Unit 2 Cells Specialisation and Divisions

Question 1

What is special about the first group of cells within an embryo?

Answer 1

They are all identical

Question 2

After the embryo matures what happens to the initial identical cells?

Answer 2

The cells become specialised to a specific role or function

Question 3

How are all the cells in the human body produced from a fertilised egg?

Answer 3

The cells divided by mitosis

Question 3

What does specialisation of the cell do?

Answer 3

Specialisation of the cell allows the cell to become more suited for its role

Question 4

If all the cells divided through mitosis what does the mean each cell contains?

Answer 4

Each cell contains the same genes

Question 5

What allows each cell to become specialised?

Answer 5

Each cell has the same genes however if the genes are expressed or not can allow the cell to become suited for its function

Question 6

What is different about the specialised cells for each particular role that it carries out?

Answer 6

The shape of the cell is different and the number of organelles are all different

Question 7

Why does a sperm cell have more mitochondria than an epithelial cell?

Answer 7

Sperm cell has more mitochondria because it needs to release more energy for cellular respiration in order for it move due to the flagellum

Question 8

What is a type of tissue found in the animal cell?

Answer 8

Epithelial tissue

Question 9

What do epithelial tissues do?

Answer 9

Epithelial tissues line the surface of organs and have a protective or secretory function

Question 10

What is the relation between the function of cilia and the epithelial tissue?

Answer 10

The cilia are used to move mucus along the epithelial surfaces

Question 11

What is the similar epithelial tissue in plants?

Answer 11

The xylem

Question 12

What is the function of the xylem in plants?

Answer 12

The xylem is used to transport water and mineral ions around the plant as well as give structural support

Question 13

What are the 3 things that an organ is made up of in an animal cell?

Answer 13

Muscles
Epithelial tissue
Connective tissue - Hold other tissues together in place

Question 14

What are the 5 things that an organ is made up of in a plant cell?

Answer 14

Palisade mesophyll - palisade cells that carry out photosynthesis
Spongy mesophyll - Gaseous diffusion
Epidermis - Protect the leaf and allow gaseous diffusion
Phloem - To transport organic material around the cells
Xylem - To transport water and mineral ions to the cell

Question 15

What are 2 transport tubes that are classified as organs?

Answer 15

The arteries and veins

Question 16

Are Blood Capillaries also classified as organs?

Answer 16

No because blood capillaries have a smaller size difference and therefore have a lower capacity

Question 17

What does the digestive system do and consist of?

Answer 17

The digestive system digests and processes foods and it includes the salivary glands, oesophagus, stomach, duodenum, ileum, pancreas and liver

Question 18

What does the respiratory system do and consist of?

Answer 18

The respiratory system is used for breathing and gas exchange and it consists of the trachea, bronchi, bronchioles, alveoli and the lungs

Question 19

What does the circulatory system do and consist of?

Answer 19

The circulatory system is used for pumping and circulating blood and it consists of the heart, arteries and veins

Question 20

What are the 2 ways that a cell can be divided?

Answer 20

Mitosis or meiosis

Question 21

What does Mitosis produce?

Answer 21

Mitosis produces two daughter cells that have the same number of chromosomes as each other and the parent cell

Question 22

What does Meiosis produce?

Answer 22

Meiosis produces four daughter cells that have half the number of chromosomes as the parent cell

Question 23

What is the exception that mitosis does not produce identical daughter cells?

Answer 23

Mitosis will produce 2 daughter cells that are not identical due to a mutation which could lead to a difference in DNA between the identical cells

Question 24

What is the stage in which a cell grows its organelles and does not divide?

Answer 24

Interphase

Question 25

What is the place where two copies of DNA join together?

Answer 25

The centromere of a chromosome

Question 26

What are the 4 phases after the interphase called?

Answer 26

The prophase, metaphase, anaphase and telophase

Question 27

What are visible in the prophase?

Answer 27

The chromosomes start to become visible

Question 28

What happens in the prophase? (1)

Answer 28

The chromosomes are visible as thin threads which start to shorten and thicken

Question 29

What happens in the prophase? (2)

Answer 29

Animal cells contain 2 cylindrical organelles called centrioles which move to opposite ends of the cells

Question 30

What happens in the prophase? (3)

Answer 30

Spindle fibres are made at each end of the centrioles at the opposite ends, collectively the spindle fibres together create a structure celled the spindle apparatus

Question 31

What happens in the prophase? (4)

Answer 31

The nucleolus disappears and the nuclear membrane breaks down to allow the chromosomes to be free in the cytoplasm.

