lab 6 Flashcards
what determines if plants or animals are female or male
sex chromosomes
what are non-sex chromosomes called
autosomes
females have ____________ chromosomes
two x
males have ____________ chromsomes
one x and one y
what does meiosis produce
haploids
how is sex of offspring determined
by the type of male gamete that fertilizes the female
gametes with either x or y chromosomes are created with _______ frequencies
equal
how many pairs of autosomes and sex chromsomes do humans have
22 and 1
what happens if a gamete with abnormal chromosome complement participates in fertilization
result with an abnormal amount of number of chromosomes and phenotypic abnormalities
what is a karyotype
a photograph of chromosomes of an actively dividing cell
in diploid individual the chromosome are arranged into ___________ ________
homologous pair
what are the phenotypic abnormalities of turner syndrome
-short stature and non-functioning ovaries
-webbed neck and wide chest
who does turner syndrome affect
females
how is the karyotype different from normal females with turner syndrome
missing an x
what is the phenotypic abnormalities of down syndrome
-mild to moderate mental deficiency
-almond shaped eyes
-poor muscle tone
-short limbs/neck
how is the karyotype different from normal with down syndrome
an extra chromosome on chromosome 21
what are some of the phenotypic abnormalities of klinefelter syndrome
-sterile with small testes
-low levels of testosterone
-learning disability
how is karyotypic difference from normal males different in klinefelter syndrome
an extra x chromosome
who does klinefelter syndrome effect
males
are the dominant phenotypic characteristics always the most common
no
the x chromosome carries same number of ______
as ___________
genes and autosome
y chromosome has ______ chromosomes
fewer
what are genes located on x chromosome said to be
sex-linked
are sex linked traits related to sex
no they produce phenotypes like red-green colour blindness
how is more likely to exhibit sex linked recessive trait
males
heterozygous females dont exhibit sex linked traits but are _______
carriers
what is red-green colour blindness
general term for spectrum of relatively common sex-linked recessive disorder
what is colour blindess include
protan and deutan
what is protan
deficiency caused by reduced # or complete absense of red photoreceptors in eye
what does deficiency of protan result in
reduce visibility and darkening of reds
what is deutan
deficency caused by reduced # or complete absense of green phtoreceptors
what does deficiency of deutan result in
reduced visibility or greens and is in 6% of males
what is a pedigree chart
analysis of how phenotypes are passed on from parents to off-spring
what are polygenic inheritance
phenotypic traits that involve contribution from alleles of many genes at many locations and on separate chromosomes
what are two characteristics of polygenic inheritance
continuous range of phenotypes and normal distribution
what are polygenic traits influenced by
environmental factors
what can a test cross between heteroxygous and homozygous recessive be used for
determining the occurance of non-mendelian inheritance like gene linkage
the crossover frequency between two linked genes is _________ to _________ between them
proportional and distance
if genes are close together what is the outcome
low probability of crossing over resulting in very low number of recombinants
if genes are close together what is the outcome
low probability of crossing over resulting in very low number of recombinants
if genes are further apart what is the outcome
increase probability of crossing over and higher probability of recombinants
the test cross is ______
gene linkage
how is the distance between two genes measured
mind map
what is gene linkage
% of offspring that result in recombinants or the closeness of genes
how is the percent recombination calculated
dividing # of recombinants by total # of offspring x 100
