Nat5 Biology Unit 2 Multicellular Organisms Key Area 1 Producing New Cells

Question 1

What is mitosis?

Answer 1

Division of the nucleus

A process of cell division that produces two genetically identical daughter cells

Question 2

What does mitosis do?

Answer 2

Provides new cells for growth
Repairs damaged tissues
Replaces dead or damaged cells
Maintains the diploid chromosome complement

Question 3

Stage one of mitosis

Answer 3

1. Chromosomes condense: their DNA could up more tightly

Question 4

Stage two of mitosis

Answer 4

2. Each chromosome appears as two identical/sister chromatids held together by proteins at their centromere

Spindle fibres begin to form - structural proteins

Question 5

Stage three of mitosis

Answer 5

The nuclear membrane is broken down
Replicated chromosomes line up on the equator of the cell.
Spindle fiber attach to each replicated chromosome (one fiber to each sister chromatid) at their centromere

Question 6

Stage four of mitosis

Answer 6

Sister chromatids and separated by spindle fibers

Question 7

Stage five of mitosis

Answer 7

The separated sister chromatids are now called chromosomes. They are moved towards the cell poles be spindle fibres

Question 8

Stage six of mitosis

Answer 8

The chromosomes decondense: their DNA becomes less tightly coiled up. New nuclear membranes form around them and two genetically identical nuclei are formed

Question 9

Stem cells in animals are…

Answer 9

Unspecialised cells which can divide to self-renew

Question 10

Stem cells can become…

Answer 10

Different types of cells

Question 11

Stem cells are involved in…

Answer 11

Growth and repair

Repair tissue damage (cuts,broken bones)

Question 12

Stem cells can be…

Answer 12

Obtained from the embryo at a very early stage

Tissue stem cells cane be found in the body throughout life

Question 13

What does specialization of cells lead to?

Answer 13

The formation of a variety of cells, tissues and organs doing different things (skin,blood)

Question 14

What are groups of organs called?

Answer 14

Systems

Question 15

What is the hierarchy?

Answer 15

Cells -> Tissues -> Organs -> Systems

Question 16

What are spindle threads?

Answer 16

Protein threads that pull chromatids apart during mitosis

Question 17

What is the equator?

Answer 17

The middle position of a cell where chromosome align and attach to spindle fibers in mitosis

Question 18

What is a diploid cell?

Answer 18

A cell that contains a double set of chromosomes

Question 19

What is the chromosome compliment?

Answer 19

The number of chromosomes found in a cell

Question 20

What is a Chromatid?

Answer 20

The replicated copy of a chromosome

Question 21

What is a haploid cell?

Answer 21

A cell that had one set of chromosomes (sex cells)

Question 22

What are specialised cells?

Answer 22

Cells that do a specific job in the body

Question 23

Through what process can stem cells become specialised?

Answer 23

Cell differentiation

Question 24

What are the two main types of stem cells?

Answer 24

Embryonic stem cells

Tissue stem cells

Question 25

What can embryonic stem cells become?

Answer 25

Any of the different types of cells

Question 26

What can tissue stem cells become?

Answer 26

Only a few different types of cells
(Skin stem cells can only become skin cells, blood stem cells can only become blood cells, blood cells cannot be skin cells)

Question 27

Through differentiation, what type of cell can a blood stem cells turn into?

Answer 27

Red blood cell
White blood cell
Cells that form platelets

Question 28

Why do stem cells go through self-renewal?

Answer 28

So you don’t run out

Question 29

Multicellular organisms have…… and are made up of …..

Answer 29

More than one cell type

Tissues and organs

Question 30

The cells in organs are….

Answer 30

Specialised for their function and work together to form systems