Exam 1

Question 1

Totipotent

Answer 1

potential of a single cell to develop into an entire organism (stem cell)

Question 2

Pluripotent

Answer 2

ability to develop into all cell types of the body, but not supporting structures (placenta, amnion, etc) [stem cell]

Question 3

Multipotent

Answer 3

ability to give rise to a small number of different cell types (stem cell)

Question 4

Unipotent

Answer 4

capacity to give rise to a single cell type

Question 5

Where do you find pluripotent stem cells?

Answer 5

found in early embryos

Question 6

Which stem cells are you more likely to find in adults?

Answer 6

Induced Pluripotent Stem Cells (IPSC) - Adult stem cells that are reprogrammed to embryonic state

Question 7

What are some examples of cells that can develop from hematopoietic stem cells?

Answer 7

blood cells: RRC’s, B lymphocytes, T lymphocytes, natural killer cells, neutrophils, basophils, eosinophils, monocytes, macrophages, platelets

Question 8

What are progenitor cells?

Answer 8

are early descendants of stem cells that can differentiate to form one or more kinds of cells, but cannot divide and reproduce indefinitely. They are often more limited than a stem cell in the kinds of cells it can become.

Question 9

Asymmetric vs Symmetric cell division?

Answer 9

An asymmetric cell division produces two daughter cells with different cellular fates. This is in contrast to symmetric cell divisions which give rise to daughter cells of equivalent fates. (Stem cell > stem cell / differential cell) vs. (stem cell > 2 stem cells or stem cell > 2 differential cell)

Question 10

_______ of ______ cell divison leads to cancer

Answer 10

dysregulation, asymmetric

Question 11

What are proteoglycans made of?

Answer 11

Masses of GAGs and protein

Question 12

What are GAGs

Answer 12

Glycosaminoglycans (disaccharides of acidic sugar and amino sugar)

“sulfated” glycosaminoglycans - dermatan, chondroitin, keratan, and heparan

Question 13

What impact does the negative structure of GAGs have on its function?

Answer 13

Attracts water but repulses other GAGs (this is what gives it the “bottle brush” structure)

Question 14

What is the difference between a proteoglycan monomer and aggregate?

Answer 14

Monomer: protein core with GAGs attached to it (except hyaluronic acid), repulsion of GAGs causes it to have “bottle brush” appearance

Aggregate: protein core with hyaluronic acid

Question 15

Where are proteoglycans located in the body?

Answer 15

mucus and synovial fluid

Question 16

How is collagen assembled (in general)?

Answer 16

“chains” of repeating amino acids
note: need for Vitamin C
three chains form helix, exocytose to exterior of cell
assembled into fibrils

Question 17

How might collagen be organized in skin vs. tendons?

Answer 17

Multi-directional in skin, to stretch in different directions. Stretch in one direction in tendons in muscles attached to bones

Question 18

There is ____ ECM in epithelial cells

Answer 18

little

Question 19

Epithelial tissue is also known as ______ or ______

Answer 19

basement membrane, basal lamina

Question 20

What separates epithelial cells from connective tissue

Answer 20

Basement membrane

Question 21

Components of ECM

Answer 21

Proteoglycans, fibrous proteins and adhesive proteins

Question 22

Types of fibrous proteins in ECM

Answer 22

collagen, elastin

Question 23

Fibrous proteins provide ____, and are made up of _____.

