bio clicker questions

Molecules that are _____________ and _____________ are able to move across the cell membrane via simple diffusion. A)Hydrophobic; large B)Hydrophobic; small C)Hydrophilic; large D)Hydrophilic; small

B)Hydrophobic; small

Some regions of the plasma membrane, called lipid rafts, have higher concentrations of cholesterol molecules. As a result, these lipid rafts: A)Are more fluid than the surrounding membrane. B)Are more rigid than the surrounding membrane. C)Are able to flip from one side of the membrane to the other. D)Are equally fluid as the surrounding membrane. E)Detach from the plasma membrane and clog arteries.

B)Are more rigid than the surrounding membrane.

What is the most likely reason why a phospholipid on the cytoplasmic side of the cell membrane will rarely flip to the extracellular side if both environments are polar? A)The polar head group cannot pass through the nonpolar interior. B)The two sides have different functions and thus the phospholipid would not function properly. C)The cytoplasmic phospholipid is too big to pass through the membrane. D)Cholesterol does not allow lipids to move. E)The fatty acid tails interact with each other too tightly.

A)The polar head group cannot pass through the nonpolar interior.

A beaker is divided by a membrane that is permeable to water and glucose, but not to sucrose. Equal volumes of solutions are added to side A and B with the initial concentrations as shown below. Initially, the liquid levels on both sides are the same. After the system described above reaches equilibrium, what can you predict about the water levels? A)The water will be higher on side A than side B. B)The water will be higher on side B than side A. C)The water will be the same on both sides.

A)The water will be higher on side A than side B.

At equilibrium, there will be no net movement of molecules across the cell membrane. A)True B)False

A)True. even though molecules are still randomly moving through the membrane there is no net movement across the membrane

If a mutation were to occur that resulted in inactivation of the Golgi retention signal (of the glycosylation enzyme), what can you predict about the ABO type? A.Individual would be O type. B.Individual would be AB type. C.Individual would be a universal blood type recipient. D.Individual would be A or B type but not O type.

A.Individual would be O type

If a mutation were to occur that resulted in inactivation of the glycosyltransferase, what result can you predict?A.Individual would be O type. B.Individual would be AB type. C.Individual would be universal blood type recipient. D.Individual would be A or B but not O type.

A.Individual would be O type.

If membrane fluidity needs to be maintained, which of the following would be most important in an animal cell as a response to a decrease in temperature? A)Increasing (slightly) cell size to change its surface area/volume ratio. B)Introducing more double bonds into the fatty acid chains in the phospholipid bilayer. C)Decreasing the amount of cholesterol in the membrane. D)Increasing phospholipid fatty acid tail length in the membrane.

B)Introducing more double bonds into the fatty acid chains in the phospholipid bilayer.

You successfully extract the nucleus of a cell. Will this method remove all of the cell's DNA? A)Yes B)No

B)No mitochondria and chloroplasts have their own

Which of the following represents the order that molecules cross a phospholipid membrane with no proteins, from most easily (freely permeable) to least easily (not permeable)? A)O2, sodium ions (Na+), water (H2O), glucose (C6H12O6) B)O2, water (H2O), glucose (C6H12O6), sodium ions (Na+) C)Sodium ions (Na+), glucose (C6H12O6), water (H2O), O2 D)Water (H2O), glucose (C6H12O6), sodium ions (Na+), O2 E)Glucose (C6H12O6), water (H2O), O2, sodium ions (Na+)

B)O2, water (H2O), glucose (C6H12O6), sodium ions (Na+)

If you inactivate the signal recognition particle that binds the ER signal peptide and takes the peptide to the ER, where will the acid hydrolase end up? A. Lysosome B. Cytoplasm C. Extracellular space D. Golgi apparatus E. Endoplasmic reticulum

B. Cytoplasm

The plasma membrane proteins that carry the ABO-antigens are synthesized on: A. Free ribosomes. B. ER-bound ribosomes. C. Plasma membrane-bound ribosomes.

B. ER-bound ribosomes.

In normal cells, how many sorting signals do acid hydrolases have? A. None B. Two C. Three D. Four E. Six

B. Two , ER signal and Golgi sorting signal to lysosome

In normal cells, acid hydrolases are sorted into the lysosomes. Their synthesis must occur on: A.Ribosomes found free in the cytosol. B.Ribosomes bound to the endoplasmic reticulum. C.Acid hydrolases synthesis is completed on both types of ribosomes.

B.Ribosomes bound to the endoplasmic reticulum.

If the glycosylation enzymes were integral membrane proteins of the Golgi, which direction would their catalytic domain face in the ER? A.The cytoplasm B.The lumen

B.The lumen

If cells had single-layer membranes like micelles, how would the structures of transmembrane proteins be affected? A)Transmembrane proteins would only have hydrophobic regions B)Transmembrane proteins would only have hydrophilic regions C)Transmembrane proteins would possess a hydrophobic region in the cell interior and a hydrophilic region outside the cell. D)Transmembrane proteins would possess a hydrophilic region in the cell interior and a hydrophobic region outside the cell. E)The structures of transmembrane proteins would remain the same as if cells had lipid bilayers.

C)Transmembrane proteins would possess a hydrophobic region in the cell interior and a hydrophilic region outside the cell.

The enzymes that add the ABO antigens to the proteins are found: A. In the cytoplasm. B. In the nucleus. C. In the Golgi apparatus. D.Outside the cell in the extracellular matrix. E.In the lysosome.

