Chapter 1: The Cell (Kaplan)

Question 1

Because prokaryotes do not form multicellular organisms, each bacterium is responsible for protecting itself from the environment. The ____ ____ forms the outer barrier of the cell.

Answer 1

cell wall

p. 18

Question 2

Prokaryotes
After the cell wall, the next layer is the cell _______ (aka ______ ________), which is composed of phospholipids, similar to that of a eukaryote. Together, the cell wall and the cell membrane are known as the ________.

Answer 2

membrane
plasma membrane
envelope

p. 18

Question 3

In bacteria, there are 2 main types of cell walls: gram positive and gram negative. The type of cell wall is determined by the Gram staining process: a _______ ______ stain, followed by a counterstain with a substance called ________.

Answer 3

crystal violet stain
safranin

p. 19

Question 4

In regards to Gram staining…..
If the envelope absorbs the crystal violet stain, it will appear deep ______, and the cell is said to be gram positive. If the envelope does not absorb the crystal violet stain, but absorbs the safranin counterstain, the the cell will appear _______, and the cell is said to be gram negative.

Answer 4

purple
pink-red

p. 19

Question 5

Gram-positive cell walls consist of a thick layer of _____________, a polymeric substance made from amino acids and sugars.
In addition to this, the gram-positive cell wall also contains ___________ acid. It is not clear what role this acid serves for the bacterium, but the human immune system may be activated by exposure to these chemicals.

Answer 5

peptidoglycan
lipoteichoic acid

p. 19

Question 6

Gram-negative cell walls are very thin and also contain peptidoglycan, but in much smaller amounts. The peptidoglycan cell walls of these bacteria are adjacent to the cell membrane, and are separated from the membrane by the ___________ space. In addition the cell wall and cell membrane, gram-negative bacteria also have outer membranes containing phospholipids and ___________________. Interestingly, these feature is the part of the gram-negative bacteria that triggers an immune response in human beings, and accounts for the stronger inflammatory response caused by gram-negative bacteria compared to gram-positive bacteria.

Answer 6

periplasmic

lipopolysaccharides

p. 19

Question 7

Define chemotaxis.

Answer 7

The ability of a cell to detect chemical stimuli and move toward or away from it in response.

p. 19

Question 8

Prokaryotic flagella
The filament is a hollow, helical structure composed of _________. The basal body is a complex structure that anchors the flagellum to the cytoplasmic membrane and is also the motor of the flagellum, which rotates at rates up to ___ Hz.
(Remember that Hz are a unit of _________.)
The hook connects the ________ and the _____ ____ so that, as the basal body rotates, it exerts torque on the filament, which thereby spins and propels the bacterium forward.

Answer 8

flagellin
300 Hz
frequency

filament
basal body

p. 19

Question 9

Do archaea also contain flagella?

Answer 9

yes, but their structure is quite different from bacteria

Question 10

Prokaryotes may carry DNA acquired from external sources on smaller circular structures known as ________.

Answer 10

plasmids

p. 20

Question 11

If prokaryotes lack mitochondria, how do they make ATP?

Answer 11

the cell membrane is used for the electron transport chain and generation of ATP.

p. 20

Question 12

Prokaryotes also contain ribosomes, but they are a different size from eukaryotes. Prokaryotic ribosomes contain ___ and ___ subunits, whereas eukaryotic ribosomes contain ___ and ___ ribosomes.

Answer 12

30S and 50S

40S and 60S
(Remember that prokaryotes are weird or odd, thus their ribosome type starts with an odd digit - 3 and 5.)

p. 20

Question 13

Can OBLIGATE AEROBES survive if oxygen is present?
Carry out aerobic metabolism?
Can they survive if oxygen is absent?
Can they carry out anaerobic metabolism?

Answer 13

Yes
Yes
No
No

p. 21

Question 14

Can FACULTATIVE ANAEROBES survive if oxygen is present?
Carry out aerobic metabolism?
Can they survive if oxygen is absent?
Can they carry out anaerobic metabolism?

Answer 14

Yes
Yes
Yes
Yes

Question 15

Can OBLIGATE ANAEROBES survive if oxygen is present?
Carry out aerobic metabolism?
Can they survive if oxygen is absent?
Can they carry out anaerobic metabolism?

Answer 15

No
No
Yes
Yes

Question 16

Can AEROTOLERANT ANAEROBES survive if oxygen is present?
Carry out aerobic metabolism?
Can they survive if oxygen is absent?
Can they carry out anaerobic metabolism?

Answer 16

Yes
No
Yes
Yes

Question 17

Why can binary fission proceed more rapidly than mitosis?

Answer 17

It requires fewer events.

p. 25

Question 18

Many bacteria also contain extrachromosomal (extra_______) material known as plasmids. These often carry genes that impart some benefit to the bacterium, such as antibiotic resistance. A subset of plasmids called ________ are capable of integrating into the genome of the bacterium.

Answer 18

extragenomic
episomes

p. 26

Question 19

Bacterial genetic ____________ helps increase bacterial diversity and thus permits evolution of a bacterial species over time. These recombination processes include transformation, conjugation, and transduction.

