Plasma membrane

Question 1

The Lipid Bilayer

Answer 1

The basic structural framework of the plasma membrane. 2 back to back layers made up of 3 types of lipid molecules.

Question 2

Lipid molecules of lipid bilayer

Answer 2

1. Phospholipids (75%)
2. Cholesterol Molecules (20%)
3. Glycolipids (5%)

Question 3

Amphipathic

Answer 3

Has both polar and non polar parts

Question 4

Membrane proteins

Answer 4

1. Integral proteins
2. Transmembrane proteins
3. Peripheral proteins
4. Glycoproteins

Question 5

Ion channels

Answer 5

pores or holes that specific ions can flow through to get into or out of the cell.

Question 6

Types of integral proteins

Answer 6

• Carriers
• Receptors
• Ligand
• Enzymes
• Linkers

Question 7

“Carriers”

Answer 7

selectively moves a polar substance or ion from one side of the membrane to the other.

Question 8

“Receptors”

Answer 8

integral proteins that serve as cellular recognition sites.

Question 9

“Ligand”

Answer 9

A specific molecule that binds to a receptor

Question 10

“Enzymes”

Answer 10

Catalyst specific chemical reactions inside or outside surface of cell

Question 11

“Linkers”

Answer 11

Anchor proteins in the plasma membranes of neighboring cells to one another or to protein filaments.

Question 12

Integral proteins

Answer 12

extended into or through the lipid bilayer among the fatty acid tails and are firmly embedded into it.

Question 13

Transmembrane proteins

Answer 13

span the entire bilayer and protrude into both the cytosol and extracellular fluid

Question 14

Peripheral proteins

Answer 14

Span the entire bilayer

Question 15

Glycoproteins

Answer 15

proteins with carbohydrate groups attached to the ends that protrude into the extracellular fluid. (often serve as cell identity markers)

Question 16

Gradients across plasma membrane

Answer 16

• concentration gradient (difference of chemical concentration)
• electrical gradient (difference in electrical charges)
• electrochemical gradient (combined influence)

Question 17

Passive process

Answer 17

when a substance moves down its concentration or electrical gradient to cross plasma membrane using only its own kinetic energy.

Question 18

Active process

Answer 18

Cellular energy is used to drive substance against it’s concentration/electrical gradient

Question 19

cellular energy

Answer 19

adenosine triphosphate

Question 20

Types of transport across plasma membrane

Answer 20

• passive processes
• active processes
• transport via vesicle

Question 21

Endocytosis

Answer 21

Vesicles detach from plasma membrane while bringing materials INTO a cell

Question 22

Exocytosis

Answer 22

merging of vesicles with the plasma membrane to release materials OUT OF the cell

Question 23

Isotonic solution

Answer 23

any solution in which a cell maintains its normal shape and volume

Question 24

Hypotonic solution

Answer 24

a solution which has a LOWER concentration of solutes inside the cell

Question 25

Hypertonic solution

Answer 25

a solution that has a HIGHER concentration of solutes inside the cell

Question 26

Crenation

Answer 26

(Shrinkage) when water molecules move out of the cells faster than they enter- causing shrinkage.

Question 27

Tonicity

Answer 27

a measure of a solutions ability to change the volume of cells by altering their water content.

Question 28

Primary active transport

Answer 28

a mediated active transport process that requires energy provided by ATP

Question 29

secondary active transport

Answer 29

the energy stored in Na+ or H+ concentration gradients in used to drive a substance across the membrane

Question 30

pumps

Answer 30

carrier proteins that mediate primary active transport

Question 31

Transport in vesicles

Answer 31

vesicles are formed from an existing membrane to transport large molecules

Question 32

Exocytosis

Answer 32

the process of secreting a substance OUT of a cell using vesicular transport

Question 33

Endocytosis

Answer 33

movement of a substance INTO a cell in a vesicle.

Question 34

Transcytosis

Answer 34

movement of a substance through a cell as a result of endocytosis on one side and exocytosis on the opposite side.

Question 35

Phagocytosis

Answer 35

a form of endocytosis in which the cell engulfs large solid particals (worn out cells, whole bacteria or viruses)

Question 36

Phagocytes

Answer 36

the cells that carry out phagocytosis