Bio Chp 5

Which statement best describes phagocytosis? 1.A receptor on the plasma membrane binds to a molecule, and the cell engulfs both the receptor and the molecule. 2.A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole. 3.Small droplets of extracellular fluid and all the dissolved solutes enter the cell by this process. 4.Cells use this process to export products such as insulin or thyroxine.

A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole.

Green olives may be preserved in brine, which is a 20-30% salt solution. How does this method prevent contamination by microorganisms? 1.High salt concentrations lower the pH, thus inhibiting the process of glycolysis. 2.Bacterial cell walls are shriveled up by salt, causing the cell to burst. 3.Bacteria can't survive in a hypertonic solution because they lose water. 4.High salt concentrations raise the pH, thus inhibiting the process of glycolysis.

Bacteria can't survive in a hypertonic solution because they lose water.

Which of the following is an accurate comparison of active transport and facilitated diffusion? 1.In both types of movement, phosphate groups alter the shape of transport proteins. 2.Active transport requires membrane proteins; facilitated diffusion does not require membrane proteins. 3.Facilitated diffusion requires the use of ATP; active transport does not require ATP. 4.Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient.

Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient.

Which of these statements describes what occurs in facilitated diffusion? 1.Facilitated diffusion requires energy from the cell to drive a concentration gradient. 2.Facilitated diffusion of solutes occurs through protein pores in the membrane. 3.Facilitated diffusion is another name for osmosis. 4.Facilitated diffusion of solutes occurs through phospholipid pores in the membrane.

Facilitated diffusion of solutes occurs through protein pores in the membrane.

Antibiotics - for example, penicillin - cannot be used to treat viral infections, such as the common cold. Why? 1.Antibiotics enhance viral function. 2.Only protease inhibitors can be used to fight viral infections. 3.Antibiotics inhibit enzymes that are essential to the survival of bacteria only. 4.They may poison the patient.

Antibiotics inhibit enzymes that are essential to the survival of bacteria only.

Taq polymerase is an enzyme isolated from the organism Thermophilus aquaticus. This organism has been found living in the hot springs of Yellowstone National Park. This enzyme is used to copy human DNA from crime scenes. Most reactions are performed at ranges similar to those of the human body; however, what considerations should be made for optimum use of this enzyme? 1.The pH should be decreased. 2.Nothing should be altered. 3.The temperature should be raised. 4.The enzyme will not work on human DNA.

The temperature should be raised.

Which of these is exhibiting kinetic energy? 1.an archer with a flexed bow 2.a space station orbiting Earth 3.a rock on a mountain ledge 4.the high-energy phosphate bonds of a molecule of ATP 5.a person sitting on a couch while watching TV

a space station orbiting Earth

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP? 1.anabolism 2.redox 3.potentiation 4.digestion 5.cellular respiration

cellular respiration

During enzymatic reactions, substrates are converted to products. A property of enzymes that facilitates this reaction is that they are catalysts and therefore _____. 1.provide activation energy for the reactions they facilitate 2.can make an endergonic reaction exergonic 3.change the rate of a reaction without being consumed by the reaction 4.are proteins

change the rate of a reaction without being consumed by the reaction

The phosphorylation of ADP to form ATP is an _____ reaction that _____ energy. 1.exergonic ... releases kinetic 2.endergonic ... releases 3.exergonic ... requires an input of 4.endergonic ... requires an input of

endergonic ... requires an input of

"Conservation of energy" refers to the fact that _____. 1.if you conserve energy you will not be as tired 2.the entropy of the universe is always increasing 3.energy cannot be created or destroyed but can be converted from one form to another 4.no chemical reaction is 100 percent efficient 5.the net amount of disorder is always increasing

energy cannot be created or destroyed but can be converted from one form to another

When considering the formation of membranes, they __________. 1.require enzymes to form into bilayer structures 2.are constructed using specialized scaffolding proteins 3.form spontaneously in aqueous environments 4.are formed under the direction of the cell's DNA

form spontaneously in aqueous environments

Which of these are by-products of cellular respiration? 1.water 2.glucose and water 3.heat and water 4.ATP and water 5.ATP

heat and water

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule? 1.entropic 2.dehydration synthesis 3.hydrolysis 4.dehydration decomposition 5.anabolism

hydrolysis

The mechanism of enzyme action is to _____. 1.change the direction of thermodynamic equilibrium 2.change endergonic into exergonic reactions 3.lower the energy of the activation of a reaction 4.create an energy barrier between substrates

lower the energy of the activation of a reaction

What name is given to the process by which water crosses a selectively permeable membrane? 1.osmosis 2.diffusion 3.pinocytosis 4.phagocytosis 5.passive transport

osmosis

The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance? 1.glucose and lactose 2.sodium and hydrogen ions 3.oxygen and carbon dioxide 4.starch and cellulose

oxygen and carbon dioxide

Chemical energy is a form of _____ energy. 1.heat 2.entropic 3.motion 4.kinetic 5.potential

potential

The molecules responsible for membrane transport are 1.proteins. 2.phospholipids. 3.steroids. 4.carbohydrates.

proteins.

When placed in a hypotonic environment, where the solute concentration is below that of the cell, a houseplant will _____. 1.go limp and lifeless 2.go brown at the edges of its leaves 3.die 4.remain standing upright

remain standing upright

The lipids in a cell membrane are arranged _____. 1.so that the hydrophilic components are arranged to face each other 2.so that the nonpolar parts of two lipids point toward each other 3.between two layers of protein 4.on either side of a single layer of protein

so that the nonpolar parts of two lipids point toward each other

Succinylcholine is structurally almost identical to acetylcholine, but if combined with the enzyme that normally hydrolyzes acetylcholine, the enzyme is no longer able to hydrolyze acetylcholine. This suggests that _____. 1.succinylcholine must regulate the activity of this enzyme by negative feedback 2.succinylcholine must be a competitive inhibitor of acetylcholine 3.the active site must have the wrong configuration to permit succinylcholine binding 4.succinylcholine must be a noncompetitive inhibitor

succinylcholine must be a competitive inhibitor of acetylcholine

What controls the direction of a molecule, such as oxygen, involved in passive transport? 1.the type of cell to or from which the oxygen molecule is moving 2.the direction of the oxygen concentration gradient 3.the amount of energy available to transport oxygen 4.the size of the oxygen molecule

the direction of the oxygen concentration gradient

The active site of an enzyme is 1.the region of an enzyme that attaches to a substrate. 2.the highly changeable portion of an enzyme that adapts to fit the substrates of various reactions. 3.the region of a substrate that is changed by an enzyme. 4.the region of a product that detaches from the enzyme.

the region of an enzyme that attaches to a substrate.

What substance is transported by aquaporins? 1.water 2.urine 3.salt 4.proteins

water

Which of the following statements is true about passive transport? 1.Passive transport requires no expenditure of cellular energy. 2.Passive transport phenomena can never reach equilibrium. 3.Passive transport operates independently of diffusion. 4.Passive transport operates independently of concentration.

Passive transport requires no expenditure of cellular energy.