NEOPLASM

Question 1

Neoplasia vs. Neoplasm

Answer 1

1. new growth process
   Vs
2. the growth

Question 2

Differentiation vs. Proliferation

Answer 2

1. determination of cell’s fate, specialization, the cell does not return back to its previous state
2. cell division and growth of new cells

Question 3

What are stem cells w/ potential for multiple different cellular outcomes?

spleen cell and a skin cell?

Answer 3

pluripotent cells

based on their morphology, intercellular characteristics, staining patterns in histology lab etc.

Question 4

What can determines the kind of tumor you have

Answer 4

the differentiation state of the cell when it divides, or where it is in this process of development will determine the kind of tumor you will get if a mutation occurs in that cell.

Question 5

What happens when differentiated cells mutate

Answer 5

differentiated tumors— benign tumors

Question 6

What happens when undifferentiated cells mutate

Answer 6

form rapidly dividing tumors— malignant tumors

Question 7

how checkpoints work in animal cells

Answer 7

Internal and external

cells generally have built-in stop signals until overridden by go-ahead signals

Question 8

What events happen during the cell cycle?

Answer 8

1] Duplication of genetic material- more mistakes, lots of base pairs, prone to error
2] Alignment of chromosomes,
3] Cell division,
4] Pauses in cell cycle

Question 9

Why are the pauses useful during the cell cycle?

Answer 9

serve as checkpoints, allow for monitoring duplication accuracy

Question 10

What happens in G1 (gap 1) phases of the cell cycle

Answer 10

post-mitosi
cell growth phase
no DNA synthesis

Question 11

What happens in S phase

Answer 11

DNA Synthesis

replication of DNA

Question 12

What happens in G2 (gap 2) phase

Answer 12

no DNA synthesis the pre-mitosis phase

Question 13

What happens in M phase

Answer 13

mitosis

Question 14

What happens in G0 phase

Answer 14

quiescence, resting phase, coming out of the cycle

Question 15

What are the function of CDK

Answer 15

Cyclin-dependent kinases, phosphorylation of enzymes

Question 16

What are the function of cyclins

Answer 16

bind to CDKs
regulated by CDK inhibitors

cyclically proteins -increasing and decreasing concentration in the cell.

Question 17

What is the most important checkpoint for most cells and why?

Answer 17

**G1 checkpoint most important, “restriction point”.
If a cell receives a go-ahead signal at the G1 checkpoints, then divides
If it doesnt, it will switch into a non-dividing (arrested) - G0 phase

Question 18

What type of cells never divide and what organ will go back to the cell cycle?

Answer 18

Nerve and muscle cells

LIVER- Growth factors, cytokines, molecules d/t rauma bring the liver cells back for repair

Question 19

Why are cyclin-dependent kinases ?

Answer 19

w/in cell , cell cycle control molecules

Protein kinases -inactive form, go ahead fro mitosis

cyclin kinase that must be attached to a cyclin

Question 20

What is the go signal that moves a cell into mitosis?

Answer 20

Cyclin binding to Cdk to form MPF -maturing promoting factor . M-phase promoting factor of mitosis via phosphorlyation

moves the cell cycle into mitosis

Question 21

How does MPF turn off?

Answer 21

During anaphase, MPF helps switch itself off by initiating a process that leads to the destruction of its own cyclin.
Ending M phase

Question 22

How many Cdk proteins are involved in the G1 check point

Answer 22

at least 3 CDKs

many cyclins

Question 23

What is the suffix for benign tumor vs. malignant tumor?

Answer 23

oma vs. carcinoma

Glandular benign tumor is an adenoma
Glandular malignant tumor is an adenocarcinoma

Question 24

What characteristics make a tumor malignant?

Answer 24

1] proliferate to form new tissue, 2] do not wait for “go ahead” signals, 3] ignore “stop dividing” signals, 4] often do not mature normally (differentiate) to do the “job” the tissue is supposed to do, 5] do not die off (apoptosis) to keep the number of total cells constant

Question 25

Genes that turn off or decrease the rate of cell division classes of genes control checkpoints?

Answer 25

tumor suppressor genes- KEY p53

1] repair damaged DNA, 2] control the adhesion of cells to each other or to the extracellular matrix; proper cell anchorage is crucial in normal tissue, 3] components of cell signaling pathways that inhibit the cell cycle.

Question 26

Genes that turn on or increase the rate of cell division classes of genes control checkpoints?

Answer 26

proto-oncogenes KEY RAS

Code for
1] Growth factors and receptors
2]G proteins,
4] Enzymes that produce second messengers,
5] Genes that turn the production of these proteins on and off

Question 27

What mutated form of proto oncogen promote cancer?

Answer 27

oncogenes

Question 28

What is the incidence rate of mutation in ras and p53?

Answer 28

Mutation in Ras occurs in about 30% of human cancers,

Mutation in p53 in more than 50%- Li-Fraumeni syndrome-mutation of p53 on chromosome 17, high rate tumors

Question 29

What are the 3 ways that the p53 protein prevents damaged DNA from passing on?

Answer 29

1] blocks the ability of cyclins,
2] can directly turn on genes involved in DNA repair,
3] DNA irreparable, p53 activates “suicide” genes, whose protein products cause cell death by apoptosis.

Question 30

how p53 blocks the ability of cyclins?

Answer 30

p53 induces the expression of another gene called P21

Question 31

In addition to the preventing the passing of DNA, what other tumor suppressing function does p53 protein?

Answer 31

inhibits angiogenesis necessary for tumor development, target of cancer research

Question 32

Describe the function of tumor suppresor gene RB

Answer 32

Rb gene prevents the cell from entering S-phase until growth signals are present

Question 33

What does mutation of Rb gene on chromosome 13 result in?

Answer 33

Retinoblastoma, cancer of the retina

Question 34

Mutations of what genes would modify apoptosis?

Answer 34

1] bcl-2-preventing apoptosis
2] bax, bad, bcl-xS, bid, and p53-promoting apoptosis
3] c-myc- w/ p53 leads to apoptosis; w/ bcl-2 inhibits apoptosis

Question 35

What are telomeres?

Answer 35

DNA sequences at the ends of chromosomes where enzymes attach that duplicate DNA

telomeres do not get replicated w/ DNA

Division- loses length thus DNA damage

Question 36

What is transformation carcinogenesis?

Answer 36

process of going from non-malignant to malignant cell

Initiation- exposure, don’t know exactly when that happens

Promotin- induction of unregulated growth, formation of a tumor

Progression- tumor cells acquire malignant phenotype

Question 37

What type of cells do neoplasm often arise from

Answer 37

90% epithelium-Skin, respiratory tract, alimentary canal, surfaces of organs, colon, pancreatic, stomach, liver

10% mesenchymal-Muscle, bone

Question 38

Why are epithelium cells more likely to undergo neoplasia

Answer 38

1] It proliferates rapidly, so high turnover,

2] first to encounters environmental carcinogen