BIO EXAM #4 PRACTICE QUESTIONS

A gray wolf's sperm contains 3 9 3939 chromosomes. He mates with a female gray wolf. How many chromosomes will there be in the resulting zygote? Choose 1 answer: Choose 1 answer: (Choice A) A 7 8 7878 (Choice B) B 1 5 6 156156 (Choice C) C 3 9 3939 (Choice D) D 1 9 . 5 19.5

A 78

DNA mutation lead to cancer. T/F

False

What two distinct subunits is MPF composed of?

it is composed of a protein kintanese and a cyclin.

Lucia, a researcher at Michigan State University, views a chimpanzee zygote under a microscope. She sees that it has 48 chromosomes. How many chromosomes would be in a chimpanzee's gamete? Choose 1 answer: Choose 1 answer: (Choice A) A 96 (Choice B) B 12 (Choice C) c 24 (Choice D) D 48

C

Several genes are responsible for preventing cells from dividing when conditions are not right. Two examples are tumor suppressor genes and proto-oncogenes. Which of the following accurately compares tumor suppressor genes and proto-oncogenes? Choose 1 answer: Choose 1 answer: (Choice A, Incorrect) INCORRECT Both tumor suppressor and proto-oncogenes prevent the spread of cancer by targeting and destroying existing cancer cells. Tumor suppressor genes and proto-oncogenes play roles in the regulation of cell division. They do not directly target cancer cells. (Choice B, Incorrect) INCORRECT A person who has both tumor suppressor and proto-oncogenes will always develop cancer. All people have tumor suppressor and proto-oncogenes. They only become a problem if they are affected by mutations. (Choice C, Checked, Correct) CORRECT (SELECTED) Proto-oncogenes code for growth factors, while tumor suppressor genes inhibit cell division of damaged cells. Normal proto-oncogenes code for growth factors that regulate cell division. Tumor suppressor genes prevent cancer by inhibiting the cell cycle when a damaged cell is identified. (Choice D, Incorrect) INCORRECT When a proto-oncogene mutates, it becomes a tumor suppressor gene. When a proto-oncogene mutates, it becomes an oncogene.

C

Which of the following are true regarding the process of meiosis I? a) Sister chromatids in a cell undergoing meiosis are always identical. (Choice B) B Most homologue pairs do not have any crossovers during prophase I. (Choice C) C Chromosome number is reduced from diploid to haploid. (Choice D) D Sister chromatids separate to opposite ends of the cell.

C

Which of the following statements accurately compares somatic cells and gametes? A Gametes are diploid, while somatic cells are haploid. (Choice B, Checked) B Somatic cells are involved in reproduction, and gametes are not. (Choice C) C Somatic cells have 2n chromosomes and gametes have n chromosomes. (Choice D) D Gametes and somatic cells both contain homologous pairs of chromosomes.

C

When does crossing over occur during meiosis?

Prophase I

All cancers arise from cells in which cell-cycle checkpoints have failed. T/F

True!!!!

Anaphase II

Which stage is this cell undergoing during Meiosis II

Proto-oncogenes become what when mutated?

Oncogenes, which can cause cancer if introduced to a cell.

Which two genes can disturb the cell cycle when they are mutated?

1. proto-oncogenes -Tell cells to go (act as gas) -Defects make proteins required for cell growth active when they should not be (Go left on) 2. tumor-suppressor genes -Tell cells to stop (act as brake) -Defects that prevent tumor suppressor genes from shutting down the cell cycle (Brake failure)

A porcupine has a chromosome number of 2 n = 3 4 2n=34, n, equals, 34. Which of the following is true? Choose 1 answer: Choose 1 answer: (Choice A) A A gamete from this species is haploid with 1 7 1717 chromosomes. (Choice B) B The species is diploid with 3 4 3434 sets of chromosomes. (Choice C) C The species is haploid with 3 4 3434 homologous pairs. (Choice D) D The species is diploid with 7 8 7878 chromosomes.

A

Which of the following best describes the formation of a zygote? Choose 1 answer: Choose 1 answer: (Choice A) A A sperm cell nucleus and an egg cell nucleus fuse. (Choice B) B Mitosis in a cell is accelerated. (Choice C) C Cell division produces a solid mass of cells. (Choice D) D A cell divides to form cells with half the initial genetic material.

A

During meiosis, a process known as crossing over occurs. Which of the following is true of crossing over? Choose 1 answer: Choose 1 answer: (Choice A) A Segments of DNA are traded between unrelated chromosomes. (Choice B) B A chiasma indicates that a crossover has occurred. (Choice C) C Most homologue pairs do not have any crossover events (Choice D) D Crossing over occurs more often in male gametes than female gametes.

B

This cell is in which stage of mitosis? Choose 1 answer: Choose 1 answer: (Choice A) A Early prophase (Choice B) B Late prophase (prometaphase) (Choice C) C Metaphase (Choice D) D Anaphase (Choice E) E Telophase

B Pro-metaphase

At which checkpoint does the cell decide to divide?

G1 checkpoint

At which checkpoint does the cell make a commitment to mitosis?

G2 checkpoint

the cell ensures that all chromosomes are attached to the spindle AT THE?

M-Phase checkpoint.

What is MPF? What does it do and which phase of Mitosis is it found in?

MPF stands for Mitosis promoting factor and it is present in the cytoplasm of G2-phase cells and induces mitosis in all eukaryotes.

This cell is in which stage of mitosis?

Metaphase

When cancer cells spread to other parts of the body this is called?

Metastasizing

A Kinase is an enzyme that can phosphorylate a protein (add a phosphate group). T/F?

True

Either a loss of cell cycle growth control or the loss of death signals can have the same outcome: unregulated cell growth. t/f

True

P53 triggers apoptosis when DNA damage is beyond repair. t/f

True

Programmed cell death is called

apoptosis

What is p53 and what does it do?

either pauses the cell cycle or initiates apoptosis- programmed cell death - if the DNA is physically damaged. p53 is an example of a tumor suppressor; damage to the p53 gene can lead to uncontrolled cell division