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Genetics Exam Study Guide
Topics:
• Mitosis and Meiosis
o Mitosis: mechanism of cell reproduction in all somatic cells
o Know the different phases of the cell cycle and what occurs during each
o DNA quality and quantity are duplicated in each new cell after mitosis
o Meiosis is not a cycle, but a terminal process resulting in gamete production
o Quantity of DNA is cut in half in each new gamete, while reshuffling of genes
creates new allele combinations
• Genetics
o Chromosomes are condensed DNA
o Genes are sections of DNA that code for specific traits
o Different versions of genes are on homologous chromosomes
o Different versions of gene are called alleles
• Mendel’s Theories
o Segregation- parental traits (alleles on homologous chromosomes) separate
during gamete formation. (Meiosis II)
o Independent assortment- traits separate independently of one another.
Homologous chromosomes are randomly aligned at Meiosis I.
• Post-Mendelian Genetics
o Co-dominance, Incomplete dominance
o Plieotropy, Continuous variation, genetic and environmental interactions
o Linkages, full vs incomplete; autosomal vs sex linked traits
o Replication errors: duplication, deletion, insertion and translocation
o Meiosis errors: disjunction results in wrong number of chromosomes
• DNA replication:
o The DNA is un-zipped and copied
o The result is two “old” and two “new” strands
o This process occurs during S phase
o The result is an identical copy of original DNA
o Codons are three DNA base pairs that code for specific amino acids when
transcribed to RNA
• Protein Synthesis
o DNA codes for amino acid sequence in proteins
o Transcription- mRNA creates a copy of information
Delivers from nucleus to cytoplasm
Codons are group of three bases that code for specific amino acid
o Translation- tRNA and ribosomes form a complex on which peptide chain is
assembled in three stages:
Initiation- “start” tRNA binds to ribosomal unit
Elongation-tRNA have anticodon complimentary to codon and
corresponding amino acid on other end. These deliver amino acids in
specified sequence
Termination- process continues until “end” codon is reached
Mendel’s Monohybrid crosses
• Understand the difference between genotype and phenotype
• Know what homozygous and heterozygous means
• Know the possible outcomes of monohybrid crosses in terms of genotypes and
phenotypes
• Know the generation designations: P, F1, F2
Exam 2 Genetics
A.
B.
C.
D.
1. The process that produces an exact copy of a cell's DNA is called _____.
mitosis
meiosis
cytoplasmic division
cell division
A.
B.
C.
D.
2. In mitosis, each daughter cells gets _____.
one copy of each chromosome
two copies of each chromosome
half of the original chromosomes
a random number of chromosomes
A.
B.
C.
D.
3. Which of the following is not a phase of the cell cycle?
interphase
mitosis
cytoplasmic division
meiosis
A.
B.
C.
D.
4. Cells spend most of their time growing and functioning during _____.
prophase
metaphase
anaphase
Interphase
A.
B.
C.
D.
5. DNA is duplicated during which portion of the cell cycle?
S
D
G1
G2
A.
B.
C.
D.
6. A molecule of DNA that is in its condensed form is called a _____.
centromere
chromosome
nucleosome
gene
A.
B.
C.
D.
7. Which process is characteristic of sexual reproduction?
mitosis
meiosis
cell division
DNA replication
A.
B.
C.
D.
8. Homologous chromosomes _____.
May exchange material during meiosis
have different versions of the same genes called alleles
are in pairs, one from the father and one from the mother
all of the choices
A.
B.
C.
D.
9. Chromatids are _____.
Duplicate chromosomes attached at the centriole
Duplicate chromosomes attached at the centromere
Uncondensed DNA
Sister genes attached at the hip
A.
B.
C.
D.
10. Which process is characteristic of asexual reproduction?
mitosis
meiosis
cell division
DNA replication
A.
B.
C.
D.
11. A DNA molecule is made up of how many strands.
1
23
46
2
A.
B.
C.
D.
12. Before messenger RNA is mature.
All exons are deleted
All introns are deleted
Anticodons are assembled
It duplicates itself
A.
B.
C.
D.
13. Which of the following is a transfer of genes between non-homologous chromosomes.
Crossing over
aneuploidy
trisomy
translocation
A.
B.
C.
D.
14. Replication of DNA
Produces RNA molecules
Produces only new DNA
Produces two molecules, each of which is half new and old DNA
Generates excessive DNA which leads to cell division
A.
B.
C.
D.
15. The RNA molecule is made up of how many strands?
1
2
3
4
A.
B.
C.
D.
16. DNA and RNA are alike in
The molecular composition of the sugar
All the nitrogenous bases used to assemble the genetic code
The number of strands
None of the above
A.
