1. An egg cell in a gorilla contains 24 chromosomes. When the egg cell is fertilized, which of the
following occurs?
A. The 24 original chromosomes replicate, resulting in 48 chromosomes in the fertilized egg.
B. The 24 original chromosomes split at the centromere, resulting in 48 chromosomes in the fertilized egg.
C. The nucleus of a sperm cell fuses with the nucleus of the original egg cell, resulting in 48 chromosomes in the fertilized egg.
D. The nucleus of another egg cell pairs with the nucleus of the original egg cell, resulting in 48 chromosomes in the fertilized egg.
2. Under normal conditions, which of following causes a zygote to form?
A. Mitosis takes place.
B. Meiosis takes place.
C. Two gametes combine.
D. Asexual reproduction occurs.
3. The human body regularly sheds and replaces its skin cells. Which of the following processes is
directly responsible for replacing these cells?
A. meiosis
B. mitosis
C. osmosis
D. transcription
4. Some unicellular protists, such as dinoflagellates, use mitosis to reproduce. Which of the
following statements describes the offspring?
A. The offspring are twice as large as the parent.
B. The offspring are genetically identical to the parent.
C. The offspring develop from a parent’s fertilized egg.
D. The offspring have half as many chromosomes as the parent.
5. Which of the following normally results from meiosis in a human cell that contains 46
chromosomes?
A. an egg cell with 46 chromosomes
B. a liver cell with 23 chromosomes
C. a blood cell with 46 chromosomes
D. a sperm cell with 23 chromosomes

6. The diagram below represents steps in sexual reproduction.
Which of the following occurs in the step labeled Z ?
A. fertilization
B. meiosis
C. mitosis
D. translocation
7. Sarah and her biological sister Danielle have some physical characteristics that are the same
and some that are different, as shown in the table below.
Sarah Danielle
Eye Color blue
Natural Hair Color light brown brown dark brown
Ring Finger Length shorter than index shorter than index
Skin Tone olive olive a. Identify the molecule that stores the hereditary information for these characteristics in the chromosomes of every body cell. b. Identify the total number of chromosomes that should be in one of Sarah’s body cells and the number of chromosomes that should have been contributed by each biological parent. c. Explain the roles of meiosis and fertilization in achieving the chromosome numbers you identified in part (b).

d. Explain why Sarah and Danielle have some physical characteristics that are different from each other, even though they have the same biological parents.
8. Gregor Mendel developed an understanding of heredity through his experiments with pea
plants. The diagram below shows a cell with two pairs of homologous chromosomes and a
genotype of AaBb . a. Identify all the possible allele combinations that could be formed if this cell undergoes meiosis. b. Identify one of Mendel’s laws that is illustrated when you write out these allele combinations.
Explain this law.
9. When looking at a child, many people make statements such as “She has her mother’s eyes” and “She has her father’s hair color.” a. Describe the roles of the following in sexual reproduction:
 meiosis
 gametes
 fertilization
 zygote b. Explain in detail why children’s features may be similar to, but not exactly the same as, their parents’ features.