Genetics Study Guide Answers
S7L3. Students will recognize how biological traits are passed on to successive generations.
1. Passing of traits from parent to offspring
2. Different forms of a characteristic
3. Form of a gene
4. Traits are controlled by
Single Genes
define
2 alleles
example
Freckles
Multiple Alleles
2 or more different alleles control a single trait
Blood type
Many genes
2 or more genes control a trait
Skin color
Sex-linked
Alleles for a trait are on the sex chromosomes
Color blindness
Incomplete Dominance
Blend together
Pink flower
Co-dominance
Alleles work together; both appear
AB blood type
5.
Genotype: 2 or more alleles that control a trait
Phenotype: physical appearance of a trait
6.
Homozygous/purebred: 2 same alleles
Heterozygous/hybrid: 2 different alleles
7. Tool used to predict the outcome of a genetic cross
8. Complete the following genetic crosses.
TT x tt
TT x Tt
T
T
T
t
t
9.
Tt
Tt
Tt
Tt
T
TT
t
Tt
Tt x Tt
T
T
TT
T
Tt
List the possible genotypes and phenotypes for the crosses above.
Tt: tall 100%
TT: Tall 75%
Tt: tall 25%
t
TT: tall 25%
Tt: tall 50%
TT
Tt
t
Tt
tt
tt: short 25%
10. A diagram that shows the inheritance of a trait through a family
11.
AA = _______normal___________________
Aa = ________normal__________________
aa = _________albino_________________
12. Fill out the blanks on the pedigree below.
aa
Aa
13. How many children does this family have?
14. How many males are albino? 1
Aa
Aa
3 What are the sexes of the children? female
females?
1
15. A disease caused by an abnormality in DNA
16. A mutation or change in DNA
17. If it decreases the chances of an organism surviving and/or reproducing
18. A picture of a person’s chromosomes. It is used to diagnose some genetic disorders
19. 46 in body cell 23 in sex cells
20. The division of sex cells
21. 4 cells with half the number of chromosomes
22. males? XY
and females? XX
23. a twisted double helix (ladder) that contains the genetic information for an organism
24. in the nucleus
25. twisted ladder
26. TTGACAT
aa