All Cells Arise From Other Cells

Question 1

Why do you use stain to look at cells?

Answer 1

Provides contrast
Stains chromosomes
Allow to see stage of mitosis

Question 2

Why are cells squashed to be seen under a microscope?

Answer 2

To allow light to penetrate to make chromosome visible

Question 3

Why are cells placed in a watch glass full of HCl before looking at under a microscope?

Answer 3

To fix and kill cells

Stops cells dividing so the stay in same stage of mitosis

Make cellulose cell wall more porus so stain absorbed easier

Question 4

Why is the last 2mm of a root used to study mitosis?

Answer 4

End of root grows by producing more cells (mitosis)

Back of tip grows by elongating cells (less cells per unit area= less mitosis)

Question 5

What is a mitotic index?

Answer 5

The proportion of cells undergoing mitosis

Question 6

What stain is used to observe mitosis ?

Answer 6

Toluidene blue stain

Question 7

What is mitosis important for ?

Answer 7

Growth

Repair

Reproduction

Question 8

What two stages can the cell cycle be split into?

Answer 8

Interphase and metaphase

Question 9

What are the sub sections of interphase called?

Answer 9

Growth 1

Synthesis

Growth 2

Question 10

How much of the cell cycle is interphase?

Answer 10

90%

Question 11

How long is the average cell cycle ?

Answer 11

24 hrs

Question 12

What occurs during G1?

Answer 12

Cell prepares for DNA replication

Cell grows

Protein is synthesised

Question 13

What occurs during synthesis phase?

Answer 13

DNA is replicated

Question 14

What occurs during G2?

Answer 14

Organelles replicate

Cell grows (increased volume)

Protein synthesis

Question 15

What are te stages of mitosis called?

Answer 15

Prophase

Metaphase

Anaphase

Telophase

Question 16

What occurs during prophase?

Answer 16

Nucleolus and nuclear membrane break down

Chromosomes condense (are visible)

Spindle fibres form from centrioles at poles of cell

Spindle fibres attach to centromeres

Question 17

What occurs during metaphase ?

Answer 17

Spindle fibres align chromosomes at equator of cell

Question 18

What occurs during anaphase?

Answer 18

Centromeres divide

Spindle fibres contract to pull chromatids to opposite poles of cell
Mitochondria around spindle fibres provide energy

Question 19

What occurs during telophase?

Answer 19

Spindle fibres disintegrate

Nucleolus and nuclear membrane form

Chromosomes elongate

Question 20

What occurs during cytokinesis?

Answer 20

Cytoplasm divides in two

Two genetically identical daughter cells form

Question 21

How does cytokinesis occur?

Answer 21

Cell membrane is pulled inwards

Pinches of cytoplasm

Question 22

What is binary fission?

Answer 22

Method of reproduction in prokaryotic cells

Question 23

How does binary fission occur?

Answer 23

Circular DNA and plasmids duplicate

Nucleoids and plasmids move to opposite poles of the cell

Cell membrane extends inwards and pinches of cytoplasm

Cell wall divides

Question 24

Why aren’t the daughter cells created in binary fission not always genetically identical?

Answer 24

Plasmids are shared unevenly

Question 25

Why is binary fission simpler than mitosis?

Answer 25

Binary fission doesn’t involve chromosomes, spindle fibres or nuclear envelopes

Question 26

What does acellular mean?

Answer 26

No cells

Question 27

How do viruses replicate (2 methods)

Answer 27

Virus attaches to cell host and injects nucleic acids OR virus is engulfed and releases nucleic acids into cell Host cell metabolic processes are used to manufacture proteins, enzymes and nucleic acids to produce more viruses

Question 28

What is cancer?

Answer 28

Uncontrolled cell division

Question 29

What is cancer also know as?

Answer 29

Growth disorder of cells

Question 30

How does cancer arise?

Answer 30

A mutation to genes that regulate the cell cycle

Question 31

What is the difference between a tumor and cancer?

Answer 31

Cancer is when tumor cells break off and form a secondary tumor (malignant)

Question 32

How do cells naturally control their numbers?

Answer 32

Programmed cell death Some lose ability to divide

Question 33

What factors control the rate of mitosis?

Answer 33

Environmental factors Genes Growth factors

Question 34

How are mutant cells different to normal cells?

Answer 34

They are structurally and functionally different

Question 35

What is the difference between malignant and benign tumors?

Answer 35

Benign don’t form secondary tumors (not cancer) Benign are more compact Benign grow slower

Question 36

What is metastasis?

Answer 36

The movement of cancer cells from primary to secondary sites/ tumors

Question 37

What do cancer treatments do?

Answer 37

Disrupt the cell cycle

Question 38

Give examples of the effects of cancer treatment on cancer cells

Answer 38

Prevent DNA unwinding Prevent formation of spindle fibres (metaphase) Prevent cells producing nucleotides

Question 39

What type of cells does cancer treatment work best against?

Answer 39

Rapidly dividing cells Cancer and hair cells

Question 40

Why do cancer patients lose their hair?

Answer 40

Hair cells are rapidly dividing and so are more effected by cancer treatment than other body cells