Apoptosis and Necrosis

Question 1

Define multiplicative growth

Answer 1

Increase in cell numbers by mitotic cell division

Question 2

Define auxetic growth

Answer 2

increased size of individual cells

Question 3

Where is auxetic growth seen

Answer 3

Skeletal muscle

Question 4

Where is combined patterns of multipleand auxetic growth

Answer 4

Embryological development

Question 5

Define differentiation

Answer 5

Process where a cell develops a specialised function

Question 6

How does differentiation take place

Answer 6

Expression and repression of specific genes and gene products to produce a a cell

Question 7

Define morphogenesis

Answer 7

Highly complex process of development of the structural shape and form of organs, limbs and facial features

Question 8

What must happen for morphogenesis to take place

Answer 8

Primitive cell mass must undergo co-ordinated growth, differentiation and apoptosis

Question 9

What are non=proliferative cells called

Answer 9

Quiescent

Question 10

What are roles of quiescent cells

Answer 10

Differentiate and adopt specific phenotypes capable of carrying out specific function

Question 11

Property of labile cells

Answer 11

• Rapid turnover

- short lifespan

Question 12

Property of stable cells

Answer 12

Good regenerative ability but low turnover rate

Question 13

Problem with pancreatitis

Answer 13

Excessive enzyme production - The pancreas essentially eats itself.

Question 14

What is caseous necrosis

Answer 14

TB - is a form of cell death in which the tissue maintains a cheese-like appearance.

Question 15

What two stages occur during the M phase of mitotic division

Answer 15

Mitosis

Cytokinesis

Question 16

What phase begins the cell cycle

Answer 16

Gap Phase 1

Question 17

What two phases can daughter cells undergo after cell division is completed

Answer 17

Back to Gap Phase 1
OR
Gap Phase 0

Question 18

What is Gap Phase 0

Answer 18

Cells leave the cell cycle and go into rest

Question 19

What stage are cells at if they’ve differentiated

Answer 19

Gap Phase 0

Question 20

Why do checkpoints exist during the cell cycle

Answer 20

1. Ensure DNA has replicated fully

2. Cells do not replicate too early in the cycle

Question 21

What proteins control the production and activation of enzymes and proteins involved with DNA replication (e.g. spindle formation)

Answer 21

Cyclin-dependant kinases (CDKs)

Question 22

How do CDKs activate target proteins

Answer 22

Phosphorylation

Question 23

What proteins regulates activity of CDKs

Answer 23

Cyclins

Question 24

What allows transition from one phase of a cycle to the next

Answer 24

Rises in cyclin concentration

Question 25

How is cyclin affected if DNA replication is faulty

Answer 25

CDK inhibitors inhibit cyclin from working

Question 26

In what condition is interruption of the cell cycle vital in

Answer 26

Cancer

Question 27

Why is anaemia, bleeding tendency and immunosuppression a side effect of cancer chemotherapy

Answer 27

Drugs administered inhibit other rapidly dividing cells of the body (not just cancer cells) like bone marrow and lymphoid tissues

Question 28

Define apoptosis

Answer 28

Programmed cell death without the release of products harmful to surrounding cells

Question 29

Why is a coexistence of apoptosis and mitosis in a cell population needed

Answer 29

Ensure continuous renewal of cells Allows tissue to be more adaptable to environmental demands

Question 30

How are products harmful to surrounding cells not released

Answer 30

Resultant breakdown products from inside the cell are kept in the cell membrane

Question 31

Define neoplasia

Answer 31

Abnormal growth of tissue

Question 32

How can viruses effect apoptosis

Answer 32

They can disable apoptosis induction in cells they infect

Question 33

How is apoptosis regulated

Answer 33

1. Inhibitors (growth factors + extracellular matrix)

Question 34

How is apoptosis induced vs necrosis

Answer 34

1. Can be physiological or pathological | 2. Pathological

Question 35

How many cells are effected by apoptosis vs necrosis

Answer 35

1. Single cells | 2. Cell groups

Question 36

What happens to morphology of cells during apoptosis vs necrosis

Answer 36

1. Cell shrinkage and fragmentation (dense chromatin) | 2. Cell swelling + lysis

Question 37

Inflammatory response in apoptosis vs necrosis

Answer 37

1. None | 2. Usual

Question 38

What pathways initiate apoptosis

Answer 38

1. Extrinsic pathway | 2. Intrinsic Pathway

Question 39

Describe the intrinsic pathway of apoptosis

Answer 39

1. Bax-Bax dimers are formed which enhance apoptotic stimuli 2. Tissue expansion / apoptosis triggered

Question 40

Role of Bax

Answer 40

Determine's susceptibility to apoptotic stimuli

Question 41

What does the intrinsic pathway respond to

Answer 41

Stimuli such as growth factors and biochemical stress

Question 42

How does DNA damage cause activation of the intrinsic pathway for apoptosis

Answer 42

1. Leads to stabilisation of p53 gene 2. Induces apoptosis by activating BCL-2 family 3. Activation of caspases

Question 43

What is the role of p53

Answer 43

Induces the cell cycle arrest and initiates DNA damage repair

Question 44

How does the extrinsic pathway induce apoptosis

Answer 44

Ligand-Binding at death receptors on cell surface (TNFR) 2. Ligand binding causes clustering of receptor molecules and initiates signal transduction cascade 3. Activation of caspases

Question 45

Under what conditions is the extrinsic pathway usually activated

Answer 45

Immune system when it wants to eliminate lymphocytes that would produce self-antigens

Question 46

What is the end product of both the extrinsic and intrinsic pathway of apoptosis

Answer 46

Initiator caspases (caspase 8)

Question 47

What does caspase 8 go on to do

Answer 47

Cleaves pro-caspases | Produces executioner caspases

Question 48

Role of executioner caspases

Answer 48

Degrade many targets such as cytoskeleton and nuclear proteins

Question 49

Role of caspase-3

Answer 49

Activates DNase which fragments DNA

Question 50

Name of the process of nucleus shrinking

Answer 50

Pyknosis

Question 51

Name of the process of fragmenting of the nucleus

Answer 51

Karyorrhexis

Question 52

Describe the process of apoptosis after the production of executioner caspases

Answer 52

1. Pyknosis and karyorrhexis take place 2. Membrane alters but retained 3. Altering causes phagocytosis

Question 53

What are apoptotic bodies

Answer 53

Dead cells not phagocytose further

Question 54

Why is there no inflammatory response to apoptotic cells

Answer 54

Cell membrane is intact

Question 55

Name three disorders that can arise from apoptotic failure

Answer 55

1. Cleft Palate 2. Spina Bifida 3. Fistula

Question 56

What two features characterise necrosis

Answer 56

Bioenergetic failure | Loss of plasma membrane integrity