the cells in your reproductive organs – the ovaries or testes – that develop into eggs or sperm
germ cells
germ cells and somatic cells
All of the different cells in your body can be divided into two groups: ____ and ____
only the DNA in the egg or sperm cells
The DNA from what cells are passed to the offspring?
23
How many pairs of chromosomes do humans have?
T
T/F
Each species has a characteristic number of chromosomes per cell
F
T/F
chromosome number is related to the size or complexity of an organism
germ cells
Do gametes come from germ cells or somatic cells?
46 (23*2)
What is the total number of chromosomes that our body has?
2 X chromosomes
What is the chromosome arrangement for females?
1 X chromosome and 1 Y chromosome
What is the chromosome arrangement for males?
haploid; ONLY gametes are haploid
Are gametes haploid or diploid cells?
diploid cells
Are body cells haploid or diploid cells?
A
Produces genetically identical cells?
A. mitosis
B. meiosis
B
Produces genetically unique cells?
A. mitosis
B. meiosis
A
Results in 2 identical diploid cells?
A. mitosis
B. meiosis
B
Results in 4 haploid cells?
A. mitosis
B. meiosis
A
Takes place throughout an organisms’s lifetime?
A. mitosis
B. meiosis
B
Takes place only at certain times in an organism’s life cycle?
A. mitosis
B. meiosis
A
Is involved in asexual reproduction?
A. mitosis
B. meiosis
B
Is involved in sexual reproduction?
A. mitosis
B. meiosis
development, growth, and repair
Mitosis is used for?
•A pair of chromosomes in a diploid cell are called HOMOLOGOUS.
•One member of the homologous pair comes from your Mom -the other comes from Dad. They are not identical, but they DO carry similar sequences of DNA!
•One member of the homologous pair comes from your Mom -the other comes from Dad. They are not identical, but they DO carry similar sequences of DNA!
What do you call each pair of chromosomes in a diploid cell? Is each chromosome similar or identical?
Haploid means “one set”.
Haploid cells in the body include gametes, or sex cells.
What does haploid mean? What type of cell in your body is haploid?
*Sperm producing cells in males are found in the testes.
•Egg producing cells in females are found in the ovaries.
•Both of these cells undergo meiosis in order to produce haploid (N) egg and sperm cells.
•Egg producing cells in females are found in the ovaries.
•Both of these cells undergo meiosis in order to produce haploid (N) egg and sperm cells.
What type of cell undergoes meiosis to produce gametes? Where are these cells found?
2N=8
Answer: 4
If a diploid cell with 8 chromosomes goes through meiosis, how many chromosomes will the resulting haploid cells have?
female
What is the sex of a person with the sex chromosomes XX
haploid
In meiosis, the parent cell (germ cell) has a diploid number of chromosomes, and the resulting daughter cells have a ________ number of chromosomes.
are not
Homologous chromosomes _____copies of each other.
Homologous chromosomes (replicated).
What is separating in meiosis I?
•The 2 cells produced by meiosis I now enter a second meiotic division. Unlike the first division, neither cell goes through a round of replication before entering meiosis II.
•Each of the cell’s chromosomes has 2 chromatids. During metaphase II, chromosomes line up in the center of the cell. In anaphase, the paired chromatids separate.
•Each of the cell’s chromosomes has 2 chromatids. During metaphase II, chromosomes line up in the center of the cell. In anaphase, the paired chromatids separate.
What is separating in meiosis II?
Diploid (2N)
When a sperm (1N) fertilizes an egg (1N), what is the chromosome number of the resulting zygote (haploid or diploid)?
Somatic cell: 46 chromosomes, Gamete: 23 chromosomes.
How many chromosomes do humans have in a somatic cell? In a gamete/sex cell?
* meiosis has 2 cell divisions; mitosis has only 1 cell division
*meiosis results in haploid cells; mitosis results in diploid cells
*meiosis results in haploid cells; mitosis results in diploid cells
What are the two key differences between the processes of meiosis and mitosis?
Production of sperm cells. Number of sperm produced: 4
What is spermatogenesis? How many sperm are produced from each germ cell?
Production of egg cells. Number of eggs produced: 1
What is oogenesis? How many eggs are produced from each germ cell?
D
Fertilization results in
a). a zygote.
b). a diploid cell.
c). a cell with a new genetic combination.
d). All of these are correct.
a). a zygote.
b). a diploid cell.
c). a cell with a new genetic combination.
d). All of these are correct.
D
The diploid number of chromosomes in humans is 46. The haploid number is
a). 138.
b). 92.
c). 46.
d). 23.
a). 138.
b). 92.
c). 46.
d). 23.
