Question 1

Which of the following best describes the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Sister chromatids are identical DNA strands joined at the centromere, while homologous chromosomes have the same genes but may have different alleles.

Question 2

A plant species has a diploid chromosome number of 12. After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

6

Question 3

Which process is responsible for the genetic variation observed in sexually reproducing organisms?

Accepted Answer

Random assortment of chromosomes during meiosis and crossing over between homologous chromosomes.

Question 4

In a human karyotype, chromosomes are displayed in pairs. What is the biological significance of this arrangement?

Accepted Answer

It demonstrates the diploid nature of somatic cells, with one chromosome of each pair inherited from each parent.

Question 5

Which statement about the relationship between genotype and phenotype is correct?

Accepted Answer

Genotype is the genetic makeup, which interacts with the environment to produce the phenotype.

Question 6

Hydrangea flowers can be pink or blue depending on soil pH. What does this illustrate about gene action?

Accepted Answer

Environmental factors can influence the expression of genetic traits.

Question 7

During which phase of the cell cycle do sister chromatids first appear?

Accepted Answer

S phase (DNA replication)

Question 8

What is the primary purpose of mitosis in multicellular organisms?

Accepted Answer

To ensure that each daughter cell receives an exact copy of the parent cell's DNA.

Question 9

Which of the following equations correctly represents the reduction in chromosome number during meiosis?

Accepted Answer

$$2N \rightarrow N$$

Question 10

A person with blood type AB has which genotype?

Accepted Answer

IAIB

Question 11

Which structure is the constricted region of a chromosome that joins sister chromatids?

Accepted Answer

Centromere

Question 12

If a cell with genotype Bb produces gametes through meiosis, what is the expected genotype of the gametes?

Accepted Answer

Either B or b

Question 13

Which of the following best explains why sexual reproduction leads to greater genetic diversity than asexual reproduction?

Accepted Answer

Sexual reproduction includes meiosis and fertilization, which shuffle alleles and combine genetic material from two parents.

Question 14

Which of the following is true about the structure of DNA?

Accepted Answer

Nitrogenous bases form the 'rungs' of the ladder, while the sugar-phosphate backbone forms the 'ribbons'.

Question 15

Which of the following is NOT a function of crossing over during meiosis?

Accepted Answer

Ensuring each gamete receives a complete set of genes.

Question 16

A karyotype is most useful for which of the following?

Accepted Answer

Visualizing the number and structure of chromosomes in a cell.

Question 17

Which of the following best describes the role of histones in the organization of DNA?

Accepted Answer

Histones are proteins that help package DNA into chromatin.

Question 18

During mitosis, what happens to the sister chromatids?

Accepted Answer

They separate and move to opposite poles of the cell.

Question 19

Which of the following is a real-world example of a trait determined solely by genetics, with no environmental influence?

Accepted Answer

ABO blood group

Question 20

If a mutation occurs at a locus on a chromosome, which of the following is most likely to happen?

Accepted Answer

An alternative allele may be created, potentially altering the phenotype.

Genetics and Molecular Biology: Mitosis, Meiosis, and Chromosome Structure

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