Quiz 3 Recap

Question 1

Number these events in the evolution of life from 1 to 6.

• Cyanobacteria
• First chloroplast
• First land plants
• First aerobic bacteria
• First anaerobic bacteria
• First mitochondria

Answer 1

1. First anaerobic bacteria
2. Cyanobacteria
3. First aerobic bacteria
4. First mitochondria
5. First chloroplast
6. First land plants

Question 2

Eukaryotes can be distinguished from prokaryotes on the basis of which features?

• Cell wall
• Mitochondria and chloroplast organelles
• Lipid bilayer membrane
• Membrane-bound nucleus that encloses the DNA

Answer 2

• Mitochondria and chloroplast

- Membrane-bound nucleus that encloses DNA

Question 3

What is TRUE about eukaryotes?

• There are eukaryotes cells that obtained the ability of photosynthesis by engulfing a photosynthetic eukaryotic cell
• Plant cells have chloroplasts and they don’t have mitochondria
• All organelles in eukaryotic cells were once free-living bacteria
• Mitochondria were once free-living bacteria from the proteobacteria phylum

Answer 3

1 & 4

Question 4

Key innovations to photosynthesis by cyanobacteria include?

1. Cyanobacteria combined two photosystems from two different phototrophic bacteria
2. Cyanobacteria were the first photosynthetic organisms
3. Cyanobacteria combined two photosystems in a linear form rather than cyclical
4. Cyanobacteria were the first organisms to split water and form 02 as a biproduct

Answer 4

1,3,4

Question 5

N2 fixation and nitrification:

1. Only performed by bacteria and archea
2. Occur in both soil and ocean ecosystems
3. Can’t be performed by autotrophs
4. Ancient processes that are no longer important today

Answer 5

1,2

Question 6

What’s true about the global carbon cycle?

1. Photosynthesis is able to offset the carbon that humans add to the atmosphere
2. Some carbon that humans add to the atmosphere is being absorbed by the ocean, making the ocean more acidic
3. Microbial loop is the short-term balance of heterotrophic and autotrophic organisms releasing and removing CO2 from the atmosphere
4. Only geological processes affect the flux of carbon from one stock to another

Answer 6

2,3

Question 7

What is true about how plants obtain nitrogen?

1. Some plants can get nitrate or ammonia straight from the soil
2. Some plants can fix nitrogen themselves inside their cells
3. Some plants can use atmospheric nitrogen but it’s not readily available
4. Some plants can form a symbiotic relationship with bacteria because the bacteria are able to fix nitrogen and give it to the plant

Answer 7

1,4