Test 2- Stem Cells And Viruses

Question 1

How is the Philadelphia chromosome related to the multistep model of cancer development?

Answer 1

~Mutation of chromosome 22 because it switches (translocated) with chromosome 9.
~The product of the switch is the BCR-ABL
~Related to the multi step model of cancer development because it is a oncogene (always turned on)

Question 2

What are the 3 germ layers of development

Answer 2

~Mesoderm: blood, connective tissue
~Ectoderm: skin, nervous system
~Endoderm: digestive, respiratory

Question 3

Adult (somatic) stem cells

Answer 3

~Replace non-reproducing cells
~Help to heal and maintain our bodies
~Bone marrow, blood, brain, teeth, gut

Question 4

Embryonic stem cells

Answer 4

~Reproduce indefinitely

~Give rise to anything

Question 5

Pluripotent vs. Multi-potent stem cells

Answer 5

~Pluripotent: give rise to many/any cells
~Multi-potent: Give rise to a handful of cells
Which is most therapeutic?

Question 6

If a gene is involved in cell signaling

Answer 6

~Decreases transcription
~Broken/ inactive
~Can’t turn off cell cycle

Question 7

Stem Cell

Answer 7

~Reproduce itself indefinitely

~Unspecialized

Question 8

Cancer development

Answer 8

~Cancer results from accumulation of mutations
~Normal cells convert to cancer cells by the accumulation of mutations affecting the proto-oncogenes and tumor suppressor genes
~Certain viruses promote cancer by integrating viral DNA into a cell’s genome
~Individuals that inherit a mutant oncogene or tumor-suppressor allele have a predisposition to develop a certain cancer

Question 9

Multi step model of cancer development

Answer 9

~Oncogenes: code for proteins that stimulate cell growth and division (Ras, BCR-ABL) (proto before converted to active) (over production of cell division)
~Tumor suppressor genes: code for proteins that block or inhibit cell growth or division (P53) (not being inhibited anymore)
If you have only one mutation, your body will not develop cancer

Question 10

Philadelphia chromosome

Answer 10

~Mutation, oncogene for cancer development
~Only expressed in certain tissue (tissue selective): white blood cells
~Produces BCR-ABL, which causes CML (a cancer development in white blood cells). Cured by Gleevec (some people resistant because of their binding sites).

Question 11

Bacteriophages vs animal viruses

Answer 11

~Bacteriophages: prokaryotic viruses, more simple (Virulent phases and temperate phages)
~Animal viruses: eukaryotic viruses, more complex (Influenza, HIV)

Question 12

Lytic vs. lysogenic cycles

Answer 12

~Lytic (virulent phage): classic lifestyle that ends in the death of host cell. Attaches, injects phage DNA and degrades host DNA, synthesis, and assembly of viral genome/protein. (T4 phage)
~Lysogenic (temperate phage): remains inactive, phage DNA splices into bacterial chromosome, when cell replicates the phage DNA is also replicated- can become lytic later. (Lambda phage)

Question 13

HIV

Answer 13

~Effects the body like the common flu, the HIV virus destroys immune system cells and the body is prone to infections (AIDS)
~HIV is a retrovirus because the RNA genome transcribes back into the DNA of the host cell; called reverse transcriptase

Question 14

Retro virus

Answer 14

~RNA viruses that insert their DNA copy into the host cell to replicate (called reverse transcriptase)

Question 15

RNA viruses vs. DNA viruses

Answer 15

~RNA is more prone to mutation, which leads to rapid mutation
~DNA is less prone to mutation
~Both viruses inject their DNA into a cell which hijacks the reproductive machinery of the cell to produce more mutations, eventually the cell dies and infects more cells