Answer 23

structure, amino acids

Question 24

Collagen type I

Answer 24

most abundant, located in bones, skin and tendons (also, found in scar tissue)

Question 25

Collagen type II

Answer 25

location: hyaline cartilage | body specific location: end of ribs, larynx, trachea and bronchi, & articular surface of bone

Question 26

Collagen type III

Answer 26

made during wound healing | location: artery walls, intestine and uterus

Question 27

collagen type IV

Answer 27

component for filtration in kidneys | location: basement membrane and eye lens

Question 28

Collagen gets attacked by ______

Answer 28

free radicals

Question 29

Collagen vs. Elastin

Answer 29

Collagen: resist force, different types vary for structural role, ECM function- support and strength Elastin: rubber-like connective tissue (stretch and relax without ripping)

Question 30

Fibrous proteins and disease

Answer 30

``` Scurvy osteogenesis imperfecta Ehlers - Danlos syndrome Marfan syndrome a1 - Antitrypsin deficiency ```

Question 31

Osteogenesis Imperfecta

Answer 31

"brittle bone" inherited (mutation in collagen gene which causes decreased synthesis) Type 1 (most common) type 2 (lethal around birth)

Question 32

Ehlers-Danlos syndrome

Answer 32

genetic defect of fibril collagen (defect in structure, synthesis or processing) 6-types (all affect joints and some affect skin)

Question 33

Marfan Syndrom

Answer 33

Autosomal dominant (mutation in gene necessary for ELASTIN)

Question 34

a1 - Antitrypsin Deficiency

Answer 34

WBC in lungs elastase (Elastase digest elastin & is inhibited by the protein a1 - Antitrypsin)

Question 35

a1 - Antitrypsin Deficiency

Answer 35

WBC in lungs elastase (Elastase digest elastin & is inhibited by the protein a1 - Antitrypsin)

Question 36

Which cell junction and proteins seals epithelial cells together?

Answer 36

tight junctions (also prevents leakage [prevents leaky gut])

Question 37

What do integrins bind to for cell-cell or cell-ECM interactions?

Answer 37

Ligands (molecule that binds to another molecule) cell to cell: binds to members of the immunoglobulin superfamily cell to ECM: binds to arginine-glycine-aspartic acid residue in collagen and fibronectin (or may bind to laminin)

Question 38

What it the main adhesive protein in epithelial tissue?

Answer 38

Laminin

Question 39

• What is the main adhesive protein in connective tissue?

Answer 39

Fibronectin

Question 40

What are desmosomes?

Answer 40

anchors filaments between cells

Question 41

Which cell junction protein joins cells by binding actin bundles?

Answer 41

Adherens

Question 42

Which cell junction and proteins are involved with anchoring to the basement membrane?

Answer 42

Hemidesmosomes

Question 43

How are adhesion molecules related to cancer?

Answer 43

involved with the progression of cancer and metastasis | E-cadherin activity is lost in most epithelial tumors

Question 44

How are adhesion molecules related to leukocyte?

Answer 44

Genetic defect results in recurrent bacterial infections most cases do not live past 2 years old

Question 45

How are adhesion molecules related to pemphigoid?

Answer 45

Autoimmune condition, causes disruption of cadherin cell-cell adhesion, and gets a lot of blistering because epidermal cells are not allowed to adhere to one another

Question 46

Which molecules are overexpressed during asthma?

Answer 46

increased ICAM-1 expression, causes excessive migration of WBC to respiratory tract, leads to chronic inflammation

Question 47

Which molecules are overexpressed during rheumatoid arthritis?

Answer 47

Autoimmune disease, bone cells overexpress adhesion molecules (integrin LFA-1 & ICAM-2), increased leukocyte adhesion which causes synovial inflammation

Question 48

What does selectin do?

Answer 48

-Short term -cell to cell adhesions Functions: mediate WBC migration to areas of inflammation and important for the immune system Selectin on one cell binds to lectin on another cell

Question 49

What is extravasation?

Answer 49

Migration of cells from circulation into the tissue

Question 50

How are cell adhesion molecules involved in the 4 steps of extravasation?

Answer 50

1. Selectin on the WBC (leukocyte) binds to ligand (immunoglobulin superfamily) on the surface of the endothelial cell causing rolling of leukocyte along endothelium of blood vessel 2. activation of an integrin on the leukocyte 3. integrin can bind to its ligand on the endothelium. This is firm arrest 4. Diapedesis = movement of the leukocyte through the endothelial layer