Unit 3 Part B: Structure and Function

Question 1

Structure of the cell membrane (Plasma membrane)

Answer 1

Made of phospholipids, glycolipids, cholesterol, and proteins

Question 1

Characteristics of phospholipids

Answer 1

has two layers, making the membrane a bilayer. Have a polar head and a non polar tail. Their heads point out and the tails face each other in the membrane

Question 2

Function of Glycocalyx

Answer 2

Acts as an ID card or the cell, protects/ cushions the membrane, cell adhesion, cell migrations during embryonic development

Question 3

How does the glycocalyx identify a cell (3 ways)?

Answer 3

1) Species of organism: identifies the species the cell belongs to
2)identifies the person the cell belongs to
3)Identified the cell type within the organism: such as skin cell or nerve cell

Question 4

Membrane transport function

Answer 4

Allow for the import and export of solutes

Question 5

What is membrane transport performed by?

Answer 5

Channel proteins, and carrier proteins

Question 6

Cell to cell communication is performed by…?

Answer 6

Receptors, each ligand carries a message

Question 7

Enzymes function

Answer 7

Allows reactions to occur

Question 8

Identification is done by …?

Answer 8

Glycoproteins in the glycocalyx

Question 9

CAMS (Cell Adhesion Molecules) Functions

Answer 9

1) form cell junctions to bind together neighboring cells
2)Bind cell to extracellular molecules

Question 10

Carrier proteins

Answer 10

bind a solute and change shape to transfer the solute across the membrane, some use ATP (called protein pumps)

Question 11

Channel proteins

Answer 11

form a channel like structure in the membrane, can be always open or they can be gated

Question 12

Downhill movement of a solute

Answer 12

solute moves “down: its gradient, moves from an area of high solute concentration to an area of low solute concentration.

Question 13

What kind of transport does downhill movement use?

Answer 13

Passive transport, does not require ATP (uses potential and kinetic energy)

Question 14

Uphill movement of a solute

Answer 14

Solute moves “up” its gradient. Moves for an area of low solute concentration to an area of high solute concentration.

Question 15

What type of transport does uphill movement use?

Answer 15

Active transport and requires a cell to use ATP

Question 16

Diffusion

Answer 16

example of a passive transport

Question 17

What are the features of diffusion

Answer 17

Downhill movement of a solute, goal of movement is to achieve equilibrium (equal solute concentration on each side of the membrane)

Question 18

Osmosis

Answer 18

a special type of diffusion.
Downhill movement of water across a semipermeable membrane

Question 19

What is the goal of movement in osmosis?

Answer 19

Equilibrium, to dilute the concentration of the solute in order for the solute concentration to be the same on each side

Question 20

Simple diffusion

Answer 20

solute crosses membrane by itself without the need of a membrane protein, able to wiggle between the phospholipids

Question 21

Facilitated diffusion

Answer 21

solute is unable to cross the membrane by itself, needs the assistance of membrane protein

Question 22

Characteristics of a solute that can use simple diffusion

Answer 22

1) Must be non-polar and soluble in lipids (Alcohols, some vitamins, O2, CO2)
2) Have a relatively small size (O2 and CO2)

Question 23

Can the cell regulate or control the process of simple diffusion?

Answer 23

No it cant, the cell cannot stop simple diffusion from happening.

Question 24

Characteristics of solute that must use facilitated diffusion

Answer 24

1) Polar and non lipid soluble (unable to pass through the fatty acid area of the membrane)
2)Are a little larger in size vs the ones that use simple diffusion

Question 25

Primary active transport

Answer 25

Energy source: ATP
Example of primary active transport : Na+/ K+ pump

Question 26

What is the gradient of each solute in primary active transport?

Answer 26

Na+ is high outside the cell but low inside, K+ is low outside but low inside

Question 27

Which way does each solute move in primary active transport?

Answer 27

Uphill

Question 28

Secondary active transport energy source

Answer 28

Potential energy store in a solute gradient

Question 29

Would secondary active transport function without the primary system?

Answer 29

No, the gradient that is needed (PE) is created by primary active transport system

Question 30

Endocytosis (vesicular transport)

Answer 30

substance enters cell, vesicle forms around the extracellular particle, vesicle enters the cell

Question 31

Exocytosis (vesicular transport)

Answer 31

substance exists the cell, an intracellular vesicle fuses with the membrane, solute(s) leave the cell

Question 32

What are the three types of endocytosis?

Answer 32

Phagocytosis, pinocytosis, receptor mediated endocytosis

Question 33

Phagocytosis

Answer 33

“cell eating”, a cell takes in large particles such as entire cells like bacteria found in the extracellular region (present after an injury)

Question 34

Pinocytosis

Answer 34

“cell drinking”, cell takes in very small droplets of extracellular fluid

Question 35

Receptor mediated endocytosis

Answer 35

cell takes in solutes after the solute binds to its receptor

Question 36

Transcytosis

Answer 36

the process of using a vesicle to get “across” a cell