Study Guide for Test
Name
Inheritance and Genetics
Honors Biology
Terms and Concepts
Reproduction
Sexual Reproduction
Asexual Reproduction
DNA
Gene
Genotype
Phenotype
Chromosome
Recessive
Dominant
Allele
Heterozygous
Homozygous
Genetic Pedigrees
Punnett Squares
Genetic Probability
Genotypic Ratio
Phenotypic Ratio
Incomplete Dominance
Codominance
Meiosis
Germ Cell
Haploid (1n)
Diploid (2n)
Ovaries
Testes
Gametes
Ova/Ovum
Sperm
Fertilization
Zygotes
Embryo
Autosomal trait
Sex-linked trait (or X-linked)
Trisomy / Monosomy
Homologous Pair
Sister Chromatids
Independent Assortment
Crossing Over/GeneticRecombination
Nondisjunction
Generations (P, F1, F2)
Pedigree
Karyotype
Autosomes
Sex Chromosomes
Chromosomal Abnormalities
(numbers and/or structures)
“To do” list and tips for studying: Form a small study group and discuss all of the following.
 Understand all terms above and be able to put them into context. Pick three words (at random) and be
able to form one sentence, incorporating all ideas together.
 Review all journal entries, notes, and returned/stamped/scored/unscored work. Make corrections
where appropriate and review corrections.
 Be able to interpret Punnett Square problems and simple family pedigrees.
 Be able to explain the Meiosis Profile (who does it, when does it happen, where does it happen, why
does it happen, how).
 Be able to interpret a human karyotype and understand its uses.
 Be able to complete genetics problems involving sex-linked traits, complete dominance, codominance,
and incomplete dominance.
 Know the difference between “regular” body cells and gametes (locations, functions, types, etc.)
 Be able to explain the relationship between chromosomes, DNA, alleles, genes, traits, genotypes, and
phenotypes.
Practice Problems
1.
Continuity of species (the goal of reproduction) requires that individuals of a species must __________________________
their genetic information.
2.
In __________________ reproduction, offspring inherit their entire DNA from one parent.
3.
In __________________ reproduction, offspring inherit ____ their DNA from each of two parents.
4.
How many copies of each gene do you have? _________
5.
How many chromosomes are in every human body (somatic) cell? _____________
6.
How many chromosomes are in a human gamete (sex cell)? ____________
7.
Describe the difference between asexual and sexual reproduction in terms of number of parents, variation between the
offspring and parents, variation between offspring.
8.
Describe in words and diagrams the process of meiosis. Include the number of chromosomes and the number of cells in
each step. (You do NOT have to name all the steps).
9.
If an organism has 6 chromosomes, how many chromosomes will each gamete have at the end of meiosis?
10. How many gamete cells are formed from the original cell?
11. How many chromosomes would you have in a zygote if the gametes each had 25 chromosomes in them?
12. How many chromosomes are in the germ cell that produces gametes with 11 chromosomes?
13. How many chromosomes are in a gamete that arose from a germ cell having 6 chromosomes?
14. If you have two alleles that are identical/the same, you are _______________________ for the trait.
15. In hound dogs floppy ears (F) are dominant to straight ears (f):
a.
b.
What is the phenotype of a hound dog that is heterozygous for ear shape?
What would be the genotype of a hound dog with floppy ears?
16. What do you call a gene that hides or masks another (different) one?
17. Label each of the following as homozygous or heterozygous.
a.
HH _____________________________
b. Tt _______________________________
18. Label each of the following as a genotype or a phenotype.
a.
Blue eyes _______________________________ b. Hh _______________________________
19. In pea plant height, tall is dominant and short is recessive. If you cross a heterozygous tall pea plant with a short pea plant,
what are the phenotypic and genotypic ratios?
Parents: _____ x _____
Genotypic ratio ________ : ________ : ________
TT Tt
tt
Phenotypic ratio ________ : ________
Tall
short
20. In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (R) and white (W).
a.
b.
c.
What is the genotype of a snapdragon with red flowers?
What is the genotype of a snapdragon with white flowers?
What is the genotype of a snapdragon with pink flowers?
21. If you cross two pink snapdragons, what is the probability of producing the following kinds of flowers:
a. Red ___________ %
b. White ___________ %
Parents: ______ x _____
c. Pink ___________ %
Some traits like fur color and human blood types are controlled by yet another form of inheritance: Codominance. This is where two
alleles are equally dominant (like blood types A and B, having the alleles A and B respectively) over a recessive allele (blood type O),
but when paired together (like AB), both show up in the phenotype. Observe the following table for how codominant alleles interact
with each other to produce the various offspring genotypes and therefore genotypes.
Write a statement here to explain, in your own words, how codominance is different from incomplete dominance
and complete dominance:
22. In some cows, the gene for color is controlled by codominance. The allele for red is R and the allele for white is W. The
heterozygous trait is known as roan (red and white spotted fur).
a. What is the genotype for a red cow? ________
b. What is the genotype for a white cow? ________
c. What is the genotype for a roan cow? ________
23. If you cross a roan cow and a red cow, what are the probable offspring they will produce?
Parents: ________ x ________
Red _____________ %
White _____________ %
Roan ____________ %
24. What are the sex chromosomes in a human female? ___________ male? _________
25. In humans, the gene for color-blindness is sex-linked (X-linked) and recessive. Cross a normal vision heterozygous female
( XCXc ) with a color-blind male ( Xcy )
Parents: ___________ x ____________
a.
What are all of the possible genotypes of the offspring?
_________________________________________
b.
What are the possible phenotypes of the offspring?
__________________________________________
c.
What is the probability they will have a colorblind son?
d.
What is the probability they will have a colorblind daughter? ______% chance
26. What are two roles of the chromosomes?
______% chance
A dihybrid cross is like a Punnett Square in that it uses parent information to infer possible offspring genotype combinations, but it
tracks two traits being passed down together instead of one and the traits are both heterozygous. The possible parent combinations
result in unique offspring combinations. Follow the same rules in combining alleles to determine possible offspring genotypes as you
would in a normal Punnett Square.
27. In pea plants smooth seeds (S) is dominant to wrinkled seeds (s). Yellow seed color (Y) is dominant to green seed color
(y). Two pea plants heterozygous for both traits are crossed in the Punnett square above.
a. What genotype should be in square A? ________________
b. What genotype should be in square B? ____________
c. What is the phenotype of the offspring in square B? ___________________________________
d. How many of the offspring in this cross will be expected to be wrinkled and green? _____out of 16.
28. Create a pedigree showing the following members of a family for the Sickle Cell Disease (recessive disease, NOT sexlinked)
Mother – carrier (heterozygous) for Sickle Cell Disease
Father – carrier (heterozygous) for Sickle Cell Disease
Son – affected by Sickle Cell Disease
Son – carrier for Sickle Cell Disease
Son – affected by Sickle Cell Disease
Daughter – no Sickle Cell Disease
29. Color in the pedigree using the following information
Colorblindness is a recessive, sex-linked disorder.
Grandma and Grandpa are NOT colorblind.
Mickey is colorblind; all of their other children have normal color vision.
Sonny and John both inherited colorblindness, as did their cousins Barney and Janet.
Grandpa
Liz
David
Fred
Grandma
Wilma
Michelle
Mickey Monica
Barney
Sonny
John
Krista Janet
30. What are the genotypes of Barney, Krista, and Janet?
Barney’ genotype:____________
Krista’s genotype: _____________
Janet’s genotype: _____________