Lesson 13: Mitosis-Cell Cycle

Question 1

What are chromosomes?

Answer 1

ONE very long DNA molecule that is made of chromatin

Question 2

What is chromatin?

Answer 2

Complex of DNA and proteins that make up eukaryotic chromosomes

Question 3

What is the difference between prokaryotes and eukaryotes in cell division?

Answer 3

Prokaryotes:
One chromosome, arranged in a circle, can also have smaller circles of DNA (plasmids) that carry certain genes

Eukaryotes:
Multiple chromosomes, linear in structure, each eukaryotic species has a characteristic number of chromosomes

Question 4

How many chromosomes do humans have?

Answer 4

46 chromosomes (1 set of 23 from mom and 1 set of 23 from dad)

Question 5

What are diploid chromosomes?

Answer 5

2 sets of chromosomes

Question 6

What are haploid chromosomes?

Answer 6

1 set of chromosomes

Question 7

What is the difference between haploid and diploid chromosomes?

Answer 7

Haploid (n):
1 copy of each chromosome, gametes (sperm and egg), in humans: egg cell= 23 chromosomes and sperm cell= 23 chromosomes

Diploid (2n):
2 copies of each chromosome (1 from mom and 1 from dad), somatic cells (body cells), in humans: body cells have 46 chromosomes (23 pairs)

Question 8

Where does mitosis occur?

Answer 8

In somatic (body) cells

Question 9

What does mitosis make?

Answer 9

Identical diploid cells

Question 10

What does a cell need to do before it divides into two identical cells?

Answer 10

It must copy ALL of its DNA

Question 11

What happens when a cell duplicates?

Answer 11

Each chromosome becomes a duplicated chromosome (X shaped) and half of each X (chromatid) will go to each new cell

Question 12

What are chromosomes made of structurally?

Answer 12

Two sister chromatid joined at a centromere

Question 13

What happens later in mitosis to help pull the chromatids apart?

Answer 13

A protein complex connects at the centromere forming the kinetochore

Question 14

What happens in the interphase stage of the cell cycle?

Answer 14

Cell has prepared to divide, made (G1) where enough organelles for 2 cells are made and the protein needed for division is made, DNA is copied and centrioles have been duplicated (S), checkpoints have been cleared (G1, S, G2)

Question 15

What happens in prophase of mitosis?

Answer 15

Nuclear membrane begins to disappear (so that chromosomes can move), chromosomes condense, and centrosomes form and begin moving apart

Question 16

What kind of centrosomes are in animal and plant cells?

Answer 16

Centrioles: animal cells
Spindle fibers: made of microtubules

Question 17

What happens in the prometaphase of mitosis?

Answer 17

Nucleus disappears, spindle fibers extend and attach to the kinetochore, and chromosomes begin to move/line up

Question 18

What happens in the metaphase phase of mitosis?

Answer 18

Chromosomes align in the middle of the cell at the metaphase plate, single

Question 19

What happens in anaphase?

Answer 19

Sister chromatids separate and move to opposite poles

Question 20

What happens in telophase/cytokinesis during mitosis?

Answer 20

Daughter cells begin to form nuclear membranes, nucleolus returns, chromosomes unravel and become chromatin again, this happens at the same time/sequentially as cytokinesis (division of the cytoplasm)

Question 21

What happens in animal cells during cytokinesis in mitosis?

Answer 21

As new nuclei form around each set of chromatin, a cleavage furrow forms between them (looks like a butt cheek), cells pull apart making 2 new cells

Question 22

What happens to plant cells during cytokinesis in mitosis?

Answer 22

Plant cells can not undergo traditional cytokinesis because of the cell wall, golgi sends vesicles to form a growing cell plate, eventually the cell plate completely divides the two new cells creating a new cell wall