ch. 4 cell-to cell interactions

Question 1

a basic feature of multicellular animals is the formation of diverse kinds of ______, such as skin, blood, or muscle, where cells are organized in specific ways.

Answer 1

tissue

Question 1

what do cells do when they make contact

Answer 1

they “read” each other’s cell-surface markers and react accordingly.
-cells that are part of the same tissue type recognize each other, and frequently respond by forming connections between their surfaces.

Question 2

glycolipids

Answer 2

most tissue-specific cell-surface markers are glycolipids, (lipids with carbohydrate heads)
-the ones on the surface of red blood cells are also responsible for the A, B, and O blood types.

Question 3

major histocompatibility complex

Answer 3

the immune system of vertebrates uses a particular set of markers to distinguish self from non self cells, encoded by genes of the major histocompatibility complex.

Question 4

adhesive junctions

Answer 4

-first to evolve
-mechanically attach the cytoskeleton of a cell to the cytoskeletons of other cells or to the ECM.

Question 5

adherens junctions

Answer 5

-formed by cadherin (a single-pass transmembrane protein w/ an extracellular domain that can interact with the extracellular domain of a cadherin in an adjacent cell to join them together) molecules on the surface of cells.

Question 6

desmosomes

Answer 6

-cadherin-based junction unique to vertebrates.
-contain cadherins desmocolin and desmoglein.

Question 7

Hemidesmoses and focal adhesions

Answer 7

-connect cells to the basal lamina or other ECM.

Question 8

Septate junctions

Answer 8

-found in invertebrates and vertebrates and form a barrier that can seal off a sheet of cells.
-their wide distribution indicates that they evolved soon after or with adherins junctions.

Question 9

tight junctions

Answer 9

-unique to vertebrates and contain proteins called Claudins because of their ability to occlude or block substances from passing between cells.
-acts ts as a wall within the tissue, keeping molecules on one side or the other.

Question 10

animal cells

Answer 10

-round and irregular in shape
-both plant and animal cells are eukaryotic
-both have a cell membrane, and cell organelles, like the nucleus, mitochondria, and endoplasmic reticulum.

Question 11

plant cells

Answer 11

-fixed and rectangular in shape
-both plant and animal cells are eukaryotic
-both have a cell membrane, and cell organelles, like the nucleus, mitochondria, and endoplasmic reticulum.