BSC 324: Genetics - Exam 1 Prep Study Guide
How many chromosomes are there in a human OVUM (unfertilized egg)? - ANSWER 23
How many chromosomes are there in a dividing cell at the beginning of human Meiosis?
- ANSWER 46, Duplicated
How many chromosomes are there in a human cell at the ANAPHASE of MITOSIS? -
ANSWER 92
How many HOMOLOGOUS PAIRS of chromosomes are there in a human meiotic cell at
FIRST METAPHASE? (or, metaphase of Meiosis II) - ANSWER 23
A dog's sperm cell has 39 chromosomes. How many chromosomes does dog's somatic
(body) cell have? - ANSWER 78
How many CHROMATIDS are there in a human primary oocyte? - ANSWER 92
Fruit flies have diploid number 2n=8. How many chromosomes are there in a fruit fly
meiosis at FIRST METAPHASE? (or, metaphase I) - ANSWER 8, Duplicated
In imaginary trolls, red eyes (A) are dominant over green eyes (a). A green-eyed troll is
born to two red-eyed troll parents. What are genotypes of the parents? - ANSWER both
Aa
Blue eye color is recessive to brown. What is the chance of two heterozygous
brown-eyed parents to have a blue-eyed child? - ANSWER 25%
How many chromosomes does a human zygote have? - ANSWER 46
Blue eye color is recessive to brown. What is the chance of a blue-eyed father and a
brown-eyed mother to have a blue-eyed child? - ANSWER Impossible to tell since we do
not know mother's genotype
Sickle-cell anemia (SCA) and cystic fibrosis (CF) are two Mendelian recessive mutations
(on different chromosomes). One parent is heterozygous for SCA (A>a) (but does not
have any recessive CF alleles); another parent is heterozygous for CF (B>b) (but does
not have any recessive SCA alleles). What is the chance that they have a healthy child? -
ANSWER 100%
Cystic fibrosis (CF) is a Mendelian recessive mutation. If a father suffers from CF and a
mother is heterozygous, what its the chance their child will be born sick with CF? -
ANSWER 50%
How many chromosomes are there in a human meiosis at SECOND METAPHASE? (or,
metaphase II) - ANSWER 23, Duplicated
, In Mendel's experiment, what was a chance of two yellow-pea plants of first offspring
generation (F1) to yield another yellow-pea plant? - ANSWER 75%
Sickle-cell anemia (SCA) and cystic fibrosis (CF) are two Mendelian recessive mutations
(on different chromosomes). What is the chance for a HEALTHY child to be born if EACH
parent is heterozygous by BOTH sickle-cell (A>a) and CF (B>b) genes? - ANSWER 9/16
Fruit flies have diploid number 2n=8. How many CHROMATIDS are there in a fruit fly
meiotic cell at SECOND METAPHASE? (or, metaphase II) - ANSWER 8
Cystic fibrosis (CF) is a Mendelian recessive mutation. If both parents are heterozygous,
what is the chance their child is homozygous dominant? - ANSWER 25%
Sickle-cell anemia (SCA) is a disease due to a recessive Mendelian mutation.
Phenylketonuria (PKU) is a disease due to another recessive Mendelian mutation on a
different chromosome. A husband is heterozygous for both SCA and PKU; his wife
expresses PKU disease and also is a carrier of (heterozygous for) SCA mutation. What is
the ratio of PHENOTYPES (scored for both traits together!) expected in their offspring? -
ANSWER 3:3:1:1
Achondroplasia (dwarfism, "midgets") is a DOMINANT Mendelian mutation. "Midget"
phenotype always has heterozygous genotype. Homozygous dominant genotype does
not develop (a lethal combination). Can two achondroplastic dwarfs ("midgets") have a
normal child? - ANSWER Yes
Yellow mice always have heterozygous genotype, A^Y A. Wild type ("agouti") is AA.
Homozygous dominant genotype A^Y A^Y does not develop (a lethal combination). What
phenotypes of the offspring will result from breeding of two yellow mice? - ANSWER 33%
agouti, 66% yellow
Palomino horses are always heterozygous (R^1 R^2 - incomplete dominance!); R^1 R^1
are chestnut color; R^2 R^2 are cremello color. What are the resulting phenotypes and
their ratio in a cross between two palomino horses? - ANSWER 25% cremello, 50%
palomino, 25% chestnut
Pink snapdragon flowers are always heterozygous (incomplete dominance). Dominant
homozygotes are red, recessive homozygotes are white. What phenotypes are expected
in the offspring of a red and a pink snapdragons? - ANSWER 50% red, 50% pink
Which of the following notations refers to a genotype of a sperm cell in a two-gene
(dihybrid) cross? - ANSWER AB
A woman with blood group AB marries a man with blood group A (heterozygous
genotype). What is the chance (%) that their child will be group B? - ANSWER 25%
A man with blood group A (heterozygous) marries a woman with blood group B
(homozygous). Both man and woman are also heterozygous by Bombay mutation, a
recessive trait that "masks" expression of the gene determining blood group antigen
production. Bombay gene (H>h) and blood group gene (alleles I^A, I^B, i) segregate
How many chromosomes are there in a human OVUM (unfertilized egg)? - ANSWER 23
How many chromosomes are there in a dividing cell at the beginning of human Meiosis?
