Chapter 2 - Cell division

Question 1

What are 3 reasons new cells are needed?

Answer 1

for an organism…
to grow
to replace damaged cells
to replace work out cells

Question 2

why do the new cells need to have the same genetic material as the originals?

Answer 2

so that they can do the same job

Question 3

In the cell, where are the chromosomes?

Answer 3

in the nucleus

Question 4

What do chromosomes carry?

Answer 4

genes

Question 5

What do genes contain?

Answer 5

the instructions both new and old cells and all the tissues and organs need to make a new you

Question 6

What is a gene?

Answer 6

a pocket of information that controls a characteristic of your body. A section of DNA

Question 7

How many chromosomes do we have in the nucleus of our body cells?

Answer 7

46, 23 pairs, 1 from the father and 1 from the mother

Question 8

What is the cell cycle?

Answer 8

the series of stages the body cells divide in

Question 9

What does mitosis produce?

Answer 9

the additional cells needed for growth and development

Question 10

In asexual reproduction, how are the cells of an offspring produced?

Answer 10

by mitosis

Question 11

What 2 factors affect the time of the cell cycle?

Answer 11

the cells involved and the stage of life of the organism

Question 12

At what stage of life is the cell cycle:

1. Short
2. Rapid
3. Slow

Answer 12

1. as a baby develops before being born
2. during childhood
3. once puberty is over and it is the beginning of adulthood

Question 13

What are the 3 stages of the cell cycle?

Answer 13

1. the cells grow bigger: increase their mass, subcellular structures like: mitochondria, ribosomes and chloroplasts. replicate their DNA to form 2 copies of each chromosome. still do normal cell activities.
2. one set of chromosomes is pulled to each end of the diving cell and the nucleus divides.
3. the cytoplasm and the cell membranes also divide to form 2 identical daughter cells

Question 14

Which type of cell is always rapidly dividing using mitosis?

Answer 14

skin cells

Question 15

In what stage of life and animal and plant cells unspecialised?

Answer 15

early development

Question 16

What are 2 examples of cells that cannot divide at all?

Answer 16

red blood cells and skin cells

Question 17

What are adult stem cells used for?

Answer 17

replace the dead of damaged cells that cannot divide

Question 18

Why are nerve cells not replaced when they are damaged?

Answer 18

because they do not divide once they have differentiated and cannot be replaced by stem cells?

Question 19

In what type of cells is differentiation not permanent? What can they do?

Answer 19

plant cells. re differentiate and become a completely different type of cell

Question 20

What is cloning?

Answer 20

producing identical offspring

Question 21

How can you clone plants?

Answer 21

get a tiny piece of leaf tissue, it will become unspeciallised and undergo mitois many times. Each undifferentiated cell will produce more cells by mitosis. then these will differentiate to form tissues like xylem, phloem, photosynthetic cells and root hair cells. this new plant will be identical to the parent

Question 22

Why can’t you clone animals?

Answer 22

most animal cells differentiate permanently in early embryo development and the cells cannot change back.

Question 23

What are stem cells? (literally)

Answer 23

undifferentiated cells

Question 24

Where are stem cells found?

Answer 24

early human embryos

Question 25

Where are adult stem cells found?

Answer 25

in bone marrow

Question 26

What is the difference between stem cells and adult stem cells?

Answer 26

adult stem cells cannot turn into any cell, only specific ones, like blood cells

Question 27

How do we use adult stem cells already? eg?

Answer 27

in medicine to cure diseases. adult step cells taken from bone marrow could replace fatty blood cells in another person

Question 28

How can we use embryonic stem cells? 2 eg?

Answer 28

to replace faulty cells in sick people. could make insulin producing cells for people with diabetes, nerve cells for paralysed people

Question 29

What can happen during therapeutic cloning?

Answer 29

an embryo could be made to have the same genetic information as the patient, so the stem cells produced by it would have the same genes as the patient so they wouldn’t be rejected when needed to replace faulty cells.

Question 30

What is a disadvantage of stem cells?

Answer 30

coz they grow in a lab, they may become contaminated with a virus which could be passed on to the patient and make them sicker

Question 31

What is an argument AGAINST using stem cells?

Answer 31

people fell that the human embryos that are used for experiments shouldn’t be used because they are a potential human life

Question 32

What are 2 arguments FOR using stem cells?

Answer 32

treating sick patients is more important than the rights of embryos, the embryos used are unwanted embryos which would be destroyed if not used.

Question 33

Where are stem cells found in plants?

Answer 33

in the meristems (part of the plant where growth occurs)

Question 34

throughout the plants entire life, the stem cells in the meristem tissues ______ differentiate into ___ type of _____ cell

Answer 34

can, any, plant

Question 35

What are 3 advantages of using stem cells to grow more plants?

Answer 35

• can be produced quickly and cheaply
• can grow more plants of rare species so they don’t go extinct
• can grow crops with desired features like disease resistant