Biology: Unit 06 Review

1. 1. What is cell differentiation? When and why does it happen? What controls it?
2. 2. In simple dominance, what genotype can be determined by the phenotype? (heterozygous, homozygous, dominant, recessive)
3. 3. B = blue hair, b = pink hair. A blue haired man and a pink haired woman have a boy with blue hair and a girl with pink hair. What are the genotypes of all the family members? ANSWER Make a pedegree for the cross.
4. 4. In pea plants, tall plants are dominant over short plants, yellow seeds are dominant over green seeds. Do a dihybrid cross of a tall (Tt) plant with green (yy) seed and a plant that is short and heterozygous for yellow seeds. ANSWER
5. 5. Review Meiosis. How does it relate to the way we set up a punnet square?
6. 6. You may have noticed your dog or cat shedding during the spring as it loses its winter coat. Similarly, in northern latitudes, some rabbits have a white coat in the winter, and a brown coat in the summer. What is the advantage of this? Is it controlled by genetics, environment, neither, or both? ANSWER
7. 7. Compare and contrast complete dominance, incomplete dominance, and co-dominance. Which types of inheritance allow you to determine the genotype from the phenotype?
8. 8. Human females have two X chromosomes (XX). Human males have one X and one Y chromosome (XY).
9. 9. Normal human body cells have 46 chromosomes (23 pair). That can be called diploid, or 2n. Gametes, like sperm and egg, are haploid or 1n. So a human sperm or egg would have half the number of chromosomes. When a sperm joins an egg, how many chromosomes are in the resulting zygote?
10. 10. What is crossing over and what does it do to increase genetic variability in offspring?

Vocabulary

homozygous, heterozygous, recessive, dominant, genotype, phenotype, meiosis, zygote, crossing over, variability.