6 - Cell Division

Question 1

Humans have __ pairs of ______ chromosomes

Answer 1

23 pairs of homologous chromosomes

Question 2

What are homologous chromosomes

Answer 2

Each code for the same thing, one is paternally inherited, one is maternally inherited

Question 3

When 1 chromosome is replicated it makes _____ joined by a ____

Answer 3

A pair of chromatids joined by a centromere

Question 4

What is a pair of chromatids?

Answer 4

2 identical chromosomes joined by a centromere

Question 5

What is chromatin?

Answer 5

DNA wrapped around proteins called histones

Question 6

What are chromosomes made from?

Answer 6

Chromatin (DNA and histone proteins)

Question 7

What is a diploid?

Answer 7

Full set of chromosomes- 23 pairs of homologous chromosomes (pre pick and mix, di- 2 one from each parent)

Question 8

What is a haploid?

Answer 8

1/2 a diploid, one chromosome inherited randomly from a parent (think pic and mix)

Question 9

What are the 2 parts of the mitosis cell cycle?

Answer 9

Cell growth and cell division

Question 10

What happens during cell growth in mitosis?

Answer 10

Interphase:

• cell grows in size
• synthesis of organelles
• DNA checking
• fuel stores

Question 11

What happens during cell division stage in mitosis?

Answer 11

• mitosis

- cytokenesis

Question 12

Name the stages of mitosis interphase in order

Answer 12

G1
S
G2
(then mitosis and cytokenesis)

Question 13

What happens in G1 stage of interphase?

Answer 13

Cell contents (everything but chromosomes) are duplicated
-cell grows in size

Question 14

What does G1 checkpoint in interphase check for?

Answer 14

• DNA damage
• Cell size
• Cell nutrients

Question 15

What is the G0 stage of interphase?

Answer 15

Cells leaving the cell cycle, either temp. or permanently, because of DNA damage or the cells are specialised

Question 16

What is the S stage of interphase?

Answer 16

DNA replicated and sister cromatids form

Question 17

What is the G2 stage of interphase?

Answer 17

Cell continues to grow in size

energy (ATP) stores replenished

Question 18

What does G2 checkpoint in interphase check for?

Answer 18

• DNA damage

- Cell size

Question 19

What happens after the G2 phase of interphase

Answer 19

Mitosis

Question 20

BLURT! Draw the cell cycle for mitosis from G1 of interphase to cytokinesis (including checkpoints and the function of each stage)

Answer 20

Photo 1 in revision folder

Question 21

Name the stages mitosis

Answer 21

Prophase, Metaphase, Anaphase, Telophase

Question 22

State what happens in prophase in mitosis (5)

Answer 22

• chromosomes condense
• nuclear envelope dissolves
• nucleolus disappears
• centrioles produce spindles
• spindles from poles of cells attach to centromere

Question 23

State what happens in Metaphase

Answer 23

Chromosomes are pulled to the centre, to the metaphase plate

Question 24

State what happens in anaphase

Answer 24

Chromatids are separated, pulled to the poles of the cells

Question 25

State what happens in Telophase

Answer 25

- chromatids reach poles of the cell - nuclear envelope reappears - nucleolus reappears - chromosomes recondense into nuclei

Question 26

What happens in cytokinesis of animal cells?

Answer 26

Cleavage furrow forms and cytoskeleton pulls the cell in two

Question 27

BLURT! Draw the stages of mitosis in order with explainations

Answer 27

Revision photo 2

Question 28

What are the stages of meiosis?

