BIOL 2070 - LECTURE 4 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE VERIFIED SOLUTIONS
FITB: A lipid bilayer is selectively ____________
permeable
What are the consequences of a lipid bilayers semi-permeability?
- Material inside the cell may be held at different concentrations than the outside
- Different ion, food, ATP, and small molecule concentrations
- Reactions can happen more efficiently
True or False: The movement of ions across a semipermeable membrane drives
many processes within a cell
true
Permeability varies depending on what?
Size, charge, and polarity of the molecule
What does it mean to be semipermeable?
allowing certain substances to pass through it but not others
The lipid bilayer is most permeable to what substances?
Small, nonpolar molecules and those that are hydrophobic
What is the lipid bilayer impermeable to?
Charged molecules
What is the lipid bilayer only somewhat permeable to?
Slightly larger molecules that are uncharged
, FITB: Since ions and polar molecules cannot diffuse freely across a
semipermeable membrane, they must be assisted by _________.
Proteins
FITB: Transport proteins can be classified as _________ (carrier proteins) or
channel proteins.
Transporters
Which type of transport protein utilizes a solute binding site?
transporters/carrier proteins
True or False: Facilitated movement across membranes can lead to different ion
concentrations
True
What is the main purpose of an aquaporin?
To diffuse water through the plasma membrane.
What is passive transport?
The movement of molecules from an area of high concentration to low concentration
What is active transport?
Movement that requires the input of energy and can move molecules against their
concentration gradient
What two types of gradients influence the passive diffusion of compounds?
Concentration and voltage/charge
True or False. When voltage and concentration gradients work in opposite
direction, the electrochemical gradient is favourable.
False. It is much harder to perform passive transport
WITH COMPLETE VERIFIED SOLUTIONS
FITB: A lipid bilayer is selectively ____________
permeable
What are the consequences of a lipid bilayers semi-permeability?
- Material inside the cell may be held at different concentrations than the outside
- Different ion, food, ATP, and small molecule concentrations
- Reactions can happen more efficiently
True or False: The movement of ions across a semipermeable membrane drives
many processes within a cell
true
Permeability varies depending on what?
Size, charge, and polarity of the molecule
What does it mean to be semipermeable?
allowing certain substances to pass through it but not others
The lipid bilayer is most permeable to what substances?
Small, nonpolar molecules and those that are hydrophobic
What is the lipid bilayer impermeable to?
Charged molecules
What is the lipid bilayer only somewhat permeable to?
Slightly larger molecules that are uncharged
, FITB: Since ions and polar molecules cannot diffuse freely across a
semipermeable membrane, they must be assisted by _________.
Proteins
FITB: Transport proteins can be classified as _________ (carrier proteins) or
channel proteins.
Transporters
Which type of transport protein utilizes a solute binding site?
transporters/carrier proteins
True or False: Facilitated movement across membranes can lead to different ion
concentrations
True
What is the main purpose of an aquaporin?
To diffuse water through the plasma membrane.
What is passive transport?
The movement of molecules from an area of high concentration to low concentration
What is active transport?
Movement that requires the input of energy and can move molecules against their
concentration gradient
What two types of gradients influence the passive diffusion of compounds?
Concentration and voltage/charge
True or False. When voltage and concentration gradients work in opposite
direction, the electrochemical gradient is favourable.
False. It is much harder to perform passive transport
