Bio 211 EvCC Pottle Chapter 5 Study Guide

You are sailing on Lake Superior from Copper Harbor, Michigan, to Isle Royale National Park. A sudden storm causes your sailboat to spring a leak. You immediately grab a bucket and begin bailing water out of the boat. Briefly explain how your predicament could be used as an analogy to help explain both active and passive transport.

If you simply let the water flow into the boat, then water will travel down its concentration gradient (into your boat) until the gradient is abolished (your boat sinks). If you want your boat to stay afloat, then you simply bail water out of the boat. In effect, you are moving water against its concentration gradient to maintain that gradient (keeping your boat afloat).

Movement across a cell membrane that requires no work from the cell

Passive transport

Which portion of the Figure 5.10 on page 84 of your textbook illustrates the second law of thermodynamics?

The portion where heat is being given off by both the cell and the car illustrates the second law of thermodynamics.

Penicillin is a drug that affects bacterial cells and not human cells. How is this possible?

This is possible because the drug is targeting a structure not found in eukaryotic cells

Every cell has a(n) __________________ that allows it to maintain a cellular environment that is separate from the environment in which it is found.

plasma membrane

Nonpolar is to diffusion as ____________ is to facilitated diffusion.

polar

Diffusion of water across a selectively permeable membrane

Osmosis

The phosphorylation of ADP creates ______________

ATP

Competitive inhibitors

Bind directly to the active site of an enzyme and inhibit the binding of the proper substrate.

Noncompetitive inhibitors

Bind to a location on the enzyme other than the active site and cause a change in the enzyme's active site. This keeps the enzyme from binding to the proper substrate.

When there exists a difference in the amount of a substance across a distance

Concentration gradient

Potential energy

Description - Energy associated with a substance that can be converted to kinetic energy Example - A candy bar

Kinetic energy

Description - The energy of motion Example - Solar energy

Exocytosis and endocytosis both ____________

Don't deal with gradients. They both deal in the specialized transport of large substances or large amounts of substances

Hypotonic solution

Effect on an animal cell if placed in a(n) - Lyse Effect on a plant cell if placed in a(n) - Turgid Each term refers to - A solution that has less solute than the solution it is being compared to

Isotonic solution

Effect on an animal cell if placed in a(n) - Normal Effect on a plant cell if placed in a(n)- Flaccid Each term refers to - Two solutions that have the same solute concentrations

Hypertonic solution

Effect on an animal cell if placed in a(n) - Shrivel Effect on a plant cell if placed in a(n) - Shriveled Each term refers to - A solution that has more solute than the solution it is being compared to

A reaction that requires an input of energy

Endergonic reaction

Facilitated diffusion -- is energy required from the cell and is a description

Energy required: No Description: Diffusion of a substance down its concentration gradient through a transmembrane protein channel within the plasma membrane

Osmosis -- is energy required from the cell and is a description

Energy required: No Description: The diffusion of water across a semipermeable membrane

Diffusion -- is energy required from the cell and is a description

Energy required: No Description: The movement of a substance from an area of high concentration to an area of low concentration

A reaction that gives off energy

Exergonic reaction

In pole vaulting, the higher the bar is placed, the more difficult it is to clear it. Explain why this is a good analogy to help students understand enzymes and activation energy.

In this analogy, the bar represents the activation energy necessary for the reaction to occur. The higher the bar, the harder it is to jump. The more activation energy that is required, the harder it will be for the reaction to occur.

In the following reaction, what is the enzyme Lactose → Glucose + Galactose

Lactase

A series of reactions that either build or break down a molecule

Metabolic pathway

The sum of all chemical reactions in an organism

Metabolism

Sucrase is the enzyme that breaks down sucrose into glucose and fructose. Will sucrose also catalyze the breakdown of the disaccharide maltose? Briefly explain your answer.

No, because maltose will have a different structure than sucrose and so it will not fit into the active site of sucrase.

Movement of a substance from high to low concentration

Simple diffusion

Use Figure 5.15B on page 89 of your textbook to answer this question. Assume that a toxin is introduced to the cell that binds to and removes substance C from the pool of molecules par- ticipating in the reaction. Briefly explain what would happen to the amount of substance B.

The amount of substance B would increase because there would no longer be any feedback inhibition.

Dr. Agre's research into aquaporins hinged on two key observations. List both observations.

The antibody they made did not bind to any part of the Rh antigen and the antibody bound to red blood cells in large quantities.

Endocytosis

The movement of bulk substances into the cell.

Exocytosis

The movement of bulk substances outside the cell.

hat feature does diffusion, osmosis, and facilitated diffusion all share?

They are all types of passive transport.

Noncompetitive inhibitors and competitive inhibitors both ____________

They both work to inhibit the activity of enzymes.

Biologists have described a cell's plasma membrane as being a fluid mosaic. Briefly explain why this is an accurate description.

This is an accurate description because a plasma membrane is made of multiple types of mol- ecules with many different functions (the mosaic) and the molecules are in constant motion around each other (fluid).

A cell pumps certain ions against their concentration gradient to maintain those gradients. What type of cellular work is this considered?

This would be considered transport work.

True or false: Aquaporins form the specific protein channel through which water diffuses. If false, make it a correct statement.

True

True or false: The fact that all cells have a plasma membrane supports the evolutionary linkage of all life. If false, make it a correct statement.

True

The food we eat contains chemical energy. Is it possible for a candy bar to have potential en- ergy for two different reasons at the same time? Briefly explain your answer.

Yes, it is. The candy bar has potential energy because of the bonds within the molecule, but it could also have potential energy if you placed it near the edge of a table.

The graph on page 87 in your textbook illustrates the difference between a chemical reaction with and without an enzyme. Could the reaction represented by the black line still occur with- out the enzyme? Briefly explain your answer.

Yes, it would just take more energy to get the reaction started.

A chemical reaction is determined to be endergonic. If you were trying to get that reaction to occur using an additional and separate reaction, what would you do?

You could couple it to an exergonic reaction.

The energy needed to initiate a chemical reaction is the . a. activation energy b. substrate energy c. active site d. inhibition site

a.

Which of the following statements regarding transport across a plasma membrane is false? a. Passive transport requires an input of energy from the cell. b. Osmosis is the diffusion of water across a selectively permeable membrane. c. Substances always travel down their concentration gradient in passive transport. d. Facilitated diffusion requires a specific transport protein found in the membrane.

a.

Anything that inhibits ATP synthesis in a cell would most likely a. force the cell to use ADP as an energy source. b. result in the death of the cell. c. make the cell start using lipids as energy. d. cause the cell to stop doing mechanical work but not transport work.

b.

Which of the following best describes the structure of a plasma membrane? a. Proteins sandwiched between two layers of phospholipids b. Proteins embedded in two layers of phospholipids c. A layer of protein on top of a layer of phospholipids d. Phospholipids sandwiched between two layers of protein

b.

The relationship between an enzyme's active site and its substrate is most like which of the following? a. A comb and hair b. A car and a driver c. A scarf and a hand d. A key and a lock

d.

Energy is never created or destroyed. What happened to the energy that was stored in your gas tank after your lawnmower comes to a stop as a result of running out of gas? a. The energy was lost. b. Entropy decreased in the universe. c. It was converted to heat. d. The lawnmower gained energy.

c.

In contrast to passive transport, active transport pumps a substance ____________ its gradient.

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