Unit 2 Mitosis & Cell Division

Question 1

What happens in metaphase?

Answer 1

the centromeres of the duplicated chromosomes line up across the center of the cell. The shortest phase

Question 2

Difference between chromsomes and chromatin (presense in the cell)

Answer 2

Chromatin - Is found throughout interphase
Chromosomes - Seen only during cell division

Question 2

What are the two reasons why cells have to divide?

Answer 2

• The cell has more trouble moving necessary items across the cell membrane
• “DNA overload”

Question 3

Explain what DNA overload means

Answer 3

The larger a cell becomes, the more demands the cell places on its DNA

Question 4

Explain what happens to the surface and volume ratio as a cell enlarges.
In a living cell, what part of the cell represents surface area and which part of the cell represents volume?

Answer 4

DECREASES

Cell membrane represents the surface area
Cytoplasm represents the volume

Question 5

What are some adaptations that cells have developed that allow for a greater surface area volume ratio?

Answer 5

If the cell gets too large, cells can divide, change shape, and slow down metabolism

Question 6

Cell division occurs in two main stages. What are they?

Answer 6

Mitosis - division of the nucleus
Cytokinesis - division of the cytoplasm

Question 7

What is the cell cycle?

Answer 7

A series of events that takes place as a cell grows and divides

Question 8

G1

Answer 8

cell growth - the cell increases in size and synthesize new proteins and organelles
Cells do most of their growing in this stage

Question 9

S Phase

Answer 9

DNA replication - new DNA is synthesized as the chromosomes are replicated
In the end, the cells contain twice as much DNA from the beginning

Question 10

G2

Answer 10

Preparing for cell division - many of the organelles and molecules required for cell division are produced
When G2 phase ends, cell is ready to enter the M phase

Question 11

Mitosis

Answer 11

the period after the DNA is duplicated and the cell prepares to divide - checks for errors

Question 12

What is the G0 stage? Give 3 examples of cells that, once matured in the G1 phase, enter the G0 stage indefinitely.

Answer 12

The G0 phase is where the cells never divide. An example of this would be sperm, egg, and neuron cells, and red blood cells, cardiac cells

Question 13

Cells spend most of their lifetime in what stage? What 3 phases of the cell cycle does this include?

Answer 13

Cells spend most of their lifetime in interphase, which consists of G1, S phase, and G2

Question 14

What are the four stages of mitosis, in order?

Answer 14

Prophase, Metaphase, Anaphase, Telophase

Question 15

What happens in prophase?

Answer 15

the genetic material inside the nucleus condenses and the duplicated chromosomes become visible. Nucleolus disappears, the nuclear envelope breaks down

Question 16

What happens in anaphase

Answer 16

the chromosomes separate and move along the spindle fibers to opposite ends of the cell

Question 17

What happens in telophase

Answer 17

chromsomes move to opposite ends of the cell and start to uncoil into chromatin again

nucleolus becomes visible in each daughter cell
nuclear envelope reforms
spindle fibers disappear

Question 18

Difference between chromsomes and chromatin (structure)

Answer 18

Chromatin - DNA is wrapped around proteins called histones, which are bundled further (nucleosomes)
Chromosomes - Chromosomes are condensed and supercoiled chromatin fibers

Question 19

Difference between chromsomes and chromatin (appearance)

Answer 19

Chromatin - Long, thin and loosely coiled
Chromosomes - Supercoiled, tightly would compact

Question 20

Difference between chromsomes and chromatin (organization)

Answer 20

Chromatin - not in an organized fashion, but is spread throughout the nucleus, which makes it easier for replication and transcription
Chromosomes - Is in an organized fashion, which is necessary and helpful for cell division

Question 21

Difference between chromsomes and chromatin (visualization on the microscope)

Answer 21

Chromatin - you can only see on a super powerful microscope (appears as “beads on a string” when stained under a ELECTRON microscope
Chromosomes - you can see under a powerful light microscope (not as powerful)

Question 22

Briefly explain how six feet of DNA is packed into the nucleus of every cell of our body! Use the terms: histone, nucleosome, chromatin, loosely coiled, supercoiled

Answer 22

The loosely coiled DNA strand is wrapped around proteins called histones, which are bundled further, being called nucleosomes. Then, the DNA becomes super coiled into chromatin fibers.

Question 23

How many chromosomes are found in human body cells? How many chromosomes are found in human sex cells (egg and sperm)?

Answer 23

Humans have 46 chromosomes - 23 pairs
Egg and sperm have 23 chromosomes each

Question 24

What is the name of the proteins that regulate the cell cycle

Answer 24

Cyclin

Question 25

Define cancer

Answer 25

A disorder in which some of the bodies cells lose the ability to control cell growth

Question 26

What are tumors and what are the 2 types of tumors

Answer 26

Clusters of cells (that can be cancerous) that are clumped together. The 2 types of tumors are benign tumors (noncancerous), and malignant tumors (cancerous).

Question 27

What causes cancer

Answer 27

Smoking, chewing tobacco, radiation exposure, viral infections, genetics, lifestyle

Question 28

What are the 3 most common ways to treat cancer

Answer 28

Chemotherapy, surgery, and target radiation

Question 29

What is apoptosis?

Answer 29

Programmed cell death, they die when they are supposed to

Question 30

What is cancer a result of?

Answer 30

Internal regulators

Question 31

What is cytoxan?

Answer 31

Chemo treatment - haults the S phase

Question 32

What is taxol?

Answer 32

Chemo treatment - stops spindal fibers from forming

Question 33

What is P53?

Answer 33

• A type of tumor supresser gene

Question 34

What happens when there is a defective p53?

Answer 34

Causes the cells to lose the information needed to respond to signals that would normally control their growth

Question 35

What does a centromere do?

Answer 35

Links a pair of sister chromatids together during cell division

Question 36

ANGIOGENESIS

Answer 36

Tumors attract new blood vessel growth that will shunt all blood flow to the cancerous cells, hence cutting off blood flow to normal cells (which die)