Cells

Question 1

Cell

Answer 1

the basic functional unit of all living things

Question 2

plasma membrane (cell membrane)

Answer 2

bounds the cell and encloses the nucleus and cytoplasm

Question 3

cytoplasm

Answer 3

consists of specialized bodies called organelles suspended in a fluid matrix, the cytosol, which consists of water and dissolved substances such as proteins and nutrients

Question 4

plasma membrane separates…

Answer 4

internal metabolic events from the external environment and controls the movement of materials into and out of the cell

Question 5

peripheral protein

Answer 5

proteins attached loosely to the inner or outer surface of the membrane

Question 6

integral protein

Answer 6

proteins that extend into the membrane; AMPHIPATHIC (hydrophobic region embedded in the membrane and the hydrophobic regions exposed to the aqueous solutions bordering the membrane

Question 7

transmembrane protein

Answer 7

integral proteins that span across the membrane appearing on both surfaces

Question 8

phospholipid membrane

Answer 8

selectively permeable. only small, uncharged, polar molecules (such as H2O and CO2) and hydrophobic molecules (nonpolar molecules like O2 and lipid-soluble molecules such as hydrocarbons) freely pass across the membrane

Question 9

channel proteins

Answer 9

provide open passageways through the membrane for certain hydrophilic (water-soluble substances such as polar and charged molecules

Question 10

ion channels

Answer 10

allow the passage of ions across the membrane

Question 11

ion channels (in nerve and muscle cells)

Answer 11

called gated channels. open and closein response to specific chemical or electrical stimuli to allow the passage of specific ions (such as Na+ and K+)

Question 12

Porins

Answer 12

proteins that allow the passage of certain ions and small polar molecules through membranes

Question 13

aquaporins

Answer 13

found in the plasma membranes of certain cells (such as kidney and plant roots), dramatically increase the passage rate of H2O molecules.

Question 14

carrier proteins

Answer 14

bind to specific molecules, which are then transferred across the membrane after the carrier protein undergoes a change of shape

Question 15

the passage of glucose into a cell is by…

Answer 15

a carrier protein

Question 16

transport protein

Answer 16

use energy (ATP) to transport materials across the membrane

Question 17

active transport

Answer 17

when energy is used to transport materials across the materials

Question 18

example of active transport

Answer 18

(Na+)-(K+) pump; uses ATP to maintain higher concentration of Na+ and K+ on opposite sides of the plasma membrane

Question 19

Recognition protein

Answer 19

gives each cell type a unique identification; provides for a distinction between cell types, between self cells and foreign cells, and between normal cells and cells infected with viruses.

Question 20

example of recognition protein

Answer 20

glycoproteins because they have short polysaccharide chains (oligosaccharides) attached.

Question 21

adhesion protein

Answer 21

attach cells to neighboring cells or provide anchors for the internal filaments and tubules that give stability to the cell

Question 22

receptor proteins

Answer 22

provide binding sites for hormones or other trigger molecules.