Cell Division and Cellular Organsiation

Question 1

What does the cell cycle consist of?

Answer 1

Interphase, mitosis and cytokineses

Question 2

What happens during interphase?

Answer 2

It is split up into 3 phases
G1: cell checks chemical needed for replication are present
S: cell replicates its ready ready for mitosis
G2: The cell checks whether all the DNA has been replicated without damage

Question 3

What is mitosis?

Answer 3

This is cell replication, creating a genetically identical cell

Question 4

In mitosis state the stages and what happens in each stage

Answer 4

Prophase: Centrioles move to opposite ends of the cell, forming a network of spindle fibers
Metaphase: the chromosomes line up along the middle of the cell and become attached to the spindle by their centromere
Anaphase: sister chromatids move to opposite ends of the cell
Telophase: The chromatids reach the opposite poles and the nucleus envelope forms

Question 5

What is cytokinesis?

Answer 5

The cytoplasm divides

Question 6

How many chromosomes do a haploid and diploid cell have

Answer 6

Haploid: 23
Diploid: 46

Question 7

What is meiosis?

Answer 7

This the production of gametes

Question 8

In meiosis state the stages and what happens in each stage

Answer 8

Prophase 1: Chromosomes condense, get shorter and fatter
Metaphase 1: pairs line ip across the centre of the cell and attach to spindle fibres
Anasphase 1: Spindles contract, pulling the pairs apart (one goes to each end)
Telophase 1:
A nuclear envelope forms around each chromosome

Meiosis 2: (only difference is half number of chromosomes)
(anaphase 2 sister chromatids are separated)

Question 9

Why is genetic variation needed in individuals?

Answer 9

This causes evolution individuals become immune to diseases and surviving against harsh environmental conditions.

Question 10

What is cross over of chromatids and its effect?

Answer 10

Cromatids cross over meaning now they have a new combination of alleles
This causes genetic variation

Question 11

What is a stem cell?

Answer 11

This is an unspecilied cell, it can develop into different types of cells

Question 12

What is differentiation?

Answer 12

This when stem cells become new cells, then become specialized.
Stem cells are also able to divide to produce more undifferentiated stem cellls

Question 13

What is a totipotent stem cell?

Answer 13

Found in a fertilised cell.

Can differentiate into any type of cell

Question 14

What is a pluripotent stem cell?

Answer 14

Present in early embroys

They can form all tissues but not whole organsims

Question 15

What is a multipotent stem cell?

Answer 15

Found in bone morrow

These stem cells can only form a range of cells within a type of tissue

Question 16

How are erthrocytes adapted to fit there function?

Answer 16

They have a large SA for gas exchange (bicocave disk)

No nucleus to provide more room

Question 17

How are Netrophils adapted to fit there function?

Answer 17

They have a flexible shape which allows them to engulf foreign particles

Question 18

How are Epithelial adapted to fit there function?

Answer 18

This covers the surface of organs, they contain cilia which wafts the substances

Question 19

How are sperm cells adapted to fit there function?

Answer 19

They have a flagellum so they can swim. They have lots of mitochondria to provide energy to swim.

Question 20

How are palisade mesophyll cell adapted to fit there function?

Answer 20

This is found in most leaves. They contain many chloroplast for photosynthesis. They are also one cell thick do carbon dioxide can diffuse easily.

Question 21

How are root hair cell adapted to fit there function?

Answer 21

They have a large surface area and a thin cell wall. The cytoplasm contains extra mitochondria to provide the energy needed for active transport

Question 22

How are guard cells adapted to fit there function?

Answer 22

These are found in between the stomata. When guard cells take up water they become turgid resulting in the stomata opening

Question 23

What is a tissue?

Answer 23

A group of similar cells that carry out a function

Question 24

What is an organ?

Answer 24

A group of similar tissues that carry out a function