BIOLOGY

Question 9 of 48

3.75 Points

If an integrin protein is mutated what cell function might be affected?

A.communication between cytoskeleton and proteglycan

B.fluidity of phospholipids

C.cellular motility

D.cytoplasmic communication Reset Selection

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Question 10 of 48

3.75 Points

Buffers are important for doing experiments in labs, but they are not relevant to living systems.

True

False

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Question 11 of 48

3.75 Points

The cell theory states

A.all cells will contain DNA, all cells are the smallest living things that can divide and all organisms are composed of cells

B.all organisms are composed of multiple cells, all cells arise spontaneously and all cells require nutrients

C.all cells are the smallest living things, all organisms are composed of one or more cells and all cells arise spontaneously

D.all organisms are composed of one or more cells, all cells are the smallest living things and all cells arise from other cells Reset Selection

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Question 12 of 48

3.75 Points

Hiking in the snowy woods, you peek inside a cave and encounter a hibernating grizzly bear! Its metabolic rate seems to be very low. What do you predict is the predominant type of reaction occurring in this bear?

A.fatty acid anabolism

B.carbohydrate catabolism

C.carbohydrate anabolism

D.fatty acid catabolism Reset Selection

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Question 13 of 48

3.75 Points

Rosenberg, a chemist, was observing the effects of an electric field on bacterial growth. He observed that bacteria stopped dividing when in an electric field. This research led to the anti-cancer drug cisplatin, a platinum containing compound. Rosenberg’s discovery was an example of

science.

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Question 14 of 48

3.75 Points

Enzymes are catalysts in reactions. What statements describe functions of enzymes? Select all that apply.

A. Enzymes are specific in their actions.

B. Once an enzyme binds to a substrate, it cannot be used again.

C. Enzymes lower the energy of activation needed for a reaction

D. Enzymes change the amount of free energy produced

E. Enzyme activity can be affected by temperature.

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Question 15 of 48

3.75 Points

In biological macromolecules like proteins, the hydrophobic residues tend to clump together in the interior of the folded structure. What is the best explanation for why this occurs?

A.Polar residues tend to bind to water in the cytoplasm as well as to each other. The water and polar residues cannot bind to the hydrophobic ones, so in the lowest energy state the hydrophobic residues are pushed together in the middle.

B.Protein folding machinery interprets the amino acid code to pack hydrophobic residues into the center of proteins. This process must be important, because the cell expends large amounts of ATP to precisely coordinate protein folding.

C.Hydrophobic residues bind to each other in specific ways. For instance, Ala forms di-methyl bonds, and phenylalanine binds isoleucine. This creates a tightly bound hydrophobic inner core.

D.Hydrophobic residues bind each other, while polar residues cannot bind each other. Therefore the hydrophobic ones end up stuck to each other in the core of the protein. Reset Selection

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Question 16 of 48

3.75 Points

If two solutions are different, the one will the higher concentration of solutes is

A.isotonic

B.hypertonic

C.hypotonic Reset Selection

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Question 17 of 48

3.75 Points

You are designing a museum exhibit to teach people about cells. In the entrance to the exhibit, visitors riding a moving walkway under flashing lights will gradually “shrink” down in size. To create this illusion, visitors will pass giant models of various biological parts, accompanied by scale bars.

Match each model to the appropriate scale bar to go with it.

A. 1 μm

B. 1nm

C. 10μm

D. 1cm

E. 1m

F. 0.1 nm

1. Carbon atom

2. cell nucleus

3. DNA molecule (10bp)

4. human being

5. human eyeball

6. skin cell

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Question 18 of 48

3.75 Points

The fluid mosaic model describes membranes as fluid due to

A.phospholipids sporadically placed throughout the membrane

B.the membrane is mostly composed of water

C.the proteins and the phospholipids can move laterally throughout the membrane

D.higher amounts of cholesterol

E.higher amounts of cholesterol Reset Selection

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Question 19 of 48

3.75 Points

Cholera kills over 100,000 people each year worldwide due to diarrhea. The cholera toxin opens the CFTR chloride channel in the intestines, so that sufferers lose chloride, sodium and massive amounts of water.

On the other hand, the same CFTR channel is mutated in cystic fibrosis patients. With activity too LOW, they lack chloride flow and mucus builds up in the lungs.

This illustrates the importance of precise control of channel opening, known as

____________regulation.

A.gated

B.ungated

C.passive Reset Selection

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Question 20 of 48

3.75 Points

When viewing the shape of a human cheek cell, what microscope would most likely be used?

A.light

B.dissecting

C.transmission electron

D.scanning electron Reset Selection

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Question 21 of 48

3.75 Points

At a meal, you are served a hamburger with cheese, onions, and beef on a bun. What ingredients represent the most carbohydrates? Select all that apply.

A. beef

B. bun

C. onion

D. cheese

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Question 22 of 48

3.75 Points

Estrogen and testosterone are structurally related to cholesterol. Based on what you have learned about cholesterol, predict how these steroid hormones signal to the cell.

A.They are phagocytosed, degraded, and then released into the cell.

B.They make the membrane so fluid that small pores appear, allowing them to pass through.

C.They diffuse directly through the plasma membrane and into the cell.

D.They bind to receptors on the outside of the membrane, which then activate an intracellular signaling cascade. Reset Selection

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