Biology 102 Exam 2 WSU Carloye
Heterozygous - CORRECT ANSWER-When two different alleles combine to form
a trait.
Example: A tall person and a short person have a child who is short. The short
allele is dominant so the child grew up to be short.
Gene - CORRECT ANSWER-A section of DNA that controls a certain trait.
Example: Eye color.
Dominant - CORRECT ANSWER-Determines the expression of a trait (visually).
Example: Brown eyes, dark hair.
Homozygous - CORRECT ANSWER-A homozygous trait is when two of the
same kind of alleles combine to form a trait.
Example: When two tall people have a tall child. Both parents had the same
allele and gave it to their child to create a trait.
Genotype - CORRECT ANSWER-Genotype: The set of genes that an organism
carries.
"True-Breeding" - CORRECT ANSWER-When parents product offspring that will
carry the same phenotype. This means that the parents are homozygous for
every trait.
Example: Two purebred labs having purebred puppies with the same traits as
them.
When doing genetic crosses, what does it mean to be a "carrier" of a trait? -
CORRECT ANSWER-A carrier is someone who has (carries) a recessive allele
for a genetic trait or mutation but doesn't display that trait physically or show
symptoms of the trait.
Example: Sickle cell anemia.
Which process gives rise to gametes - mitosis or meiosis or both? - CORRECT
ANSWER-Meiosis gives rise to gametes but mitosis does not.
, Define "Polygeny" - CORRECT ANSWER-The theory that humans evolve from
several independent pairs of ancestors.
Define "Epistasis" - CORRECT ANSWER-The idea that traits are often produced
through a series of steps. If one step fails, then you don't get to the end result.
How does polygeny give rise to such a wide array of skin colors? - CORRECT
ANSWER-Each dominant allele contributes to 1 increment of pigment. Recessive
allele contributes to no pigment.
Example: Someone with aabbcc would have very light skin, and someone with
AABBCC would have very dark skin.
Explain how two blue-eyed parents can have a brown-eyed child. Discuss the
two genes involved, what role each plays in creating the pigment of the eyes and
what combination of alleles gives rise to blue and brown-eyed phenotypes. -
CORRECT ANSWER-If the parents are both carriers of the brown eyed gene, it
is possible to have a brown eyed baby. A functional gene has pigment, while a
non-functional gene has no pigment.
Define "sex-linked". - CORRECT ANSWER-A trait associated with a gene that is
only carried by the male or female parent.
What combination of chromosomes is associated with the sex of an individual in
humans? - CORRECT ANSWER-A female has two X chromosomes (XX) and a
male has an X and a Y chromosome (XY).
What gene determines the sex of a developing embryo? - CORRECT
ANSWER-The Y-chromosome carries the SRY gene, which is the "Sex
Determining Region of the Y". The SRY gene stimulates testosterone production
in growing fetuses. The SRY gene also triggers embryonic gonad gene to
become testes.
In what way are ovaries and testes the same in a 7-week old embryo? -
CORRECT ANSWER-At 7 weeks, sex is undetermined. The only areas that can
be determined at 7 weeks are the anus, urethra and tail.
Heterozygous - CORRECT ANSWER-When two different alleles combine to form
a trait.
Example: A tall person and a short person have a child who is short. The short
allele is dominant so the child grew up to be short.
Gene - CORRECT ANSWER-A section of DNA that controls a certain trait.
Example: Eye color.
Dominant - CORRECT ANSWER-Determines the expression of a trait (visually).
Example: Brown eyes, dark hair.
Homozygous - CORRECT ANSWER-A homozygous trait is when two of the
same kind of alleles combine to form a trait.
Example: When two tall people have a tall child. Both parents had the same
allele and gave it to their child to create a trait.
Genotype - CORRECT ANSWER-Genotype: The set of genes that an organism
carries.
"True-Breeding" - CORRECT ANSWER-When parents product offspring that will
carry the same phenotype. This means that the parents are homozygous for
every trait.
Example: Two purebred labs having purebred puppies with the same traits as
them.
When doing genetic crosses, what does it mean to be a "carrier" of a trait? -
CORRECT ANSWER-A carrier is someone who has (carries) a recessive allele
for a genetic trait or mutation but doesn't display that trait physically or show
symptoms of the trait.
Example: Sickle cell anemia.
Which process gives rise to gametes - mitosis or meiosis or both? - CORRECT
ANSWER-Meiosis gives rise to gametes but mitosis does not.
, Define "Polygeny" - CORRECT ANSWER-The theory that humans evolve from
several independent pairs of ancestors.
Define "Epistasis" - CORRECT ANSWER-The idea that traits are often produced
through a series of steps. If one step fails, then you don't get to the end result.
How does polygeny give rise to such a wide array of skin colors? - CORRECT
ANSWER-Each dominant allele contributes to 1 increment of pigment. Recessive
allele contributes to no pigment.
Example: Someone with aabbcc would have very light skin, and someone with
AABBCC would have very dark skin.
Explain how two blue-eyed parents can have a brown-eyed child. Discuss the
two genes involved, what role each plays in creating the pigment of the eyes and
what combination of alleles gives rise to blue and brown-eyed phenotypes. -
CORRECT ANSWER-If the parents are both carriers of the brown eyed gene, it
is possible to have a brown eyed baby. A functional gene has pigment, while a
non-functional gene has no pigment.
Define "sex-linked". - CORRECT ANSWER-A trait associated with a gene that is
only carried by the male or female parent.
What combination of chromosomes is associated with the sex of an individual in
humans? - CORRECT ANSWER-A female has two X chromosomes (XX) and a
male has an X and a Y chromosome (XY).
What gene determines the sex of a developing embryo? - CORRECT
ANSWER-The Y-chromosome carries the SRY gene, which is the "Sex
Determining Region of the Y". The SRY gene stimulates testosterone production
in growing fetuses. The SRY gene also triggers embryonic gonad gene to
become testes.
In what way are ovaries and testes the same in a 7-week old embryo? -
CORRECT ANSWER-At 7 weeks, sex is undetermined. The only areas that can
be determined at 7 weeks are the anus, urethra and tail.
