lecture 1

Question 1

all cells have the same

Answer 1

basic chemistry

Question 2

all cells today evolved from the same

Answer 2

ancestral cell

Question 3

cells can vary — and —

Answer 3

morphologically (structurally)
physiologically (functionally)

Question 4

ancestral cells occurred — yrs ago

Answer 4

3.5-3.8 billion

Question 5

what causes divergent descendants of the ancestral cell?

Answer 5

interplay between mutation and natural selection

Question 6

3 reasons that cells are so small

Answer 6

1. the more volume the cell has in the cytoplasm, the longer it will take for messages to travel
2. surface area to volume ratio; if a cell grows beyond a certain size, it will not be able to take up enough nutrients/oxygen through its surface to support cell activity
3. diffusion; as the cell becomes bigger, the distance travelled becomes larger and time of travel increases

Question 7

outside the cell, a virus exists as a

Answer 7

particle (or virion)

Question 8

are viruses alive?

Answer 8

no, viruses are not considered as organisms or to be alive

they are unable to reproduce, metabolize or carry out any of the activities associated with life

Question 9

most complex type of virus

Answer 9

bacterial viruses (or bacteriophages)

Question 10

what does each virus have on its surface?

Answer 10

a protein that is able to bind to a particular component of its host cell

Question 11

the movement of a prokaryotic cell is accomplished by the

Answer 11

flagellum (protein filament)

Question 12

prokaryote taxonomic groups

Answer 12

1. Archaea (archaeabacteria); more related to eukaryotes
2. Bacteria (eubacteria)

Question 13

provirus

Answer 13

=integrated viral DNA
the infecting virus integrates its DNA into the DNA of the host cell’s chromosome

Question 14

3 effects of an integrated provirus

Answer 14

Bacterial cells containing a provirus behave normally until exposed to a stimulus, such as ultraviolet radiation, that activates the dormant viral DNA, leading to the lysis of the cell and release of viral progeny.

Some animal cells containing a provirus produce new viral progeny that bud at the cell surface without lysing the infected cell. Human immunodeficiency virus (HIV) acts in this way; an infected cell may remain alive for a period, acting as a factory for the production of new virions.

Some animal cells containing a provirus lose control over their own growth and division and become malignant. This phenomenon is readily studied in the laboratory by infecting cultured cells with the appropriate tumor virus.

Question 15

origin of the eukaryotic cell?

Answer 15

prokaryotic cells arose before eukaryotic cells and gave rise to eukaryotic cells