Bio 331 Midterm Exam 100% Solved
Correctly A+ Pass
What molecules are Hydrophobic? - Answer ✔✔- Non-polar molecules
What molecules are Hydrophilic? - Answer ✔✔- Polar molecules
Why is a molecule polar? - Answer ✔✔- Uneven distribution among the molecule
What makes a molecule non-polar - Answer ✔✔- A even distribution of charges
What makes a phospholipid saturated - Answer ✔✔- It lacks the double bond on the
hydrocarbon chain
What makes a phospholipid unsaturated? - Answer ✔✔- The hydrocarbon chain has
one or more double bond
What creates a phospholipid? - Answer ✔✔- A phosphate group and fatty acid
hydrocarbon tails
What are Phosphoglycerides? - Answer ✔✔- Phospholipids built on glycerol, they make
up most of the phospholipids
What are Sphingolipids? - Answer ✔✔- - Built on Sphingosine,
-Amphipathic,
- Tend to be longer and more highly saturated fatty acid chains the Phosphoglycerides,
- Roles in signal transduction and membrane structure
Define Cholesterol? - Answer ✔✔- - Makes up a large amount of plasma membrane
lipids in some animal cells
- Amphipathic
- Impairs the movement of the fatty acid tails on the phospholipids
- Small hydrophilic head faces the membrane surfaces
What are the 4 components of Phosphoglycerides? - Answer ✔✔- - Phosphate
- Glycerol
- Additional group
- Fatty acid tail
Which of the following terms are Sphingolipids?
1. Sphingomyelin
2. Ceramides
3. Phosphatidylserine
,4. Both 1 and 2
5. All are true - Answer ✔✔- 4
What makes up how membrane carbohydrates are linked to lipids and proteins? -
Answer ✔✔- - 90% of membrane carbohydrates are linked to glycolipids
- 10% of membrane carbohydrates are linked to glycoproteins
What can lipid composition determine? - Answer ✔✔- :• The physical state of the
membrane
• Facilitate protein interactions
• Roles in signal transduction
Define Amphipathic? - Answer ✔✔- A component that has both a hydrophilic part and
hydrophobic part
What is membrane Asymmetry? - Answer ✔✔- A different composition between lipids
and proteins on the endoplasmic and exoplasmic membrane
What is the composition of cell membranes? - Answer ✔✔- Exoplasmic
- Sphingomyelin
- Phosphatidylcholine
Endoplasmic
- Phosphatidylserine
- Phosphatidylethanolamine
- Phosphatidylinositol
Both share equal amounts of Cholesterol
What are the 7 membrane functions? - Answer ✔✔- 1. Compartmentalization
2. Scaffold for biochemical activities
3. Selectively permeable barrier
4. Transporting solutes
5. Responding to external signals
6. Intracellular interaction
7. Energy transduction
What impacts transition temperature? - Answer ✔✔- 1. Fatty acid chain saturation:
a. Saturated fatty acids with no double bonds
b. Cis-unsaturated fatty acids bends at the double bonds which increases membrane
fluidity
2. Cholesterol content: Flat, rigid, hydrophobic rings that impair the movement of the
phospholipid fatty acid tails and eliminates the sharp transition temperature (creates
immediate fluidity)
3. Fatty acid chain length: Shorter fatty acid chains = fewer interactions (van der Waals)
less energy to break apart
, How do membranes change in response to cold temperature? - Answer ✔✔- -
Desaturate single bonds in fatty acid chains to double bonds. Enzyme: Desaturate
- Change the types of phospholipids that are synthesized, synthesize more fatty acids
with unsaturated bonds and shorter chain length
If the percentage of fatty acids are increased how will it affect transition temperature? -
Answer ✔✔- It will increase
Linoleic acid has 2 cis double bonds. Stearic acid has 0 ( both are 18-carbon fatty
acids).
A. Which is more likely to be liquid at lower temperatures?
B. Which has a higher transition temperature? - Answer ✔✔- A. Linoleic acid
B. Stearic acid
What are the three classes of membrane proteins? - Answer ✔✔- 1. Integral
(transmembrane) protein
2. Peripheral proteins
3. Lipid-anchored proteins
Bitopic - Answer ✔✔- Something passes through the transmembrane protein once
Polytopic - Answer ✔✔- Something passes through the transmembrane protein multiple
times
Why are transmembrane proteins amphipathic? - Answer ✔✔- - Transmembrane
domains tend to be hydrophobic (Form Van Der Waals interactions with the fatty acids
in the Bilayer)
- Portions of the protein at the surface tend to be hydrophilic
How can some transmembrane domains be identified? - Answer ✔✔- Through the
analysis of a sting of 20 common non-polar amino acids
Integral membrane proteins - Answer ✔✔- proteins that are at least partially embedded
in the plasma membrane, usually transmembrane
What are peripheral membrane proteins? - Answer ✔✔- Proteins associated with but
not embedded within the plasma membrane via noncovalent bonds. Hydrophilic
What role do peripheral membrane proteins play in signal transduction? - Answer ✔✔-
They are involved in the process of transmitting signals across the membrane.
What is one function of peripheral membrane proteins related to the membrane
structure? - Answer ✔✔- They provide mechanical support for the membrane.
