genetics hw- meiosis, mitosis, nondisjunction
How many sex chromosomes are present in a somatic cell of a human male?
2
A diploid somatic cell from a rathas a total of 42 chromosomes. What is the total number of chromatids present in the cell during metaphase II of meiosis II?
21
Human haploid gametes contain:
23 chromosomes
A diploid somatic cell from a rat has a total of 42 chromosomes. Based on this information, which of the following is true?
2n=42
A diploid somatic cell from a rat has a total of 42 chromosomes. What is the total number of chromosomes present in the cell during metaphase I of meiosis I?
42
Human somatic cells have 46 chromosomes. How many of these are autosomes?
44
A diploid somatic cell from a rat has a total of 42 chromosomes. What is the total number of DNA molecules present in the cell during prophase I of meiosis I?
84
A diploid somatic cell from a rat has a total of 42 chromosomes. What is the total number of telomeres in a rat cell in metaphase II of meiosis II?
84
What term best describes the following chromosome structure?
Acrocentric
Independent assortment occurs during ______________. (assume there is NO crossing over or recombination)
Anaphase I of Meiosis I
A cell from a human female has just undergone meiosis. For unknown reasons, the centromere of the paternal copy of chromosome 18 failed to divide at the appropriate time. What will be the chromosomal content of the four resulting daughter cells?
Gamete one: 23 total chromosomes Gamete two: 23 total chromosomes Gamete three: 22 total chromosomes Gamete four: 24 total chromosomes
Sister chromatids segregate during _________.
Meiosis II anaphase II
The cell illustrated below belongs to a species where 2N = 8 and, as with humans, sex is determined by the presence of X and Y sex chromosomes. Identify the most probable stage of mitosis or meiosis that is represented. (M and P represent Maternal or Paternally derived chromosomes respectively.) pic description: dyads aligned on the middle line of the cellb
Metaphase of meiosis II
Upon successful completion of meiosis, a diploid cell would produce gametes with how many chromosomes, written in n-notation?
N
Duchene Muscular Dystrophy (DMD) is an X-linked recessive condition with the normal allele represented as XDMD and the disease allele represented as Xdmd. Identify the most correct answer from the following options to describe the nondisjunction event associated with the mating and offspring depicted below. (Assume NO crossing over or recombination took place between homologous chromosomes regarding the DMD locus.) XDMDXdmd X XDMDY → XdmdXdmdY (aneuploidy in child with 3 total sex chromosomes, XXY)
Nondisjunction ocurred in the mother during meiosis II
Crossing over or recombination occurs during:
Prophase
Homologous chromosomes have the same genes but can have different alleles for those genes. T/F
True
Identify whether the following statement is true or false. Mitosis results in 2 genetically identical daughter cells whereas meiosis results in 4 genetically unique daughter cells. T/F
True
In the cell cycle, at which stages are chromosomes present as dyads?
beginning of mitosis