- ANSWER 46, Duplicated
How many chromosomes are there in a human cell at the ANAPHASE of MITOSIS? -
ANSWER 92
How many HOMOLOGOUS PAIRS of chromosomes are there in a human meiotic cell at
FIRST METAPHASE? (or, metaphase of Meiosis II) - ANSWER 23
A dog's sperm cell has 39 chromosomes. How many chromosomes does dog's somatic
(body) cell have? - ANSWER 78
How many CHROMATIDS are there in a human primary oocyte? - ANSWER 92
Fruit flies have diploid number 2n=8. How many chromosomes are there in a fruit fly
meiosis at FIRST METAPHASE? (or, metaphase I) - ANSWER 8, Duplicated
In imaginary trolls, red eyes (A) are dominant over green eyes (a). A green-eyed troll is
born to two red-eyed troll parents. What are genotypes of the parents? - ANSWER both
Aa
Blue eye color is recessive to brown. What is the chance of two heterozygous
brown-eyed parents to have a blue-eyed child? - ANSWER 25%
How many chromosomes does a human zygote have? - ANSWER 46
Blue eye color is recessive to brown. What is the chance of a blue-eyed father and a
brown-eyed mother to have a blue-eyed child? - ANSWER Impossible to tell since we do
not know mother's genotype
Sickle-cell anemia (SCA) and cystic fibrosis (CF) are two Mendelian recessive mutations
(on different chromosomes). One parent is heterozygous for SCA (A>a) (but does not
have any recessive CF alleles); another parent is heterozygous for CF (B>b) (but does
not have any recessive SCA alleles). What is the chance that they have a healthy child? -
ANSWER 100%
Cystic fibrosis (CF) is a Mendelian recessive mutation. If a father suffers from CF and a
mother is heterozygous, what its the chance their child will be born sick with CF? -
ANSWER 50%
How many chromosomes are there in a human meiosis at SECOND METAPHASE? (or,
metaphase II) - ANSWER 23, Duplicated
, In Mendel's experiment, what was a chance of two yellow-pea plants of first offspring
generation (F1) to yield another yellow-pea plant? - ANSWER 75%
Sickle-cell anemia (SCA) and cystic fibrosis (CF) are two Mendelian recessive mutations
(on different chromosomes). What is the chance for a HEALTHY child to be born if EACH
parent is heterozygous by BOTH sickle-cell (A>a) and CF (B>b) genes? - ANSWER 9/16
Fruit flies have diploid number 2n=8. How many CHROMATIDS are there in a fruit fly
meiotic cell at SECOND METAPHASE? (or, metaphase II) - ANSWER 8
Cystic fibrosis (CF) is a Mendelian recessive mutation. If both parents are heterozygous,
what is the chance their child is homozygous dominant? - ANSWER 25%
Sickle-cell anemia (SCA) is a disease due to a recessive Mendelian mutation.
Phenylketonuria (PKU) is a disease due to another recessive Mendelian mutation on a
different chromosome. A husband is heterozygous for both SCA and PKU; his wife
expresses PKU disease and also is a carrier of (heterozygous for) SCA mutation. What is
the ratio of PHENOTYPES (scored for both traits together!) expected in their offspring? -
ANSWER 3:3:1:1
Achondroplasia (dwarfism, "midgets") is a DOMINANT Mendelian mutation. "Midget"
phenotype always has heterozygous genotype. Homozygous dominant genotype does
not develop (a lethal combination). Can two achondroplastic dwarfs ("midgets") have a
normal child? - ANSWER Yes
Yellow mice always have heterozygous genotype, A^Y A. Wild type ("agouti") is AA.
Homozygous dominant genotype A^Y A^Y does not develop (a lethal combination). What
phenotypes of the offspring will result from breeding of two yellow mice? - ANSWER 33%
agouti, 66% yellow
Palomino horses are always heterozygous (R^1 R^2 - incomplete dominance!); R^1 R^1
are chestnut color; R^2 R^2 are cremello color. What are the resulting phenotypes and
their ratio in a cross between two palomino horses? - ANSWER 25% cremello, 50%
palomino, 25% chestnut
Pink snapdragon flowers are always heterozygous (incomplete dominance). Dominant
homozygotes are red, recessive homozygotes are white. What phenotypes are expected
in the offspring of a red and a pink snapdragons? - ANSWER 50% red, 50% pink
Which of the following notations refers to a genotype of a sperm cell in a two-gene
(dihybrid) cross? - ANSWER AB
A woman with blood group AB marries a man with blood group A (heterozygous
genotype). What is the chance (%) that their child will be group B? - ANSWER 25%
A man with blood group A (heterozygous) marries a woman with blood group B
(homozygous). Both man and woman are also heterozygous by Bombay mutation, a
recessive trait that "masks" expression of the gene determining blood group antigen
production. Bombay gene (H>h) and blood group gene (alleles I^A, I^B, i) segregate
