Lecture 4 (Membrane Structure & Function)

Question 1

What is RNA and DNA made of?

Answer 1

Nucleotides

Question 2

What are made of Nucleic acids?

Answer 2

Nucleotides, RNA and DNA

Question 3

What are proteins made from?

Answer 3

Peptides

Question 4

What are Peptides made of?

Answer 4

Amino Acids

Question 5

What are triglycerides made of?

Answer 5

Fatty acid and Glycerol

Question 6

What are made of carbohydrates?

Answer 6

Polysaccharides, Disaccharides and Monosaccharides

Question 7

what are Polysaccharides made of?

Answer 7

Disaccharides

Question 8

What are Disaccharides made of?

Answer 8

2 Monosaccharides

Question 9

What bonds are involved in the primary structure of Protein? What does the structure consist of?

Answer 9

Peptide bonds

Sequence of amino acids from amino -> carboxyl end

Question 10

What bonds are involved in the secondary structure of Protein? What interactions does the structure consist of?

Answer 10

Hydrogen Bonds

Interactions between backbone portions of nearby amino acids

Question 11

What bonds are involved in the tertiary structure of Protein? What interactions does the structure consist of?

Answer 11

Hydrogen, disulfide, van der Waal, Ionic, and hydrophobic bonds / interactions

Results from interactions between R groups

Question 12

What bonds are involved in the quaternary structure of Protein? What interactions does the structure consist of?

Answer 12

H bonds,
disulfide bonds,
van der Waals
forces, ionic
bonds,
hydrophobic
interactions

Results from R
group interactions
between multiple
protein chains
(subunits)

Question 13

What steps change amino acids into a protein?

Answer 13

Sequence
Folded / helix
3-d folding / wrapping
Presence of another amino acid chain

Question 14

Myelin shealth

Answer 14

The electrical insulation for a nerve cell

Question 15

what are amphipathic lipids?

Answer 15

Lipids that contain both hydrophilic and hydrophobic regions

Question 16

What are phospholipids and phosphoglycerates?

Answer 16

lipids with a Phosphate group
Phospholipids built on a glycerol backbone

Question 17

What is the composition of Sphingosine?
What about Ceramides and what are they the basic unit of?

Answer 17

An amino alcohol that contains a long hydrocarbon chain

Sphingosine linked to a fatty acid on the (R) of the Amino acid. Ceramide is the basic unit of all Sphingolipids

Question 18

What is unique about cholesterol?

Answer 18

Smaller and less amphipathic lipid
makes up 50% of animal membranes

Question 19

what are the 3 components of Plasma Membranes in Eukaryotic cells?

Answer 19

Carbohydrates, Glycoproteins and glycolipids

Question 20

What are the functions of integral membrane proteins?
How are they anchored to the membrane?

Answer 20

function as receptors that bind ligands

channels / transporters to move ions & solutes across membrane

Anchored in membrane through Van Der Waals forces between amino acids and lipids

Question 21

What are Peripheral membrane proteins and their function?
How are they bound to the membrane?

Answer 21

proteins on the surface of the membrane, act as enzymes, transmit membrane signals, can be recruited or released when needed.

Bound to membrane through weak electrostatic bonds

Question 22

How are Lipid-anchored membrane proteins bound? what’s the difference in binding on the external face from the internal face?

Answer 22

They are covalently bonded to a lipid group in the membrane

The external face is bound through a GPI-protein while the internal is bound by a hydrocarbon chain.

Question 23

What effects the fluidity / viscosity of cell membranes?

Answer 23

Temperature

Question 24

How do cells maintain membrane fluidity when exposed to temperature changes?

Answer 24

By altering phospholipid composition

The cell changes the types of phospholipids being made in favor of more unsaturated fatty acids

Desaturation through desaturases

Question 25

What are lipid rafts composed of? What is the purpose of Lipid rafts?

Answer 25

Tightly packed Cholesterol and sphingolipids

Lipid rafts provide a favorable position for cell receptors

Question 26

What can move phospholipids in the membrane to flip between external and internal sides?

Answer 26

Enzymes called Flippases

Question 27

What types of movements can proteins have?

Answer 27

Immobile
mobile in a directed manner
Randomized movement

Question 28

Outline the general structure and functions of the
plasma membrane.

▪ Identify the basic structures and functions of the
carbohydrates and lipids within cellular membranes.

▪ Describe the three classes of membrane proteins and

their function within the lipid bilayer.
▪ Explain the importance of fluidity to plasma membrane
properties