Lec. 22: Microbes and the Environment

Question 1

Microorganisms and their environment interact with and modify each other. True or false?

Answer 1

True

Question 2

What is an ecosystem?

Answer 2

the community of organisms and their physical and chemical environment functioning as a unit

Question 3

Primary Production by Microorganisms

Answer 3

• the building of organic molecules such as carbon or nitrogen
• can be done by plants or bacteria

Question 4

Decomposition by Microorganisms

Answer 4

• the breaking down of organic matter for use by the organism
• done by any heterotroph (eg. fungi, people)

Question 5

Microbes can modify their environment. What was responsible for the initial rise of oxygen levels in the Earth’s atmosphere?

Answer 5

Cyanobacteria

Question 6

Molecular Chronometer

Answer 6

• looks at parts of the cell, that share a common ancestor, that have evolved over time
• more closely related organisms will show less change in the parts
• different parts are looked at for different time frames
• ex: rRNA

Question 7

In the sulfur cycle, this form of sulfur can be assimilated into organic material by some living organisms:

Answer 7

sulfate (SO4)

Question 8

What genus forms associations with some plants in order to fix nitrogen?

Answer 8

Rhizobium