Lecture 6 - The Cell Cycle

Question 1

General Knowledge

Answer 1

Chromosome duplicates
Becomes Sister Chromatids
Identical sister chromatids separate into the 2 daughter cells

Question 2

What forms when a egg fuses with a sperm

Answer 2

Zygote

Question 3

What forms after a Zygote

Answer 3

Embryo

Question 4

How long is the cell cycle

Answer 4

Less than 24 hours

Question 5

What Affects the length of cell cycle

Answer 5

Temperature
Nutrients
Oxygen
Type of cell

Question 6

Where are stem cells found

Answer 6

Found in bone marrow (adult), umbilical cord blood and embryos (ethics)

Question 7

What’s good about stem cells

Answer 7

Unspecialised (undifferentiated)
Has the ability to differentiate into any type of cell

Question 8

Interphase

Answer 8

The cell grows in prep for cell division
Chromosomes duplicate with DNA copied precisely

Question 9

Mitosis

Answer 9

Chromosomes copies are separated and moved to opposite ends of cell

Question 10

Cytokenesis

Answer 10

Cell divides into 2 daughter cells and are genetically identical to parent cell

Question 11

Interphase is divided into ?

Answer 11

Interphase divided into G1, S and G2

Question 12

Cell division

Answer 12

Cell division -M phase (Mitosis & Cytokinesis)
Mitosis = nuclear division
Cytokinesis = cytoplasm division
Regulated by check points

Question 13

Mitosis PMAT stands for ?

Answer 13

Prophase
Metaphase
Anaphase
Telophase

Question 14

Why is mitosis important?

Answer 14

Growth

Repair

Asexual Reproduction

Question 15

General Information

Answer 15

Interphase (G1 + S + G2)
G1 – first phase of growth
Cytoplasm/organelles increases
S – Synthesis of DNA
Semi-conservative replication/new histones synthesised
G2 – second phase of growth
Replicated DNA checked
Mitosis (P + M + A + T)
Cytokinesis (division of cytoplasm)

Question 16

What’s G1

Answer 16

G1 – first phase of growth
Cytoplasm/organelles increases

Question 17

what’s S phase

Answer 17

S – Synthesis of DNA
Semi-conservative replication/new histones synthesised

Question 18

whats G2

Answer 18

G2 – second phase of growth
Replicated DNA checked

Question 19

What’s Cytokinesis

Answer 19

Cytokinesis (division of cytoplasm)

Question 20

Why are check Points Important ?

Answer 20

Check points occur at key points in the cell cycle to make sure it is ok for the process to continue.

Question 21

Tell me the 3 Check Points

Answer 21

Metaphase check point
G1 check point
G2 check point

Question 22

What happens If the cell fails the check point ?

Answer 22

It will leave the cell cycle and enter G0

Question 23

Interphase

Answer 23

Prepares to divide
(G1, S and G2)

Question 24

Prophase

Answer 24

Chromosomes condense (shorter and fatter)
Nuclear envelope breaks down

Question 25

Metaphase

Answer 25

Chromosomes (each with 2 chromatids) line up along the middle. Check point checks chromosomes are attached to spindle

Question 26

Anaphase

Answer 26

Centromeres divide, separating each pair of sister chromatids. Spindle contract, pulling chromatids to opposite ends of the cell

Question 27

Telophase

Answer 27

Chromatids reach opposite poles on the spindle Uncoil –long and thin again (chromosomes again) Nuclear envelope forms around each set of chromosomes

Question 28

When does Cytokinesis end and start

Answer 28

Cytokinesis – starts in anaphase ends in telophase

Question 29

How do you work out length of time in a phase ?

Answer 29

Observed N.O. cells at stage / Total observed cells x Total length of time of cell cycle

Question 30

Mitosis in plant cells

Answer 30

Mitosis can be observed in any tissue that is actively dividing. A tissue in which it is easy to observe mitosis is the growing tip of a plant root In plants, mitosis takes place in tissues called meristems (found at the growing tips of shoots and roots) undifferentiated.

Question 31

Mitotic index

Answer 31

MITOTIC INDEX = NUMBER OF CELLS IN THE FIELD OF VIEW UNDERGOING CELL DIVISION / TOTAL NUMBER OF CELLS IN THE FIELD OF VIEW

Question 32

Important about mitotic index

Answer 32

If you can see nucleus include it in total amount of visible cells

Question 33

Cancer

Answer 33

Mitosis is a controlled process (genes) Mutations can lead to Uncontrolled cell division can lead to the formation of tumours and cancers Blood/lymphatic system

Question 34

What's Primary cancer

Answer 34

Primary cancer – where the cancer begins

Question 35

What's Secondary cancer

Answer 35

Secondary cancer – where cancer spreads and grows in other areas

Question 36

How would you name Cancer

Answer 36

Cancers are named by where they first began developing

Question 37

Benign

Answer 37

Slow growth/no metastasis

Question 38

Malignant

Answer 38

Quick growth/metastasis

Question 39

Metastatic

Answer 39

Metastatic cancer is cancer that has spread from where it started to another part of the body.

Question 40

Mutations to what 2 Genes cause cancer ?

Answer 40

Tumour Suppressor gene and Proto-onco gene

Question 41

Whats the purpose of a Tumour suppressor genes (TSG)

Answer 41

It inhibit cell division

Question 42

Whats the purpose of Proto-oncogenes

Answer 42

Stimulate normal cell growth and division

Question 43

What does the Mutation to TSG and P-Onco do

Answer 43

Mutation decreases normal function – stimulating growth Thus leading to Uncontrolled division leading to Cancer

Question 44

TSG

Answer 44

TSG - Responsible for making proteins involved in slowing cell division or causing them to self-destruct (apoptosis) TSG – if a mutation occurs the gene will be inactivated. No protein is produced. Cell divides uncontrollably

Question 45

Proto-oncogenes

Answer 45

Proto-oncogenes – these stimulate cell division by producing proteins that make the cell divide If a mutation occurs this gene can become overactive (stimulates the cell to divide uncontrollably)- resulting in a tumour Mutated proto-oncogenes are called oncogenes

Question 46

Methylation

Answer 46

Methylation means adding a methyl (-CH3 ) group DNA methylation Control whether or not a gene is transcribed & translated Hypermethylation & hypomethylation The growth of tumours can be caused by abnormal methylation of certain cancer-related genes

Question 47

What is the longest part of the cell cycle?

Answer 47

Interphase

Question 48

At which stage of mitosis do the chromosomes appear in a V shape formation?

Answer 48

Anaphase

Question 49

Which part of the cell contains the chromosomes needed for mitosis?

Answer 49

Nucleus

Question 50

How do you convert mm to micrometers?

Answer 50

x1000

Question 51

What is this definition describing? "A cell that has the ability to differentiate into any type of cell?".

Answer 51

Stem Cell

Question 52

Total magnification equation

Answer 52

Total Magnification=Eyepiece Magnification×Objective Magnification