Bio Exam Chapter 5 PLQ

Most cellular work is accomplished by _____ energizing molecules by _____ them.

ATP ... phosphorylating

Which of the following is a difference between active transport and facilitated diffusion?

Active transport requires the expenditure of cellular energy, and facilitated diffusion does not.

Frequently, transplanted organs are rejected by the recipient's body. How is this reaction related to plasma membranes?

Each person has a unique set of carbohydrate chains attached to his or her plasma membranes.

Which of the following statements is true about passive transport?

Passive transport requires no expenditure of cellular energy.

Cellular respiration is an example of __________.

an exergonic process

The phosphorylation of ADP to form ATP is an _____ reaction that _____ energy.

endergonic ... requires an input of

The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance?

oxygen and carbon dioxide

The transport of molecules of a particular solute from inside an animal cell across the cell membrane to the extracellular fluid always requires energy when _____.

the concentration of the solute is lower inside the cell than outside it

What substance is transported by aquaporins?

water

In the figure below, working from the inside out, what would be the order of components observed?

water, hydrophilic head, hydrophobic tail, hydrophobic tail, hydrophilic head, water

Which of these statements describes what occurs in facilitated diffusion?

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

Macrophages are white blood cells that roam the body searching for invading microbes. Inside macrophage vacuoles these invaders are destroyed. How do the microbes get inside the macrophages?

Microbes are engulfed into the macrophage via phagocytosis.

During enzymatic reactions, substrates are converted to products. A property of enzymes that facilitates this reaction is that they are catalysts and therefore _____.

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

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via _____.

endocytosis

What condition might result from an excess of aquaporins?

fluid retention in pregnant women

Which of the following enables a cell to pick up and concentrate a specific kind of molecule?

receptor-mediated endocytosis

The first law of thermodynamics _____.

states that energy is neither created nor destroyed

Which statement best describes phagocytosis?

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

Cells A and B are the same size and shape, but cell A is metabolically quiet and cell B is actively consuming oxygen. Oxygen will diffuse more quickly into cell _____ because _____.

B ... the diffusion gradient there is steeper

Review the figure below of passive transport, then choose one of the following statements as being descriptive of this process.

Passive transport can transport molecules without the assistance of proteins from an area of high concentration to an area of lower concentration.

The movement of atoms, ions, or molecules from a region of higher concentration to regions of lower concentration is called _____.

diffusion

When placed in a hypotonic environment, where the solute concentration is below that of the cell, a houseplant will...

remain standing upright

Which of the following is an example of the second law of thermodynamics?

The aerobic respiration of glucose generates heat.

Utah's Great Salt Lake has an average salinity seven times higher than that of the oceans. Very few multicellular organisms live in this harsh environment. An example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. These brine shrimp must _____.

actively pump water back into their cells to counter its loss due to osmosis

The mechanism of enzyme action is to _____.

lower the energy of the activation of a reaction

The lipids in a cell membrane are arranged _____.

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

Green olives may be preserved in brine, which is a 20-30% salt solution. How does this method prevent contamination by microorganisms?

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

When considering the formation of membranes, they __________.

form spontaneously in aqueous environments

The diffusion of water across a selectively permeable membrane is called __________.

osmosis

According to the second law of thermodynamics, which of the following is true?

The ordering of one system depends on the disordering of another.

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?

The temperature should be raised.

Lactase is essential for digesting lactose in milk. This enzyme is specific for this sugar. Why?

There is a precise compatibility between the active site and the lactose molecule.

The concentration of solutes in a red blood cell is about 2%. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?

a hypertonic sucrose solution

When in solution, a molecule that moves slowly across an artificial membrane moves rapidly across a plasma membrane. This molecule rapidly enters the cell regardless of whether its concentration is higher inside or outside the cell. Using this information, which transport mechanism is most likely to be responsible for the movement of the molecule across a plasma membrane?

active transport

Fluidity of an animal cell plasma membrane is enhanced by __________.

cholesterol molecules - At low temperatures, cholesterol hinders solidification of the cell membrane b/c it prevents the close packing of phospholipids.

What controls the direction of a molecule, such as oxygen, involved in passive transport?

the direction of the oxygen concentration gradient. The direction material moves in passive transport is determined solely by the material's concentration gradient, with material diffusing from regions of higher concentration to regions of lower concentration.

A reaction is designated as exergonic rather than endergonic when _____.

the potential energy of the products is less than the potential energy of the reactants