BIOL251- EXAM 2 STUDY GUIDE QUESTIONS WITH
CORRECT ANSWERS 2026 RATED A+
1. Chapter 7-ANSWER- Microbial nutrition, ecology, growth
2. Name, define, and discuss the categories of nutrition types among microbial
organisms.-ANSWER- •In general, C, H, O, P, K, N, S, Ca, Fe, Cl, Mg, are elements required for life.
Many variations in ratios occur, but ALL microbes require a carbon source and an energy source.
•Organic compounds that cannot be synthesized by an organism because they lack the genetic
and metabolic
mechanisms to synthesize them
•Growth factors must be provided as a nutrient (Essential amino acids, vitamins)
3. Differentiate between organic and inorganic carbon sources, and describe
the different microbial nutrition types that use each.-ANSWER- Heterotroph - must obtain
carbon in
an organic form made by other living organisms such as proteins, carbohydrates, lipids, and
nucleic acids
Autotroph - an organism that uses CO2, an inorganic gas as its carbon source (Not nutritionally
dependent on other
living things)
4. Describe the different energy sources needed for each bacterial nutrition
type.-ANSWER- Chemotroph - gain energy from chemical compounds
Phototrophs - gain energy through photosynthesis
CO2 + H2O (CH2O)n + O2
5. Chemoheterotrophs-ANSWER- Gets carbon and energy from degrading organic molecules-
Use Aerobic respiration
CH2On + O2 CO2 + H2O + ATP (energy)
Saprobes-ANSWER- free-living microorganisms that feed on organic detritus from dead
organisms
,•Extracellular digestion
•Opportunistic pathogen
•Facultative parasite
Parasites-ANSWER- derive nutrients from host
•Pathogens
•Some are obligate parasites
6. Describe the basic factors in cell transport.-ANSWER- Passive transport - does not require
energy;
substances exist in a gradient and move from areas of higher concentration toward areas of
lower concentration
Biol251- Exam 2 Study Guide
Study online at https-ANSWER-//quizlet.com/_9hc170-Diffusion-Osmosis - diffusion of water-
Facilitated diffusion - requires a carrier
Active transport - requires energy and carrier proteins; gradient independent-Ex-ANSWER-
endocytosis, exocytosis, pinocytosis
7. Discuss diffusion and passive transport mechanisms.-ANSWER- 1. Inset shows a close-up of
the osmotic process. The gradient goes from the outer container (higher concentration of H2O)
to the sac (lower
concentration of H2O). Some water will diffuse the opposite direction but the net gradient
favors osmosis into the sac.
2. As the H2O diffuses into the sac, the volume increases and forces the excess solution into the
tube, which will rise
continually.
3. Even as the solution becomes diluted, there will still be osmosis into the sac. Equilibrium will
not occur because the
solutions can never become equal.
8. Define osmosis and describe varying osmotic conditions.-ANSWER- Osmosis is a process by
, which molecules of a solvent tend to pass through a semipermeable membrane from a less
concentrated solution into
a more concentrated one --> equalizing the concentrations on each side of the membrane.
9. Be comfortable with osmosis-focused cellular transport questions (ex-ANSWER- Q1-3
on lecture quiz 2).-ANSWER- A. Cell A has 60% glucose and is placed in a solution with 15%
glucose and the cell
membrane is permeable to the solvent.
•Based on this background answer the following questions-ANSWER-
1. What type of problem is this?
-Osmosis
2. Which way will water move?
-Into the cell
3. The solution is ___ to the cell.
-Hypotonic
B. •Cell A has 20% glucose and cell B has 30% glucose and the protein carrier in the cell
membrane is pumping solute
across the membrane.
