Chapter 15

Question 1

What biochemica, process led to an increase in oxygen levels in the Earth’s atmosphere about 2.7 billion years ago?

a. Glycolysis
b. Cell respiration
c. Photosynthesis
d. Citric acid cycle

Answer 1

c. Photosynthesis

Question 2

Endosymbiosis explains the origin of the _____ of eukaryotes.

a. chloroplasts and mitochondria
b. endomembrane system
c. nuclear envelope
d. membrane-bound organelles

Answer 2

a. chloroplasts and mitochondria

Question 3

The absence of _____ in the primitive atmosphere was essential to the origin of life on Earth.

a. N2
b. CO2
c. CH4
d. O2

Answer 3

d. O2

Question 4

Which of the following would likely be the most difficult to kill were you to can your own food?

a. microscopes
b. endospores
c. sporophylls
d. megaspores

Answer 4

b. endospores

Question 5

Streptobacillus bacteria are…

a. spherical-shaped and form clump-like colonies
b. spiral-shaped and form chain-like colonies
c. spiral-shaped and form clump-like colonies
d. rod shaped and form chain-like colonies

Answer 5

d. rod shaped and form chain-like colonies

Question 6

Which of the following most accurately describes how prions lead to mad cow disease?

a. PrPsc causes PrPc to misfold, leading to sponge-like appearance in the brain.
b. PrPsc is an enzyme that lysosomes in cells use to destroy PrPc and thereby cause a sponge-like appearance in the brain.
c. PrPc is consumed by cows and transmitted to humans through the air.
d. Lysosomes carrying PrPsc cross the blood brain barrier and destroy the brain through enzymatic degradation.

Answer 6

a. PrPsc causes PrPc to misfold, leading to sponge-like appearance in the brain.

Question 7

What are the four stages of the origin of life?

Answer 7

1. First, inorganic matter is formed into monomers like amino acids.
2. Secondly, these monomers form macromolecules with dehydration reactions.
3. Then, the macromolecules are protected in pre-cells with a phospholipid bilayer.
4. After that, pre-cells are able to replicated and natural selection occurs.