BIO BASES PSYD 705 End term Exam
with Correct Answers 2025
Mendel's early experiments challenged the central premise upon which previous ideas
about inheritance had rested. This was the premise that:
a. there is only one gene for each trait.
b. there are two genes for each trait.
c. offspring can inherit only those traits that are displayed by their parents.
d. white seeds are dominant.
e. some traits are dominant and some are recessive. - Correct Ans-a. there is only one
gene for each trait
An organism's observable traits are referred to as its
a. genotype.
b. phenotype.
c. dominant traits.
d. recessive traits.
e. none of the above - Correct Ans-b. phenotype
The two genes, one on each chromosome of a pair, that control the same trait are
called
a. dominants.
b. phenotypes.
c. genotypes.
d. gametes.
e. alleles. - Correct Ans-e. alleles
Individuals who possess two identical genes for a particular trait
a. are homozygous for that trait.
b. are heterozygous for that trait
c. cannot have offspring of the same phenotype for that trait
d. cannot have offspring of the same genotype for that trait
e. none of the above - Correct Ans-a. are homozygous for that trait.
If an individual has a recessive phenotype for a particular trait, it can be concluded that
a. both parents also had a recessive phenotype for that trait.
b. only one parent had a recessive phenotype for that trait.
c. both parents were homozygous for the dominant gene for that trait.
d. each parent had at least one recessive gene for that trait.
e. both A and C - Correct Ans-d. each parent had at least one recessive gene for that
trait.
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In each cell of the human body, there are normally
a. 21 chromosomes.
b. 21 pairs of chromosomes.
c. 23 genes.
d. 23 chromosomes.
e. 23 pairs of chromosomes. - Correct Ans-e. 23 pairs of chromosomes.
Gametes are produced by
a. mitosis.
b. mitotic cell division.
c. meiosis.
d. copulation
e. fertilization. - Correct Ans-c. meiosis.
Just prior to mitotic cell division, the number of chromosomes in the cell
a. doubles.
b. is reduced by half.
c. doubles twice.
d. stays the same.
e. is increased by 50%. - Correct Ans-d. stays the same.
The "letters" of the genetic code are
a. deoxyribose bases.
b. phosphates.
c. nucleotide bases.
d. amino acids.
e. peptides. - Correct Ans-c. nucleotide bases.
How many different nucleotide bases are there in DNA?
a. l
b. 2
c. 4
d. 7
e. 26 - Correct Ans-c. 4
In Down syndrome, there is
a. no guanine
b. no adenine.
c. no thymine.
d. no cytosine.
e. an extra chromosome in each cell. - Correct Ans-e. an extra chromosome in each cell
Accidental alteration in individual genes during replication is called
a. crossing over.
b. translation.
c. linkage.
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d. mutation.
e. self-duplication. - Correct Ans-d. mutation.
Female mammals have
a. only one X chromosome.
b. only one Y chromosome.
c. two X chromosomes.
d. two Y chromosomes.
e. both A and B - Correct Ans-two X chromosomes.
Color blindness occurs more frequently in males than in females because it is
a. dominant.
b. rare.
c. quite common.
d. a recessive sex-linked trait.
e. both A and B - Correct Ans-d. a recessive sex-linked trait.
Sex-linked traits that are controlled by dominant genes occur more frequently in
a. females.
b. males.
c. neural disorders.
d. XY individuals.
e. both B and D - Correct Ans-a. females
Proteins that bind to DNA and influence the rate at which particular structural genes will
be expressed are called
a. transcription factors.
b. autosomes.
c. enhancers.
d. sex-linked traits.
e. mutations. - Correct Ans-a. transcription factors.
All mitochondrial genes are inherited only
a. if they have first undergone mutation.
b. from one's mother.
c. from one's father.
d. from one's siblings.
e. if they have first been transcribed. - Correct Ans-b. from one's mother
The two major divisions of the nervous system are the
a. ANS and the CNS.
b. SNS and the CNS.
c. PNS and the CNS.
d. ANS and the PNS.
e. brain and the spinal cord - Correct Ans-c. PNS and the CNS.
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