BIO 171 UNIT 1 PRACTICE QUESTIONS AND
CORRECT ANSWERS
True or false? Meiosis involves two cell divisions. DNA replicates once in
preparation for meiosis, before meiotic cell division I. - ANSWER false
Esther & Joshua Lederberg conducted an experiment in order to determine
whether or not antibiotics caused mutations in bacterial cells. The hypothesis for
the experiment was that antibiotic-resistant strains of bacteria surviving an
application of antibiotics had resistance before their exposure to the antibiotics,
not as a result of the exposure to antibiotics.
What was the independent variable in this experiment?
A. Bacterial colony growth
B. Presence or absence of antibiotic
C. Bacterial antibiotic resistance - ANSWER B. Presence or absence of
antibiotic
Which of the following is the correct definition of "gene expression"?
A. The portion of DNA we call 'coding DNA' is copied during S phase.
B. Coding DNA is transcribed into RNA that is replicated and transcribed into
amino acids.
C. DNA is transcribed into a stretch of RNA; if the transcribed RNA is mRNA,
then the ribosome will translate it to produce the amino acid chain. - ANSWER
C. DNA is transcribed into a stretch of RNA; if the transcribed RNA is mRNA,
then the ribosome will translate it to produce the amino acid chain.
Two blue lizards, both parents, mated and all of their progeny (more than 1000
babies!) were also blue. The body color in this lizard is determined by a single
,gene, T, that has two alleles: T (dominant) and t (recessive). What can you
conclude about the genotype(s) of these parents? Select the most complete/
correct answer.
A. Both parents were homozygous for the T allele
B. Both parents were homozygous for the t allele
C. Both parents were heterozygous for the T gene
D. At least one parent was homozygous; the other parent could have been
heterozygous if blue color is dominant.
E. At least one parent was heterozygous; the other parent must have been
homozygous if blue color is recessive. - ANSWER D. At least one parent was
homozygous; the other parent could have been heterozygous if blue color is
dominant.
Because male and female squirrels reproduce sexually, baby squirrels have
maternal and paternal alleles on their chromosomes. From where do the
maternal and paternal alleles arise in a male squirrel, Damon, which is
producing sperm, and in a female squirrel, Leila, which is producing eggs?
A. In Damon's sperm, only paternal alleles come from Damon's father. Maternal
alleles do not pass on in sperm.
B. Leila's eggs contain only maternal alleles from Leila's mother. The
paternal alleles are not passed on in eggs.
C. Leila's eggs will contain chromosomes from both her mother and father;
Damon's sperm will contain chromosomes from both his mother and father.
D. Recombination results in chromosomes in Leila's eggs that are a combination
of her parents' chromosomes and Damon's parents' chromosomes.
E. Both A and B - ANSWER C. Leila's eggs will have chromosomes from
both mom and dad; Damon's sperm will have chromosomes from both mom and
dad.
, Some lakes and ponds maintain relatively constant levels of freshwater,
providing a stable habitat for animals. Under these conditions, Daphnia,
otherwise known as water fleas, are mostly female and reproduce
parthenogenically. Males are present in low oxygen environments and/or when
food supplies become scarce. With this information,
a researcher suggests that male Daphnia develop in response to unfavorable
environmental conditions. This researcher's "suggestion" is best described as
a(n):
A. Prediction
B. Hypothesis
C. Theory
D. Observation
E. Experiment - ANSWER B. Hypothesis
Which of the following is FALSE about mutations?
A. Point mutations always affect an organism's DNA sequence and
sometimes affect an organism's phenotype.
B. Only mutations in germ cells can be passed on to offspring.
C. Genetic variation is created by mutations during S phase only in
organisms that undergo sexual reproduction.
D. Since non-synonymous mutations in coding regions alter the amino acid
sequence of the protein that is made, they can have an impact on an organism's
phenotype.
E. Mutations can produce either dominant or recessive alleles. - ANSWER C.
Genetic diversity is created by mutation in S phase only in sexually reproducing
organisms.
