Week 15

Question 1

Stem cells are characterized by

Answer 1

• The ability to self-renew
• Generation of proliferating precursors that can differentiate into many cells types

Question 2

Define “potency”

Answer 2

varying ability of stem cells to differentiate into specialized cell types

Question 3

Embryonic stem cells

Answer 3

derived from the inner cell mass of blastocysts. The embryos are generated by In Vitro Fertilization. To isolate ICM cells and generated ES cells we need to create and destroy an embryo

Question 4

Somatic stem cells

Answer 4

Repair and maintenance and highly specific to their compartment

Question 5

Induced pluripotent stem cells

Answer 5

Cells are generated by reprogramming the fate of a differentiated cell

Question 6

reprogramming

Answer 6

Reprograming requires changes in chromatin structure and gene expression. Reprogramming factors include: Oct4, Sox2, Klf4, cMyc.

Question 7

Recombinant DNA

Answer 7

A technology that uses enzymes to cut and paste together DNA sequences of interest

Question 8

Reproductive Cloning

Answer 8

involves creating an animal that is genetically identical to a donor animal through somatic cell nuclear transfer

Question 9

Therapeutic Cloning

Answer 9

The transfer of nuclear material isolated from a somatic cell into an enucleated oocyte in the goal of deriving embryonic cell lines with the same genome as the nuclear donor.

Question 10

somatic cell nuclear transfer

Answer 10

Summary of procedures:
1. Acquire DNA from donor.
2. Remove DNA from unfertilized egg
3. Fuse embryo with donor DNA
4. Implant in surrogate for nutrition and growth
5. Donor has been duplicated

Question 11

Compare and contrast reproductive and therapeutic cloning

Answer 11

 Reproductive cloning: Creates a whole new embryo with the desired characteristics or traits.
 Therapeutic cloning: Involves manipulation of Pluripotent Embryonic Stem cells which are inserted into the patient with missing/mutated cell type.

Question 12

CRISPR-Cas 9 genome editing

Answer 12

CRISPR/Cas9 edits genes by precisely cutting DNA and then letting natural DNA repair processes to take over. The system consists of two parts: the Cas9 enzyme and a guide RNA.
* Cas9 is a bacterial RNA-guided endonuclease

Question 13

Organoids

Answer 13

• Organoids are tiny, self-organized three-dimensional tissue cultures that are derived from stem cells

Question 14

Cancer

Answer 14

Cancer is a large group of diseases in which abnormal cells divide without control and can invade nearby tissues.
- Cancer cells proliferate in defiance of the normal constrains and invade and colonize territories normally reserved for other cells (invasion and metastasis).

Question 15

Carcinomas

Answer 15

epithelial tissue origin.

Question 16

Sarcomas

Answer 16

Connective tissue origin

Question 17

Hematopoietic malignancies

Answer 17

Lymphoma, leukemias, mast cell, myeloma etc.

Question 18

Neuroectodermal malignancies

Answer 18

undeveloped nerve cells in the brain

Question 19

Ames Test

Answer 19

• The Ames test is a commonly used method that utilizes bacteria to test whether a particular chemical can cause mutations in the DNA of the test organism. It is a biological assay that is formally used to assess the mutagenic potential of chemical compounds

Question 20

how human papilloma viruses inhibit the function of p53 and Rb

Answer 20

• HPV uses E6 protein to bind to p53 which promotes it destruction. This in return causes the G1/S checkpoint to be altered.
• HPV uses E7 protein to inhibit the function of Rb and disrupts its ability to halt cells at the restriction point this promotes G1 to S transition regardless of the cells condition when dividing.

Question 21

Oncogenes

Answer 21

• Oncogenes code for abnormal forms or excessive quantities of such proteins.
• Oncogenes stimulate excessive cell proliferation and/or promote cell survival.

Question 22

Tumor Suppressor Gene

Answer 22

• Tumor suppressor genes are genes whose total inactivation can leader to cancer.
• Their normal function is to restrain proliferation.

Question 23

Explain why loss of APC function in gut epithelia promotes uncontrolled cell proliferation

Answer 23

 Wnt signaling promotes proliferation, APC is a tumor suppressor protein.
 Loss of both copies of APC, a tumor suppressor gene can result in the beginning of abnormal proliferation because it is equivalent to inactivating APC function.
 A. Shows the consequences of having too much of an APC repressing gene.
 B. Shows the consequences of having no protein to active APC, causing uncontrolled cell growth from Wnt.

Question 24

Explain why loss of p53 leads to chromosomal instability

Answer 24

Loss or inhibition of p53 prevents cellular death and apoptosis. Allowing cancer cells to proliferate indefinitely.
- but tumors are not usually detected until they have hundreds of millions of cells

Question 25

Define the process of metastasis

Answer 25

Metastasis: Invasion of surrounding tissues brought about by:
 Decreased cell-cell adhesion
 Increased motility
 Secretion of protests that degrade ECM and BL

Question 26

Angiogenesis

Answer 26

 Angiogenesis is the formation of new blood vessels. This process involves the migration, growth, and differentiation of endothelial cells, which line the inside wall of blood vessels. This supplies the tumor with nutrients and promotes its growth

Question 27

Cancer cells can:

Answer 27

anchorage independent growth (can grow in soft agar)
* Are less susceptible to density-dependent inhibition of growth – do not stop dividing when they touch each other (Hippo signaling mutated)