Answer 28

``` Prophase I Metaphase I Anaphase I Telophase I Cytokinesis ``` ``` Prophase II Metaphase II Anaphase II Telophase II Cytokinesis ```

Question 29

How many chromosomes are present in Prophase I of meiosis, what is this set called?

Answer 29

Diploid, 46 chromosomes (23 each with a homologous pair)

Question 30

What is special about Prophase I in meiosis

Answer 30

Chromosomes pair up and cross over

Question 31

When do chromosomes pair up and cross over

Answer 31

Prophase I in meiosis

Question 32

What causes genetic variance in meoisis

Answer 32

Chromosomes pair up and cross over in meoisis I and randomly line up (independent assortment) in Metaphase I

Question 33

BLURT! Draw the stages of meosis I and II in order with explainations

Answer 33

Picture 3 and 4 revision folder

Question 34

What is different between metaphase I and metaphase II in meiosis

Answer 34

Metaphase I the homologous pairs are separated (one chromosome to each pole) Metaphase II the chromatid pairs are separated (from centromere)

Question 35

How many chromosomes are present in Prophase II of meiosis, what is this set called?

Answer 35

23, a haploid (one randomly pic and mixed from one of your parents)

Question 36

What is the result of meoisis

Answer 36

4 genetically different daughter cells (gametes) | -haploid

Question 37

Cells group together to form __

Answer 37

tissues that perform a common function

Question 38

Organs are ___

Answer 38

groups of tissues that work together to form a wider function

Question 39

Organ systems are ___

Answer 39

groups of organs that work together to perform and essential life function

Question 40

What is the function of xylem?

Answer 40

transport minerals and water as well as providing structural support

Question 41

What is the structure of xylem?

Answer 41

Long, open-ended tubes formed of dead tissue

Question 42

What are xylem cells made by

Answer 42

Meristem cells

Question 43

What is the function of phloem?

Answer 43

movement of food substances and nutrients from leaves to storage organs and growing parts of plants

Question 44

What is the structure of phloem?

Answer 44

Long tubes made of living cells

Question 45

What are phloem cells made by

Answer 45

Meristem cells

Question 46

What are the features of cells that the meristem produces

Answer 46

meristem tissue | produce cells that elongate and line up end to end to form tubes

Question 47

What are Epithelial cells

Answer 47

sheets of cells that serve as a lining or to cover a surface

Question 48

What are the 2 types of Epithelial cells

Answer 48

- -squamous which are smooth, flat and very thin | - -ciliated, cylinder in shape and have cillia

Question 49

What are the 3 types of role for cells

Answer 49

Connective Muscle Nervous

Question 50

What is a stem cell?

Answer 50

undifferentiated cells which have the ability to | develop into any kind of cell

Question 51

Discuss the differences between human and plant stem cells

Answer 51

Plants retain their ability to differentiate into different types of cells throughout their life Humans do not, we can only make some particular types of cell eg. RBCs erythrocytes

Question 52

Where does the division of plant cells occur at the highest rate?

Answer 52

Meristem

Question 53

Name a specialised cell in a human and how it is specialised

Answer 53

Sperm cell adapted to reach, penetrate and fertilise the ovum (enzymes in head and flagellum)

Question 54

What is totipotent

Answer 54

stem cell able to become any cell/ form a whole organism

Question 55

What is pluripotent

Answer 55

stem cell able to become any tissue type but not a whole organism

Question 56

what is multipotent

Answer 56

stem cell able to become only a range of cell types

Question 57

What is the difference between ciliated cells and ciliated epithelium

Answer 57

ciliated epithelium in a tissue - a group of cells working together ciliated cells are any single cells with cillia

Question 58

Why are cells checked frequently in the cell cycle?

Answer 58

``` dna errors cell does not divide too often cell divides at right time is right size chromosomes in the right position ```

Question 59

3 sources of sttem cells

Answer 59

embryos umbilical cord meristematic tissue

Question 60

How can stem cells help treat heart disease?

Answer 60

repair tissue muscle in the heart damaged by heart attacks

Question 61

How can stem cells help treat diabetes?

Answer 61

replace beta cells destroyed by immune system

Question 62

How can stem cells help treat genetic diseases?

Answer 62

reverse previously untreatable birth defects