Question 32

What happens in the prophase? (5)

Answer 32

These chromosomes are drawn towards the equator of the cell by the spindle fibres attached to the centromere

Question 33

Which phase is after the prophase?

Answer 33

The metaphase

Question 34

How are the chromosomes seen to be in the metaphase?

Answer 34

The chromosomes are seen to be made up of 2 chromatids

Question 35

What is each chromatid an identical copy of?

Answer 35

Each chromatid is the identical copy of DNA from the parent cell

Question 36

What are the chromatids joined by?

Answer 36

The centromere

Question 37

What happens in the metaphase? (1)

Answer 37

The centromere has some microtubules from the poles attached to it which allows the chromosomes to be pulled along the spindle apparatus to arrange themselves along the equator of the cell

Question 38

What phase is after the metaphase?

Answer 38

Anaphase

Question 39

What happens in the anaphase? (1)

Answer 39

The centromere divides into two and the spindle fibres pulls the individual chromatids making a single whole chromosome

Question 40

Where is the energy for the process of pulling the chromatids apart come from?

Answer 40

Cellular respiration from the release of energy from glucose that comes from mitochondria

Question 41

Where are the mitochondria gathered around when the anaphase process occurs?

Answer 41

The mitochondria are gathered around the spindle fibres

Question 42

What happens if a chemical destroys the spindle within a cell?

Answer 42

The chromosomes are unable to reach the opposite poles of the cells and therefore remain at the equator of the cell

Question 43

What is the phase after the anaphase?

Answer 43

The telophase

Question 44

What happens in the telophase? (1)

Answer 44

The chromosomes reach their respective poles and become longer and thinner finally disappearing altogether leaving the chromatin widely spread

Question 45

What happens in the telophase? (2)

Answer 45

Next, the spindle fibres disintegrate and the nuclear envelope and nucleolus re-form.

Question 46

What is the process after telophase called and what happens in it?

Answer 46

Cytokinesis is the process of the cytoplasm dividing

Question 47

Describe how prokaryotic cells divide through binary fission? (1)

Answer 47

The circular DNA molecule replicates and both attaches to the cell membrane

Question 48

Describe how prokaryotic cells divide through binary fission? (2)

Answer 48

The plasmids replicate

Question 49

Describe how prokaryotic cells divide through binary fission? (3)

Answer 49

The cell membrane begins to grow between the 2 DNA molecules and pitches inwards, dividing the cytoplasm in two

Question 50

Describe how prokaryotic cells divide through binary fission? (4)

Answer 50

A new cell wall then forms in between the 2 DNA molecules dividing the the original cell into two daughter cells, each with a single copy of DNA and variable number of plasmids

Question 51

What is cancer?

Answer 51

Cancer is a group of diseases caused by a growth disorder in cells

Question 52

What leads to the uncontrolled growth and division of cells?

Answer 52

The damage of genes that help in the process of mitosis and the cell cycle

Question 53

What forms as a result of uncontrolled growth?

Answer 53

Tumours - a group of abnormal cell that constantly expands in size

Question 54

What stage is cancer considered cancerous?

Answer 54

From benign to malignant

Question 55

Why does the size of a tissue need to be bigger?

Answer 55

So that the cells can divide by mitosis for the use in repairing dead or worn out cells and for growth during the development of the organism

Question 56

How is the rate of mitosis affected?

Answer 56

By external growth factors such as the environment and the growth of the cell and the two type of genes that control this

Question 57

Describe how malignant tumours can become life-threatening?

Answer 57

Malignant tumours grow rapidly producing clone of themselves so they spread to other parts of the body faster

Question 58

What does the treatment of cancer involve?

Answer 58

Cancer Treatment involves the blocking of the cell cycle by killing cells in the dividing process which can disrupt the cancer growth

Question 59

What are the 2 ways in which the cell cycle can be disrupted?

Answer 59

1) Preventing the DNA from being replicated 2) Inhibiting the metaphase stage by interfering with the spindle formation

Question 60

What is the disadvantage of cancer treatment such as chemotherapy?

Answer 60

Chemotherapy targets cancerous cells that have high division time during mitosis but can however also affect the the cells with high division times such as normal hair cells