Chapter 2: Reproduction

Question 1

What are the five stages of the cell cycle? What happens in each stage? 1. 2. 3. 4. 5.

Answer 1

1.G1: Cell grows and performs its normal functions, DNA is examined and repaired. 2. S: DNA is replicated 3. G2: Cell continues to grow and replicates organelles in preparation for mitosis. Cell continues to perform its normal functions. 4. M: Mitosis (Cell Division) Occurs 5. G0: The cell performs its normal functions and is not preparing to divide.

Question 2

What are the four phases of mitosis? What happens in each phase? 1. 2. 3. 4. 5.

Answer 2

1. 1. Prophase: Chromosomes condense, nuclear membrane dissolves, centrioles migrate to opposite poles and begin forming the spindle apparatus.
2. Metaphase: Chromosomes gather along the metaphase plate in the center of the cell under the guidance of the spindle apparatus.
3. Anaphase: Sister chromatids separate, and a copy of each chromosome migrates to opposite poles.
4. Telophase & Cytokinesis: Chromosomes decondense, nuclear membrane reforms, nucleoli reappear, spindle apparatus breaks down, cell divides into two identical daughter cells.

Question 3

What is the main protein to control DNA repair in cell division?

Answer 3

p53

Question 4

The molecules that are responsible for the cell cycle are know as ___ and ___.

Answer 4

Cyclins Cyclin Dependent Kinases (CDK)

Question 5

The CDK-cyclin complex phosphorylates ___.

Answer 5

Transcription Factors

Question 6

Transcription Factors

Answer 6

promote transcription of genes required for the next stage of the cell cycle.

Question 7

When the the cell cycle becomes deranged and damaged ___ may result.

Answer 7

Cancer

Question 8

One of the most common mutations found in cancer is mutation of the gene that produces ___. It is then called ___.

Answer 8

P53 TP53

Question 9

What are the functions of interstitial cells of Leydig and Sertoli cells? -Interstitial cells of Leydig: -Sertoli cells:

Answer 9

-Interstitial cells of Leydig: secrete testosterone and other male sex hormones (androgens) -Sertoli cells: nourish sperm during their development

Question 10

During which phase of meiosis is a primary oocyte arrested? During which phase of meiosis is a secondary oocyte arrested? -Primary oocyte: -Secondary oocyte:

Answer 10

-Primary oocyte: arrested in prophase 1 -Secondary oocyte: arrested in metaphase 2

Question 11

What is the acrosome? What organelle form the acrosome?

Answer 11

The acrosome contains enzymes that are capable of penetrating the corona radiate and zona pellucid of the ovum, permitting fertilization to occur. It is a modified Golgi apparatus

Question 12

Which hormones are key to sexual differentiation in a fetus with XY genotype? Describe the expected phenotype if receptors to these hormones are absent?

Answer 12

Androgens, such as testosterone, lead to male sexual differentiation. Absence of androgen receptors, a condition known as androgen insensitivity syndrome, leads to an XY genotype with phenotypically female characteristics.

Question 13

Biological sex is determined by the ___ pair of chromosomes.

Answer 13

23rd

Question 14

Males are termed ____ with respect to many of the genes on the X chromosome because they only have one copy.

Answer 14

Hemizygous

Question 15

Which chromosome carries most genetic material? X or Y Which chromosome carries little genetic information? X or Y

Answer 15

X Y (it does have the SRY gene which is the sex determining region.

Question 16

Mnemonic seX-linked =

Answer 16

X-linked

Question 17

Mnemonic Pathway of sperm though the male reproductive system.

Answer 17

SEVE(N) UP

• Seminiferous Tubules
• Epididymis
• Vas deferens (also called ductus deferens)
• Ejaculatory tract
• Nothing
• Urethra
• Penis

Question 18

Where is sperm produced?

What are they nourished by?

Answer 18

Seminiferous Tubules

Serotili Cells

Question 19

Whats important about the Interstital Cells of Leydig?

Answer 19

They secrete testosterone and other male sex hormones (androgens).

Question 20

Where are the testes located?

Answer 20

Scrotum (Pouch/Ball Sack)

Question 21

Epididymis

Answer 21

Where a sperms flagella gains motility and where they are stored until ejaculation.

Question 22

During ejaculation, sperm travel thourgh the ____ and enter the ____.

Answer 22

Vas Deferens

Ejaculatory tract.

Question 23

The two ejaculatory ducts then fuse to form the ____. Then they come out of the ___.

Answer 23

Urethra

Penis

Question 24

During which phase of meiosis is a primary oocyte arrested?During which phase of meiosis is a seconday oocyte arrested?

Answer 24

• Prophase 1
• Metaphase 2

Question 25

What is the acrosome? What organelle forms the acrosome?

Answer 25

The acrosome contains enzymes that are capable of penetrating the corona radiate and zona pellucida of the ovum, permitting fertilization to occur. It is a modified GolgI Apparatus.

Question 26

Which hormones are key to sexual differentiation in a fetus with XY genotype? Describe the expected phenotype if receptors to these hormones are absent.

Answer 26

Androgens, such as testosterone, lead to male sexual differentiation. Absence of androgen receptors, a condition known as androgen insensitivity syndrome, leads to an XY genotype with phenotypically femal characteristics.

Question 27

What are the four phases of the female menstrual cycle?

Answer 27

Question 28

Mitosis occus in ____ cells.

Meiosis occurs in ___ cells.

Answer 28

Somatic Cells

Germ line (sex) cells

Question 29

After S phase there are ____ chromatids organized into ____ chromosomes, which are organized into ____ homologous pairs.

Answer 29

92

46

23

Question 30

THE DIFFERENCES IN MITOSIS AND MEIOSIS

Mitosis

1.

2.

3.

4

Meiosis

1.

2.

3.

4.

Answer 30

Mitosis

1. 2n -> 2n
2. Occurs in Somatic Cells
3. Crossing Over does not happen (Prophase)
4. Homologous chromosones do not pair (Metaphase)

Meiosis

1. 2n -> n
2. Occurs in Germ-line cells
3. Crossing-Over happens (Prophase)
4. Homologous chromosomes pair (Metaphase)

Question 31

What is the number and ploidy of the daughter cells produced from meiosis.

• Meiosis 1
• Meiosis 2

Answer 31

• Meiosis 1
  
  • 2 Haploid daughter cells
• Meiosis 2
  
  • 4 Haploid Gametes

Question 32

What is the difference between homologous chromosomes and sister chromatids?

• Homologous Chromosomes
• Sister Chromatids

Answer 32

• Homologous Chromosomes
  
  • Related chromosomes of opposite parental origin (such as maternal chromosome 15 and paternal chromosome 15, or in males the X and Y chromosomes)
• Sister Chromatids
  
  • Identical copies of the same DNA that are held together at the centromere. After the S phase, a cell contains 92 chromatids, 46 chromosomes, and 23 homologous pairs.

Question 33

For each phase of meiosis I listed below, what are the differences from the analogous phase of mitosis?

• Prophase I:
• Metaphase I:
• Anaphase I:
• Telophase I:

Answer 33

• Prophase I:
  
  • Homologous chromosomes come together as tetrads during synapsis, Crossing Over
• Metaphase I:
  
  • Homologous chromosomes line up on opposite sides of the metaphase plate, rather than individual chromosomes lining up on the metaphase plate.
• Anaphase I:
  
  • Homologous Chromosomes seperate from each other, centromeres do not break.
• Telophase I:
  
  • Chromatin may or may not decondense; interkinesis occurs as the cell prepares for meiosis 2.