Meiosis/ Genetics Study Guide—Test Wednesday 2/ 22/12
1. Why is crossing over important?
2. What is the purpose of meiosis? What is the end result?
3. What type of gametes would be produced by an individual with the genotype Hh?
a. What is the probability the gamete will be passed on to the next generation?
4. Describe the 23rd pair of chromosomes if the individual is a male.
5. Describe the 23rd pair of chromosomes if the individual is a female.
6. What are autosomes?
7. Describe the process of meiosis and draw a sketch.
8. What does Chi-square determine?
9. What are factors for Hardy Weinberg equilibrium?
10. A red flowering plant is crossed with a blue flowering plant and all offspring are purple, what
type of dominance is this?
a. What is the phenotypic ratio of HhGg X HhGg?
11. Describe the differences between P, F1, and F2 generations.
12. Brown hair (B) is dominant to red hair (b). Round eyes (R) are dominant to almond eyes (r).
The parents are both heterozygous for each trait. What are the chances of having a child with
red hair and round eyes?
13. What are the chances the child will have the same genotype as the parents?
14. Using the letter G, what monohybrid cross will produce offspring with a genotypic ratio of
1:2:1?
15. What is the law of independent assortment? states that separate genes for separate traits are
passed independently of one another from parents to offspring. That is, the biological
selection of a particular gene in the gene pair for one trait to be passed to the offspring has
nothing to do with the selection of the gene for any other trait. More precisely the law states
that alleles of different genes assort independently of one another during gamete formation.
16. What is the law of segregation? when any individual produces gametes, the copies of a gene
separate so that each gamete receives only one copy (allele).
17. Hemophilia is a sex-linked recessive trait. In one family, the father, mother, daughter and
elder son do not have hemophilia do not have hemophilia, while the youngest son has
hemophilia. Who must be the carrier? Construct a pedigree as evidence. The mother is a
carrier… be able to construct the pedigree!
18. Compare autosomal dominant, autosomal recessive, sex linked dominant and sex linked
recessive. Autosomal dominant- trait is dominant, for example AA- hitchhiker thumb, Aahitchhiker thumb, aa- normal thumb
a. Autosomal recessive- trait is recessive AA- normal thumb, Aa- Normal thumb, aaHitchhiker thumb
b. Sex-linked dominant-trait is located on the x chromosome and is dominant XAXA –
affected female XAXa—affected female XaXa- unaffected female XAY-affected male
XaY- unaffected male **Very Rare
c. Sex-linked recessive-** More Common XaXa- affected female XXa- unaffected
female but a carrier XaY- affected male XY- unaffected male
19. What occurs during prophase I of meiosis? –Homologous chromosomes pair
a. Metaphase I? – Homologous chromosomes line up—CROSSING OVER CAN
OCCUR HERE
b. Metaphase II? Replicated chromosomes line up.
20. Two brown mice bred and produced 3 brown mice and 2 albino offspring, assuming no
mutations have occurred, which mice are heterozygous? Parental brown mice.
21. Breeding occurs between two individuals HhGg x HhGG, what is the expected ratio of
offspring, HhGg? ½ X ½ = ¼
22. Trisomy of chromosome 21 causes what condition? DOWN SYNDROME—STUDY
KARYOTYPING LAB!!!
23. What is nondisjunction? What occurs if this happens? Homologous Chromosomes fail to
separate- one gamete ends up with too many chromosomes (3) or not enough (1)