Deck 4: A Field Guide to the Microorganisms

Question 1

The feeding and reproducing stage of many protozoa is known as a:

A) trophozoite.
B) cyst.
C) vector.
D) protista.
E) mastigophora.

Answer 1

A

Question 2

What are mycorrhizial relationships? Provide an example.

Answer 2

Mycorrhizal associations are relationships between plant roots and associated fungi that grow on the roots. Because both the plant and the fungus benefits from the relationship, this is an example of a mutualistic relationship. In the Zygomycota, the fungus supplies the plant with phosphorus, while the fungus obtains necessary sugars from the plant. Basidiomycota also frequently form mycorrhizal associations, in which the plant obtains nitrogen from the fungus in return for sugars provided by the plant.

Question 3

How are rRNA genes used to deduce evolutionary relationships?

Answer 3

All genes experience mutations (changes in their nucleotide sequences) over time. Ribosomal RNA (rRNA) genes mutate slowly and at a fairly constant and predictable rate. By comparing the nucleotide sequence in rRNA genes of any two species, scientists can deduce how long ago the two species shared a common ancestor. Only after the common ancestor split into separate lineages will rRNA mutations accumulate independently in different lineages. Consequently, many differences in the rRNA genes between two species indicate that they diverged long ago. Fewer differences indicate a more recent common ancestor, meaning that the organisms being compared are more closely related.

Question 4

The bacteria that causes diphtheria is called corynebacterium diphtheria. Which of the following has the name of this bacterial species written in proper scientific form?

A) corynebacterium diphtheria
B) Corynebacterium Diphtheria
C) Corynebacterium diphtheria
D) corynebacterium Diphtheria

Question 5

Which of the following statements is true about archaea?

A) They are in the domain Bacteria.
B) They have cells walls identical to those of bacteria.
C) They have eukaryotic cells.
D) They often are found in extreme environments.
E) All known archaea require oxygen for survival.

Question 6

Which of the following are the most closely related?

A) Two animals that are in the same phylum
B) Two plants that are in the same class
C) Two fungi that are in the same order
D) Two bacteria that are in the same family

Question 7

Which of the following is true about viral penetration?

A) All non-enveloped and enveloped viruses enter host cells via endocytosis.
B) All non-enveloped and enveloped viruses enter host cells via fusion.
C) All non-enveloped viruses enter cells by endocytosis. All enveloped viruses enter cells by fusion.
D) All non-enveloped viruses enter cells by fusion. All enveloped viruses enter cells by endocytosis.
E) Non-enveloped viruses enter cells by endocytosis. Some enveloped viruses also enter by endocytosis, while others enter by fusion.

Question 8

The classification of living things according to their evolutionary relationships is called:

A) taxonomy.
B) phylogenetics.
C) taxonomic hierarchy.
D) the five-kingdom system of classification.
E) the three-domain system of classification.

Question 9

In which of the following ways are prions believed to differ from all other infectious agents?

A) Unlike any other infectious agents, they are acellular.
B) Unlike any other infectious agents, they can infect many different species of hosts.
C) Unlike any other infectious agents, are able to reproduce without any nucleic acid.
D) Prions appear to be unusual viruses that have both DNA and RNA.
E) Unlike other infectious agents, which are found only in specific host tissues, prions have the ability to infect any tissue in a host's body.

Question 10

Viruses go through a series of defined steps in their replicative cycle. In which of the following are these steps listed in proper order?

A) attachment » uncoating » penetration » synthesis » release » assembly
B) penetration » attachment » uncoating » assembly » synthesis » release
C) uncoating » attachment » penetration » synthesis » assembly » release
D) attachment » penetration » uncoating » synthesis » assembly » release
E) penetration » synthesis » assembly » attachment » release » uncoating

Question 11

Which of the following is true about photosynthetic bacteria?

A) They are the most primitive of all bacteria.
B) Photosynthesis appears to have evolved several separate times.
C) Photosynthetic bacteria all appear to be closely related.
D) A comparison of rRNA genes in different lineages of photosynthetic bacteria would reveal that the genes are almost identical in all lineages.
E) All photosynthetic bacteria appear to have evolved relatively recently.

Question 12

What is different about the synthesis stage in a plus- and a minus-strand RNA virus?

Question 13

Fungi that grow on dead material are called:

A) autotrophs.
B) saprophytes.
C) filamentous fungi.
D) fleshy fungi.
E) Zygomycota.