B.
C.
D.
17. The nitrogenous base found in RNA but not DNA is
adenine
cytosine
guanine
uracil
A.
B.
C.
D.
18. The synthesis of an RNA molecule from a DNA template is
replication
translation
transcription
DNA synthesis
A.
B.
C.
D.
19. Transcription starts at a region of DNA called a
promoter
sequencer
activator
terminator
A.
B.
C.
D.
20. Mendel's experiments with peas showed that _____.
observable traits are passed from generation to generation in predictable patterns
chromosomes contain genes made of DNA
pea flowers can only be purple or white
all of the choices
A.
B.
C.
D.
21. A heterozygous parent Aa will produce gametes in which proportion?
all Aa
half A and half a
all A
3 A for every 1 a
A.
B.
C.
D.
22. Which of the following is true of Mendel's monohybrid crosses?
all the F1 generation shows the dominant trait
each parent breeds true for a single trait
the F2 generation shows the dominant trait in a ratio of 3:1
all of the choices
A.
B.
C.
D.
23. The F2 results of Mendel's monohybrid crosses led to his theory of_____.
generation dominant traits
random assortment
generation recessive
segregation
A.
B.
C.
D.
24. If a heterozygous plant (Aa) self-fertilizes, what are the possible genotypes in the F1
generation?
Aa only
A only
AA, Aa, and aa
A and a
A.
B.
C.
D.
25. In a dihybrid cross, two _____ are tracked.
traits
parents
chromosomes
gametes
A.
B.
C.
D.
26. Mendel's dihybrid crosses led to his theory of_____.
generation dominant traits
independent assortment
generation recessive
separation
A.
B.
C.
D.
27. The ABO blood types are examples of
pleiotropy
co-dominance and multiple alleles
incomplete dominance
co-dominance
A.
B.
C.
D.
28. The pink color obtained from crossing red and white snap dragons is an example of
Complete dominance
recessiveness
codominance
incomplete dominance
A.
B.
C.
D.
29. The range of skin colors in humans is an example of _____ in genes.
continuous variation
pleiotropy
codominance
incomplete dominance
A.
B.
C.
D.
30. Which of the following is an example of an environmental factor that alters gene
expression?
an enzyme that works in cool temperatures but stops working when the temperature is warm
a plant that grows tall at low altitudes but stays short at high altitudes
a flower that is pink when grown in acid soil but blue when grown in alkaline soil
all of the choices
A.
B.
C.
D.
31. a condition in which a single gene affects more than one trait is known as
pleiotropy
codominance
incomplete dominance
continuous variation
A.
B.
C.
D.
32. In sexual reproduction, a male child is produced when _____.
the egg carries a Y chromosome
the sperm carries a Y chromosome
the egg carries an X chromosome
the sperm carries an X chromosome
A.
B.
C.
D.
33. Genes occurring along the length of single chromosome are _____.
autosomal dominant
linked
autosomal recessive
none of the choices
A.
B.
C.
D.
34. An X-linked genetic disorder _____.
is found on the X chromosome
is inherited only from the mother
is always recessive
all of the choices
A.
B.
C.
D.
35. If chromosomes fail to separate properly during meiosis, what can result?
aneuploidy
change in species
spontaneous clone
twin
A.
B.
C.
D.
36. Which of the following statements about the genetic code in DNA is true?
It’s universal for all organisms
It’s based upon 64 codons made up of three nucleotides
It’s redundant, so most amino acids have more than one codon
all of the choices
A.
B.
C.
D.
37. Which of the following is a correct pairing of nitrogen-containing bases in DNA?
A=T
T=G
C=A
G=A
A.
B.
C.
D.
38. Adenine, guanine, thymine and cytosine are _____.
Amino acids
nitrogen-containing bases
deoxyribose sugars
phosphate groups
A.
B.
C.
D.
39. Transfer RNA differs from other types of RNA because it
Transfers genetic instructions from nucleus to cytoplasm
Specifies amino acids sequences
Carries an amino acid at one end
all of the choices
A.
B.
C.
D.
40. In DNA replication, a permanent alteration in the DNA sequence is called a _____.
genetic code
mutation
proofreading error
semiconservative replication
ANSWERS
1. A
2. A
3. D
4. D
5. A
6. B
7. B
8. D
9. B
10. A
11. D
12. B
13. D
14. C
15. A
16. D
17. D
18. C
19. A
20. A
21. B
22. D
23. D
24. C
25. A
26. B
27. B
28. D
29. A
30. D
31. A
32. B
33. B
34. A
35. A
36. D
37. A
38. B
39. C
40. B