
G2
preparation for division
function of mitosis
separate genetic info into 2 quantities
organize microtubules of spindle apparatus
centrosomes
region where chromatids are held together
centromere
protein structure on chromatids where spindle microtubules attach
kinetochore
kinetochore is located at the __ region
centromere
interphase has __ nucleus
1
interphase has __ chromosomes, each consisting of __ chromatid(s)
46, 1
prophase has __ nucleus
1
prophase has __ chromosomes, each consisting of __ chromatid(s)
46, 2
telophase has __ nucleus
2
t/f: cell cycle includes both interphase and mitosis
true
t/f: interphase is much longer and complicated than mitosis
true
__ phase of cell cycle is the key phase in controlling cell division
G1
determines whether cell divides
restriction point of G1
stimulates other cells to divide
growth factor
says that crowded cells usually stop dividing
density dependent inhibition
a single individual is the sole parent and passes on all of its genes directly to its offspring
asexual reproduction
group of genetically identical individuals
clone
t/f: no multicellular organisms can reproduce asexually
false, some can
the only possible differences between the parent and offspring will be via __
mutations
much greater genetic variation results from __ reproduction compared to __ reproduction
sexual, asexual
karyotype organizes chromosomes according to
number, size, type
chromosomes in karyotype are arrested in the __ stage of mitosis
metaphase
chromosomes that look quite similar but were inherited from different parents
homologous chromosomes
in __ organisms, chromosomes are matched in homologous pairs
diploid
specific location of a gene
locus
homologs differ in the version of some genes at their corresponding __
loci
X and Y
sex chromosomes
non sex chromosomes
autosomes
cell with a single set of chromosomes
haploid
cell containing 2 sets of chromosomes, one from each parent
diploid
process that halves the diploid set to a single haploid set of chromosomes
meiosis
restores the diploid set from meiosis
fertilization
meiosis II results in __ daughter cells instead of 2 and each has only __ the number of chromosomes
4, half
arrangement of chromosomes on the __ plate determines which chromosomes will be packaged together
metaphase I
a point at which paired chromosomes remain in contact during metaphase I of meiosis, and at which crossing over and exchange of genetic material occur.
chiasmata
crossing over occurs during __ of meiosis I
prophase
__ produces individual chromosomes that combine genes inherited from our 2 parents
crossing over
when homologous portions of 2 non sister chromatids trade places
recombination
humans have - crossovers per pair of chromosomes
2-3
yellow, purple, round
dominant
green, white, wrinkled
recessive
each gamete has __ allele(s)
1
members of a pair of genes separate from each other during gamete formation
law of segregation
each character an organism inherits __ allele(s)
2
alternate versions of genes
alleles
genetic composition
genotype
outward appearance
phenotype
cross involving genes at 1 locus
monohybrid cross
to determine genotype of a parent with a dominant phenotype, a __ can be done on unknown genotype
test cross
tester
homozygous recessive
mendel's second law
law of independent assortment
says that genes for a pair of traits are distributed independently of one another when gametes are formed
law of independent assortment
law of independent assortment only occurs when the genes are
on separate chromosomes
examines the inheritance of genes at __ loci
2
dominant allele codes for
functional protein
recessive allele codes for
nonfunctional protein
__ dominance says that YY and Yy have the same phenotype
complete
__ dominance says that both alleles are expressed. ex: AB blood
co
__ dominance says that the phenotype is intermediate between homozygous phenotypes
incomplete
an individual can only have __ alleles per locus
2
t/f: an individual can only have 2 alleles per locus, but there can be more than 2 in the population
true
blood groups are examples of (2)
multiple alleles and codominance
t/f: each sperm and egg can have multiple alleles
false; only 1
gene interaction
epistasis
a gene at one location may affect more than one trait
pleiotropy
multiple genes affect one trait
polygenic inheritance
phenotype is the results of interaction between
genotype and environment
males designated with __
squares
females designated with __
circles
trait being traced is designated with __
shaded area
a death is designated with __
slashed area
chromosomes occur in __ nuclei
2n
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