Cell Membrane

Question 1

Lipid-based structure that separates aqueous

interior of a cell from the aqueous environment surrounding the cell

Answer 1

Cell Membrane

Question 2

Fatty acids = ____; Phosphate or sugar group = ____

Answer 2

tails; head

Question 3

Up to ___ of plasma membrane is lipid material

Answer 3

80%

Question 4

The membranes are lipid ____ made up of

phospholipids

Answer 4

bilayers

Question 5

Lipid bilayer: Nonpolar tails of phospholipids are in the middle and polar heads are on the surface
■ ____ nanometers thick
■ Contains at least ___ unsaturated fatty acid

Answer 5

6 to 9

one

Question 6

Cholesterol molecules are also components of plasma membranes. Cholesterol helps regulate membrane ____ –the
fused-ring system does not allow rotation of fatty acid tails in the vicinity and it fits between _____ of the lipid bilayer

Answer 6

fluidity; fatty acid chain

Question 7

Lipid bilayers also contain proteins

Answer 7

○ Responsible for moving substances such as nutrients and electrolytes across the membrane
○ Act as receptors that bind hormones and neurotransmitters

Question 8

The membrane proteins and some lipids further react with carbohydrate molecules

Answer 8

Act as markers, substances that play roles in processes by which different cells recognize each other

Question 9

Membrane proteins can be differentiated into two types of protein

Answer 9

Integral Protein

Peripheral Protein

Question 10

Penetrates in the lipid bilayer structure, can be complete penetration or partial penetration.

Answer 10

Integral membrane proteins

Question 11

Integral membrane protein extends across the lipid bilayer

Answer 11

Complete Penetration

Question 12

Integral membrane protein embedded in one side of the lipid bilayer

Answer 12

Partial penetration

Question 13

Proteins only found on the surface of lipid bilayer structure

Answer 13

Peripheral Proteins

Question 14

Proteins embedded with carbohydrate markers

Answer 14

Glycoproteins

Question 15

Three types of transport

Answer 15

Passive transport
Facilitated transport
Active transport

Question 16

Process in which a substance moves across a cell membrane by diffusion from a region of higher concentration to a region of lower concentration

Answer 16

Passive Transport

additional info - No cellular energy expenditure
Only a few types of molecules, including O2, N2, urea, and ethanol, can cross membranes by this process

Question 17

Process in which a substance moves across a cell membrane, with the aid of a membrane protein, from a region of higher concentration to a region of lower concentration

Answer 17

Facilitated Transport

Additional info - No cellular energy expenditure
Specific protein carriers or transporters are involved in the process

Question 18

Driving Force in Passive Transport

Answer 18

Concentration gradient - movement is from high concentration to low concentration

Question 19

What type of molecules undergo passive transport

Answer 19

Small organic molecules

Some relatively large molecules can pass if they are lipid soluble

Question 20

Transport used for polar molecules; Also follows concentration gradient but protein channel is used.

Answer 20

Facilitated Transport

Question 21

Process in which a substance moves across a cell membrane, with the aid of membrane proteins, against a concentration gradient

Answer 21

Active Transport

additional info - ○ Involves expenditure of cellular energy (Supplied by ATP molecules)
Proteins involved in active transport are called “pumps”

Question 22

Carrier in active transport can be called as ___

Answer 22

Pumps