•Based on this background answer the following questions-ANSWER-
1. What type of problem is this?
-Active transport
Biol251- Exam 2 Study Guide
Study online at https-ANSWER-//quizlet.com/_9hc170
2. Cell B is ____ to cell A.
-Hypertonic
3. If a protein pump is transporting
glucose from cell A to cell B, that
CORRECT ANSWERS 2026 RATED A+
1. Chapter 7-ANSWER- Microbial nutrition, ecology, growth
2. Name, define, and discuss the categories of nutrition types among microbial
organisms.-ANSWER- •In general, C, H, O, P, K, N, S, Ca, Fe, Cl, Mg, are elements required for life.
Many variations in ratios occur, but ALL microbes require a carbon source and an energy source.
•Organic compounds that cannot be synthesized by an organism because they lack the genetic
and metabolic
mechanisms to synthesize them
•Growth factors must be provided as a nutrient (Essential amino acids, vitamins)
3. Differentiate between organic and inorganic carbon sources, and describe
the different microbial nutrition types that use each.-ANSWER- Heterotroph - must obtain
carbon in
an organic form made by other living organisms such as proteins, carbohydrates, lipids, and
nucleic acids
Autotroph - an organism that uses CO2, an inorganic gas as its carbon source (Not nutritionally
dependent on other
living things)
4. Describe the different energy sources needed for each bacterial nutrition
type.-ANSWER- Chemotroph - gain energy from chemical compounds
Phototrophs - gain energy through photosynthesis
CO2 + H2O (CH2O)n + O2
5. Chemoheterotrophs-ANSWER- Gets carbon and energy from degrading organic molecules-
Use Aerobic respiration
CH2On + O2 CO2 + H2O + ATP (energy)
Saprobes-ANSWER- free-living microorganisms that feed on organic detritus from dead
organisms
,•Extracellular digestion
•Opportunistic pathogen
•Facultative parasite
Parasites-ANSWER- derive nutrients from host
•Pathogens
•Some are obligate parasites
6. Describe the basic factors in cell transport.-ANSWER- Passive transport - does not require
energy;
substances exist in a gradient and move from areas of higher concentration toward areas of
lower concentration
Biol251- Exam 2 Study Guide
Study online at https-ANSWER-//quizlet.com/_9hc170-Diffusion-Osmosis - diffusion of water-
Facilitated diffusion - requires a carrier
Active transport - requires energy and carrier proteins; gradient independent-Ex-ANSWER-
endocytosis, exocytosis, pinocytosis
7. Discuss diffusion and passive transport mechanisms.-ANSWER- 1. Inset shows a close-up of
the osmotic process. The gradient goes from the outer container (higher concentration of H2O)
to the sac (lower
concentration of H2O). Some water will diffuse the opposite direction but the net gradient
favors osmosis into the sac.
2. As the H2O diffuses into the sac, the volume increases and forces the excess solution into the
tube, which will rise
continually.
3. Even as the solution becomes diluted, there will still be osmosis into the sac. Equilibrium will
not occur because the
solutions can never become equal.
8. Define osmosis and describe varying osmotic conditions.-ANSWER- Osmosis is a process by
, which molecules of a solvent tend to pass through a semipermeable membrane from a less
concentrated solution into
a more concentrated one --> equalizing the concentrations on each side of the membrane.
9. Be comfortable with osmosis-focused cellular transport questions (ex-ANSWER- Q1-3
on lecture quiz 2).-ANSWER- A. Cell A has 60% glucose and is placed in a solution with 15%
glucose and the cell
membrane is permeable to the solvent.
•Based on this background answer the following questions-ANSWER-
1. What type of problem is this?
-Osmosis
2. Which way will water move?
-Into the cell
3. The solution is ___ to the cell.
-Hypotonic
B. •Cell A has 20% glucose and cell B has 30% glucose and the protein carrier in the cell
membrane is pumping solute
across the membrane.
•Based on this background answer the following questions-ANSWER-
1. What type of problem is this?
-Active transport
Biol251- Exam 2 Study Guide
Study online at https-ANSWER-//quizlet.com/_9hc170
2. Cell B is ____ to cell A.
-Hypertonic
3. If a protein pump is transporting
glucose from cell A to cell B, that
