Cells, Organelles, & Transport Flashcards
The basic component of the phospholipid membrane is made up of (a) __________.
A. Steroids
B. Glycerol backbone and three fatty acid chains
C. Saturated triglycerides
D. Unsaturated triglycerides
E. Phosphate head and two fatty acids
Phosphate head and two fatty acids
The phospholipid membrane is __________
Amphipathic
The term “amphipathic” regarding the phospholipid bilayer means __________.
A. It only has a hydrophobic component
B. It only has a hydrophilic component
C. It has both a hydrophobic and hydrophilic component
D. It is made up of carotenoids
E. It is made up of waxes
It has both a hydrophobic and hydrophilic component
Which component of the phospholipid bilayer is hydrophilic?
A. Phosphate head
B. Fatty acid tails
C. Glycerol backbone
D. Carotenoid
E. Wax
Phosphate head
Which component of the phospholipid bilayer is hydrophobic?
A. Wax
B. Carotenoid
C. Lanolin
D. Phosphate head
E. Fatty acid tails
Fatty acid tails
Which of the following most easily diffuses through the phospholipid bilayer?
A. Hydrophilic molecules
B. Hydrophobic molecules
C. Large polar molecules
D. Glucose
E. Ions
Hydrophobic molecules
The hierarchy of membrane permeability is as follows, from most to least permeable:
(MOST) Small, Hydrophobic Molecules: O2, CO2, N2, Steroid Hormones
Small, Uncharged, Polar Molecules: H2O, Urea, Glycerol, NH3
Large, Uncharged, Polar Molecules: Glucose, Sucrose
(LEAST) Ions: H+, Na+, HCO3–, K+, Ca2+, Cl–, Mg2+
Thus, we know that hydrophobic molecules will most easily diffuse through the phospholipid bilayer (shown below). This is because they can pass through the non-polar, inner portion of the bilayer, whereas polar and charged molecules do not easily diffuse through this inner, nonpolar portion, as they are not very soluble in it.
Which of the following cannot diffuse through the phospholipid bilayer?
A. Steriods
B. Carbon dioxide
C. Nitrogen
D. Calcium
E. Oxygen
Calcium
The hierarchy of membrane permeability is as follows, from most to least permeable:
(MOST) Small, Hydrophobic Molecules: O2, CO2, N2, Steroid Hormones
Small, Uncharged, Polar Molecules: H2O, Urea, Glycerol, NH3
Large, Uncharged, Polar Molecules: Glucose, Sucrose
(LEAST) Ions: H+, Na+, HCO3–, K+, Ca2+, Cl–, Mg2+
Thus, we know that ions (charged molecules) are least able to passively diffuse through the phospholipid bilayer (shown below). An ion’s charge makes it highly polar and thus is unable to solvate in the non-polar, inner portion of the bilayer, making ions unable to diffuse through the membrane. To transport ions across the membrane, dedicated transmembrane protein channels are needed, such as the sodium-potassium pump or proton pump.
Polar molecules pass through the phospholipid membrane if they are __________.
A. Large
B. Charged
C. Hydrophilic
D. Ions
E. Uncharged
Uncharged
The hierarchy of membrane permeability is as follows, from most to least permeable:
(MOST) Small, Hydrophobic Molecules: O2, CO2, N2, Steroid Hormones
Small, Uncharged, Polar Molecules: H2O, Urea, Glycerol, NH3
Large, Uncharged, Polar Molecules: Glucose, Sucrose
(LEAST) Ions: H+, Na+, HCO3–, K+, Ca2+, Cl–, Mg2+
While polar, if the molecule is both small enough and uncharged, then it still experiences some membrane permeability. The passive diffusion of small, uncharged, polar molecules is still possible, however, it is less energetically favorable than the passive diffusion of small, hydrophobic molecules. Therefore, given the same amount of time, less polar, uncharged molecules can cross a membrane (shown below) than small, non-polar molecules.
What is the function of cholesterol in the animal cell membrane?
A. Marker for cell recognition
B. Viral defense
C. Organizes DNA
D. Contains chromatin
E. Structural support
Structural support
Cholesterol is an amphipathic molecule—it has a single hydroxyl group, which interacts with the polar heads of surrounding phospholipids, and 4 hydrocarbon rings, which make up the non-polar portion. Cholesterol’s job is to alter membrane fluidity. Under normal to high temperatures, cholesterol stiffens the membrane, making it less fluid, providing structural support to the cell. If the membrane was too fluid and phospholipids moved too much, it would decrease the integrity of the membrane. At low temperatures, cholesterol increases membrane fluidity by preventing phospholipids from getting too close to each other, impairing cellular functions. Shown below is an image of the cell membrane and where cholesterol is located:
Which of the following is used as structural support in the membrane of prokaryotes?
