BZ440 Midterm 2 Exam Questions with Correct Answers Latest Update 2025-2026
passive transport - Answers - spontaneous and down the concentration gradient
- does not need cellular energy input
electrochemical gradient - Answers - the cells inside are usually negative compared to the
outside
active transport - Answers - non spontaneous and uphill movement of ions against the gradient
- coupled with ATP hydrolysis
channels - Answers - mediate simple or facilitated diffusion down the gradient
- fast transport, won't saturate
- steep exponential curve
carriers - Answers - mediate simple or facilitated diffusion down the gradient
- secondary active transport
- open/close, slower than channels, can saturate
- much less steep curve bc it follows Michaelis-Menten kinetics
pumps - Answers - movement of ions against the gradient using ATP
- primary active transport that facilitates secondary active transport
co-transport - Answers - transport of one molecule is coupled to the transport of another
- includes antiporters and symporters
secondary active transport - Answers - carriers!
- transports protons and a second ion/solute but ATP is not used directly
membrane potential (electrochemical gradient) - Answers - the proton pump creates a gradient
- drives the diffusion of cations into the cell which accumulates solutes from the proton
gradient
- like a cascade where one can't exist without the other
stomatal opening/closing - Answers blue light activates H+-ATPase which polarizes the plasma
membrane and created deep proton motive force (PMF). This causes ions to be taken up and
the stomata to open
, essential nutrients - Answers necessary to plants and must meet three criteria:
1) a plant must be unable to complete its life cycle without the element
2)the function of the element must not be replaced by another
3)the element must be directly involved in plant metabolism
beneficial elements - Answers not essential but enhance growth and development and the plant
can still grow in its absence
macronutrients - Answers needed in large amounts
micronutrients - Answers needed in smaller amounts BUT not necessarily less essential!
mobile elements - Answers - can be redistributed within the plant as needed
- symptoms appear on OLDER leaves first
immobile elements - Answers - an element that cannot be removed from mature tissues
- symptoms appear on YOUNGER leaves first
remobilization - Answers the process through which nutrients are translocated within the plant
(happens through phloem elements)
hydroponics - Answers pros: uses less nutrients/water. small chance of infestation, no off
season
cons: need expensive systems, adjusting pH all the time, power/electricity
bioremediation - Answers the process of using living organisms to clean up the environment by
neutralizing or removing contaminant
deficient concentration - Answers tissue concentration below the critical concentration so
growth is limited by the element
critical concentration - Answers tissue concentration of an element just below the level that
gives maximum growth
adequate concentration - Answers tissue concentration above the critical concentration so
growth doesn't increase even if concentration does
toxic concentration - Answers tissue concentration above the critical toxicity level so there is
reduced growth or death
chemical fertilizers - Answers uses inorganic salts with different rotation of NPK based on what
deficiency there is (fast response)
passive transport - Answers - spontaneous and down the concentration gradient
- does not need cellular energy input
electrochemical gradient - Answers - the cells inside are usually negative compared to the
outside
active transport - Answers - non spontaneous and uphill movement of ions against the gradient
- coupled with ATP hydrolysis
channels - Answers - mediate simple or facilitated diffusion down the gradient
- fast transport, won't saturate
- steep exponential curve
carriers - Answers - mediate simple or facilitated diffusion down the gradient
- secondary active transport
- open/close, slower than channels, can saturate
- much less steep curve bc it follows Michaelis-Menten kinetics
pumps - Answers - movement of ions against the gradient using ATP
- primary active transport that facilitates secondary active transport
co-transport - Answers - transport of one molecule is coupled to the transport of another
- includes antiporters and symporters
secondary active transport - Answers - carriers!
- transports protons and a second ion/solute but ATP is not used directly
membrane potential (electrochemical gradient) - Answers - the proton pump creates a gradient
- drives the diffusion of cations into the cell which accumulates solutes from the proton
gradient
- like a cascade where one can't exist without the other
stomatal opening/closing - Answers blue light activates H+-ATPase which polarizes the plasma
membrane and created deep proton motive force (PMF). This causes ions to be taken up and
the stomata to open
, essential nutrients - Answers necessary to plants and must meet three criteria:
1) a plant must be unable to complete its life cycle without the element
2)the function of the element must not be replaced by another
3)the element must be directly involved in plant metabolism
beneficial elements - Answers not essential but enhance growth and development and the plant
can still grow in its absence
macronutrients - Answers needed in large amounts
micronutrients - Answers needed in smaller amounts BUT not necessarily less essential!
mobile elements - Answers - can be redistributed within the plant as needed
- symptoms appear on OLDER leaves first
immobile elements - Answers - an element that cannot be removed from mature tissues
- symptoms appear on YOUNGER leaves first
remobilization - Answers the process through which nutrients are translocated within the plant
(happens through phloem elements)
hydroponics - Answers pros: uses less nutrients/water. small chance of infestation, no off
season
cons: need expensive systems, adjusting pH all the time, power/electricity
bioremediation - Answers the process of using living organisms to clean up the environment by
neutralizing or removing contaminant
deficient concentration - Answers tissue concentration below the critical concentration so
growth is limited by the element
critical concentration - Answers tissue concentration of an element just below the level that
gives maximum growth
adequate concentration - Answers tissue concentration above the critical concentration so
growth doesn't increase even if concentration does
toxic concentration - Answers tissue concentration above the critical toxicity level so there is
reduced growth or death
chemical fertilizers - Answers uses inorganic salts with different rotation of NPK based on what
deficiency there is (fast response)
