5 - The Mitotic Cell Cycle

Question 1

What are chromosomes made of?

Answer 1

1 very long condensed DNA molecule associated with proteins

In eukaryotic cells, chromosomes consist of DNA and histones.

Question 2

What is the main protein associated with DNA that organizes and condenses it?

Answer 2

Histones

Question 3

What is chromatin?

Answer 3

The tightly coiled combination of DNA and proteins, what chromatids and chromosomes are made of

Question 4

What occurs during the S phase of interphase?

Answer 4

DNA replicates to create 2 identical chromatids joined by centromere

Question 5

What are sister chromatids?

Answer 5

The 2 chromatids that make up a chromosome, identical to each other, contain the same genes

Question 6

What are telomeres?

Answer 6

Protective structures that seal the end of chromatids, made of non-coding DNA and short repeating base sequences

Question 7

What is the function of telomeres?

Answer 7

Ensure that ends of DNA molecules are included in DNA replication during mitosis

They act as a buffer region to prevent important coding sections from being lost.

Question 8

What is mitosis?

Answer 8

The process of nuclear division by which two genetically identical daughter nuclei are produced

Question 9

What are the importance of mitosis?

Answer 9

• Growth of multicellular organism
• Repair of tissues
• Replacement of damaged cells
• Asexual reproduction

Question 10

What are the three phases of the cell cycle?

Answer 10

• Interphase
• Nuclear Division (mitosis)
• Cell division (cytokinesis)

Question 11

What happens during interphase?

Answer 11

The cell increases in mass and size, carries out normal functions

Question 12

What are the three stages of interphase?

Answer 12

• G1 (gap)
• S (synthesis)
• G2

Question 13

What occurs during the G1 phase?

Answer 13

Cell growth, signal received telling cell to divide again

Question 14

Fill in the blank: During the S phase, DNA in the nucleus _______.

Answer 14

replicates

Question 15

What happens during the G2 phase?

Answer 15

Cell continues to grow, synthesized DNA checked for error

Question 16

What follows interphase in the cell cycle?

Answer 16

M phase (mitosis)

Question 17

What is cytokinesis?

Answer 17

The process that follows M phase, where the whole cell divides to produce 2 genetically identical daughter cells

Question 18

How does cytokinesis occur in animals?

Answer 18

Involves constriction of cytoplasm between 2 nuclei

Question 19

How does cytokinesis occur in plants?

Answer 19

Formation of new cell wall

Question 20

What is telomerase?

Answer 20

Enzyme that adds more bases at each end of chromatid to avoid risk of losing genes

Question 21

What are stem cells?

Answer 21

Cells that can divide by mitosis an unlimited number of times and can turn into specialized cells

Question 22

What is differentiation?

Answer 22

The process by which unspecialized cells become specialized and distinct

Question 23

What is potency in stem cells?

Answer 23

The ability of stem cells to differentiate into more specialized cell types

Question 24

What are the three types of potency?

Answer 24

• Totipotency
• Pluripotency
• Multipotency

Question 25

What are totipotent stem cells?

Answer 25

Cells that can differentiate into any cell type found in the embryo and extra-embryotic cells

Question 26

What are pluripotent stem cells?

Answer 26

Embryonic stem cells that can differentiate into any cell types in the embryo, not extra-embryotic cells

Question 27

What are multipotent stem cells?

Answer 27

Cells that can differentiate into multiple, but limited, types of cells within a specific tissue lineage

Question 28

What is a tumor?

Answer 28

When cells divide repeatedly and uncontrollably, forming an irregular mass of cells

Question 29

What causes cancers?

Answer 29

Uncontrolled mitosis due to mutations in genes controlling cell division

Question 30

True or False: Most mutations lead to cancer.

Answer 30

False

Question 31

What is an oncogene?

Answer 31

A mutated gene that causes cancer and does not result in early cell death

Question 32

What are oncoviruses?

Answer 32

Cancer-causing viruses

Question 33

What are carcinogens?

Answer 33

Cancer-causing agents, e.g., UV light, x-rays, tar in tobacco smoke

Question 34

What is a benign tumor?

Answer 34

Tumors that don’t spread from the original site and don’t cause cancer

Question 35

What is a malignant tumor?

Answer 35

Tumors that can spread to other cells, invade and destroy other tissues, causing cancer

Question 36

What is metastasis?

Answer 36

Spread of cancer by malignant tumors moving around the body to form secondary growth

Question 37

What are the stages of mitosis?

Answer 37

PMAT: Prophase, Metaphase, Anaphase, Telophase

Question 38

What occurs during prophase?

Answer 38

Chromosomes condense, centrosomes move to opposite poles, spindle fibers emerge

Question 39

What happens during metaphase?

Answer 39

Chromosomes line up at the equator of the cell, spindle fibers attach to centromeres

Question 40

What occurs during anaphase?

Answer 40

Sister chromatids divide and are pulled to opposite poles of the cell

Question 41

What happens during telophase?

Answer 41

Chromosomes reach opposite poles and decondense, nuclear envelope forms

Question 42

What are meristems?

Answer 42

Regions of plants where growth occurs