unit 7 - cellular communities

Question 1

connective tissue general characteristics

Answer 1

most abundant tissue in the body, supports and binds other tissues. consists of cells scattered throughout an extracellular matrix

Question 2

extracellular matrix in connective tissue

Answer 2

protein (usually collagen) fibers embedded in ground substance (carbohydrates).

Question 3

collagen structure

Answer 3

• triple helices, 3 polypeptide chains
  *unique amino acid (hydroxyproline)
• repeats of Gly-X-Y, X is typically proline and Y is typically hydroxyproline

Question 4

formation of hydroxyproline

Question 5

why does lack of vitamin C cause scurvy?

Answer 5

enzyme prolyl hydroxylase that converts proline to hydroxyproline requires vitamin C. without hydroxyproline, the collagen structure is disrupted. scurvy develops as a result of weakened connective tissue

Question 6

formation of collagen fibers

Question 7

totipotent stem cells

Answer 7

• divide to produce any type of body cell
• only occur for a limited time in embryos, between morula and blastocyst stages

Question 8

pluripotent cells

Question 9

multipotent stem cells

Question 10

mesenchymal stem cells

Question 11

unipotent stem cells

Answer 11

• in skeletal muscle tissue - satellite cells

Question 12

regeneration of liver

Question 13

using stem cells to repair damaged tissue

Answer 13

hemopoietic stem cell transplant - bone marrow transplant. used to treat leukemia
1. body is dosed with radiation to kill diseased/cancerous bone marrow stem cells.
2. treated with donor stem cells
3. donor stem cells repopulated the bone marrow

Question 14

umbilical cord cells

Answer 14

• umbilical cords contains hematopoietic and mesenchymal stem cells
• can be used to treat many different cancers, immune deficiencies, and genetic disorders

Question 15

embryonic stem cells for repair

Answer 15

• obtained from the inner cell mass of the blastocyst, which forms 3-7 days after an egg cell is fertilized by sperm
• if grown in vitro, they can retain the pluripotent properties of stem cells to differentiate into any cell in the body
• could be an inexhaustible supply of cells to replace and repair damaged mature tissues
• usually derived from blastocysts created by IVF that are no longer needed

Question 16

reproductive vs. theraputic cloning

Question 17

induced pluripotent stem cells

Answer 17

• alternative to embryonic stem cells, with less ethical concerns and bans because they originate from adult cells
  1. specific genes are introduced to adult differentiated cells
  2. genes reprogram the cells to act as pluripotent embryonic stem cells
• expanded the field of regenerative medicine