Ch. 1

Question 1

All cells require oxygen to live.

Answer 1

false

Question 2

In what way are all cells alike?

Answer 2

They store their genetic instructions in DNA.

Question 3

How long ago is it estimated that the common ancestor for all of life existed?

Answer 3

Between 3.5 and 3.8 billion years ago

Question 4

Genetic change followed by selection are the fundamentals of what process?

Answer 4

Evolution

Question 5

Which statement is NOT true about the differences between liver cells and kidney cells from the same animal?

Answer 5

The different cells have different DNA.

Question 6

Which statement IS true about the differences between liver cells and kidney cells from the same animal?

Answer 6

• The different cells express different genes.

- he different cells have different roles in the body.

Question 7

What is the cell theory?

Answer 7

All cells are formed by the division of preexisting cells.

Question 8

Which of these structures cannot be resolved with a conventional light microscope?

Answer 8

Ribosome

Question 9

Which of these structures CAN be resolved with a conventional light microscope?

Answer 9

• Mitochondrion
• Bacterium
• Nucleus

Question 10

An individual ribosome can be seen with a fluorescence microscope.

Answer 10

True

Question 11

Individual atoms can be seen with an electron microscope.

Answer 11

False

Question 12

.What do eukaryotic cells have that prokaryotes lack?

Answer 12

A nucleus and other internal organelles

Question 13

.Which of the following are prokaryotes?

Answer 13

Archaea and bacteria

Question 14

At a molecular level, the members of the two domains of prokaryotes–the archaea and bacteria–differ as much from each other as either does from the eukaryotes.

Answer 14

True

Question 15

The DNA in the nucleus of eukaryotic cells is separated from the cytoplasm by the:

Answer 15

nuclear envelope.

Question 16

Which statement is NOT true of mitochondria?

Answer 16

Mitochondria are not present in plant cells.

Question 17

Which statement IS true of mitochondria?

Answer 17

• Mitochondria have an inner and outer membrane.
• Mitochondria contain their own DNA.
• Mitochondria are thought to have originated from bacteria.
• Mitochondria generate chemical energy for the cell.

Question 18

.Which statement is NOT true of chloroplasts?

Answer 18

Chloroplasts are present in essentially all eukaryotic cells.

Question 19

.Which statement IS true of chloroplasts?

Answer 19

• Each has an internal stack of membranes and is enclosed by two membranes.
• Chloroplasts contain their own DNA.
• Chloroplasts are thought to have originated from bacteria.
• Chloroplasts produce food molecules and generate oxygen.

Question 20

Which of the following organelles is an irregular maze of interconnected spaces enclosed by a membrane that functions as the site where most cell membrane components, as well as materials destined for export from the cell, are made?

Answer 20

The endoplasmic reticulum

Question 21

Which of the following organelles is a stack of flattened membrane-enclosed sacs, functioning in receiving and often chemically modifying the molecules made in the endoplasmic reticulum, and then directing them to the exterior of the cell or to various locations inside the cell?

Answer 21

The Golgi apparatus

Question 22

Which of the following organelles is a small, irregularly shaped organelle in which intracellular digestion occurs?

Answer 22

Lysosome

Question 23

What mediates the exchange of materials between the endoplasmic reticulum, Golgi apparatus, the lysosomes, and the outside of the cell?

Answer 23

Vesicles

Question 24

What is the name of the process by which eukaryotic cells engulf material captured from an external medium?

Answer 24

Endocytosis

Question 25

The largest single compartment in most cells is:

Answer 25

the cytosol.

Question 26

Which of these is NOT part of the cytoskeleton?

Answer 26

the cytosol.

Question 27

Which of these IS part of the cytoskeleton?

Answer 27

- Actin filaments - Microtubules - Intermediate filaments

Question 28

What role is NOT performed by the cytoskeleton?

Answer 28

Generating chemical energy

Question 29

What role IS performed by the cytoskeleton?

Answer 29

- Pulling duplicated chromosomes to opposite poles in dividing cells - Transporting organelles and molecules from one place to another in the cytoplasm - Controlling cell shape and cell movement

Question 30

In plant cells, a tough cell wall takes the place of a cytoskeleton.

Answer 30

False

Question 31

The cytoskeleton is one of the few permanent fixtures in the cell.

Answer 31

False

Question 32

Which organelle’s ancestor was likely engulfed by primitive eukaryotes to help the cell survive in an oxygen-rich atmosphere?

Answer 32

Mitochondrion

Question 33

Which statement is NOT true of E. coli?

Answer 33

E. coli is a model eukaryote.

Question 34

Which statement IS true of E. coli?

Answer 34

- E. coli is small, rod-shaped cell. - E. colican be grown in the laboratory - E. coli normally lives in the gut of humans and other vertebrates.

Question 35

What is NOT a reason scientists study yeast?

Answer 35

It lacks a nucleus so it is easy to genetically manipulate.

Question 36

What IS a reason scientists study yeast?

Answer 36

- It carries out all the basic tasks a eukaryotic cell must perform. - It is as closely related to animals as it is plants. - It reproduces rapidly in the lab.

Question 37

Which of the following is a model plant used by scientists?

Answer 37

Arabidopsis

Question 38

Early studies of Drosophila melanogaster showed that:

Answer 38

genes are carried on chromosomes.

Question 39

Which of the following is frequently studied as a model vertebrate?

Answer 39

Zebrafish

Question 40

Human cells are capable of surviving in a culture dish.

Answer 40

True

Question 41

.If two genes from different organisms have closely similar DNA sequences, it is highly probable that both genes descended from a common ancestral gene.

Answer 41

True

Question 42

Which term describes genes (and gene products) related by a common ancestral gene?

Answer 42

Homologous

Question 43

.DNA contains sequences that:

Answer 43

- code for proteins. - code for functional RNA molecules. - are seemingly dispensable. - regulate gene activity

Question 44

Eukaryotic cells contain multiple membrane-enclosed organelles. How might have this arrangement evolved? What evidence supports your theory?

Answer 44

One theory is that an ancestral eukaryotic cell was a predator that fed by capturing other cells. Eukaryotic cells are large and have a flexible membrane and cytoskeleton, characteristics that would allow them to chase down and devour other cells. The nuclear compartment may have evolved to keep the DNA segregated from the prey that this primitive eukaryotic cell engulfed. This eukaryotic cell may also have engulfed free-living, oxygen-consuming bacteria that later evolved into the mitochondria of modern eukaryotic cells. An early eukaryotic cell could similarly have engulfed photosynthetic bacteria that later evolved into chloroplast. An example of this predatory behavior is observed in modern protozoans, which are free-living single-celled eukaryotes that can prey upon and swallow other cells whole.

Question 45

Name three membrane-enclosed organelles and describe their respective roles in the cell.

Answer 45

The endoplasmic reticulum, or ER, is the site where most cell membrane components, as well as materials destined for export from the cell, are made. The Golgi apparatus is involved in the synthesis and packaging of molecules destined for export from the cell. It is also involved in the routing and transport of newly synthesized proteins to the correct cellular compartment. Lysosomes are the organelles in which intracellular digestion occurs. They release nutrients from food and break down unwanted molecules. Peroxisomes are vesicles that provide an enclosed environment in which hydrogen peroxide inactivates toxins. Endosomes are vesicles that sort and transport materials ingested by endocytosis.