A
During which stage of meiosis does crossing over occur?
a). prophase I
b). anaphase I
c). prophase II
d). telophase II
a). prophase I
b). anaphase I
c). prophase II
d). telophase II
C
Synapsis is the process whereby
a). homologous pairs of chromosomes separate and migrate toward a pole.
b). homologous chromosomes exchange chromosomal material.
c). homologous chromosomes become closely associated.
d). the daughter cells contain half of the genetic material of the parent cell.
a). homologous pairs of chromosomes separate and migrate toward a pole.
b). homologous chromosomes exchange chromosomal material.
c). homologous chromosomes become closely associated.
d). the daughter cells contain half of the genetic material of the parent cell.
A
After chromosome replication and during synapsis,
a). homologous chromosomes pair along their lengths.
b). sister chromatids pair at the centromeres.
c). homologous chromosomes pair at their ends.
d). sister chromatids pair along their lengths.
a). homologous chromosomes pair along their lengths.
b). sister chromatids pair at the centromeres.
c). homologous chromosomes pair at their ends.
d). sister chromatids pair along their lengths.
C
Terminal chiasmata are seen during which phase of meiosis?
a). anaphase I
b). prophase I
c). metaphase I
d). metaphase II
a). anaphase I
b). prophase I
c). metaphase I
d). metaphase II
D
Which of the following occurs during anaphase I?
a). Chromosomes cluster at the two poles of the cell.
b). Crossing over occurs.
c). Chromosomes align down the center of the cell.
d). One version of each chromosome moves toward a pole.
a). Chromosomes cluster at the two poles of the cell.
b). Crossing over occurs.
c). Chromosomes align down the center of the cell.
d). One version of each chromosome moves toward a pole.
C
Mitosis results in two ________ cells, while meiosis results in _______ haploid cells.
a). haploid/four
b). diploid/two
c). diploid/four
d). haploid/two
a). haploid/four
b). diploid/two
c). diploid/four
d). haploid/two
B
Genetic diversity is greatest in
a). parthenogenesis.
b). sexual reproduction.
c). asexual reproduction.
d). binary fission.
a). parthenogenesis.
b). sexual reproduction.
c). asexual reproduction.
d). binary fission.
a). 56 chromosomes would be present in somatic cells, 28 homologous pairs?somatic cells are diploid and would have the full complement of chromosomes.
b). 112 chromosomes would be present in mitotic cells at metaphase. Prior to metaphase, the chromosomes replicated and so every chromosome is a pair of identical sister chromatids. So, 56 x 2 = 112 chromosomes.
c). 112 chromosomes would be present in meiotic cells in metaphase I. Prior to metaphase I, the chromosomes replicated and so every chromosome is a pair of sister chromatids. So, 56 x 2 = 112 chromosomes. These chromosomes have also undergone crossing over during prophase I so the sister chromatids are no longer identical as in metaphase of mitosis.
d). 56 chromosomes would be present in meiotic cells in metaphase II. During metaphase I and anaphase I, homologous pairs of chromosomes were separated so that the resulting cells contained one chromosome of a homologous pair still paired as sister chromatids.
e). 28 chromosomes would be present in the gametes. Each gamete would contain one chromosome from each homologous pair. During fertilization, the chromosome will be matched up with its homologue.
b). 112 chromosomes would be present in mitotic cells at metaphase. Prior to metaphase, the chromosomes replicated and so every chromosome is a pair of identical sister chromatids. So, 56 x 2 = 112 chromosomes.
c). 112 chromosomes would be present in meiotic cells in metaphase I. Prior to metaphase I, the chromosomes replicated and so every chromosome is a pair of sister chromatids. So, 56 x 2 = 112 chromosomes. These chromosomes have also undergone crossing over during prophase I so the sister chromatids are no longer identical as in metaphase of mitosis.
d). 56 chromosomes would be present in meiotic cells in metaphase II. During metaphase I and anaphase I, homologous pairs of chromosomes were separated so that the resulting cells contained one chromosome of a homologous pair still paired as sister chromatids.
e). 28 chromosomes would be present in the gametes. Each gamete would contain one chromosome from each homologous pair. During fertilization, the chromosome will be matched up with its homologue.
An organism has 56 chromosomes in its diploid stage. Indicate how many chromosomes are present in the following, and explain your reasoning:
a). somatic cells
b). metaphase (mitosis)
c). metaphase I (meiosis)
d). metaphase II (meiosis)
e). gametes
a). somatic cells
b). metaphase (mitosis)
c). metaphase I (meiosis)
d). metaphase II (meiosis)
e). gametes
The chances of a woman’s egg receiving only maternal chromosomes is 1 in 223 or 8,388,608 and so it is quite improbable that this would occur. Because of independent assortment that occurs during metaphase I of meiosis, it is quite improbable that all of the maternal chromosomes would line up on the same side to be distributed to a single egg.
