Mitosis

Question 1

What is the structure of a nuclear chromosome

Answer 1

-Coiled up DNA around histones, in nucleus, “X”, two chromosomes held together with the centromere

Question 2

Compare and Contrast cell reproduction in prokaryotic and eukaryotic cells

Answer 2

Prokaryotic

• DNA is free-floating and circular
• Binary fission: asexual reproduction-> cell splits in half and DNA is in a circle

Eukaryotic

• Chromosomes in nucleus
• Mitosis
• Asexual-> 1 parent, exact copy
• Sexual-> 2 parents, combination

Question 3

How many chromosomes do humans have

Answer 3

46 in total, and 23 from each parent

Question 4

What are autosomes

Answer 4

Chromsosomes 1-22

Question 5

Sex chromosomes

Answer 5

Chromosome 23, determines gender

Question 6

Haploid cells in humans

Answer 6

Sperm and egg cells(gametes) that have 23 chromosomes

Question 7

Diploid cells in humans

Answer 7

Somatic cells (body cells-> pancreatic, blood, brain) that have 46 chromosomes

Question 8

What is contact inhibition

Answer 8

• The cell cannot divide because it is touching other cells so it knows that it doesn’t have room to divide
• When it is not contact inhibited, it triggers division because it has a chance and enough room to divide

Question 9

What is the role of cyclin in cell division

Answer 9

A chemical that signals for the cell to divide

Question 10

How is contact inhibition different from the hayflick limit

Answer 10

Contact inhibition stops a cell from dividing because it is touching other cells and there is no room and the Hayflick limit is the limit to the number of times a cell can divide (50 ish times). It stops cellular divides

Question 11

Why do cells in a multicellular organism divide in order for the organism to grow, rather than just growing larger cells

Answer 11

Cells cannot just grow larger because of DNA overload and Surface area to volume

Question 12

Surface area to volume ratio

Answer 12

AKA exchanging materials. As a cell gets bigger, its volume (x^3) grows at a faster rate than its surface area (X^2) and eventually the cell cannot transport enough materials across its membrane

Question 13

DNA Overload

Answer 13

As a cell gets too large, DNA cannot supply instructions to move enough protein for the entire cell to function. Too much inside to function properly, can’t keep up

Question 14

The important stages of the cell cycle

Answer 14

• Interphase
• Mitosis (prophase, metaphase, anaphase, telophase)
• Cytokensis

Question 15

Interphase

Answer 15

Period of growth, development and rest for the cell
G1: cell grows in size
S: DNA that makes up the chromatin replicates/doubles
G2: Cell undergoes rapid growth and prepares to divide, organelles double in number

Question 16

Prophase

Answer 16

• Part of Mitosis
• Nucleoi and nucleus disappears, centrosomes form centriols by dividing in half and moving to the opposite ends of the cell

Question 17

Metaphase

Answer 17

• A part of mitosis
• Chromosomes line upon the equator of the cell. Spindle fivers (microtubules, asters) attach to the kinetochore (things off of the centromere that the spindle fibers can grab on to)

Question 18

Anaphase

Answer 18

Chromatind pairs separate from each other. This stage ends when chromatids reach to the poles of the cell

Question 19

Telophase

Answer 19

Chromatids relax to form chromatin. Spindle fibers diasppear. Nucleus reforms around DNA. Stage ends with cytokenesis

Question 20

What is GO

Answer 20

A pause or checkpoint during interphase right after G1 and before G2

Question 21

Cell division and cytokenesis difference in plant and animal

Answer 21

Plant: Cell plate forms between the two cells and eventually pinches it off and becomes the cell wall of one of the cells
Animal: Cell membrane twists and pinches until it separates