Cell Membrane and Functions- Week 4

Question 1

Which of these lipids is found in 1/4 of lipids in myelin sheath?

Sphingolipids
Glycerol phospholipids
Phospholipids
Glycolipids

Answer 1

Sphingolipids

Question 2

Which of these molecules are found inside plasma membranes?

Proteins
Carbohydrates
Glycoproteins
Glycolipids

Answer 2

Proteins

Question 3

All these are types of transmembrane proteins EXCEPT __________________.

Receptors
Channels
Epoxy
Carriers

Answer 3

Epoxy

Question 4

The foundation of the plasma membrane of living organisms are __________________

Phospholipids
Starch
Glycogen
Nucleic acids

Answer 4

Phospholipids

Question 5

Which of these statements about the plasma membrane is FALSE?

Non-polar molecules can easily diffuse across the plasma membrane.
It is a sandwich of phospholipid bilayer between two layers of globular proteins.
Its phospholipids component is a bilayer.
It is made up of polar segments emerging out of each side of the membrane.

Answer 5

It is a sandwich of phospholipid bilayer between two layers of globular proteins.

Question 6

Where are peripheral proteins located in relation to a cell?

Outside the cell
Next to the extracellular minutes
Inside the cell
Inside the plasma membrane

Answer 6

Inside the cell

Question 7

Membrane proteins are not very soluble in water because they possess long stretches of non-polar amino acids that are _______________.

transport channels
hydrophilic
transmembranal
hydrophobic

Answer 7

hydrophobic

Question 8

Which mutations can interfere with the proper insertion of a protein in the plasma membrane?

A polar amino acid to a nonpolar amino acid within a cytoplasmic domain
A nonpolar amino acid to a polar amino acid within a transmembrane domain
A nonpolar amino acid to a polar amino acid within a cytoplasmic domain
A polar amino acid to a nonpolar amino acid within a transmembrane domain

Answer 8

A nonpolar amino acid to a polar amino acid within a transmembrane domain

Question 9

Which of the these is likely to make a membrane more fluid?

Many integral proteins.
Several unsaturated fatty acids.
Thick membrane.
Few packing defects.

Answer 9

Several unsaturated fatty acids.

Question 10

The feature of cell membrane which serves as main barrier between the cell and the environment is the _____________

Glycoproteins
Polar heads
Gycolipids
Non-polar tails

Answer 10

Non-polar tails

Question 11

Membrane fluidity is affected by _____________________.

Size of molecules, polarity of molecules, temperature.
hydrophilic tails, hydrophobic heads, cholesterol.
types of fatty acids, water’s affinity for hydrogen bonding
temperature, cholesterol, types of fatty acids.

Answer 11

temperature, cholesterol, types of fatty acids.

Question 12

Red blood cells have a biconcave shape that helps them to carry hemoglobin and oxygen. What protein give cells unique shapes?

Clathrin
Myosin
Actin
Spectrin

Answer 12

Spectrin

Question 13

While water continually orients phospholipids into a lipid bilayer, it does not fix the lipids permanently into position. Thus, the bilayer is considered to be _______.

Fluid
Insulating
Static
Charged

Answer 13

Fluid

Question 14

A cell is identified as being unable to carry out receptor-mediated endocytosis. Which of these is at the likely reason for this condition?

Inserted globular proteins
Malfunctioning clathrin
Presence of Cholesterol
Denatured spectrin

Answer 14

Malfunctioning clathrin

Question 15

Which of these is NOT a function of membrane proteins?

transporters
receptors
hormones
enzymes

Answer 15

hormones

Question 16

How are the tails and heads of membrane phospholipids oriented in their environment?

The hydrophobic heads are oriented toward each other and the hydrophilic tails are oriented toward the extracellular fluid and the intracellular fluid.
The hydrophobic tails are oriented toward each other and the hydrophilic heads are oriented toward the extracellular fluid and the intracellular fluid.
The hydrophilic tails are oriented toward each other and the hydrophobic heads are oriented toward the extracellular fluid and the intracellular fluid.
The hydrophlic heads are oriented toward each other and the hydrophobic tails are oriented toward the extracellular fluid and the intracellular fluid.

Answer 16

The hydrophobic tails are oriented toward each other and the hydrophilic heads are oriented toward the extracellular fluid and the intracellular fluid.

Question 17

Which of these introduces fluidity into plasma membranes?

Integral proteins
Peripheral proteins
Cholesterol
Saturated fatty acids

Answer 17

Cholesterol

Question 18

The part of a membrane protein that extends through the phospholipid bilayer is primarily composed of amino acids that are ___________.

non-polar
highly polar
positively charged
negatively charged

Answer 18

non-polar

Question 19

On the outer surface of the plasma membrane there are marker molecules that identify the cell type. Often these molecules are

peripheral proteins
integral proteins
glycolipids
glycoproteins

Answer 19

glycoproteins