Correctly A+ Pass
What molecules are Hydrophobic? - Answer ✔✔- Non-polar molecules
What molecules are Hydrophilic? - Answer ✔✔- Polar molecules
Why is a molecule polar? - Answer ✔✔- Uneven distribution among the molecule
What makes a molecule non-polar - Answer ✔✔- A even distribution of charges
What makes a phospholipid saturated - Answer ✔✔- It lacks the double bond on the
hydrocarbon chain
What makes a phospholipid unsaturated? - Answer ✔✔- The hydrocarbon chain has
one or more double bond
What creates a phospholipid? - Answer ✔✔- A phosphate group and fatty acid
hydrocarbon tails
What are Phosphoglycerides? - Answer ✔✔- Phospholipids built on glycerol, they make
up most of the phospholipids
What are Sphingolipids? - Answer ✔✔- - Built on Sphingosine,
-Amphipathic,
- Tend to be longer and more highly saturated fatty acid chains the Phosphoglycerides,
- Roles in signal transduction and membrane structure
Define Cholesterol? - Answer ✔✔- - Makes up a large amount of plasma membrane
lipids in some animal cells
- Amphipathic
- Impairs the movement of the fatty acid tails on the phospholipids
- Small hydrophilic head faces the membrane surfaces
What are the 4 components of Phosphoglycerides? - Answer ✔✔- - Phosphate
- Glycerol
- Additional group
- Fatty acid tail
Which of the following terms are Sphingolipids?
1. Sphingomyelin
2. Ceramides
3. Phosphatidylserine
,4. Both 1 and 2
5. All are true - Answer ✔✔- 4
What makes up how membrane carbohydrates are linked to lipids and proteins? -
Answer ✔✔- - 90% of membrane carbohydrates are linked to glycolipids
- 10% of membrane carbohydrates are linked to glycoproteins
What can lipid composition determine? - Answer ✔✔- :• The physical state of the
membrane
• Facilitate protein interactions
• Roles in signal transduction
Define Amphipathic? - Answer ✔✔- A component that has both a hydrophilic part and
hydrophobic part
What is membrane Asymmetry? - Answer ✔✔- A different composition between lipids
and proteins on the endoplasmic and exoplasmic membrane
What is the composition of cell membranes? - Answer ✔✔- Exoplasmic
- Sphingomyelin
- Phosphatidylcholine
Endoplasmic
- Phosphatidylserine
- Phosphatidylethanolamine
- Phosphatidylinositol
Both share equal amounts of Cholesterol
What are the 7 membrane functions? - Answer ✔✔- 1. Compartmentalization
2. Scaffold for biochemical activities
3. Selectively permeable barrier
4. Transporting solutes
5. Responding to external signals
6. Intracellular interaction
7. Energy transduction
What impacts transition temperature? - Answer ✔✔- 1. Fatty acid chain saturation:
a. Saturated fatty acids with no double bonds
b. Cis-unsaturated fatty acids bends at the double bonds which increases membrane
fluidity
2. Cholesterol content: Flat, rigid, hydrophobic rings that impair the movement of the
phospholipid fatty acid tails and eliminates the sharp transition temperature (creates
immediate fluidity)
3. Fatty acid chain length: Shorter fatty acid chains = fewer interactions (van der Waals)
less energy to break apart
, How do membranes change in response to cold temperature? - Answer ✔✔- -
Desaturate single bonds in fatty acid chains to double bonds. Enzyme: Desaturate
- Change the types of phospholipids that are synthesized, synthesize more fatty acids
with unsaturated bonds and shorter chain length
If the percentage of fatty acids are increased how will it affect transition temperature? -
Answer ✔✔- It will increase
Linoleic acid has 2 cis double bonds. Stearic acid has 0 ( both are 18-carbon fatty
acids).
A. Which is more likely to be liquid at lower temperatures?
B. Which has a higher transition temperature? - Answer ✔✔- A. Linoleic acid
B. Stearic acid
What are the three classes of membrane proteins? - Answer ✔✔- 1. Integral
(transmembrane) protein
2. Peripheral proteins
3. Lipid-anchored proteins
Bitopic - Answer ✔✔- Something passes through the transmembrane protein once
Polytopic - Answer ✔✔- Something passes through the transmembrane protein multiple
times
Why are transmembrane proteins amphipathic? - Answer ✔✔- - Transmembrane
domains tend to be hydrophobic (Form Van Der Waals interactions with the fatty acids
in the Bilayer)
- Portions of the protein at the surface tend to be hydrophilic
How can some transmembrane domains be identified? - Answer ✔✔- Through the
analysis of a sting of 20 common non-polar amino acids
Integral membrane proteins - Answer ✔✔- proteins that are at least partially embedded
in the plasma membrane, usually transmembrane
What are peripheral membrane proteins? - Answer ✔✔- Proteins associated with but
not embedded within the plasma membrane via noncovalent bonds. Hydrophilic
What role do peripheral membrane proteins play in signal transduction? - Answer ✔✔-
They are involved in the process of transmitting signals across the membrane.
What is one function of peripheral membrane proteins related to the membrane
structure? - Answer ✔✔- They provide mechanical support for the membrane.
