BIOL 3301 EXAM QUESTIONS AND ANSWERS
LATEST UPDATE (GRADED A+)
Pea plant flowers are both:
male and female.
Pea plants have both male and female reproductive parts, which are:
the pistil and stamen, respectively.
What is cross-fertilization?
pollen from one plant fertilizes a flower (oocyte) on a different plant
What is self-fertilization?
pollen from one plant fertilizes a flower (oocyte) on that same plant (could be the same flower)
What is a monohybrid cross?
a cross in which both parents are heterozygous (or a hybrid) for a single (mono-) trait
When Mendel performed a monohybrid cross between smooth seeds and wrinkled seeds, he noticed
that the offspring peas were all smooth peas. How is the disappearance of the wrinkled phenotype
explain?
The parental strains that were used must have been true-breeding. So, when self-crossed (against
themselves), they must continually give rise to a consistent phenotype, whether it be smooth or
wrinkled.
What four things were summarized by Mendel after performing his monohybrid cross with the pea
plants?
1) Start with true-breeding pea plants, smooth and wrinkled.
2) One trait (wrinkled) was hidden in the F1. But, wrinkled peas reappear in the F2!
3) Having the same appearance does NOT mean the plants are genetically identical (smooth can be PP or
Pp)
4) Ratios are reproducible - there are rules!
How did Mendel explain the happenings of the monohybrid cross with the pea plants (5 things)?
1) Each parent plant contains two 'particulate factors'.
2) Plants contribute just one of these 'factors' to oocytes and pollen.
3) At fertilization, haploid oocytes and pollen come together to form a diploid organism.
4) One of the factors was DOMINANT, one of the factors was RECESSIVE
5) Dominance and recessiveness do not depend on the sex of the contributing parent
What are the two approaches to Mendelian problems?
, 1) Punnett squares
2) Branch diagram
What is a dihybrid cross?
a cross in which both parents are heterozygous (or a hybrid) for two (di-) traits
• Check out Mendel's dihybrid cross example in the slides. It will explain things much better than I could!
Principle of Independent Segregation
the principle that only one or the other allele of a given gene will be delivered to a gamete
Principle of Independent Assortment
the principle that separate genes are delivered to gametes independent of one another (only applies if
genes are on different chromosomes, or are quite far apart on the same chromosome)
What is the purpose of a test cross?
to determine an unknown genotype by crossing it with a homozygous recessive parent
What is pedigree analysis?
working out the patterns of inheritance in family trees
What is pedigree analysis most useful for?
traits that are caused by one gene that comes in normal and mutant allelic forms and displays standard
dominance and recessive relationships (just like smooth and wrinkled)
What are genes?
linear sequences of nucleotide chemicals (G, A, T, C)
Genes are strung together in much larger strings called:
chromosomes.
Chromosomes, which hold many genes, can vary in shape between prokaryotes and eukaryotes. What
are these shapes?
circular in bacteria, linear in eukaryotes
Humans have autosomal chromosomes and sex chromosomes. How many pairs of each of these types
of chromosomes do humans have?
22 pairs of autosomal chromosomes and 1 pair of sex chromosomes (XX for female, XY for male)
For each chromosome pair, how many paternal chromosomes and maternal chromosomes are there?
one is maternal, one is paternal
During the G1 phase of the cell cycle, the cell is _______ and contains two copies of each
chromosome.
LATEST UPDATE (GRADED A+)
Pea plant flowers are both:
male and female.
Pea plants have both male and female reproductive parts, which are:
the pistil and stamen, respectively.
What is cross-fertilization?
pollen from one plant fertilizes a flower (oocyte) on a different plant
What is self-fertilization?
pollen from one plant fertilizes a flower (oocyte) on that same plant (could be the same flower)
What is a monohybrid cross?
a cross in which both parents are heterozygous (or a hybrid) for a single (mono-) trait
When Mendel performed a monohybrid cross between smooth seeds and wrinkled seeds, he noticed
that the offspring peas were all smooth peas. How is the disappearance of the wrinkled phenotype
explain?
The parental strains that were used must have been true-breeding. So, when self-crossed (against
themselves), they must continually give rise to a consistent phenotype, whether it be smooth or
wrinkled.
What four things were summarized by Mendel after performing his monohybrid cross with the pea
plants?
1) Start with true-breeding pea plants, smooth and wrinkled.
2) One trait (wrinkled) was hidden in the F1. But, wrinkled peas reappear in the F2!
3) Having the same appearance does NOT mean the plants are genetically identical (smooth can be PP or
Pp)
4) Ratios are reproducible - there are rules!
How did Mendel explain the happenings of the monohybrid cross with the pea plants (5 things)?
1) Each parent plant contains two 'particulate factors'.
2) Plants contribute just one of these 'factors' to oocytes and pollen.
3) At fertilization, haploid oocytes and pollen come together to form a diploid organism.
4) One of the factors was DOMINANT, one of the factors was RECESSIVE
5) Dominance and recessiveness do not depend on the sex of the contributing parent
What are the two approaches to Mendelian problems?
, 1) Punnett squares
2) Branch diagram
What is a dihybrid cross?
a cross in which both parents are heterozygous (or a hybrid) for two (di-) traits
• Check out Mendel's dihybrid cross example in the slides. It will explain things much better than I could!
Principle of Independent Segregation
the principle that only one or the other allele of a given gene will be delivered to a gamete
Principle of Independent Assortment
the principle that separate genes are delivered to gametes independent of one another (only applies if
genes are on different chromosomes, or are quite far apart on the same chromosome)
What is the purpose of a test cross?
to determine an unknown genotype by crossing it with a homozygous recessive parent
What is pedigree analysis?
working out the patterns of inheritance in family trees
What is pedigree analysis most useful for?
traits that are caused by one gene that comes in normal and mutant allelic forms and displays standard
dominance and recessive relationships (just like smooth and wrinkled)
What are genes?
linear sequences of nucleotide chemicals (G, A, T, C)
Genes are strung together in much larger strings called:
chromosomes.
Chromosomes, which hold many genes, can vary in shape between prokaryotes and eukaryotes. What
are these shapes?
circular in bacteria, linear in eukaryotes
Humans have autosomal chromosomes and sex chromosomes. How many pairs of each of these types
of chromosomes do humans have?
22 pairs of autosomal chromosomes and 1 pair of sex chromosomes (XX for female, XY for male)
For each chromosome pair, how many paternal chromosomes and maternal chromosomes are there?
one is maternal, one is paternal
During the G1 phase of the cell cycle, the cell is _______ and contains two copies of each
chromosome.
