Study Guide: Exam 2 Ch. 18

Question 1

(a) In Fig. 18.1 of your textbook you see life divided between Archaea and Bacteria. To which one does
Eukarya belong? This is the same thing as asking: Are Archaea more closely related to Bacteria, or to
Eukarya?

Answer 1

Archaea and Eukarya are more closely related to each other.

Question 2

(b) Which are the 3 domains of life?

Answer 2

Bacteria, prokaryotic Archaea, and Eukarya

Question 3

(a) What are some of the differences between prokaryotic and eukaryotic cells?:
i. Which one has membrane-bound organelles?
ii. Which one has DNA in a nucleus?
iii. Which one has a cellular membrane which contains Peptidoglycan?

Answer 3

eukaryotic:
- i.
- ii.

neither:
iii.

Question 4

(a) What is lateral gene transfer? This is explained in Section 18.1 of the textbook, which includes a nice
figure (Fig. 18.4) that explains it clearly

Answer 4

From early in evolution to the present day, some genes have been moving “sideways” from one prokaryotic species to another, a phenomenon known as lateral gene transfer

Question 5

(a) Which group of bacteria include those that cause syphilis? This is illustrated in Fig. 18.10B of your
textbook.

Answer 5

Treponema pallidum

Question 6

(b) Which group of prokaryotes was responsible for converting Earth’s early atmosphere from anaerobic to
aerobic?

Answer 6

cyanobacteria

Question 7

(c) Is the chlorophyll of cyanobacteria similar to that of plants?

Answer 7

Yes

Question 8

(d) What are hyperthermophilic bacteria? What type of environment do they prefer? See Section 18.2 of
the textbook.

Answer 8

are another group of extremophiles, they love high temperatures.

Question 9

(a) What is the difference between autotrophs and heterotrophs? This is in Table 18.2 of your textbook.

Answer 9

autotrophs - prepare their own foods
heterotrophs - rely on other sources for their food

Question 10

(b) Between chemoautotrophs and chemoheterotrophs?

Answer 10

chemoautotrophs -
energy ~ inorganic substances
carbon source ~ carbon dioxide

chemoheterotrophs -
energy ~ usually organic compound; sometimes inorganic substances.
carbon source ~ organic compounds

Question 11

(c) Between photoheterotrophs and chemoautotrophs?

Answer 11

photoheterotrophs -
energy ~ Light
carbon source ~ organic compounds

chemoautotrophs -
energy ~ inorganic substances
carbon source ~ carbon dioxide