Humans have 23 pairs of chromosomes. Ignoring the effects of crossing over, what proportion of a woman’s eggs contains only chromosomes she received from her mother?
fertilized egg
zygoteq
C
A kidney cell is an example of which type of cell?
a. sex cell
b. germ cell
c. somatic cell
d. haploid cell
a. sex cell
b. germ cell
c. somatic cell
d. haploid cell
B
How many chromosomes are in a human gamete?
a. 46
b. 23
c. 22
d. 44
a. 46
b. 23
c. 22
d. 44
D
Which of the following best describes the genetic material a person receives from his or her
father?
a. 22 pairs of homologous chromosomes and an X and Y chromosome
b. 22 haploid cells and an X or Y chromosome
c. 23 diploid cells and an X and Y chromosome
d. 22 autosomes and an X or Y chromosome
father?
a. 22 pairs of homologous chromosomes and an X and Y chromosome
b. 22 haploid cells and an X or Y chromosome
c. 23 diploid cells and an X and Y chromosome
d. 22 autosomes and an X or Y chromosome
D
Which phrase best describes the process of meiosis?
a. occurs in body cells
b. results in genetically identical cells
c. happens only in haploid cells
d. produces haploid gametes
a. occurs in body cells
b. results in genetically identical cells
c. happens only in haploid cells
d. produces haploid gametes
C
At fertilization, what happens to the sex cells?
a. They retain half of their chromosomes.
b. Half of the cells copy their DNA twice.
c. Their nuclei fuse to form one nucleus.
d. One becomes an egg, and one becomes a sperm cell.
a. They retain half of their chromosomes.
b. Half of the cells copy their DNA twice.
c. Their nuclei fuse to form one nucleus.
d. One becomes an egg, and one becomes a sperm cell.
B
Which of the following statements is true of homologous chromosomes?
a. They are exact copies.
b. They contain the same genes.
c. They divide during meiosis II.
d. They connect to each other.
a. They are exact copies.
b. They contain the same genes.
c. They divide during meiosis II.
d. They connect to each other.
C
Which phrase best describes meiosis I?
a. duplication of paired chromosomes
b. fusion of sister chromatids
c. division of homologous chromosomes
d. creation of two diploid cells
a. duplication of paired chromosomes
b. fusion of sister chromatids
c. division of homologous chromosomes
d. creation of two diploid cells
B
What happens to sister chromatids in meiosis II?
a. They duplicate.
b. They are divided.
c. They remain together.
d. They do not take part.
a. They duplicate.
b. They are divided.
c. They remain together.
d. They do not take part.
A
Gametogenesis is the term for
a. the production of gametes.
b. the fertilization of eggs.
c. the development of polar bodies.
d. the movement of sperm.
a. the production of gametes.
b. the fertilization of eggs.
c. the development of polar bodies.
d. the movement of sperm.
B
What does an egg contribute to the embryo that a sperm does not contribute?
a. polar bodies
b. organelles
c. DNA
d. germ cells
a. polar bodies
b. organelles
c. DNA
d. germ cells
C
Which of the following is an example of a biological trait? (4)
a. personality
b. hair style
c. eye color
d. regional accent
a. personality
b. hair style
c. eye color
d. regional accent
D
Mendel began his experiments with purebred pea plants. This approach enabled him to
determine that variations among offspring were the result of (3)
a. random mutations.
b. self-pollination.
c. genetic uniformity.
d. his crossings.
determine that variations among offspring were the result of (3)
a. random mutations.
b. self-pollination.
c. genetic uniformity.
d. his crossings.
A
When Mendel crossed plants that were purebred purple-flowered with plants that were purebred
white-flowered, the resulting offspring all had purple flowers. When allowed to self-pollinate, this F
generation gave rise to white-flowered plants as well as purple. As a result, Mendel determined that
individual traits are (3)
a. inherited as discrete units.
b. diluted in offspring.
c. merged with successive generations.
d. lost in the pollination process.
white-flowered, the resulting offspring all had purple flowers. When allowed to self-pollinate, this F
generation gave rise to white-flowered plants as well as purple. As a result, Mendel determined that
individual traits are (3)
a. inherited as discrete units.
b. diluted in offspring.
c. merged with successive generations.
d. lost in the pollination process.
D
Mendel was able to identify predictable patterns of heredity. He succeeded mainly because he
chose to study traits that (3)
a. were always dominant.
b. tended to be recessive.
c. could be diluted.
d. had only two forms.
chose to study traits that (3)
a. were always dominant.
b. tended to be recessive.
c. could be diluted.
d. had only two forms.