C. In the Golgi apparatus

How many sorting signals do the glycosyltransferases have? A. None B. One C. Two D. Three E. Four

C. Two, ER signal, sorting signal to remain in Golgi

Where does the glycosylation enzyme end up if the Golgi retention signal is lost? A.Lysosome B.Plasma membrane protein C.Secreted D.Mitochondrion E.Cytoplasm

C.Secreted

If the glycosylation enzymes were integral membrane proteins of the Golgi and a mutation occurs that inactivates the Golgi retention signal, what direction would the catalytic domain face in the plasma membrane? A.The cytoplasm B.The lumen C.The extracellular space

C.The extracellular space

The defining characteristics of active transport are that this category of transport moves substances _________ their concentration gradient and requires ___________. A)Down; energy B)Down; protein transporters C)Against; protein transporters D)Against; energy E)Against; proton pumps

D)Against; energy

Imagine you have a radioactively labeled protein in the lumen of the ER. Where would you predict the labeled protein will end up? A)The lumen of the Golgi apparatus B)The lumen of a vesicle C)Outside the cell D)All of the above

D)All of the above

If FRAP is performed on two membranes, one at 25°C and the other at 40°C, which one of the following results would most likely be observed? A)Only the membrane at the higher temperature would recover fluorescence in the bleached area B)Only the membrane at the lower temperature would recover fluorescence in the bleached area C)Both membranes would recover fluorescence in the bleached area, but the colder membrane would recover more rapidly D)Both membranes would recover fluorescence in the bleached area, but the warmer membrane would recover more rapidly E)Both membranes would recover fluorescence at the same rate

D)Both membranes would recover fluorescence in the bleached area, but the warmer membrane would recover more rapidly

A fruit smoothie should be consumed shortly after preparation to get the most nutrients from it. This is because the blending process shears open cell organelles and releases their contents, leading to the degradation of biomolecules. Which organelle contributes the most to this degradation after shearing? A)Smooth ER B)Nucleus C)Rough ER D)Lysosome E)Golgi apparatus

D)Lysosome

Which of the following is NOT part of the endomembrane system? A)Endoplasmic reticulum B)Golgi apparatus C)Lysosome D)Mitochondria E)Plasma membrane

D)Mitochondria

A container is divided into two compartments by a membrane that is fully permeable to water but not to larger molecules. Water is added to one side of the membrane (side A), and an equal volume of a 5% solution of glucose is added to the other (side B). What would you predict will happen? A)Glucose will diffuse from side A to side B B)Glucose will diffuse from side B to side A C)The water level on side A will increase and on side B will decrease. D)The water level on side B will increase and on side A will decrease.

D)The water level on side B will increase and on side A will decrease.

How many sorting signals would glycosyltransferases have if they were integral membrane proteins? A. None B. One C. Two D. Three E. Four

D. Three ER signal, signal anchor sequence, sorting signal to remain in Golgi

Suppose a genetics researcher has constructed a fusion protein that has BOTH a nuclear localization signal AND an ER signal sequence. Where will this protein end up?A.Lysosome B.Nucleus C.ER D.Secreted E.Cytoplasm

D.Secreted the ER tag is acted on first, directing the lysosome to the ER. Since internal sequencing to the nucleus occurs in cytoplasm, the nuclear location signal cannot be recognized

Which of the following graphs correctly illustrates the effect of phospholipid fatty acid tail saturation on membrane fluidity? a) unsaturated = more fluid, saturated=less fluid b)no relation c)unsaturated=less fluid, saturated=more fluid

a) unsaturated = more fluid, saturated=less fluid

Which of the following graphs correctly illustrates the effect of phospholipid fatty acid tail length on membrane fluidity? a) when the tail is shorter the membrane is more fluid , and when the tail is longer the membrane is less fluid b) no relation c)when the tail is longer the membrane is more fluid , and when the tail is shorter the membrane is less fluid

a) when the tail is shorter the membrane is more fluid , and when the tail is longer the membrane is less fluid

Which of the following graphs correctly illustrates the effect of temperature on membrane fluidity? a) when the temperature is high the membrane is less fluid and when the temperature is low the membrane is more fluid b) there is no relationship c) when the temperature is low the membrane is less fluid and when the temperature is high the membrane is more fluid

c) when the temperature is low the membrane is less fluid and when the temperature is high the membrane is more fluid

Which of the following graphs correctly illustrates the effect of the number of double bonds in membrane phospholipids? a) when there are no double bonds the membrane is more fluid, when there are several the membrane is less fluid b) no relation c) when there are no double bonds the membrane is less fluid, when there are several the membrane is more fluid

c) when there are no double bonds the membrane is less fluid, when there are several the membrane is more fluid

In intestinal epithelial cells, a transport protein moves glucose into the cytoplasm against its concentration gradient at the same time that it transports Na+ into the cell with its electrochemical gradient. Which of the following CORRECTLY describes this cotransport of glucose and sodium? A)Primary active transport by a symporter B)Secondary active transport by an antiporter C)Secondary active transport by a symporter D)Primary active transport by an antiporter E)Facilitated diffusion

c)Secondary active transport by a symporter

Purified phospholipids gather together and form membranes only if the appropriate enzyme is present. true or false ?

false bilayer and liposome formation is spontaneous