mitosis/meiosis/mendelian genetics practice

different phenotypic ratios occur in crosses with single gene pairs or two gene pairs - what types of ratios are likely to occur in crosses dealing with a single gene pair?

3:1, 1:1, 1:2:1

the B-globin gene has many alleles. What is the maximum number of different alleles of the B-globin gene that could be carried by 6 children with the same mom and dad given that the parents are heterozygous?

4

meiotic divisions can produce:

haploid gametess, haploid spores, haploid cells

meiosis involves the creation of haploid cells from diploid cells. The haploid chromosome number is created when

homologous chromosomes separate

at the end of mitosis, each G1 daughter cell has

identical DNA to that of the G1 parent cell

a man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation) - albinism is an autosomal (not sex-linked) recessive trait; what is the probability that their first child will be an albino?

1/4

when Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow seeded- when he took these F1 yellow-seeded plants and crossed them to green-seeded plants, what genotypic ratio is expected?

1:1 (typical test cross)

a certain species of animal has six pairs of chromosomes - how many molecules of DNA do the nuclei of these animals have during G2 phase?

24

in tigers, a recessive allele causes a white tiger (absence of fur pigmentation). If two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring is expected to be white?

25%

a diploid cell 2N=12 undergoes meiosis - how many chromosomes are present in the resulting cells?

6

a black guinea pig crossed with an albino guinea pig produced 12 black offspring. When the albino was crossed with a second black animal, 6 blacks and 6 albinos were obtained. What is the best explanation for this genetic situation?

Albino is recessive; black is dominant.

a man is heterozygous for two genes (R and L) that are located on different chromosome - which process would result in different combinations of the alleles for these two genes in his sperm?

Independent assortment

metaphase occurs prior to the splitting of centromeres. It is characterized by

aligning of chromosomes on the equator

sister chromatids separate during

anaphase II

although the process of chromosome partitioning during mitosis is visible through a light microscope, the process of DNA replication is not, why?

chromosomes are too extended during S phase to be seen by light microscopy.

the egg of a fruit fly has 4 chromosomes- how many chromosomes are in a somatic cell of a fruit fly?

eight

if meiosis produces haploid cells, how is the diploid number restored for those organisms that spend most of their life cycle in the diploid state?

fertilization

a diploid (2N) cell from an individual that is heterozygous for alleles at many genetic loci undergoes a meiosis followed by cytokinesis - this results in:

four genetically distinct haploid cells

chromosomes and their homologues align at the equator of the cell during

metaphase I

asexual reproduction takes place by which process?

mitosis

at what stage of meiosis does DNA replication take place?

none.... DNA replication occurs before meiosis I begins

in sexual reproduction, the variation among offspring, and the fact that they are genetically different from their parents, is due to what processes?

random process of fertilization, crossing over, random alignment of homologs during meiosis I, independent assortment

mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation - the results were as follows: 6022 yellow and 2001 green (8023 total). The allele for green seeds has what relationship to the allele for yellow seeds?

recessive

crossover, the exchange of segments of homologous chromosomes, takes place during which of the following processes?

synapsis

a parent cell divides to form two genetically identical daughter cells in the process of mitosis. For mitosis to take place

the parent cell must replicate its entire genome prior to mitosis

T or F: homologous chromosomes carry info for the same traits

true

somatic cells of roundworms have four chromosomes. How many chromosomes would you find in an ovum from a roundworm?

two

a diploid (2N) cell undergoes a mitotic nuclear division followed by cytokinesis - this results in:

two genetically identical diploid cells

a haploid (1N) cell undergoes a mitotic nuclear division followed by cytokinesis - this results in:

two genetically identical haploid cells (a mitotic nuclear division produces two nuclei identical to the original nucleus. During cytokinesis the nuclei are partitioned into separate cells. The result is two identical cells with the same number of chromosomes as the parent cell.