A. Cholesterol
B. Hopanoids
C. Glycocalyx
D. Carotenoids
E. Sterols
Hopanoids
The glycocalyx is made up of __________.
A. Carbohydrates
B. Peptidoglycan
C. Lipopolysaccharides
D. Bacteria
E. Nucleic acids
Carbohydrates
Analyzing the word glycocalyx can help us remember what it means. The first part of the word, gylco–, should make us think “sugar,” and we know that sugar is a carbohydrate. We define the glycocalyx as a carbohydrate coat which covers the cell membrane of some animal cells and the outer face of the cell wall of some bacteria. It consists of both glycolipids and glycoproteins. In the TEM image below, the “furry” fringe around the cell are the carbohydrates protruding from their lipid or protein anchors.
The glycocalyx is present in some __________.
A. Animal cell plasma membrane
B. Bacterial cell wall
C. Gram-positive bacterial cell wall
D. Plant cell wall
E. Animal plasma membrane and bacterial cell wall
Animal plasma membrane and bacterial cell wall
The glycocalyx can do all the following except __________.
A. Adhere to the cell
B. Protect the cell from infection
C. Cover the plasma membrane of some animal cells
D. Act as a marker for cell-cell recognition
E. Structural support
Structural support
The glycocalyx (shown below) directly adheres to the cell because both glycolipids and glycoproteins are integrated into the membrane. It is found in both some animal and some bacterial cells. Different kinds of cells have unique sugar signatures from the glycocalyx, allowing for cell-cell recognition. The glycocalyx can also help mask adhesion points for potential cell invaders, thus preventing infection. On the other hand, especially in bacteria, the glycocalyx helps form a slime layer, which is mucus-like and sticky, promoting adhesion. Because the glycocalyx anchors to the exterior of the cell, it does not provide structural support.
The glycocalyx is made up of __________.
A. Glycolipids and glycoproteins
B. Glycolipids and cholesterol
C. Glycolipids and ribosomes
D. Glycolipids and glycolipids
E. Glycolipids and DNA
Glycolipids and glycoproteins
The glycocalyx is the multifunctional extracellular carbohydrate coat found in both some animal and some bacterial cells. These carbohydrates anchor to the outer leaflet of the cell membrane or cell wall via either a protein or lipid, thus making the glycocalyx consist of glycolipids and glycoproteins, as shown below:
Which of the following are common cell surface markers used regularly for cell-cell recognition?
A. Glycoproteins
B. Glycolipids
C. Glucocorticoids
D. Phospholipids
E. Steroids
Glycoproteins
The animal cell membrane is made up of __________.
A. Phospholipid membrane, carotenoids, glycocalyx
B. Phospholipid membrane, waxes, glycocalyx
C. Phospholipid membrane, cholesterol, glycocalyx
D. Phospholipid membrane, sterol, glycocalyx
E. Phospholipid membrane, hopanoid, glycocalyx
Phospholipid membrane, cholesterol, glycocalyx
Which of the following is used as structural support in the membrane of plants?
A. Sterols
B. Cholesterol
C. Peptidoglycan
D. Glycocalyx
E. Carotenoids
A. Sterols
If an organism has sterols to add structural support to its cellular membrane, then it is most likely a __________.
A. Plant
B. Mammal
C. Prokaryote
D. Bacteria
E. Virus
Plant
If an organism has hopanoids to add structural support to its cellular membrane, then it is most likely a __________.
A. Mammal
B. Prokaryote
C. Virus
D. Planet
E. Bird
Prokaryote
Which of the following possess centrioles?
A. Plant cells
B. Animal Cells
C. Bacteria
D. Fungi
E. Archaea
Animal Cells
Microtubules are made up of __________.
A. Keratin
B. Tubulin
C. Actin
D. Collagen
E. Clathrin
Tubulin
Microfilaments are made up of __________.
A. Keratin
B. Tubulin
C. Actin
D. Collagen
E. Intermediate filaments
C. Actin
A transmembrane protein is __________.
A. Not attached to the cellular membrane
B. Loosely attachment to the cellular membrane
C. Embedded in the nucleus
D. Embedded in the cellular membrane
E. Embedded from one side to the other side of the cellular membrane
Embedded from one side to the other side of the cellular membrane
A transmembrane protein is a type of __________.
A. Peripheral protein
B. Integral protein
C. Glycolipid
D. Glycoprotein
E. Cholesterol
Integral protein