Exam-1 Flashcards
If the somatic cells of a diploid organism have 24 total chromosomes, how many chromosomes are expected in each gamete of that organism?
12
Meiosis I separates _____ into daughter cells, while meiosis II separates ______ into daughter cells
homologous chromosomes
sister chromatids
If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents?
it has half the amount of DNA as the starting cell that began meiosis.
A sexually reproducing plant has 2 independently assorting genes, one for stem height (T) and one for petal color (P). Its genotype is TTPP. What is a possible genotype from this plant
TP
Consider an organism that is heterozygous for two genes A and B, located on the same chromosome. AB/ab. If a single crossover occurs between the genes in every cell undergoing meiosis (in 100% of meiotic cells.) what would the recombination frequency between the genes be?
50%
Isolated congenital asplenia (ICA) is a genetic defect that is characterized by the absence of a spleen at birth with no other developmental defects. ICA predisposes individuals to severe bacterial infections in early childhood. Most cases of ICA are sporadic, however some are inherited in an autosomal dominant mode. a 2018 study identified several new mutations that caused ICA and identified a few individuals with one of these new mutations that had a spleen. ICA appears to display.
incomplete penetrance
On a fox ranch, a mutation arose that gave a “platinum” coat color, which became very popular with buyers of fox coats. However, breeders could not develop a true-breeding platinum strain of foxes. Every time two platinum foxes were crossed, some normal foxes appeared in the progeny. Repeated mating of the same pair of platinums produced 82 platinum and 38 normal. This allele is behaving as
a recessive lethal allele
A gamete has experienced a chromosomal mutation and the offspring exhibit a reduction in chromosome number but no loss of gene segments. Which type of chromosomal variation has likely occurred?
a robertsonian translocation
You setup a cross between two parents EF/EF and ef/ef. The F1 offspring are then test crossed with tester parents with this genotype ef/ef. What genotypes would you see if the offspring if there is complete genetic linkage
EF/ef and ef/ef
What ratio of offspring would be expected from a cross of individuals that are heterozygous for both height and color? (tall and yellow are dominant
9:3:3:1
Chrysanthemums have a haploid chromosome number of 9. How many chromosomes are found in a tetraploid chrysanthemum?
n=9
4n=36
The wild guava, is a diploid plant with a haploid chromosome number of 22.
a) how many sets of chromosomes are in the diploid somatic cells
b) how many total chromosomes are each somatic cell?
c) how many total chromosomes are in each gamete?
d) how many total chromatids are there in a germ cell in metaphase II of meiosis?
e) how many sets of each chromosome are there in an egg cell? (gamete)
f) how many total chromosomes are there in that egg cell?
a) 2 sets
b) 44
c) 22
d) 44
e) 1
f) 22
Why do polyploid individuals with an even number of chromosome sets have a higher likelihood of fertility than those with an odd number of chromosome sets
odd numbered polyploids cant all pair with a homolog, because there will be one without a partner. Leaving it with incomplete chromosome sets
In humans, the gene for beta globin which encodes a polypeptide that is a component of the protein hemoglobin, is located on chromosome 11. The gene for alpha globin is located on chromosome 16, would these two chromosomes be expected to pair with each other during meiosis?
no because the are not homologs, they would not pair with each other. they are likely different in size, shape and centromere position. They express proteins of a similar function but do not pair with each other
