CHAPTER 20 & 21 REVIEW

Name:

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

Fossil evidence of the earliest living organisms now dates back

a.	570 million years.
b.	1.4 billion years.
c.	about 3.8 billion years.
d.	more than 5 billion years.
e.	to 4004 b.c.

Many of the organic compounds essential for life, such as amino acids and nucleotides, could NOT assemble spontaneously in the presence of

a.	hydrogen.
b.	free oxygen.
c.	carbon dioxide.
d.	nitrogen.
e.	argon.

Experiments like those first performed by Stanley Miller in 1953 demonstrated that

a.	DNA forms readily and reproduces itself.
b.	many of the lipids, carbohydrates, proteins, and nucleotides required for life can form under abiotic conditions.
c.	complete, functioning prokaryotic cells are formed after approximately three months.
d.	a lipid-protein film will eventually be formed by thermal convection.
e.	all of these

The first organisms

a.	absorbed their food supplies from the organic molecules that surrounded them.
b.	were eukaryotes.
c.	utilized fermentation for energy production.
d.	utilized ATP.
e.	all of these except "were eukaryotes."

The early atmosphere

a.	was essentially the same as occurs now.
b.	was changed drastically by the liberation of oxygen following the evolution of photosynthesis.
c.	was characterized by high concentrations of oxygen and ozone.
d.	was characterized by high concentrations of inert gases before the evolution of living organisms.

Lynn Margulis and other biologists believe that

a.	the mitochondrial DNA code was a parallel but more ancient code than nuclear DNA.
b.	mitochondria were at one time separate, free-living organisms similar to bacteria, rather than organelles.
c.	mitochondria were obligate symbionts, with both the mitochondrion and the cell it inhabited benefiting from the relationship.
d.	all of these
e.	none of these

Which of the following are of the smallest size?

a.	viruses
b.	bacteria
c.	fungi
d.	protistans
e.	plants

Bacteria

a.	have cell walls composed of cellulose.
b.	reproduce primarily by conjugation.
c.	have a single chromosome.
d.	are eukaryotic.
e.	that stain Gram-negative have thick peptidoglycan cell walls.

Spherical bacteria are called

a.	bacilli.
b.	spirilla.
c.	cocci.
d.	bacteriophages.
e.	all of these

10.

The bacterium E. coli

a.	is a normal inhabitant of the human intestinal tract.
b.	produces conditions that prevent invasion by other bacteria.
c.	enhances digestion, especially of fats.
d.	produces vitamin K.
e.	all of these

11.

A virus is characterized by all but which one of the following?

a.	enzymes of respiration
b.	nucleic acid core
c.	noncellular organization
d.	protein coat

12.

Which of the following statements about viruses is true?

a.	They were the first forms of life to evolve.
b.	They do not attack plants.
c.	They are able to reproduce without using other organisms.
d.	They are made of protein only.
e.	They include some forms that are able to attack bacteria.

13.

When a virus takes over the machinery of a cell, it forces the cell to manufacture

a.	more mitochondria for energy for the virus.
b.	more liposomes to isolate themselves from water.
c.	more food particles.
d.	more viral particles.
e.	more Golgi bodies so that the cell will secrete the excess viruses.

14.

This endemic disease was declared eradicated from the earth by the WHO in 1980, however, there exists concern that it could be used as a biological weapon.

a.	HIV
b.	anthrax
c.	influenza
d.	smallpox
e.	food poisoning

15.

Sexually transmitted diseases include:

a.	syphillis
b.	chlamydia
c.	genital warts
d.	all the above
e.	only a and b