Heredity Unit 1
Test Review
1. Identify the process that creates
gametes.
MEIOSIS
GAMETE
Define “____________.”
2. Another name for a sex cell.
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.
23
8. Chromosome number of all other cells.
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
TETRAD
Define a “_____________.”
12. This is created during prophase I of meiosis
and consists of a homologous pair of
chromosomes joined together.
Describe homologous chromosomes
and identify the chart used to organize
homologous chromosomes.
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
NONDISJUNCTION
Define “____________________.”
18. Name these type of mutations during meiosis.
Diagnose any nondisjunction errors in
a given karyotype.
19. What’s wrong with this karyotype?
TRISOMY 21
ALLELE
Define “________.”
20. The different forms of a gene.
Each sex cell has one of these for every gene.
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
Observe and practice how Punnett
squares are used to predict the
possible genotypes of offspring.
23. A Punnett Square predicts the outcome of a
genetic cross using the principles of
PROBABILITY
_________________.
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.
27. Physical Characteristic
28. Tall Pea Plant
29. Rr
PHENOTYPE
PHENOTYPE
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
CODOMINANCE
Define “_________________.”
39. When two alleles for a trait are equal in
dominance.
Complete a Punnett Square for genes
that show codominance.
W
BB= black
WW= white
W
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
INCOMPLETE
DOMINANCE
Define “________________________”
and give an example
42. When a dominant allele does not
completely dominate over a recessive allele.
Example: Snapdragons
Complete a Punnett Square for genes
that show incomplete dominance.
W
RR= red
WW= white
W
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