Biology - Cell Cycle

Question 1

What is another name for body cell and how many chromosomes?

Answer 1

Somatic/Vegetative cells

46 chromosomes

Question 2

What is another name for sex cell and how many chromosomes?

Answer 2

Gametes/Germline cells

23 chromosomes

Question 3

What happens in interphase?

Answer 3

• cell grows and carries out regular cellular functions

- cell duplicates DNA to prepare for mitosis (each of the 46 DNA molecules now consist of 2 identical sister chromatids)

Question 4

What happens in mitosis?

Answer 4

• division of DNA
• must occur before cell divides
• ensures that complete set of DNA is given to each daughter cell

Question 5

What is visible in interphase?

Answer 5

nucleus + nucleolus + nuclear membrane

Question 6

Mitosis allows what?

Answer 6

• single cells to reproduce
• multicellular organisms to grow and develop
• tissues to be repaired
• old worn out cells to be replaced

Question 7

Each body cell has __ DNA molecules; __ from maternal set and __ from paternal set

Answer 7

46 DNA molecules (23 from maternal, 23 from paternal)

Question 8

During interphase, DNA molecules gets copied to now each of __ molecules contain ___________.

Answer 8

46 DNA molecules get doubled; each 46 DNA molecules contain 2 identical sister chromatids

Question 9

Alone, a strand of the sister chromatids would be called _______. The sister chromatids are held together by __________.

Answer 9

Sister chromatids are held together by a centromere

Question 10

What is cytokinesis and the end result?

Answer 10

• the division of cytoplasm + organelles

- end result is 2 genetically identical daughter cells

Question 11

What happens in animal cytokinesis?

Answer 11

a band of protein squeezes cell membrane in middle, forming cleavage furrow until cytoplasm splits

Question 12

What happens in plant cytokinesis?

Answer 12

cell plate grows in the middle outward, sealing contents of new cells from each other

Question 13

What happens in prophase?

Answer 13

• chromatin condense to chromosomes made up of 2 sister chromatids
• nuclear membrane starts to dissolve, releasing chromosomes into cytoplasm
• centrioles move to opposites poles with spindle fibers

Question 14

What is visible in prophase?

Answer 14

maybe nucleus + nucleolus + nuclear membrane, chromatids, chromosomes, and spindle fibers

Question 15

What happens in metaphase?

Answer 15

• chromosomes line up along equatorial plate

- nuclear membrane dissolves completely

Question 16

What is visible in metaphase?

Answer 16

chromatids, chromosomes, spindle fibers

Question 17

What happens in anaphase?

Answer 17

• sister chromatids separate into daughter chromosomes, pulled to other end of cell by spindle fibers (which contract opposite ways)

Question 18

What is visible in anaphase?

Answer 18

chromosomes, spindle fibers

Question 19

What happens in telophase?

Answer 19

• chromosomes reach opposite ends of cell and lengthen to chromatin
• new nuclear membrane + nucleus + nucleolus form at each end of cell
• spindle fibers break down and disappear

Question 20

What is visible in telophase?

Answer 20

nucleus + nucleolus + nuclear membrane, maybe chromosomes

Question 21

What are spindle fibers?

Answer 21

a network of protein which grows from centrioles and attach to the centromere of each DNA molecule

Question 22

What is the equatorial plate?

Answer 22

located in middle of cell, equal distance away from 2 poles and perpendicular to spindle fibers

Question 23

Sexual reproduction?

Answer 23

The process of producing offspring by the fusion of 2 gametes; the production of offspring that have genetic information from each parent

Question 24

Asexual reproduction?

Answer 24

The process of producing offspring from only one parent; the production of offspring that are genetically identical to the parent

Question 25

What do all organisms need to survive?

Answer 25

cell division + source of energy + nutrients + water + gases to survive

Question 26

As multicellular organisms, why do number of cells increase instead of size?

Answer 26

Chemicals used during cell activity/growth enter across the membrane and travel through diffusion; where chemicals move from an area of higher concentration (amount of solute in a solution) to lower. Water enters and leaves in a process called osmosis whereas water moves in the direction of greater solute concentration. But when a cell gets too large, these necessary chemicals/water cannot move through the cell fast enough and will die!

Question 27

How does a minor cut heal over time?

Answer 27

Every day, your body sheds millions of dead skin cells, all of which are replaced by new ones. If you get a cut, cells divide to fill in the gaps.

Question 28

Checkpoints?

Answer 28

A cell should remain in interphase and not divide if:

1. signals from surrounding cells tell it not to divide
2. there are not enough nutrients to provide for cell growth
3. DNA within nucleus has not been replicated
4. DNA is damaged