UTSA BIO 1404 Biosciences I Practice Test 2 (Units 8-13) -
Questions with Correct Answers (Verified Update)
50 questions
1. Which process allows a cut on your skin to heal?
A. Mitosis
B. Meiosis
C. Fertilization
D. Crossing over
Correct Answer: A. Mitosis
Rationale: Mitosis produces identical cells for growth and repair.
2. Chromosomes first become visible as condensed structures during:
A. Interphase
B. Prophase
C. Telophase
D. Cytokinesis
Correct Answer: B. Prophase
Rationale: During interphase DNA is uncondensed chromatin.
3. A cell that permanently stops dividing, such as a mature nerve cell, enters:
A. S phase
B. G2 phase
C. Metaphase
D. G0 phase
Correct Answer: D. G0 phase
Rationale: G0 is a non-dividing state outside the active cycle.
4. Normal cells stop dividing when they touch neighboring cells. Cancer cells lose this property,
called:
A. Anchorage dependence
B. Apoptosis
C. Synapsis
D. Density-dependent inhibition (contact inhibition)
Correct Answer: D. Density-dependent inhibition (contact inhibition)
Rationale: Cancer cells keep dividing and pile up, forming tumors.
5. At the end of meiosis I, each cell is:
A. Diploid with single chromatids
B. Haploid with single chromatids
C. Haploid, but each chromosome still has two sister chromatids
D. Diploid with two chromatids each
Correct Answer: C. Haploid, but each chromosome still has two sister chromatids
Rationale: Homologs separated in meiosis I; sister chromatids separate in meiosis II.
6. Independent assortment occurs when:
A. Sister chromatids separate in anaphase II
B. Homologous pairs line up randomly at metaphase I
C. DNA replicates in S phase
D. Cytokinesis divides the cell
Correct Answer: B. Homologous pairs line up randomly at metaphase I
Rationale: The orientation of each pair is random, mixing maternal and paternal chromosomes.
, 7. Programmed cell death that removes damaged or unneeded cells is called:
A. Necrosis
B. Apoptosis
C. Mitosis
D. Binary fission
Correct Answer: B. Apoptosis
Rationale: Apoptosis is controlled cell suicide, important in development and cancer prevention.
8. Which genotype is homozygous recessive?
A. rr
B. Rr
C. RR
D. R
Correct Answer: A. rr
Rationale: Two identical recessive alleles.
9. Two heterozygous parents (Bb x Bb) have a child. What is the probability the child is
heterozygous?
A. 1/4
B. 1/2
C. 3/4
D. 1
Correct Answer: B. 1/2
Rationale: Bb arises from 2 of 4 equally likely combinations.
10. The probability that a couple's three children are all girls is:
A. 1/3
B. 1/8
C. 1/2
D. 3/8
Correct Answer: B. 1/8
Rationale: Independent events multiply: 1/2 x 1/2 x 1/2.
11. Coat color in Labrador retrievers depends on one gene for pigment color and another that
determines whether pigment is deposited. This is an example of:
A. Codominance
B. Incomplete dominance
C. Epistasis
D. Sex linkage
Correct Answer: C. Epistasis
Rationale: The deposition gene (E/e) masks the pigment gene (B/b); ee dogs are yellow regardless.
12. A single gene mutation in sickle cell disease affects red blood cells, the spleen, joints and
more. This illustrates:
A. Pleiotropy
B. Polygenic inheritance
C. Epistasis
D. Linkage
Correct Answer: A. Pleiotropy
Rationale: One gene influencing multiple traits is pleiotropy.
Questions with Correct Answers (Verified Update)
50 questions
1. Which process allows a cut on your skin to heal?
A. Mitosis
B. Meiosis
C. Fertilization
D. Crossing over
Correct Answer: A. Mitosis
Rationale: Mitosis produces identical cells for growth and repair.
2. Chromosomes first become visible as condensed structures during:
A. Interphase
B. Prophase
C. Telophase
D. Cytokinesis
Correct Answer: B. Prophase
Rationale: During interphase DNA is uncondensed chromatin.
3. A cell that permanently stops dividing, such as a mature nerve cell, enters:
A. S phase
B. G2 phase
C. Metaphase
D. G0 phase
Correct Answer: D. G0 phase
Rationale: G0 is a non-dividing state outside the active cycle.
4. Normal cells stop dividing when they touch neighboring cells. Cancer cells lose this property,
called:
A. Anchorage dependence
B. Apoptosis
C. Synapsis
D. Density-dependent inhibition (contact inhibition)
Correct Answer: D. Density-dependent inhibition (contact inhibition)
Rationale: Cancer cells keep dividing and pile up, forming tumors.
5. At the end of meiosis I, each cell is:
A. Diploid with single chromatids
B. Haploid with single chromatids
C. Haploid, but each chromosome still has two sister chromatids
D. Diploid with two chromatids each
Correct Answer: C. Haploid, but each chromosome still has two sister chromatids
Rationale: Homologs separated in meiosis I; sister chromatids separate in meiosis II.
6. Independent assortment occurs when:
A. Sister chromatids separate in anaphase II
B. Homologous pairs line up randomly at metaphase I
C. DNA replicates in S phase
D. Cytokinesis divides the cell
Correct Answer: B. Homologous pairs line up randomly at metaphase I
Rationale: The orientation of each pair is random, mixing maternal and paternal chromosomes.
, 7. Programmed cell death that removes damaged or unneeded cells is called:
A. Necrosis
B. Apoptosis
C. Mitosis
D. Binary fission
Correct Answer: B. Apoptosis
Rationale: Apoptosis is controlled cell suicide, important in development and cancer prevention.
8. Which genotype is homozygous recessive?
A. rr
B. Rr
C. RR
D. R
Correct Answer: A. rr
Rationale: Two identical recessive alleles.
9. Two heterozygous parents (Bb x Bb) have a child. What is the probability the child is
heterozygous?
A. 1/4
B. 1/2
C. 3/4
D. 1
Correct Answer: B. 1/2
Rationale: Bb arises from 2 of 4 equally likely combinations.
10. The probability that a couple's three children are all girls is:
A. 1/3
B. 1/8
C. 1/2
D. 3/8
Correct Answer: B. 1/8
Rationale: Independent events multiply: 1/2 x 1/2 x 1/2.
11. Coat color in Labrador retrievers depends on one gene for pigment color and another that
determines whether pigment is deposited. This is an example of:
A. Codominance
B. Incomplete dominance
C. Epistasis
D. Sex linkage
Correct Answer: C. Epistasis
Rationale: The deposition gene (E/e) masks the pigment gene (B/b); ee dogs are yellow regardless.
12. A single gene mutation in sickle cell disease affects red blood cells, the spleen, joints and
more. This illustrates:
A. Pleiotropy
B. Polygenic inheritance
C. Epistasis
D. Linkage
Correct Answer: A. Pleiotropy
Rationale: One gene influencing multiple traits is pleiotropy.
