Chapter 4 Homework

In your own words and with your own examples, explain fully how cells are limited in size and how some cells have modifications that allow them to be larger or more adapted to a particular function in spite of these limitations.

A cells size and functional ability is limited by its surface/volume ratio. Lets take a blue whale for our example. Although the majority of the cells are comparable in size, the nerve cells are the exception. The axons are greatly elongated due to the vast size difference in a human versus a blue whale.

Why do you suppose that viral illnesses are more difficult to treat than bacterial illnesses? a. Because viruses have fewer components and thus fewer targets than bacteria. b. Because viral enzymes are more pathogenic to the host cells than bacterial. c. Because viruses can affect all types of cells. d. Because viruses do not have their own metabolism and are fed by the host cell.

a. Because viruses have fewer components and thus fewer targets than bacteria.

Match the organelle to its function: central vacuole

turgor Pressure

Prokaryotes have ____ ribosomes with ____ and ____ subunits, whereas eukaryotes have ____ ribosomes with ____ and ____ subunits. a. 70S, 50S, 30S; 80S, 60S, 40S b. 80S, 60S, 40S; 70S, 50S, 30S c. 80S, 50S, 30S; 100S, 60S, 40S d. 70S, 40S, 30S; 80S, 50S, 30S e. 100S, 60S, 50S; 90S, 60S, 40S

a. 70S, 50S, 30S; 80S, 60S, 40S

Suggest a way to distinguish between the two elements in each of the following pairs: Rough ER; smooth ER a. Look for the presence of ribosomes, which are found on rough ER but not on smooth ER. b. Look for the presence of ribosomes, which are found on smooth ER but not on rough ER. c. Look for the presence of cisternae, which are found in smooth ER but not in rough ER. d. Look for the presence of cisternae, which are found in rough ER but not in smooth ER.

a. Look for the presence of ribosomes, which are found on rough ER but not on smooth ER.

For each of the following false statements, change the statement to make it true. DNA is found only in the nucleus of a cell. a. DNA is found not only in the nucleus of a eukaryotic cell but also in the mitochondria and, if present, in the vacuoles. b. DNA is found not only in the nucleus of a eukaryotic cell but also in the ribosomes and, if present, in the chloroplasts c. DNA is found not only in the nucleus of a eukaryotic cell but also in the mitochondria and, if present, in the chloroplasts. d. DNA is found not only in the nucleus of a eukaryotic cell but also in the ribosomes and, if present, in the vacuoles.

c. DNA is found not only in the nucleus of a eukaryotic cell but also in the mitochondria and, if present, in the chloroplasts.

Suggest a way to distinguish between the two elements in each of the following pairs: Viruses; viroids a. Look for the presence of a capsid (lipid coat); a viroid has an external lipid layer, whereas a virus does not. b. Look for the presence of a capsid (lipid coat); a virus has an external lipid layer, whereas a viroid does not. c. Look for the presence of a capsid (protein coat); a virus has an external protein layer, whereas a viroid does not. d. Look for the presence of a capsid (protein coat); a viroid has an external protein layer, whereas a virus does not.

c. Look for the presence of a capsid (protein coat); a virus has an external protein layer, whereas a viroid does not.

Match the organelle to its function Nucleus

Information Center

The ____ are prokaryotes that resemble bacteria in size and cell division but are more similar to eukaryotes in DNA replication, transcription, RNA processing, and protein synthesis.

Archaea

Match the organelle to its function cytoskeleton

Cell shape and movement of organelles

Match the organelle to its function Peroxisome

Detoxification of hydrogen peroxide

Match the organelle to its function nucleolus

Ribosome Production

Match the organelle to its function: smooth endoplasmic reticulum

Steroid synthesis

Match the organelle to its function lysosome

Storage of hydrolase

Match the organelle to its function extracellular matrix

Support and regulation of cell properties

Match the organelle to its function Golgi Complex

Synthesis of complex Polysaccharides

Match the organelle to its function rough Endoplasmic reticulum

Synthesis of secretory proteins

Suggest a way to distinguish between the two elements in each of the following pairs: Eukaryotic ribosomes; bacterial ribosomes a. Measure the sedimentation coefficient, which is about 70S for prokaryotic ribosomes and 80S for eukaryotic ribosomes. b. Measure the sedimentation coefficient, which is about 50S for prokaryotic ribosomes and 60S for eukaryotic ribosomes. c. Measure the sedimentation coefficient, which is about 60S for prokaryotic ribosomes and 50S for eukaryotic ribosomes. d. Measure the sedimentation coefficient, which is about 80S for prokaryotic ribosomes and 70S for eukaryotic ribosomes.

a. Measure the sedimentation coefficient, which is about 70S for prokaryotic ribosomes and 80S for eukaryotic ribosomes.

