Question 1

Which of the following best describes the relationship between a gene, its locus, and a trait, as illustrated in the first image?

Accepted Answer

A gene is a specific DNA sequence found at a particular locus on a chromosome, and it determines a specific trait.

Question 2

Based on the second image, which process is being demonstrated by the Hydra and the Redwoods, and what is a key genetic consequence of this process?

Accepted Answer

Asexual reproduction; offspring are genetically identical to the parent.

Question 3

A human somatic cell contains 46 chromosomes. How many pairs of homologous chromosomes does it have?

Accepted Answer

$$23$$

Question 4

Referencing the fourth image, what is the diploid number $$(2n)$$ for this cell, and how many chromosomes are in each set?

Accepted Answer

$$2n = 6$$, with $$n = 3$$ chromosomes in each set.

Question 5

Which of the following statements about the human life cycle (as shown in the fifth image) is correct?

Accepted Answer

Meiosis produces haploid gametes, which fuse during fertilization to form a diploid zygote.

Question 6

Which type of sexual life cycle, as shown in the sixth image, is characterized by an alternation of multicellular haploid and diploid generations?

Accepted Answer

Plants and some algae

Question 7

During which phase of meiosis (as shown in the seventh and eighth images) do homologous chromosomes separate, and what is the result?

Accepted Answer

Anaphase I; homologous chromosomes are separated into two haploid cells.

Question 8

What is the main genetic consequence of crossing over during prophase I of meiosis, as illustrated in the tenth image?

Accepted Answer

It produces recombinant chromosomes, increasing genetic variation.

Question 9

Which of the following events occurs in meiosis but not in mitosis, as shown in the eleventh image?

Accepted Answer

Synapsis and crossing over between homologous chromosomes.

Question 10

If a human gamete with an abnormal number of chromosomes (e.g., $$n = 24) is $$fertilized by a normal gamete ($$n = 23$$), what will be the chromosome number in the resulting zygote?

Accepted Answer

$$47$$

Question 11

Which mechanism is responsible for the independent assortment of chromosomes during meiosis, and how many possible combinations of chromosomes can be produced in human gametes?

Accepted Answer

Random orientation of homologous pairs at metaphase I; $$2^{23}$$ combinations.

Question 12

Which of the following best explains why siblings from the same parents can look different from each other?

Accepted Answer

Independent assortment, crossing over, and random fertilization create genetic variation.

Question 13

Which of the following is true regarding the products of meiosis II, as shown in the ninth image?

Accepted Answer

Each cell contains a haploid set of unduplicated chromosomes.

Question 14

Which of the following is a major difference between mitosis and meiosis?

Accepted Answer

Mitosis produces two genetically identical cells; meiosis produces four genetically unique cells.

Question 15

A mutation occurs in a gene located on a chromosome. What is the most likely consequence of this mutation for the organism?

Accepted Answer

It may result in a new allele, potentially altering the trait controlled by that gene.

Question 16

Which of the following best describes the outcome of fertilization in sexually reproducing organisms?

Accepted Answer

Fusion of two haploid gametes to form a diploid zygote.

Question 17

During which stage of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes.

Question 18

If a diploid organism has a total of $$2n = 8$$ chromosomes, how many different combinations of chromosomes can be produced in its gametes due to independent assortment?

Accepted Answer

$$2^4 = 16$

Question 19

Which of the following is NOT a mechanism that contributes to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during interphase.

Meiosis, Chromosome Behavior, and Genetic Variation: Study Notes for General Biology

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