Block C/E

Question 1

Whats a practical definition of genetic mapping in humans?

Answer 1

The identification of polymorphic markers with alleles that co-segregate with disease in extended families

Question 2

How are BACs used in the Human Genome Project?

Answer 2

To hold fragments of genomic DNA as part of the physical mapping process

Question 3

LD blocks are made up of _______

Answer 3

haplotypes

Question 4

Apoptosis is triggered by_______

Answer 4

Caspases

Question 5

What are the 2 classes of apoptotic caspases.

Answer 5

Initiator and executioner caspases

Question 6

How are initiator caspases activated

Answer 6

They are activated by dimerisation through adaptor proteins binding to the adaptor binding domain.

Question 7

How are executioner caspases activated

Answer 7

Once the protease domain is cleaved, the executioner goes through an activating conformational change

Question 8

How does an executioner caspases control apoptosis

Answer 8

They cleave a variety of key proteins, leading to controlled cell death

Question 9

Which type of caspases do extrinsic and intrinsic apoptosis activate

Answer 9

Executioner caspase

Question 10

Desrcibe extrinsic cascade

Answer 10

Extracellular proteins bind to cell surface death receptors to trigger the extrinsic pathways of apoptosis

Question 11

Describe intrinsic cascade (5 marks)

Answer 11

Cells release the mitochondrial protein, cytochrome c. Cytochrome C activates Apaf1. Assembly of 7 activated Apaf1 proteins form a complex called apoptosome. Apoptosome recruits caspase-9. Activation of caspase-9, cleaves and activates executioner caspases.

Question 12

Give 3 reasons why cells would activate apoptosis from within a cell.

Answer 12

-DNA damage
-cellular stress
-in response to a developmental cue

Question 13

Name the regulatory proteins that specifically regulate the intrinsic pathway and how (2 marks)

Answer 13

Bcl2, controls the release of cytochrome c.

Question 14

Define stem cells

Answer 14

An immortal, unspecialised cell

Question 15

Name the stem cell based on the description. Zygote created by fertilisation. Generates all cells inc placenta

Answer 15

Totipotent

Question 16

Name the stem cell based on the description. Generates all cells apart from placenta cells.

Answer 16

Pluripotent

Question 17

Name the stem cell based on the description. Produces Red Blood Cells and all White Blood Cells

Answer 17

Multipotent

Question 18

Name the stem cell based on the description. Produces sperm cells

Answer 18

Unipotent

Question 19

How do we grow Embryonic Stem cells. (3 marks)

Answer 19

To keep it in an undifferentiated state, we need to provide it with differentiation inhibitors and factors that promote proliferation.

Question 20

Name a known factor for differentiation inhibition in mice.

Answer 20

Leukaemia inhibitory factor (LIF)

Question 21

State 4 problems with using stem cells as regenerative medicine (4 marks)

Answer 21

-injecting ES cells might cause cancer
-is it histocompatible, and will you have to use immunosupressors
-cells must be able to differentiate in a controlled manner
-is stem cells from donor safe and disease free

Question 22

Give 2 pros and 2 cons of using iPS cells.

Answer 22

Pros:
-easier to create
-doesnt require human oocyte
Con:
-not clear if reprogramming is complete
-cells could cause cancer

Question 23

Describe the multiple hit theory (3 marks)

Answer 23

Its now believed that the development of tumours require 5-8 independant hits that occur over time. A single cell layer undergoes a mutation that either enhances cell proliferation or decreases cell death. Proliferation hastens the next step of tumour progression by increasing the size of the population thats at risk of another mutation.

Question 24

Describe the altered metabolism in cancer cells.

Answer 24

Tumour cells generally produce adundant lactate, because of its increased rate of glycolysis.

Question 25

Define oncogene

Answer 25

Mutated gene that has the potential to cause cancer

Question 26

Define proto-oncogene

Answer 26

A cell that plays a role in regulating normal cell division.

Question 27

What is p53 and how can it contribute to tumour development. (3 marks)

Answer 27

p53 is a nuclear transcription factor with a pro-apoptotic function. levels of p53 increase in genetically damaged cells, this causes apoptosis. however a loss of p53 function will allow genetically damaged cells to escape apoptosis and proliferate

Question 28

Which protein helps to configure duplicated chromosomes for seperation

Answer 28

Condensin

Question 29

Which protein helps form multi-subunit protein complexes and functions, structurally, to hold sister chromatids together

Answer 29

Cohesin

Question 30

Which protein catalyses the cleavage and seperation of cohesins

Answer 30

Seperase

Question 31

What protein is activated by the release of cytochrome c from mitochondria in the intrinsic pathway of apoptosis.

Answer 31

Apaf1

Question 32

Fill out the sentence describing gene amplification in cancer. A _____ protein is greatly ______

Answer 32

A normal protein is greatly overproduced.