Answer 19

recombination

p. 27

Question 20

Section: bacterial genetic recombination
Transformation results from the integration of ______ ________ material into the host genome.
This may happen when a bacterium lyses and spills its contents into the vicinity of a bacterium capable of transformation.

Answer 20

foreign genetic

Question 21

What is the bacterial form of mating (sexual reproduction)?

Answer 21

conjugation

Question 22

Section: bacterial genetic recombination

What is the only genetic recombination process that requires a vector? How does this happen?

Answer 22

transduction occurs when a virus carries genetic material from one bacterium to another

Question 23

What is the term for a virus that infects bacteria?

Answer 23

bacteriophage

p. 28

Question 24

What is a genetic element that is capable of inserting and removing itself from the genome?

Answer 24

transposon

Question 25

Bacterial growth occurs in phases. In a new environment, bacteria first adapt to the new local conditions during the ___ phase. As the bacteria adapt, the rate of division increases, causing an exponential increase in the number of bacteria in the colony during the __________ phase aka ___ phase. As the number of bacteria in the colony grows, resources are often reduced. The reduction of resources slows reproduction, and the __________ phase results. After they have exceeded the ability of the environment to support the number of bacteria, a _____ phase occurs, marking the depletion of resources.

Answer 25

lag phase
exponential phase/ log phase
stationary phase
death phase

p. 29

Question 26

How large are viruses?

For reference, how large are prokaryotic cells? Eukaryotic cells?

Answer 26

20 nm - 300 nm
1 - 10 um (micrometer) —> eukaryotes are 10 - 100 um

p. 31

Question 27

Viruses are composed of genetic material, a protein coat (aka capsid), and sometimes an envelope containing lipids. Their genetic information may be….

Answer 27

….circular or linear, single- or double-stranded, and DNA or RNA.

Question 28

Why are enveloped viruses easier to kill?

Answer 28

bc the envelope is very sensitive to heat, detergents, and desiccation.

Question 29

Because viruses cannot reproduce independently, they are considered….

Answer 29

….obligate intracellular parasites.

Question 30

Why can’t viruses reproduce on their own?

Answer 30

They lack ribosomes to carry out protein synthesis.

Question 31

Bacteriophages do not actually _____ bacteria; they inject their genetic material with their ____ ______ which acts like a syringe. The tail fibers (“spider legs”) help the bacteriophage recognize and connect to the correct host cell.

Answer 31

enter
tail sheath

p. 31-32

Question 32

Single-stranded RNA viruses may be positive _____ or negative _____.

Answer 32

sense

sense

Question 33

Section: viral genomes
Positive sense implies that the genome may be directly translated to functional proteins by the ribosomes of the host cell, just like ____.

Answer 33

mRNA.

Question 34

Section: viral genomes
Negative sense RNA viruses require that the negative-sense RNA strand act as a ________ for synthesis of a ___________ strand, which can then be used as a template for protein synthesis. Negative sense RNA viruses must carry an ___ _________ in the virion to ensure that the complementary strand is synthesized.

Answer 34

template
complementary
RNA replicase

p. 32

Question 35

Retroviruses are enveloped, _____-stranded RNA viruses in the family ___________.

Answer 35

single-stranded

Retroviridae

Question 36

Retrovirus virions contain two identical RNA molecules. These viruses carry an enzyme known as _______ _____________, which synthesizes DNA from single-stranded RNA. The DNA then integrates into the host cell genome, where it is replicated and transcribed as if it were the host cell’s own DNA. This is a clever mechanism because the integration of the genetic material into the host cell genome allows the cell to be infected indefinitely, so the only way to remove the infection is to kill the infected cell. This is why ___ is so difficult to treat.

Answer 36

reverse transcriptase

HIV

p. 32

Question 37

The 3 overarching domains into which all life is classified are:

Answer 37

Archaea
Bacteria
Eukarya

p. 15

Question 38

Initially, archaea and bacteria were classified together into the kingdom of ______.

Answer 38

Monera

p. 15

Question 39

How are archaea similar to bacteria?

Answer 39

they are single-celled and visually similar to bacteria.
They contain a single circular chromosome, and divide by binary fission or budding.

p. 15

Question 40

How are archaea similar to eukaryotes?

Answer 40

They contain genes and several metabolic pathways that are more similar to eukaryotes than to bacteria.
They both start translation with methionine, contain similar RNA polymerases, and associate their DNA with histones.

p. 15

Question 41

Some archaea are photosynthetic, but many are __________ and can generate energy from inorganic compounds, including sulfur- and nitrogen-based compounds such as ammonia.

Answer 41

chemosynthetic

p. 15

Question 42

Bacteria in the human gut produce vitamin _ and ______ (vitamin __).

Answer 42

K
biotin (vitamin B7)

p. 16

Question 43

Name an example of a bacterial pathogen that lives intracellularly.

Answer 43

Chlamydia trachomatis

p. 16

Question 44

Very few pathogenic bacteria are spiral-shaped, but the 3 most common are:

Answer 44

Treponema pallidum, the cause of syphilis

Borrelia burgdorferi, the cause of Lyme disease

Leptospira interrogans, the cause of Weil’s disease

p. 18