Eukaryotic cells are believed to have arisen a. from a symbiotic relationship between primitive nucleated cells and bacterial cells. b. independently from prokaryotic cells. c. by mutations that lead to changes in plasma membranes, leading to internal membrane-bound organelles. d. from the fusion of multiple archaeal cells into a larger, more complex cell. e. independently from prokaryotic cells by mutations that lead to changes in plasma membranes, leading to internal membrane-bound organelles.

a. from a symbiotic relationship between primitive nucleated cells and bacterial cells.

If the surface area of a cell increases by a factor of 100, the volume of that cell will a. increase by a factor of 1000. b. increase by a factor of 10. c. increase by a factor of 100. d. remain the same. e. decrease by a factor of 100.

a. increase by a factor of 1000.

Which of the following fundamental properties of life do viruses not possess? a. metabolism and irritability b. irritability and ability to reproduce c. irritability d. ability to reproduce e. metabolism

a. metabolism and irritability

One reason that it might be difficult to separate lysosomes from peroxisomes by centrifugation techniques is that a. lysosomes are smaller than peroxisomes b. lysomsomes and peroxisomes are similar in size c. lysosomes are larger than peroxisomes d. lysosomes are bound to peroxisomes

b. lysomsomes and peroxisomes are similar in size

For each of the following false statements, change the statement to make it true. Bacteria differ from eukaryotes in having no nucleus, mitochondria, chloroplasts, or ribosomes. a. Bacteria differ from eukaryotes in having no nucleus, mitochondria, or ribosomes, but, like all cells, have chloroplasts. b. Bacteria differ from eukaryotes in having no nucleus, chloroplasts, or ribosomes, but, like all cells, have mitochondria. c. Bacteria differ from eukaryotes in having no mitochondria, chloroplasts, or ribosomes, but, like all cells, have nucleus. d. Bacteria differ from eukaryotes in having no nucleus, mitochondria, or chloroplasts, but, like all cells, have ribosomes.

d. Bacteria differ from eukaryotes in having no nucleus, mitochondria, or chloroplasts, but, like all cells, have ribosomes.

For each of the following false statements, change the statement to make it true. All the ribosomes found in a typical human muscle cell are identical. a. In a typical human muscle cell, the cytoplasmic ribosomes are either eukaryotic or prokaryotic, and the mitochondrial ribosomes are the prokaryotic type only. b. In a typical human muscle cell, the cytoplasmic ribosomes are the prokaryotic type, and the mitochondrial ribosomes are the eukaryotic type. c. In a typical human muscle cell, the cytoplasmic ribosomes are either eukaryotic or prokaryotic, and the mitochondrial ribosomes are the eukaryotic type only. d. In a typical human muscle cell, the cytoplasmic ribosomes are the eukaryotic type, and the mitochondrial ribosomes are the prokaryotic type.

d. In a typical human muscle cell, the cytoplasmic ribosomes are the eukaryotic type, and the mitochondrial ribosomes are the prokaryotic type.

Suggest a way to distinguish between the two elements in each of the following pairs: Peroxisomes; lysosomes a. Look for the presence of glyoxysome (lysosomes) versus hydrolase and other basic hydrolytic enzymes (peroxisomes). b. Look for the presence of glyoxysome (peroxisomes) versus hydrolase and other basic hydrolytic enzymes (lysosomes). c. Look for the presence of catalase (lysosomes) versus hydrolase and other acid hydrolytic enzymes (peroxisomes). d. Look for the presence of catalase (peroxisomes) versus hydrolase and other acid hydrolytic enzymes (lysosomes).

d. Look for the presence of catalase (peroxisomes) versus hydrolase and other acid hydrolytic enzymes (lysosomes).

The nucleic acid of a virus is composed of a. DNA only. b. RNA only. c. both DNA and RNA . d. either DNA or RNA but not both.

d. either DNA or RNA but not both.

Which experimental finding was critical in establishing the idea that RNA may have been the first informational molecule? a. the spontaneous formation of liposomes b. Stanley Miller's experiment that generated glycine and alanine from atmospheric gases c. All of the experiments listed helped establish that RNA could serve as an informational molecule d. the discovery of ribozymes

d. the discovery of ribozymes

When the size of a cell increases, the surface area/volume ratio a. remains the same. b. increases. c. increases initially and then begins to decrease. d. decreases initially and then begins to increase. e. decreases.

e. decreases.

Which sequence reflects the locations that a secretory protein will visit on its way from its production to its secretion outside the cell? a. rough ER, secretory vesicle, Golgi complex, ER vesicle b. smooth ER, rough ER, Golgi complex, secretory vesicle c. rough ER, Golgi complex, smooth ER, ER vesicle d. nucleus, Golgi complex, rough or smooth ER, secretory vesicle e. rough ER, ER vesicle, Golgi complex, secretory vesicle

e. rough ER, ER vesicle, Golgi complex, secretory vesicle