Download Unit 7 Genetics

NAME: ____________________________
1
Unit 7 Genetics
1. Gregor Mendel- was responsible for our _______________________________________________
2. What organism did Mendel study?
3. When was Mendel’s work recognized?
4. How is Mendel referred to today?
5. In what country did Mendel do his research on peas?
6. Mendel stated that physical traits were inherited as __________________
7. Today we know that particles are actually what?
Terminology
7. Define these three terms:
a. trait b. heredity –
c. genetics 8. Name & describe two types of genetic crosses.
9. What is used to solve genetic crosses’?
10. Sketch a Punnet square & show how they are used to solve genetic problems.
11. What are alleles & what are the two forms?
12. Explain the difference between dominant & recessive alleles.
13. Using a letter of the alphabet, show how each allele would be represented.
14. What is a genotype and write 3 possible genotypes?
15. What is a phenotype and write possible phenotypes for your genotypes in question 18?
16. Using these alleles, R red flower and r yellow flowers, write all possible genotypes &
phenotypes.
17. What are homozygous genotypes?
18. Write a homozygous dominant genotype.
19. Write a homozygous recessive genotype.
20. What is meant by a heterozygous genotype?
21. Write a heterozygous genotype.
22. Heterozygous genotypes are also called ______________
Meiosis
1.
__________ is a process of nuclear division that reduces the number of chromosomes in
new cells to half the number in original cells.
2.
For example, in humans, meiosis produces ______________ reproductive cells, each called
__________. Human gametes are _________ cells and ______ cells, each of which contain _____
(1n) chromosomes.
3.
The __________ of a sperm and an egg results in a __________ (________ cell) that contains
46 (2n) chromosomes.
Meiosis I
4.
__________ is the pairing of homologous chromosomes during meiosis.
5.
___________ is a pair of homologous chromosomes.
6.
________________ is when a portion of chromatids break off and attach to adjacent
chromatids on the homologous chromosome. This permits exchange of genetic material between
maternal and paternal chromosomes.
7.
_________ _______ is the mixing of genetic material; such as crossing over during meiosis.
8.
_________ I
a.
______ coils tightly into chromosomes
b.
_______ _______ appear
c.
Nucleus and nucleolus disassemble
d.
Chromosomes line up next to their homologue
e.
__________ ________ occurs between homologous chromosomes
9.
Draw a diagram of crossing over using two different colored writing implements.
10.
___________ I
f.
______________ line up randomly along cell midline
g.
________ _________ from one pole attaché to centromere of one homologous
chromosome
h.
Spindle fibers from ______________ poles attach to the other homologous
chromosome of the pair.
11.
Draw the first four phases of Meiosis I
PROPHASE I
12.
_______________ I
METAPHASE I
ANAPHASE I
TELOPHASE I
i.
Each homologous chromosome moves to an opposite pole
j.
_____________________ ___________________ is the random separation of the
maternal and paternal chromosomes, which result in genetic variation.
13.
_________________ I
k.
Chromosomes reach opposite end of cell (movement stops)
l.
_______________ occurs
m.
New cells contain a __________ number (_____)
Meiosis II
14.
_______________ II - Spindle fibers form and ________________________ the chromosomes
toward the midline of the _____________ cell.
15.
________________ II - Chromosomes move to the midline of the dividing cell.
16.
_________________ II – chromatids separate and move toward opposite poles of the cell.
17.
_________________ II – nuclear membrane forms around chromosomes in each of the four
new cells; ___________________ occurs forming four new cells; each cell contains ______________
(__________, 1n) of the original cell’s number of chromosomes.
18.
Draw Meiosis II using two different colors of writing implements.
PROPHASE II
METAPHASE II
ANAPHASE II
TELOPHASE II
Formation of Gametes
19.
_____________________ - the production of sperm cells
20.
_____________ - immature sperm cells
21. _____________________ - production of mature egg cells; during meiosis, _____ egg cell is
produced along with 3 __________ ________. Egg cell receives most of the original cells
cytoplasm
22. ____________ __________ - 3 degenerate products of ova meiosis.
23. Draw an example of spermatogenesis and oogenesis.
Tools of the Trade
24. ___________________ is a picture of _________________ _______________ of an organism
arranged from _______________ to _______________.
25. It is a tool used to diagnosis __________________ mutations or disorders.
26. A pedigree is a diagram of family relationships that uses ____________ to represent _________,
and ___________ to represent ________________ relationships.
27. These diagrams make it easier to ____________________________________________________.
28. Pedigrees are often used to determine the __________________________________ of genetic
diseases.
29. Sketch the pedigree.
Squares = _______________________________
Circles = _________________________________
Horizontal lines = ________________________
Vertical lines =____________________________
Empty/not shaded = _____________________
Partially shaded = _________________________
Completely shaded = ____________________
Roman numbers = ________________________
Arabic numbers = ________________________
Pea Experiments
23. Give 4 reasons that Mendel used garden peas, Pisum sativum, for his experiments.
1.
2.
3.
4.
24. Explain how Mendel cross pollinated his pea plants.
25. How did Mendel’s experimental results compare to the theoretical genotypic ratios? Explain.
26. What does P1 mean?
27. What is the F1 generation?
28. What is the F2 generation?
29. Show all your work for solving a P1 monohybrid cross for
seed shape.
Trait:
Alleles:
P1 cross: ____________ x ____________
30. The offspring of the above cross are called the _____
generation.
Mendel’s Laws
31. ___________ are responsible for inherited traits.
32. Phenotype is based on ________________
33. Each trait requires genes, one from each ______________
34. State the Law of Dominance and give an example.
35. State the Law of Segregation and tell when alleles are “recombined”.
36. State the Law of Independent assortment & tell what type of crosses show this.
37. Show how to work a F1 dihybrid cross for seed shape & seed color.
Traits:
Alleles:
Fl cross ___________ x ___________
Genotypes:
Phenotypes:
Incomplete and Co-Dominance
38. Incomplete dominance occurs in
_______________ and produces a phenotype ________________ the phenotype of the two parents.
39. Show your work solving a cross for flower color in snapdragons when there is incomplete
dominance.
Trait:
Alleles:
Cross: RR X rr
40. What is co-dominance &
41. Write the genotypes for each of these blood types:
give an example?
Type A
Type B
Type AB
Type 0
42. Solve this co-dominance problem: IBIB x IA
43. Solve this co-dominance problem for blood type: ii x IAIB
Sex-Linked Traits
44. What are sex-linked traits?
45. Name the sex chromosomes.
46. Write the genotype for male and for female.
47. Most sex-linked traits are carried on what chromosome?
48. Give an example of a sex-linked trait in fruit flies.
49. Show the results of crossing a red-eyed male (XRY) with a white-eyed female (XrXr) fruit fly.
Cross: __________ x __________
50. What is meant by a female carrier?
51. Name a disease that can be carried in this manner.