mitosis and the cell cycle.

Question 1

What Is A Nucleic Acid

Answer 1

-Biological chemicals that direct the growth and development of every organism
-Two types: DNA and RNA
- genetic source code

Question 2

What is DNA

Answer 2

The main instruction manuel in all cells
-contains instructions to make RNA
- RNA contains instructions to make protiens
-Protiens carry out the function of the cell

Question 3

What is Chromatin

Answer 3

• long intertwined strands of DNA which during the process of cellular division DNA is reorganized and the threads of chromatin condense and become distinct chromosomes

Question 4

What is a chromosome

Answer 4

A length of condesed DNA and its associated protiens
the centre of a chromosome is called a centromere

Question 5

How is DNA compacted

Answer 5

-Condesing DNA requires a highly organized set of protiens called histones
- DNA is then wrapped around histones which are then tightly packed together, loops are formed with the histones wrapped in DNA to then further condense the DNA
-Loops are then attached to a protein scaffold which then folds further, condesing the DNA into chromosomes

Question 6

What is a somatic cell

Answer 6

-Somatic cells is every cell in the human body execpt egg and sperm cells
-they have 46 chromosomes
-The 46 chromosomes can be organized into 22 pairs of homologous chromosomes and one pair of sex chromosomes

Question 7

Homologous Chromosomes

Answer 7

-a pair of chromeosomes that are similar but not identical to eachpther, one member comes from each parent
-theycarry different forms of the same gene at the same location which is called an allele

Question 8

what is an allele

Answer 8

the same gene at the same location of the chromosome in a pair of homologus chromosomes but are slightly varied with their instructions like eye colour.
- same function differnt result

Question 9

polyploid meaning

Answer 9

the organism haws sets of more than two homologus chromosomes

Question 10

whaat is the purpose of the cell cycle

Answer 10

to pass genetic matieral (the dna) from one generation to another via celluale divison

Question 11

which cells in the human body undergo cellular divison

Answer 11

somatic cells and gametes

Question 12

Somatic cells and gametes chromosome count before and after cell div.

Answer 12

somatic cells have 46 before cell div and the new cells after cell div also have 46 cells MITOSIS
-cells that give rise to gametes have 46 chromosomes but after cell div the gametes only hvae 23 chromosomes MEIOSIS

Question 13

The stages of the cell cycle

Answer 13

Part One Interphase
G1
S
G2
Part Two the division Phase
Mitosis and cytokinesis

Question 14

The Interphase

Answer 14

The cell is at rest or preparing for divison by repicating dna
Longest section of the cell cycle, some never leave this phase
G1,S,G2

Question 15

The division Phase

Answer 15

Mitosis and Cytokinesis
The components of the cytoplasm and the nucleus of the parent cell are divided to give rise to two identical daughter cells, this is the smallest part of the cell cycle

Question 16

G1 Phase

Answer 16

Originally called Gap1
Now called growth phase 1 because of the rapid growth that occuers in this stage

Question 17

S phase

Answer 17

stands for synthesis phase
this is the stage where the dna is replicated
two identical chromosomes called sister chromatids are joined at the centromere

Question 18

G2 phase

Answer 18

Originally called gap 2 now called growth phase 2
this is when the cell rebuils its reserves of energy and makes the protiens required for cell division

Question 19

IPMAT

Answer 19

Interphase
Prophase
Metaphase
Anaphase
Telophase

Question 20

The division of somatic cells is known as..

Answer 20

Mitosis - remember IPMAT

Question 21

what is mitosis?

Answer 21

the process by which one cell with 46 chromosomes gives rise to 2 identical daughter cells with 46 chromosomes

Question 22

What are the four main stages of mitosis and what follows them?

Answer 22

Prophase, Metaphase, anaphase, telophase and these are followed by cytokinesis

Question 23

What is cytokinesis?

Answer 23

The splitting of the cytoplasm

Question 24

Describe the events of Prophase

Answer 24

• Prophase is the first stage of mitosis
• Chromosomes become visible
  -Centrioles migrate to opposite poles of the cell
  -The centromere joining the two chromatids anchor the chromosomes to the spindle fibers
  -Nuclear membrane appears to fade

Question 25

what are centrioles?

Answer 25

centrioles are small proteins bodies found in the cytoplasm of animal cells that provide a site for spindle fibers to attach to.

Question 26

What are spindle fibres

Answer 26

- Spindle fibers are protien structures that guide the movement of chromosomes during cell divison

Question 27

What do centrioles and spindlefiberes collectively makeup?

Answer 27

the spindle apparatus

Question 28

Describe the events of the Metaphase

Answer 28

-Second phase of mitosis -Chromosomes composed of sister chromatids move towards the centre of the cell (also called the equatorial plate) - Think M for Middle

Question 29

Describe the events of the Anaphase

Answer 29

-3rd stage of mitosis - at this stage the centromeres divide, the sister chromatids now called chromosomes move to opposite poles - the same number and type of chromosomes will be found at each pole

Question 30

Telophase

Answer 30

-4th and final stage of mitosis -chromosomes reach the oppostie poles of the cell -spindle fibres dissolve and a nuclear membrane forms around each mass of chromatin

Question 31

Cytokinesis

Answer 31

-The division of the cytoplasm - in animal cells a furrow develops, pinchinf the cell into two pairs - in plant cells a cell plate will develop into a new cell wall

Question 32

Descibe the cell clock

Answer 32

-cells have a biological clock that regulates the number of cell divisions - usually more specialized cells divide less than non-specialized cells (neurons vs skin cells) -if cel div goes sunregulated cancer develops