Mitosis and Asexual Reproduction

Question 1

What are the three stages in the cell cycle?

Answer 1

1) Interphase: Cells carry out the functions necessary for survival and cells that divide prepare for division
2) Mitosis: Duplicated nuclear material divides into two equal parts
3) Cytokinesis: Separates the two nuclei and cell contents into two daughter cells

Question 2

What are the phases of interphase?

Answer 2

1) Growth and preparation
-Cell increases in size
-Makes proteins and molecules necessary for the cell to function
2) Reparation
-DNA makes a copy of itself
-Each side becomes a template for a new side to form
-New bases pair with bases on original DNA (A->T, C->G)
3) Continued growth and preparation

Question 3

What is mitosis?

Answer 3

-The shortest stage of the cell cycle
-the content of a cell’s nucleus divide
-results in two daughter nuclei, each with the same number and types of chromosomes as the original cell
-daughter cells = to the parent cell
-sister chromatids of chromosomes that replicate during interphase are joined by a centromere
(PMATC)

Question 4

What are the stages of mitosis? Describe them.

Answer 4

1. Prophase - DNA condenses into chromosomes where each one contains two copies of the same DNA
   -Nuclear membrane disappears
   -Spindle fibres form and attach to chromosomes at their centromeres
2. Metaphase - spindle fibres pull chromosomes into a line across the middle of the cell
3. Anaphase - centromeres are pulled apart and sister chromatids move to opposite ends of the cell
4. Telophase - spindle fibres disappear and a nuclear membrane form around each set of chromosomes

Question 5

What is cytokinesis?

Answer 5

-The final stage of the cell cycle
-Separates the two nuclei into two identical daughter cells
-In animal cells, the cell membrane pinches together to divide the cytoplasm and organelles
-In plant cells, a cell plate grows toward the cell membrane forming a new cell membrane for each daughter cell

Question 6

What are checkpoints in the cell cycle?

Answer 6

-They monitor the cell cycle
-Proteins at checkpoints monitor cell activities and send the information to the nucleus
-the nucleus tells the cell whether or not to divide

Question 7

What are the reasons why a cell might not divide?

Answer 7

1) There are not enough nutrients to support cell growth
2) DNA has not been replicated
3) DNA has been damaged

Question 8

How does cancer work in the cell cyle?

Answer 8

-Rapid and uncontrolled cell division
Cancer cells:
-Don’t respond to messages from neigbouring cells telling them to stop dividing, so the cancer cells grow in multiple layers forming a tumor
-Have large abnormal nuclei because chromosomes do not divide correctly
-Are not specialized and do not function as part of the body
-Can release chemicals to attract small nearby blood vessels that branch into tumors and deliver nutrients to it, allowing tumor cells to increase speed of division

Question 9

What is asexual reproduction?

Answer 9

Where only one parent is required to produce offspring

Question 10

What is sexual reproduction?

Answer 10

Where two parents contribute genetic information to produce a zygote

Question 11

What are the types of asexual reproduction?

Answer 11

1) Binary fission
-Only single-celled organisms
-Rapid population growth
2) Budding
-repeated mitosis and cell division, developing a bud that pinches off to become an identical organism
-Yeast, hydra
3) Fragmentation
-Small part of an organism breaks off and grows into an organism identical to the parent
5) Vegetative propagation
-Special cells in plants, usually in stems, roots, or leaves, divide repeatedly to form structures that develop into a new plant identical to the parent
-Tulips and daffodils produce bulbs that become new plants, identical to the parent
-strawberries have stem runners that grow roots and become new plants, identical to the parents
6) Spore formation
-an organism produces single-celled spores that grow into new individuals by mitosis

Question 12

Why is cell division important for multicellular and unicellular organisms?

Answer 12

Multicellular:
-Replacing old/damaged cells
Unicellular:
-Produces new offspring

Question 13

What happens in the cell cycle?

Answer 13

Interphase: Cells carry out the functions necessary for survival and cells that divide prepare for division
Mitosis: Duplicated nuclear material divides into two equal parts
Cytokinesis: Separates the two nuclei and cell contents into two daughter cells

Question 14

Why might the cell not divide?

Answer 14

-There are not enough nutrients to support cell growth
-DNA has not been replicated
-DNA is damaged

Question 15

How does a mutation in the cell cycle and cancer correlate?

Answer 15

Cancer cells don’t respond to other cells to stop dividing
-large abnormal nuclei
-not specialized, don’t function as a part of the body
-can release chemicals to neabry blood vessels that create tumours

Question 16

What can human-assisted plant and animal cloning be used for?

Answer 16

-To save genetic information of endangered species
-Mass-produce an organism with a desirable trait

Question 17

What is reproductive cloning? (adult DNA cloning)

Answer 17

A genetic duplicate of an existing or previously existing organism with desirable qualities is made

Question 18

What are the steps of reproductive cloning?

Answer 18

1. Scientists remove the nucleus from a cell of the desired organism
2. This nucleus is put into an egg cell that has had the nucleus removed
3. The egg cell divides to form an embryo
4. The embryo is inserted into the uterus of a substitute mother to complete its development

Question 19

What is therapeutic cloning?

Answer 19

Using human embryonic and adult stem cells to correct health problems