Unit 5: Cell Division and Cancer

Question 1

Definition of Mitosis

Answer 1

The division of the nucleus and DNA into two daughter cells

Question 2

Cytokinesis

Answer 2

The division of the cytoplasm and organelles into two daughter cells

Question 3

How do plant cells divide?

Answer 3

• the vesticles fuse together to create a disc-shaped structure called the “cell plate” –> made up of Golgi bodies
• the cell plate extends until it fuses with the sides of the parent cell

Question 4

How do animal cells divide?

Answer 4

Contractile proteins form rings at the equator of the cell. They pull the membrane inwards to form a cleavage furrow
–> it pinches until the cell is split into two

• the nucleus, ER, GB disassemble and then are reformed during cytokinesis

Question 5

Budding

Answer 5

asymmetric division used by most yeast to reproduce asexually

Question 6

Oogenesis

Answer 6

is the production of an egg (ovum) cell
*one large egg, 3 small polar bodies

Question 7

What are processes that require cell proliferation

Answer 7

1) organism growth
2) cell replacement
3) tissue repair

Question 8

What happens in the G1 phase?

Answer 8

• the cell starts to get bigger, tries to double, replicating organelles for 2nd cell

Question 9

What happens during S phase?

Answer 9

DNA is replicated, organelles are doubled, and new proteins are made

Question 10

What happens during G2?

Answer 10

Final prep before cell divides
- replenishes energy by obtaining nutrients
- synthesizing proteins needed for division
- dismantling the cytoskeleton that is holding organelles in place
- growing size by increasing cytoplasm volume

Question 11

How does cancer initiation begin?

Answer 11

1) Random errors in DNA replication
2) A mutagen which causes a mutation to the DNA

Question 12

What is a mutagen?

Answer 12

Anything that changes genetic material

Question 13

Proto-Oncogenes

Answer 13

Code for proteins that make the cell “go”
- such as the genes that code for cyclin proteins

Question 14

Oncogene

Answer 14

• it becomes a cancer causing allele called an oncogene.

They are permanently activated even when they are not supposed to, causing the cell to grow out of control
- when activated it will cause cells to divide

Slamming the gas

Question 15

Tumor Suppressor Genes

Answer 15

• Code for proteins that make the cell cycle “stop”
• slows down cell division
• repairs mistakes

Question 16

Mutated Tumor Suppressor Gene

Answer 16

• Don’t work properly and cells can grow out of control
• Stops making the protein that inhibits cell division

Question 17

Benign Tumor

Answer 17

The cells in the tumor adhere to each other and remain in a single mass

Doesn’t cause cancer

Question 18

Malignant Tumor

Answer 18

The cells in the tumor can detach and invade neighboring tissues, lymph vessels, or blood vessels

Causes cancer

Question 19

Cancer development stages

What is initiation?

Answer 19

• a normal cell is transformed into a cancerous cell as a result of mutations to genes that regulate the cell cycle

Question 20

Cancer development stages

What is promotion?

Answer 20

• the initiated cell divides, giving rise to a large # of daughter cells containing the mutation(s)
  –> these cells are the primary tumor

Question 21

Cancer development stages

What is progression?

Answer 21

the cancerous cells often become aneuploid (having the wrong number of chromosomes) and invade surrounding tissues

Question 22

Cancer development stages

What is metastasis?

Answer 22

• Cancer cells break away from where they first formed, travel through the blood of the lymph system to form new tumors in other parts of the body.

Question 23

What is cancer?

Answer 23

• is the result of the accumulation of multiple mutations to a cell’s genetic code

Question 24

Kinetochore

Answer 24

• Microtubule attachment for movement of chromosomes
  -Protein complex that assembles at the centromere
• each sister chromatid has its own
• links chromatids to microtubule

Question 25

Chromosome

Answer 25

Formed from chromatin during mitosis and meiosis

Question 26

Chromatin

Answer 26

Nucleosomes coil and stack together to form fibers

exists in interphase

Question 27

Nucleosome

Answer 27

Eukaryotic cell DNA wraps around proteins nucleosome

Question 28

Double Helix

Answer 28

• 2 anti-parallel strands of nucleotides with 2 strands linked by hydrogen bonding between complimentary base pairs

Question 29

Cyclins

Answer 29

Regulatory proteins. Their concentrations cycle up and down as the cell progresses through the cycle

Question 30

Mitotic Index

Answer 30

Ratio of cells in mitosis relative to the total # of cells

higher the MI, the more likely the tissue is cancerous, MI decreasing indicates treatment is working

Question 31

Cyclin D

Answer 31

• Synthesized during early G1. At high concentrations activates cell’s transition from G1 to S phase

Question 32

Cyclin E

Answer 32

• Synthesized midway through G1 and peaks in S phase. At high levels, prepares cell for DNA replication

Question 33

Cyclin A

Answer 33

• Initiates DNA Replication
• Makes sure DNA is replicated once per cycle
• Tiggers mitosis

Question 34

Cyclin B

Answer 34

• Creates mitotic spindle
• Peaks at metaphase
• Degrades as anaphase begins

Question 35

Benefits of Packaging of DNA

Answer 35

• The structure and packaging of DNA plays a crucial role in ensuring the accurate segregation of chromosomes during cell division, maintaining the chromosome number in daughter cells
• condensed chromosomes are easier to organize, manipulate, and segregate during cell division
  –> also prevents tangling during interphase