Unit 7 Study Guide Biology 1 Honors

Reproduction, Meiosis, and Genetics

Types of Reproduction

1. Fill out the table below comparing asexual and sexual reproduction.

2. Why is genetic variation a good thing for species/populations to have?

3. What is fertilization? Process where a sperm and egg cell come together

4. What is a zygote? Two gametes come together to form it

Meiosis

5. What are homologous chromosomes? Pairs of chromosomes

6. How are they different from sister chromatids? homologous chromosomes can have different alleles for the same trait, while sister chromatids have the same because they are identical

7. Define the terms haploid and diploid. Haploid has one set of chromosomes, diploid has two sets of chromosomes

8. What is a gamete, and what are the two types of gametes? Reproductive cell, egg and sperm

9. In the table below, the haploid or diploid numbers for organisms is given. Fill in the blanks.

10. What is the purpose of meiosis? Cell division to make gametes 

11. How does the process of meiosis relate to sexual reproduction? Makes gametes to use for sexual reproduction

12. What gets separated in meiosis I? Homologous chromosomes

13. What gets separated in meiosis II? Sister chromatids

14. Compare mitosis and meiosis.

15. Why does meiosis make haploid cells? (aka what is the purpose of reducing the chromosome number?) to make sure when two gametes fuse during fertilization, the offspring has the correct number of chromosomes and not double the normal amount

16. What are the two ways that meiosis creates genetic variation? Crossing over and independent assortment

17. Describe what is occurring in the diagram below: the diagram shows metaphase I of meiosis I

Mendelian Inheritance

18. What is Gregor Mendel famous for? Famous for law of segregation and law of independent assortment

19. What organism did Mendel work with? Pea plants

20. What are Mendel’s three laws/discoveries? Dominance, Law of segregation, law of independent assortment

21. What is the definition of a gene? A piece of DNA that has instructions for making a specific protein that picks what trait one will have

22. What is the definition of an allele? One of multiple variations of a gene

23. What does genotype and phenotype mean? Genotype means the genetic makeup of an organism, phenotype means the physical characteristics of an organism

24. What does homozygous and heterozygous mean? homozygous means when an organism has two copies of the same allele (BB or bb), heterozygous means when an organism has two different alleles (Bb)

25. What do dominant and recessive mean? Dominant is an allele that can masks the effects of another allele, recessive is an allele that can be masked by another allele

26. For Mendelian crosses, how do you choose which letter to use? any?

    1. How do you represent dominant alleles? uppercase letters

    2. Recessive alleles? lowercase letters

27. If an organism has a heterozygous genotype for a dominant trait (such as Tt, where T=tall, t=short), will the organism have the dominant phenotype or the recessive phenotype? dominant

28. Answer the following questions about Punnett squares:

1. Are the results of a Punnett square guaranteed? Why or why not? No because they only predict the probability of an outcome

2. What do the letters along the side of the Punnett square represent? The parents

3. What do the combinations of letters inside the Punnett square represent? The possible traits for a kid

29. Be able to do Punnett squares with genotypic and phenotypic ratios, both for one and two traits.

30. Does “dominant” always mean that it’s the more common trait? no

Non-Mendelian Inheritance

31. What is incomplete dominance? What is an example? A blended phenotype, like the color pink (red and white)

32. What is codominance? What is an example?  Both alleles are equally present (like AB blood type)

33. Understand blood types and the associated genotypes and phenotypes.

34. What does multiple alleles mean? Give an example. When a gene has 3 or more alleles (ABO blood type)

35. What does polygenic trait mean? Give an example. Traits determined by two or more genes (eye color is controlled by 4+ genes)

36. What are the two different categories of chromosomes in humans? (Hint: one set is number #1-22 and the other set includes XX or XY) autosomes and sex chromosomes

37. What is a sex-linked trait? Give an example. Characteristic determined by genes in the sex cells

38. Why are sex-linked traits more common in males? Because men only have one X chromosome

39. Who does a male inherit his X-linked trait from? mom

40. Can males be carriers of X-linked traits? Explain. No because they only have one X so whatever they get they give on

41. Be able to do a Punnett square of incomplete dominance, codominance, blood types, and sex-linked traits.

42. What is a karyotype, and what is it used for? A picture of someone’s chromosomes

43. What is nondisjunction, and how does it relate to the terms monosomy and trisomy? An error where chromosomes fail to separate properly during meiosis, which leads to gametes with either an extra or missing chromosome