1406 Bio Chp 7 follow up

In the equation, C6H12O6 is a __________.

product

In the equation, the CO2 is a _______.

reactant

A cell has a membrane potential of -100 mV (more negative inside than outside) and has 1,000 times more calcium ions outside the cell than inside. Which of the following best describes a mechanism by which Ca2+ enters the cell?

) facilitated diffusion of Ca2+ into the cell down its electrochemical gradient Both the electrical and chemical (concentration) gradients contribute the energy to move Ca2+ into the cells by facilitated diffusion as long as there is a channel or carrier that is specific for Ca2+.

The internal solute concentration of a plant cell is about 0.8 M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?

1.0M This solution is hypertonic to the plant cell. Water will leave the cell, and eventually the plasma membrane will pull away from the cell wall, resulting in plasmolysis.

Green olives may be preserved in brine, which is a 30% salt solution. How does this method of preservation prevent microorganisms from growing in the olives?

A 30% salt solution is hypertonic to the bacteria, so they lose too much water and plasmolyze. f a cell is placed in a hypertonic solution, it will lose water to its environment, shrivel, and probably die.

Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B. and cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________.

B; the diffusion gradient in cell B is steeper As long as a metabolically active cell converts oxygen to water during cellular respiration shortly after it enters, diffusion into the cell will continue because the concentration gradient favors movement in that direction.

Which of the following statements about a typical plasma membrane is correct?

Because the membrane serves different functions on the cytoplasmic and exterior surfaces, the structure and composition of the surfaces must be different.

Seawater is hypertonic to cytoplasm in vertebrate cells and in plant cells. If a red blood cell and a plant cell were placed in seawater, what would happen to the two types of cells?

Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.

Which of the following statements about cotransport of solutes across a membrane is correct?

Cotransport proteins allow a single ATP-powered pump to drive the active transport of many different solutes. The electrochemical gradient created by a single ATP-dependent pump can drive the transport of many different solutes using cotransport proteins.

Glucose can be moved into cells via an active transport mechanism when the concentration of glucose inside the cell is higher than the concentration of glucose outside of the cell. This active transport mechanism moves glucose and sodium into the cell at the same time. The glucose moves up its gradient and the sodium moves down its gradient. Which of the following statements about this mechanism is accurate?

Glucose can be moved into cells via two mechanisms. An active transport mechanism can be used when the concentration of glucose inside the cell is higher than the concentration of glucose outside of the cell. This active transport mechanism moves glucose and sodium into the cell at the same time. The glucose moves up its gradient and the sodium moves down its gradient. Which of the following statements about this mechanism is most true? To pump glucose up its concentration gradient, sodium is moving down its concentration gradient and the sodium forms an electrochemical gradient in this mechanism. The protein that moves the sodium and glucose into the cell is an antiporter. To pump glucose up its concentration gradient, sodium is moving down its concentration gradient. The sodium forms an electrochemical gradient in this mechanism. All of these are true The movement of sodium down its gradient drives glucose up its gradient, and because sodium is at different concentrations on either side of the membrane and as sodium has a +1 charge, an electrochemical gradient also exists.

A plant cell surrounded by a(n) ___ solution will be flaccid (limp).

Isotonic

The ideal osmotic environment for an animal cell is a(n) ____ environment.

Isotonic

For good health, you don't want your body to run the LDL part of this diagram faster than the HDL part because ...

LDL cholesterol is stored; HDL cholesterol is destroyed: is LDL exceeds HDL, your body is probably storing excess cholesterol which may clog the arteries and cause heart disease

A selectively permeable membrane separates two solutions. Water is able to pass through this membrane; however, sucrose (a disaccharide) and glucose (a monosaccharide) cannot pass. The membrane separates a 0.2-molar sucrose solution from a 0.2-molar glucose solution. With time, how will the solutions change?

Nothing will happen, because the two solutions are isotonic to one another. Osmotic pressure is produced by the concentration of dissolved substances and is not influenced by the relative sizes of the solutes.

Consider the transport of protons and sucrose into a plant cell by the sucrose-proton cotransport protein. Plant cells continuously produce a proton gradient by using the energy of ATP hydrolysis to pump protons out of the cell. Why, in the absence of sucrose, do protons not move back into the cell through the sucrose-proton cotransport protein?

The movement of protons through the cotransport protein cannot occur unless sucrose also moves at the same time. The obligate coupling of proton movement to sucrose movement prevents the energy of the proton gradient from being lost if sucrose is not present

Active transport requires an input of energy and can also generate voltages across membranes. Based on this information, which of the following statements is true?

The sodium/potassium pump hydrolyzes ATP and results in a net charge of +1 outside the cell membrane.

A single plant cell is placed in an isotonic solution. Salt is then added to the solution. Which of the following would occur as a result of the salt addition?

Water would leave the cell by osmosis, causing the volume of the cytoplasm to decrease.

The concentration of solutes in a red blood cell is about 2%, but red blood cells contain almost no sucrose or urea. 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

6 CO2 + 6 H2O → C6H12O6 + 6 O2 the equation shows a _____ -- the breaking and forming of chemical bonds that leads to a change in the composition of matter

chemical reaction

Based on Figure 7.18 in your textbook, which of these experimental treatments would increase the rate of sucrose transport into the cell?

decreasing extracellular ph

The number of oxygen atoms on the left side of the equation is ____________ the number of oxygen atoms on the right side.

equal to

What does cholesterol have in common with sex hormones?

four linked rings

A plant cell placed in a(n) ___ solution will lose water and plasmolyze.

hypertonic

There is a net diffusion of water out of an animal cell when it is placed in a(n) ___ solution.

hypertonic

An animal cell placed in a(n) ____ solution will gain water, swell, and possibly burst.

hypotonic

The ideal osmotic environment for a plant cell is a(n) ___ environment.

hypotonic

In O2, the type of bond that holds the two oxygen atoms together is a ____________.

nonpolar covalent bond

passive transport includes

osmosis transport of an ion down its electrochemical gradient facilitated diffusion diffusion of a solute across a membrane

he presence of aquaporins (proteins that form water channels in the membrane) should

speed up the process of osmosis