Biology (Grades 9–10) Midterm — Semester 2, Form B

Part 1: Multiple Choice

1. What is the process of copying a gene's DNA into messenger RNA called?
   1. A. Replication
   2. B. Translation
   3. C. Transcription
   4. D. Mutation
2. During which phase of mitosis do chromosomes line up along the middle of the cell?
   1. A. Prophase
   2. B. Anaphase
   3. C. Telophase
   4. D. Metaphase
3. Where does translation, the building of a protein from mRNA, take place?
   1. A. At a ribosome
   2. B. In the Golgi apparatus
   3. C. In the nucleolus
   4. D. Inside a lysosome
4. A human body cell has 46 chromosomes. How many chromosomes are in a human egg cell?
   1. A. 46
   2. B. 92
   3. C. 12
   4. D. 23
5. Mitosis followed by cytokinesis produces what?
   1. A. Two cells with half the chromosomes
   2. B. Four identical sex cells
   3. C. Two genetically identical cells
   4. D. Four genetically different cells
6. Two heterozygous plants (Aa × Aa) are crossed. What is the expected phenotypic ratio if A is completely dominant?
   1. A. 1:1 dominant to recessive
   2. B. 4:0 dominant to recessive
   3. C. 3:1 dominant to recessive
   4. D. 1:2:1 dominant to recessive
7. Crossing an organism that shows the dominant trait with a homozygous recessive organism to learn its genotype is called what?
   1. A. A dihybrid cross
   2. B. A karyotype
   3. C. A pedigree
   4. D. A test cross
8. Human height varies continuously across a wide range. This is largely because height is what?
   1. A. A codominant trait
   2. B. Influenced by many genes
   3. C. A sex-linked trait
   4. D. Controlled by one gene with two alleles
9. Why is red-green color blindness more common in males than in females?
   1. A. The allele is dominant only in males
   2. B. Females have no color-vision genes
   3. C. Males have only one X chromosome
   4. D. The allele is on the Y chromosome
10. What does Mendel's law of segregation state?
    1. A. Genes on the same chromosome always stay together
    2. B. Dominant alleles are more common
    3. C. Offspring blend their parents' traits
    4. D. The two alleles for a gene separate when gametes form
11. In a population in Hardy-Weinberg equilibrium, 16% of individuals show the recessive phenotype. What is the frequency of the recessive allele?
    1. A. 0.4
    2. B. 0.84
    3. C. 0.16
    4. D. 0.6
12. What do homologous structures, such as the forelimbs of humans, cats, and whales, suggest?
    1. A. The structures evolved separately
    2. B. The species share a common ancestor
    3. C. The species can interbreed
    4. D. The species live in the same habitat
13. Which process removes carbon dioxide from the atmosphere?
    1. A. Burning fossil fuels
    2. B. Photosynthesis
    3. C. Decomposition
    4. D. Cellular respiration
14. A river splits a population in two. After many generations, the groups can no longer interbreed. What process occurred?
    1. A. Convergent evolution
    2. B. Artificial selection
    3. C. Coevolution
    4. D. Speciation through geographic isolation
15. Why do bacterial populations often become resistant to antibiotics over time?
    1. A. Resistant bacteria survive treatment and pass on their resistance genes
    2. B. Antibiotics make every bacterium stronger
    3. C. Antibiotics teach bacteria to resist them
    4. D. Bacteria decide to change their DNA

Part 2: Written Response

16. In pea plants, round seeds (R) are dominant over wrinkled (r), and yellow (Y) is dominant over green (y). A plant heterozygous for both traits is crossed with a plant that is wrinkled and green. Predict the offspring phenotypes and ratio, and show your reasoning.