Biology Now

Anne Houtman; Megan Scudellari; Cindy Malone

Chapter 4

Life Is Cellular - all with Video Answers

Educators

Chapter Questions

Problem 1

To be able to recognize a colony of bacteria that had grown from cells of Mycoplasma capricolum in which the DNA had been replaced by a synthetic DNA of Mycoplasma mycoides, Daniel Gibson added a _____ that coded for a blue pigment.
(a) cell
(b) chromosome
(c) gene
(d) bacterium

Sana Riaz

Sana Riaz

Numerade Educator

Problem 2

A phospholipid is a biomolecule composed of a phosphate group that is bonded to two lipid chains. Which of the following correctly describes the nature of those two components?
(a) The phosphate group is hydrophobic, and the lipid chains are hydrophilic.
(b) Both the phosphate group and the lipid chains are hydrophilic.
(c) Both the phosphate group and the lipid chains are hydrophobic.
(d) The phosphate group is hydrophilic, and the lipid chains are hydrophobic.

Sana Riaz

Numerade Educator

Problem 3

Link each process with the correct definition.

Joanna Quigley

Numerade Educator

Problem 4

Link each structure with the correct function.

Joanna Quigley

Numerade Educator

Problem 5

In the table below, indicate whether the specified cellular component is found in each type of cell by placing an " $\mathrm{X}^{\prime \prime}$ in the relevant columns.

Sana Riaz

Numerade Educator

Problem 6

How does the phospholipid bilayer of a liposome differ from the phospholipid bilayer of the plasma membrane of a cell?
(a) The phospholipid bilayer of a liposome contains only phospholipids, without the proteins that are embedded in the plasma membrane of a cell.
(b) The phospholipid bilayer of a liposome contains two bilayers of phospholipid molecules, whereas the plasma membrane of a cell contains only one.
(c) The phospholipid bilayer of a liposome completely envelops the liposome, whereas the plasma membrane of a cell does not completely envelop the cell.
(d) The phospholipid molecules in the phospholipid bilayer of a liposome are oriented with the lipid ends on the outside of the bilayer and the phosphate groups on the inside.

Sana Riaz

Numerade Educator

Problem 7

Examine the graph presented here. Using your knowledge of how the processes work, label each curve as representative of either simple diffusion or facilitated diffusion. Explain how you determined which curve was which.

Sana Riaz

Numerade Educator

Problem 8

Which of the following statements about transport through the plasma membrane of a cell is correct?
(a) Both passive and active transport require the input of energy.
(b) Passive transport does not require the input of energy, and active transport does.
(c) Passive transport does require the input of energy, and active transport does not.
(d) Neither active nor passive transport requires the input of energy.

Sana Riaz

Numerade Educator

Problem 9

Picture a beaker divided by a semipermeable membrane like the one in Figure 4.6. Imagine that you put 5 grams of sugar in the left side of the beaker and 10 grams of sugar in the right side, and then add water to bring both sides to the same depth. Select the correct terms in the following description of what happens next:
The water will move by osmosis to the (left side / right side) of the beaker because there are (more / fewer) molecules of solute and (more/ fewer) molecules of water on that side.

Sana Riaz

Numerade Educator

Problem 10

When the chemical oligomycin is added to cells, the production of ATP is blocked. Which of the following processes would be most affected by oligomycin?
(a) simple diffusion
(b) facilitated diffusion
(c) active transport
(d) All of these processes would be equally affected by oligomycin.
(e) None of these processes would be affected by oligomycin.

Sana Riaz

Numerade Educator

Problem 11

Use the accompanying image to select the correct terms in the statements below each of the cells shown.

(a) This red blood cell is in a(n) (hypertonic / hypotonic / isotonic) solution.
(b) In this environment, normal red blood cells (gain / lose / neither gain nor lose) water.
(c) The total solute concentration outside the cell is (lower than / higher than / equal to) the total solute concentration inside it.

(d) This red blood cell is in a(n) (hypertonic / hypotonic / isotonic) solution.
(e) In this environment, normal red blood cells (gain / lose / neither gain nor lose) water.
(f) The total solute concentration outside the cell is (lower than / higher than / equal to) the total solute concentration inside it.

(g) This red blood cell is in a(n) (hypertonic / hypotonic / isotonic) solution.
(h) In this environment, normal red blood cells (gain / lose / neither gain nor lose] water.
(i) The total solute concentration outside the cell is (lower than / higher than $/$ equal to ) the total solute concentration inside it.

Sana Riaz

Numerade Educator

Problem 12

Viruses display many of the characteristics of living organisms. In particular, they reproduce, creating new virus particles. During reproduction, viruses make copies of their genetic material, and some of the copies contain mutations that are beneficial to the virus. For example, HIV (human immunodeficiency virus], the virus that causes the disease AIDS (?cquired immunodeficiency ?ndrome] mutates so often that its surface proteins change faster than we can develop antiviral drugs. New drug-resistant strains of HIV are appearing constantly. However, viruses can reproduce only after entering a living cell of an organism, because viruses hijack the cell's machinery and use it to produce new viruses. Where does that combination of characteristics place viruses on the scale of nonlife to life? Are viruses living organisms? Nonliving? If neither of those categories fits the properties of viruses, how should they be classified?

Sana Riaz

Numerade Educator

Problem 13

What do you think? Did Venter create "new life" by inserting synthetic DNA copied from the genome of Mycoplasma mycoides into a cell of Mycoplasma capricolum from which the DNA had been removed? Be prepared to support your opinion in a class discussion.

Sana Riaz

Numerade Educator

Problem 14

Doing science Go to the National Science Foundation website (http://www.nsf.gov), and search for and read "Biologists Replicate Key Evolutionary Step in Life on Earth" (Press Release $12-009,$ January 16,2012 ). State the hypothesis that the biologists were testing, describe their experimental design, and explain their results. Was their hypothesis supported? What experiment do you think they should try next? State a hypothesis that you would test using their multicellular yeast samples.

Sana Riaz

Numerade Educator