Question 1

Which phase of the cell cycle is primarily responsible for the accurate replication of DNA, and what is the main checkpoint that ensures this process is complete before the cell proceeds to mitosis?

Accepted Answer

S phase; G2 checkpoint

Question 2

During mitosis, sister chromatids are separated and moved to opposite ends of the cell. Which protein complex is responsible for holding sister chromatids together until anaphase?

Accepted Answer

Cohesins

Question 3

A human somatic cell contains 46 chromosomes. After DNA replication during interphase, how many chromatids are present in the cell just before mitosis begins?

Accepted Answer

$$92$$

Question 4

Which of the following best describes the role of cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

Cdks phosphorylate target proteins to regulate progression through cell cycle checkpoints.

Question 5

If a mutation prevents the formation of the mitotic spindle, which stage of mitosis would be directly affected, and what would be the likely consequence?

Accepted Answer

Metaphase; chromosomes would not align at the metaphase plate

Question 6

Which checkpoint in the cell cycle ensures that all chromosomes are properly attached to the spindle before the cell proceeds to anaphase?

Accepted Answer

M checkpoint

Question 7

A chicken has 78 chromosomes in its somatic cells. How many chromosomes would be present in a chicken's gamete after meiosis?

Accepted Answer

$$39$$

Question 8

Which of the following statements about chromatin is correct?

Accepted Answer

Chromatin consists of DNA and proteins, and its condensation varies during the cell cycle.

Question 9

During anaphase of mitosis, what triggers the separation of sister chromatids?

Accepted Answer

Cleavage of cohesin proteins

Question 10

Which of the following best explains why tissue renewal in multicellular organisms depends on cell division?

Accepted Answer

Cell division replaces old or damaged cells, maintaining tissue function.

Question 11

What is the primary function of the G1 checkpoint in the cell cycle?

Accepted Answer

To ensure the cell is ready for DNA synthesis

Question 12

Which of the following events occurs during prophase of mitosis?

Accepted Answer

Chromatin fibers condense into chromosomes and the mitotic spindle begins to form

Question 13

A researcher observes that chromosomes move toward the spindle poles during anaphase. Which mechanism is primarily responsible for this movement?

Accepted Answer

Shortening of kinetochore microtubules at their kinetochore ends

Question 14

Which of the following is NOT a role of cell division in multicellular organisms?

Accepted Answer

Protein synthesis

Question 15

In a typical human cell, how long does the M phase last compared to the G1 phase?

Accepted Answer

M phase lasts less than 1 hour, while G1 phase can last 5-12 hours or longer

Question 16

Which structure is responsible for organizing the mitotic spindle in animal cells?

Accepted Answer

Centrosome

Question 17

What is the result of cytokinesis in animal cells?

Accepted Answer

Formation of two genetically identical daughter cells

Question 18

Which of the following best describes the difference between mitosis and meiosis?

Accepted Answer

Mitosis results in genetically identical cells, while meiosis produces genetically diverse gametes

Question 19

Which of the following is a correct statement about chromosomes in eukaryotic cells?

Accepted Answer

Each chromosome consists of a single DNA molecule associated with many proteins

Chapter 12 Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard