Chapter 4: End of Chapter Review Questions
1. What nutrients do microbes need to grow?
Microbes require specific macronutrients including carbon, nitrogen,
phosphorous, hydrogen, oxygen, sulfur and the cations magnesium, iron,
potassium and calcium.
They also require micronutrients such as cobalt, copper, manganese, nickel and
zinc
They usually contaminate glassware, so they rarely have to be added to the
growth medium
The organisms may also require very specialized growth factors
2. Explain the differences between autotrophs, heterotrophs, phototrophs and
chemotrophs
Autotrophs: fix carbon dioxide to make complex cell constituents such as
carbohydrates
Heterotrophs: obtain organic compounds from other organisms. They disassemble
the carbon sources producing energy and then reassemble them to make cell
constituents. When the entire molecule is oxidized, carbon dioxide is given off in
the process
Phototrophs: obtain energy through the absorption of light
Chemotrophs: obtain energy from oxidation/reduction reactions that transfer
electrons from high-energy compounds to make products of lower energy
3. Explain the basics of the carbon and nitrogen cycles
Carbon Cycle: the carbon cycle requires both autotrophs and heterotrophs. The
heterotrophs degrade complex organic compounds such as polysaccharides to
monomers, which are then broken down to smaller compounds and, when
completely oxidized, to carbon dioxide. The photosynthetic and lithotrophic
autotrophs produce energy, which is used to fix carbon dioxide and produce
glucose
Nitrogen cycle: bacteria and archaea collaborate to interconvert nitrogen gas,
ammonium ions, and nitrate ions. Certain bacteria and archaea are able to convert
atmospheric nitrogen to ammonia, which other organisms can then use for
synthesis of proteins and other essential compounds. Nitrifying bacteria oxidize
ammonia to produce nitrate. Denitrifying bacteria cab use the nitrate to produce a
series of compounds, ultimately resulting in the production of nitrogen gas
4. Describe the various mechanisms of transporting nutrients in prokaryotes and
eukaryotes. What are facilitated diffusion, coupled transport, ABC transporters,
group translocation, and endocytosis?
Facilitated Diffusion: transport down a concentration gradient until equilibrium is
reached. The aquaporin family of transporters is responsible for transport of
water; small polar molecules such as glycerol also cross the membrane by
This study source was downloaded by 100000899606396 from CourseHero.com on 10-09-2025 17:24:55 GMT -05:00
https://www.coursehero.com/file/49519361/chapter-4-end-of-chapter-questionsdocx/
1. What nutrients do microbes need to grow?
Microbes require specific macronutrients including carbon, nitrogen,
phosphorous, hydrogen, oxygen, sulfur and the cations magnesium, iron,
potassium and calcium.
They also require micronutrients such as cobalt, copper, manganese, nickel and
zinc
They usually contaminate glassware, so they rarely have to be added to the
growth medium
The organisms may also require very specialized growth factors
2. Explain the differences between autotrophs, heterotrophs, phototrophs and
chemotrophs
Autotrophs: fix carbon dioxide to make complex cell constituents such as
carbohydrates
Heterotrophs: obtain organic compounds from other organisms. They disassemble
the carbon sources producing energy and then reassemble them to make cell
constituents. When the entire molecule is oxidized, carbon dioxide is given off in
the process
Phototrophs: obtain energy through the absorption of light
Chemotrophs: obtain energy from oxidation/reduction reactions that transfer
electrons from high-energy compounds to make products of lower energy
3. Explain the basics of the carbon and nitrogen cycles
Carbon Cycle: the carbon cycle requires both autotrophs and heterotrophs. The
heterotrophs degrade complex organic compounds such as polysaccharides to
monomers, which are then broken down to smaller compounds and, when
completely oxidized, to carbon dioxide. The photosynthetic and lithotrophic
autotrophs produce energy, which is used to fix carbon dioxide and produce
glucose
Nitrogen cycle: bacteria and archaea collaborate to interconvert nitrogen gas,
ammonium ions, and nitrate ions. Certain bacteria and archaea are able to convert
atmospheric nitrogen to ammonia, which other organisms can then use for
synthesis of proteins and other essential compounds. Nitrifying bacteria oxidize
ammonia to produce nitrate. Denitrifying bacteria cab use the nitrate to produce a
series of compounds, ultimately resulting in the production of nitrogen gas
4. Describe the various mechanisms of transporting nutrients in prokaryotes and
eukaryotes. What are facilitated diffusion, coupled transport, ABC transporters,
group translocation, and endocytosis?
Facilitated Diffusion: transport down a concentration gradient until equilibrium is
reached. The aquaporin family of transporters is responsible for transport of
water; small polar molecules such as glycerol also cross the membrane by
This study source was downloaded by 100000899606396 from CourseHero.com on 10-09-2025 17:24:55 GMT -05:00
https://www.coursehero.com/file/49519361/chapter-4-end-of-chapter-questionsdocx/
