Transcript Biology WarmUp: Meiosis Vocabulary Review 1. What does it

Biology WarmUp: Meiosis Vocabulary Review
1. What does it mean for two chromosomes to be,
“homologous?”
2. How many homologous pairs of chromosomes do human
beings have?
3. What is a, “tetrad?”
4. When are tetrads visible?
5. With regards to genetic diversity, what is the significance of
tetrad formation?
6. In fruit flies, the gene for star eye and speck wing are on the
same chromosome, yet offspring from star-eyed, speckwinged parents often inherit star eyes without the speck wings.
How is this possible? Make a diagram to illustrate the process
that is responsible for the recombination.
Biology WarmUp: Meiosis Vocabulary Review
1. What does it mean for two chromosomes to be,
“homologous?”
If two chromosomes are homologous, they belong to the
same pair.
It is homologous chromosomes that line up together in
metaphase of meiosis.
Meiosis
Mitosis
Biology WarmUp: Meiosis Vocabulary Review
2. How many homologous pairs of chromosomes do
human beings have?
Human beings have 46 pairs of
chromosomes
2n = 46
That means they must have 23 pairs of
chromosomes
1n = 23
Biology WarmUp: Meiosis Vocabulary Review
3. What is a, “tetrad?”
During late prophase and
metaphase of meiosis I,
homologous chromosomes line up
in with their homologous pairs.
Since each chromosome is
composed of two sister
chromatids, the pair of
chromosomes consists of four
chromatids, hence the name,
“tetrad.”
Tetrad
Biology WarmUp: Meiosis Vocabulary Review
4. When are tetrads visible?
During late prophase and
metaphase of meiosis I,
homologous chromosomes line
up in with their homologous
pairs. Since each chromosome
is composed of two sister
chromatids, the pair of
chromosomes consists of four
chromatids, hence the name,
“tetrad.”
Tetrad
Biology WarmUp: Meiosis Vocabulary Review
5. With regards to genetic diversity, what
is the significance of tetrad formation?
Crossing over can occur only because
chromosomes form tetrads during meiosis.
Were it not for crossing over, traits on the
same chromosomes would always be
inherited together.
Biology WarmUp: Meiosis Vocabulary Review
6. In fruit flies, the gene for star eye and speck wing are on
the same chromosome, yet offspring from star-eyed, speckwinged parents often inherit star eyes without the speck wings.
How is this possible? Make a diagram to illustrate the process
that is responsible for the recombination.
Though star eyes and
speck wing are inherited
together, they could be
separated by crossing
over, particularly if they
were found far apart on
the chromosome.