CORRECT ANSWERS
True or false? Meiosis involves two cell divisions. DNA replicates once in
preparation for meiosis, before meiotic cell division I. - ANSWER false
Esther & Joshua Lederberg conducted an experiment in order to determine
whether or not antibiotics caused mutations in bacterial cells. The hypothesis for
the experiment was that antibiotic-resistant strains of bacteria surviving an
application of antibiotics had resistance before their exposure to the antibiotics,
not as a result of the exposure to antibiotics.
What was the independent variable in this experiment?
A. Bacterial colony growth
B. Presence or absence of antibiotic
C. Bacterial antibiotic resistance - ANSWER B. Presence or absence of
antibiotic
Which of the following is the correct definition of "gene expression"?
A. The portion of DNA we call 'coding DNA' is copied during S phase.
B. Coding DNA is transcribed into RNA that is replicated and transcribed into
amino acids.
C. DNA is transcribed into a stretch of RNA; if the transcribed RNA is mRNA,
then the ribosome will translate it to produce the amino acid chain. - ANSWER
C. DNA is transcribed into a stretch of RNA; if the transcribed RNA is mRNA,
then the ribosome will translate it to produce the amino acid chain.
Two blue lizards, both parents, mated and all of their progeny (more than 1000
babies!) were also blue. The body color in this lizard is determined by a single
,gene, T, that has two alleles: T (dominant) and t (recessive). What can you
conclude about the genotype(s) of these parents? Select the most complete/
correct answer.
A. Both parents were homozygous for the T allele
B. Both parents were homozygous for the t allele
C. Both parents were heterozygous for the T gene
D. At least one parent was homozygous; the other parent could have been
heterozygous if blue color is dominant.
E. At least one parent was heterozygous; the other parent must have been
homozygous if blue color is recessive. - ANSWER D. At least one parent was
homozygous; the other parent could have been heterozygous if blue color is
dominant.
Because male and female squirrels reproduce sexually, baby squirrels have
maternal and paternal alleles on their chromosomes. From where do the
maternal and paternal alleles arise in a male squirrel, Damon, which is
producing sperm, and in a female squirrel, Leila, which is producing eggs?
A. In Damon's sperm, only paternal alleles come from Damon's father. Maternal
alleles do not pass on in sperm.
B. Leila's eggs contain only maternal alleles from Leila's mother. The
paternal alleles are not passed on in eggs.
C. Leila's eggs will contain chromosomes from both her mother and father;
Damon's sperm will contain chromosomes from both his mother and father.
D. Recombination results in chromosomes in Leila's eggs that are a combination
of her parents' chromosomes and Damon's parents' chromosomes.
E. Both A and B - ANSWER C. Leila's eggs will have chromosomes from
both mom and dad; Damon's sperm will have chromosomes from both mom and
dad.
, Some lakes and ponds maintain relatively constant levels of freshwater,
providing a stable habitat for animals. Under these conditions, Daphnia,
otherwise known as water fleas, are mostly female and reproduce
parthenogenically. Males are present in low oxygen environments and/or when
food supplies become scarce. With this information,
a researcher suggests that male Daphnia develop in response to unfavorable
environmental conditions. This researcher's "suggestion" is best described as
a(n):
A. Prediction
B. Hypothesis
C. Theory
D. Observation
E. Experiment - ANSWER B. Hypothesis
Which of the following is FALSE about mutations?
A. Point mutations always affect an organism's DNA sequence and
sometimes affect an organism's phenotype.
B. Only mutations in germ cells can be passed on to offspring.
C. Genetic variation is created by mutations during S phase only in
organisms that undergo sexual reproduction.
D. Since non-synonymous mutations in coding regions alter the amino acid
sequence of the protein that is made, they can have an impact on an organism's
phenotype.
E. Mutations can produce either dominant or recessive alleles. - ANSWER C.
Genetic diversity is created by mutation in S phase only in sexually reproducing
organisms.