C
Which of the following conclusions was a result of Mendel’s observations? (3)
a. Organisms that give rise to purebreds are genetically superior.
b. Organisms that have intermediate features are self-pollinating.
c. Organisms inherit two copies of each gene, one from each parent.
d. Organisms that self-pollinate do not have “either-or” features.
a. Organisms that give rise to purebreds are genetically superior.
b. Organisms that have intermediate features are self-pollinating.
c. Organisms inherit two copies of each gene, one from each parent.
d. Organisms that self-pollinate do not have “either-or” features.
B
Which phrase best describes the term genome? (4)
a. the genetic makeup of a chromosome
b. the genes that make up an organism
c. the location of a specific set of genes
d. the sum of an organism’s physical traits
a. the genetic makeup of a chromosome
b. the genes that make up an organism
c. the location of a specific set of genes
d. the sum of an organism’s physical traits
D
Hair color and eye color are examples of a person’s (4)
a. recessive traits.
b. dominant alleles.
c. genotype.
d. phenotype.
a. recessive traits.
b. dominant alleles.
c. genotype.
d. phenotype.
C
When an organism has two alleles at a particular locus that are different, the organism is called (4)
a. purebred.
b. dominant.
c. heterozygous.
d. recessive.
a. purebred.
b. dominant.
c. heterozygous.
d. recessive.
C
If a pea plant were homozygous recessive for height, how would its alleles be represented? (5)
a. T t
b. T T
c. t t
d. t T
a. T t
b. T T
c. t t
d. t T
A
An allele is dominant in a heterozygote when it is (4)
a. expressed and the other allele is not.
b. a very common allele in a population.
c. the stronger of the two alleles.
d. more desirable than the other allele.
a. expressed and the other allele is not.
b. a very common allele in a population.
c. the stronger of the two alleles.
d. more desirable than the other allele.
B
What do the letters inside the grid of a Punnett square represent? (5)
a. phenotypes of parents
b. genotypes of offspring
c. testcrosses of offspring
d. chromosomes of parents
a. phenotypes of parents
b. genotypes of offspring
c. testcrosses of offspring
d. chromosomes of parents
B
What is the probability that the offspring of a cross between a homozygous recessive parent
and a heterozygous parent will be homozygous recessive? (5)
a. 1/1
b. 1/2
c. 1/4
d. 1/8
and a heterozygous parent will be homozygous recessive? (5)
a. 1/1
b. 1/2
c. 1/4
d. 1/8
C
The term for a cross that involves just one trait, such as pod shape, is called a (5)
a. homozygous cross.
b. test cross.
c. monohybrid cross.
d. dihybrid cross.
a. homozygous cross.
b. test cross.
c. monohybrid cross.
d. dihybrid cross.
A
What is the phenotypic ratio of a monohybrid cross between two heterozygous parents? (5)
a. 3:1
b. 1:2:1
c. 9:3:3:1
d. 1:2:2:1
a. 3:1
b. 1:2:1
c. 9:3:3:1
d. 1:2:2:1
B
Which of the following observations did Mendel make as a result of his experiments with
dihybrid crosses? (3)
a. Dominant traits are inherited together.
b. Different traits are inherited separately.
c. Similar traits are inherited in pairs.
d. Recessive traits are inherited unpredictably.
dihybrid crosses? (3)
a. Dominant traits are inherited together.
b. Different traits are inherited separately.
c. Similar traits are inherited in pairs.
d. Recessive traits are inherited unpredictably.
4
Meiosis I and meiosis II each have___ phases, similar to those in mitosis.
4
Meiosis II divides sister chromatids in ____ phases
T
T/F
DNA is not replicated between meiosis I and meiosis II.
D
Separation of ________ occurs in anaphase II of meiosis.
A) non-homologous chromosomes
B) homologous chromosomes
C) non-sister chromatids
D) sister chromatids
E) the two nuclei
A) non-homologous chromosomes
B) homologous chromosomes
C) non-sister chromatids
D) sister chromatids
E) the two nuclei
D
At the end of meiosis II, there are
A) two haploid cells, with each chromosome containing two sister chromatids.
B) two haploid cells, with each chromosome consisting of a single chromatid.
C) four haploid cells, with each chromosome containing two sister chromatids.
D) four haploid cells, with each chromosome consisting of a single chromatid.
E) four diploid cells, with each chromosome consisting of a single chromatid.
A) two haploid cells, with each chromosome containing two sister chromatids.
B) two haploid cells, with each chromosome consisting of a single chromatid.
C) four haploid cells, with each chromosome containing two sister chromatids.
D) four haploid cells, with each chromosome consisting of a single chromatid.
E) four diploid cells, with each chromosome consisting of a single chromatid.
B
Replication of chromosomes occurs between meiosis I and meiosis II.
A) True
B) False
A) True
B) False
D
What is the final product of meiosis?
A. identical diploid cells
B. unique diploid cells
C. identical haploid cells
D. unique haploid cells
XY
Which pair of sex chromosomes makes a person male? XX OR XY
