Heredity Unit 1
Test Review
1. Another name for a sex cell.
GAMETE
2. Identify the process that creates gametes.
MEIOSIS
Distinguish between haploid (N) and diploid
(2N) cells.
3. Sex cell.
4. Liver cell.
N
2N
5. Skin cell.
2N
6. Egg cell.
N
Calculate the haploid (N) number of chromosomes
given the diploid (2N) number, and vice versa.
7. Chromosome number of sex cells.
8. Chromosome number of all other cells.
23
46
9. If a diploid cell with 24 chromosomes undergoes meiosis, what will
the chromosome number be AFTER the creation of sex cells?
12
10. Explain why gametes are haploid.
Sex cells are haploid, having HALF
the number of chromosomes,
because the other half come will
come from the opposite sex cell
during fertilization
Describe the major events of meiosis.
11. How many genetically unalike
sex cells are produced from
meiosis?
4
12. This is created during prophase I of meiosis and
consists of a homologous pair of chromosomes joined
together.
TETRAD
13. Name this
chart.
KARYOTYPE
14. How many
pairs of
chromosomes
are usually
in a human?
23
15. Name the two sex chromosomes in a
human female.
XX
16. Name the two sex chromosomes in a
human male.
XY
Identify the sex chromosomes on a karyotype
to determine the gender of an individual.
17. Boy or Girl?
BOY
18. Name these type of mutations during meiosis.
NONDISJUNCTION
Diagnose any nondisjunction errors in a given
karyotype.
19. What’s wrong with this karyotype?
TRISOMY 21
20. The different forms of a gene.
Each sex cell has one of these for every gene.
ALLELE
Describe the behavior of alleles in gametes
during the production of a zygote.
21. When parents produce offspring, the offspring
receives how many alleles from each parent for each
trait?
ONE
Explain Mendel’s Law of Independent
Assortment.
22. List all of the allele combinations that the following parent will
produce in its sex cells:
AABb
There are two:
AB and Ab
23. What process is shown below?
Observe and practice how Punnett squares are
used to predict the possible genotypes of
offspring.
a
a
A
a
24. Genotype Frequency:
Aa 2/4
aa 2/4
Contrast nature and probability in producing
genetic offspring.
25. What is the chance of flipping tails when you flip a coin?
50%
26. What is the chance of a heterozygous parent donating a recessive
allele to its offspring?
50%
Identify both the genotype and phenotype of
an individual.
PHENOTYPE
27. Physical Characteristic
PHENOTYPE
28. Tall Pea Plant
29. Rr
GENOTYPE
30. Rough and yellow
PHENOTYPE
Distinguish between homozygous and
heterozygous individuals.
31. Having two identical alleles for a trait.
HOMOZYGOUS
32. Aa
HETEROZYGOUS
33. Having two different alleles for a trait.
HETEROZYGOUS
34. BB
35. rr
HOMOZYGOUS
HOMOZYGOUS
Recognize that genes on separate chromosomes
follow the Law of Independent Assortment,
while genes on the same chromosome are
“linked” and follow different inheritance
patterns than unlinked genes
36. On the diagram below, which genes would give a
9:3:3:1 ratio in a dihybrid cross? A and B, or A and C?
A and C
37. Why are A and B
“linked” traits?
They are on the same chromosome
38. Explain why fruit flies are useful in
studying the principle of genetics.
They have short generation times,
reproduce quickly, and have LOTS
of offspring
39. When two alleles for a trait are equal in dominance.
CODOMINANCE
Complete a Punnett Square for genes that
show codominance.
W
W
BB= black
WW= white
B
B
BLACK AND
40. Phenotype Frequency: WHITE 4/4
Complete a Punnett Square for genes that
show codominance.
IA
IB
i
IA
41. What are the
phenotypes and
ratios?
AB: 2/4
A: 2/4
42. When a dominant allele does not completely dominate over a
recessive allele.
Example: Snapdragons
INCOMPLETE DOMINANCE
Complete a Punnett Square for genes that
show incomplete dominance.
W
W
RR= red
WW= white
R
R
43. Phenotype Frequency: PINK 4/4
Define a “sex-linked gene.”
44. Why do males have sex-linked traits more often than females?
The genes for sex-linked traits are
recessive and carried on the X
chromosome. Males only have one
X chromosome, so they are more
likely to have the recessive trait show.
Trace a gene in a pedigree chart as it passed
down from generation to generation.
45. Using the letter “A,”
what is the genotype
of person 7?
XaY