Unit 11 Flashcards
Cellulose in the plant cell wall…
a) is produced by enzymes in the plasma membrane
b) is found only around cells that have stopped growing
c) is produced with in the Golgi and secreted
d) a and b
e) b and c
a)
Osteocytes are bone cells. Collagen fibers and calcium salts are found in abundance between and among the osteocytes. The collagen and calcium salts are…
a) components of the cytoskeleton and osteocytes
b) deposited by the circulatory system and are not associated with the osteocytes
c) components of the plasma membrane of osteocytes
d) part of the ECM secreted by osteocytes
e) extensions of the ER
d)
Proteoglycans in the ECM of animal tissues…
a) are linked to microtubules through the plasma membrane
b) chiefly provide tensile strength
c) are polysaccharides composed of glucose subunits
d) are proteins coiled into rope-like structures
e) all the tissue to resist compression
e)
Hemidesmosomes are important for…
a) attaching epithelial cells to the basement membrane
b) bending of epithelial sheets
c) creating passageways between epithelial cells
d) creating barriers
e) lining epithelial cells to glycosaminoglycans
a)
Which type of junction contributes the most to the formation of distinct membrane domains on epithelial cells?
a) desmosomes
b) tight junctions
c) gap junctions
d) adherens junctions
b)
Which of the substances on this list can pass through gap junctions?
a) ions
b) proteins
c) ribosomes
d) a and c
e) a, b and c
a)
____ associated with ____ are important in the bending of epithelial sheets during animal development
a) Tight junctions, actin filaments
b) Focal adhesions, microtubules
c) Desmosomes, intermediate filaments
d) Adherens junctions, actin filaments
d)
Hematopoietic stem cells, found in the bone marrow of adults…
a) are multipotent, in that they can differentiate into many types of blood cells
b) express all the same genes as embryonic stem cells
c) are capable of renewing themselves by mitosis for the lifetime of a healthy person
d) a and c
e) a, b and c
d)
Embryonic stem (ES) cells differ from somatic stem cells in that…
a) ES cells can only be derived from early embryos, whereas somatic stem cells are present in adult tissues
b) ES cells retain the ability to renew themselves, whereas somatic stem cells do not
c) ES cells are pluripotent and can differentiate into any cell type int eh developing embryo, whereas somatic stem cells are multipotent and can produce a more limited number of differentiated cell types
d) a and c
e) a, b and c
d)
The term carcinoma refers to…
a) immature hematopoietic cells that undergo uncontrolled division and eventually leave the bone marrow (metastasize) and invade other regions of the body
b) cells of any type that undergo uncontrolled division and eventually leave their tissue of origin (metastasize) and invade other regions of the body
c) epithelial cells that undergo uncontrolled division and eventually leave their tissue of origin (metastasize) and invade other regions of the body
d) cells of any type that undergo uncontrolled division such that they form a lump or tumour in their tissue of origin
e) a and c
c)
What is the major difference in the ECM of animal cells and plant cell walls?
a) The plant cell wall is composed primarily of proteins, whereas animal ECM is mainly carbohydrates
b) The plant cell wall is primarily carbohydrate, whereas animal ECM is mostly protein based, with some carbohydrate
c) Animal ECMs and plant cell walls are quite similar in structure and function
d) The fibrous components of plant cell walls are released extracellularly by the Gogli, whereas collagen is secreted by lysosomes of animal cells
b)
Intercalated disks are cell-cell junctions found between cardiac muscles cells. A feature of intercalated disks is a large number of gap junctions. Which of the following statements would be true about these inter-connected cardiac muscle cells?
a) Extensions of smooth ER goes through the gap junctions, making it continuous from one cardiac muscle cell to the next
b) Water and small ions can readily pass from one cardiac muscle cell to the next one
c) A single plasma membrane encompasses multiple cardiac muscle cells
d) RNA from one cardiac muscle cell can be transported into an adjacent cell through the gap junction
e) both b and d
b)
Pemphigus vulgaris is an autoimmune disorder in which antibodies are produced against desmoglein 3, a protein component of desmosomes. The blistering seen in these individuals is probably a result of:
a) a decrease in flexibility of the cell membrane
b) inadequate numbers of G-protein receptors
c) inadequate production of G-protein receptors
d) loss of cell-cell adhesion
e) leakage through tight junctions
d)
Scientists have found that ECM components may induce specific gene expression in embryonic tissues such as the liver and testis. For this to happen there must be direct communication between the ECM and the developing cells. Which kind of membrane protein would most likely be involved in this kind of induction?
a) integrins
b) collagens
c) actins
d) fibronectins
e) G-protein coupled receptors
a)
Biologists discovered fibronectin in the 1970s while comparing ECM components of healthy cells and cancer cells. Fibronectin is absent from, or greatly reduced in the ECM of cancer cells. Does this observation make sense considering what else is known about cancer cells?
a) No, because cancer cells adhere more strongly to each other than normal cells do
b) Yes, because cancer cells adhere more strongly to each other than normal cells do
c) No, because cancer cells often leave the site of the original tumour and spread throughout the body
d) Yes, because cancer cells often leave the site of the original tumour and spread throughout the body
d)
