Cell Divisions, Diversities and Differentiation

Question 1

What is mitosis?

Answer 1

• Type of nuclear division that produces 2 genetically identical daughter cells to each other and parent

Question 2

What is Chomatin?

Answer 2

• This is the complex of nucleic acids and histone protiens, being DNA unravelled state!

Question 3

What are Chomosomes?

Answer 3

• the condensed structure of the DNA double helix!

Question 4

What are Chromatids?

Answer 4

• These are structures of copied chromosomes during the preparation of cell division
• The “divided and duplicated” form of the chomosomes….

Question 5

What are Centromeres?

AND LOOK HERE RN!!!!!

Answer 5

• This is the center of chromosomes where the spindle fibres will attach during metaphase!
  *

!!!!NUMBER OF CENTROMERES = NUMBER OF CHROMOSOMES!!!!

Question 6

What are sister chromatids?

Answer 6

These are the 2 copies of the cell’s original chromosomes!

Question 7

How can there be an increase in number of chromatids, but same number of chromosomes

AHEM!!!!!!!!!!!

Answer 7

• Thes is due to the centromere-counting rule, where we count chromosomes in this manner!

ALWAYS THE CASE, SO NEVER FORGET!

Question 8

What are homologous chromosomes?

Answer 8

• These are the MATCHING PAIRS OF CHROMOSOMES, each from the correspondonding parent cell! (sperm+egg)

Question 9

What is the acronym for remembering the Cell Cycle Stages????

Answer 9

I-PMAT-C!!!!!

gotta know them in order………..!

Question 10

What takes place during Interphase?

Answer 10

1. DNA Replication
2. Cell growth in size
3. Organelle duplication

Question 11

How can we split up the massive Interphase stage into its sub-processes???

AND EXPLAIN EACH OF ‘EM!

Answer 11

1. The G1 Stage: main Organelle Replication and increase in Cell Size
2. The S Stage: just DNA Replication!
3. The G2 Stage: Stimulating protien production to allow Chromosome Condensation for mitosis stage………..

Question 12

What takes place during each of the Cell Cycles’s checkpoints?

Answer 12

1. G1 Checkpoint: Checking for DNA damages and correct cell sizes
2. G2 Checkpoint: Checking for errors in DNA Replication, before moving to mitosis
3. Metaphase Checkpoint: Checking forf even distribution of chromosomes during division!

Question 13

What is the ledgdendary G0 Stage?

Answer 13

• This is where Senescent Cells (oldy cells with max division no.50) chill, with no more mitosis!
• This is also where cells are before apoptosis takes place!

cell differentiation and neurones may also forever be in this stage!

Question 14

What protiens are actually involved with the cell cycle checkpoints??

Answer 14

1. POSITIVE REGULATORS: CDK + Cycline > the protiens that INITIATE THE FOLLOWING STAGES OF CELL CYCLE!
2. NEGATIVE REGULATORS: P53 Supressor Protiens > the protiens that HALT THE CELL CYCLE AND BRINGS THE G0 Stage!

Question 15

What happens in each of the mitosis stages in the Cell Cycle?

remember I-PMAT-C………………

Answer 15

1. Prophase: Chromosome Condensation, where nueclear membrane will break down
2. Metaphase: Chromatids attach to the spindle fibres of centriolesvia the centromeres, where Chromosomes will line at the equator!
3. Anaphase: Chromosomes are pulled away towards opposite poles via spindle fibres
4. Telophase: 2 fresh new nuclear envelopes will form around dublicated chromatids

Question 16

What happens during the cytokenises stages in the Cell Cycle?

Answer 16

1. Cytoplasme will divide, forming 2 new GENETICALLY IDENTICAL DAUGHTER CELLS,
2. (being identical to the parent cell ofc………..)

Question 17

What special about the way the Cell Cycle works?

Answer 17

• ITS A CYCLE!
• This means that it can loop around at any given moment, and can be found in whatever stage it may appear to be in!!!NEVER FORGET THIS!

Question 18

Why are cell-cycle checkpoints needed during division?

Answer 18

1. To ensure that DNA is only duplicated once
2. To ensure the cycle is never reversed
3. To prevent uncontrollable division
4. To detect and repair any damages to DNA

Question 19

What is the purpose of mitosis?

be sure to check ittttttttttt……

Answer 19

1. asexual reproduction
2. Organism growth
3. Tissue repair

in PLANTS, ANIMALS AND FUNGI!!!!!!

Question 20

What is the difference between a gene pool and a genome?

Answer 20

1. Gene Pool: This is all the genetic information within an entire population
2. Genome: Refers to all the geneitc information within an individual only

Question 21

What is cell differentiation?

Answer 21

• The process in which stem cells become specialised to become specialised cells, specific to their function

Question 22

How are erythrocytes specialised to carry out its function?

Answer 22

1. Biconcave shape = larger SA/V ratio, faster rate of oxygen diffusion into the cell
2. Very Flexible Cytoskeleton = this will allow shape changing to twist and turn inside narrow capilleries
3. Very Few Organelles (no nucleus) = More space available for oxygen to bind to haemaglobin

Question 23

How are neutrophils specialised to carry out its function?

Answer 23

1. Attraction via Chemotaxix = able to attract to sites of toxins via pathogens, to be able to engulf and digest them
2. Large Cell Size = easily able to *engulf and digest most pathogens *efficiently

Question 24

How are sperm specialised to carry out its function?

Answer 24

1.Streamlined Shape = Allows the sperm to move very easily, towards the egg cells
2.Many Mitochondria = Provides energy from ATP to allow sperm to activly swim to egg, for fertilisation

Question 25

How are ciliated epithilium specialised to carry out its function?

Answer 25

1. Have cilia (hair-like structures) = beats in a coordinated way to shift material along the surface of the epithelium tissue
1. Goblet cells secrete mucus = helps to trap dust, dirt and microorganisms - preventing them from entering vital organs where they may cause infection

Question 26

How are squamous epithilium specialised to carry out its function

Answer 26

1. Squamous epithelium consists of a single layer of flattened cells on a basement membrane
2. **The layer of cells forms a thin cross-section **= reduces the distance that substances have to move to pass through (it shortens the diffusion pathway)
3. It is permeable= for the easy diffusion of gases

Question 27

How are root hair cells specialised to carry out its function?

Answer 27

1. Root hair to increase surface area = the rate of water uptake by osmosis is greater
2. Shorter diffusion distance = water can move through easily and at a faster rate
3. Permanent vacuole contains cell more concentrated than soil water = maintaining a water potential gradient
4. Mitochondria for active transport of mineral ions
   Remember that chloroplasts are not found in these cells – there’s no light for photosynthesis underground!