BOT 331 - PRACTICE TEST QUESTIONS WITH
VERIFIED ANSWERS
List four essential mineral elements. For each, state a function and a deficiency
symptom. - Answers - Lots of possible answers
State two ways a decrease in soil pH may cause mineral deficiency symptoms. -
Answers - A decrease in soil pH means an increase in proton (H+) concentration. An
increase in soil H+ can result in cation exchange where H+ replace other cations, such
as Ca2+, from the surface of negatively charged soil particles. The Ca2+ is then
dissolved in water and can potentially leach out of the soil resulting in a calcium
deficiency.
The other way low pH could cause a mineral deficiency is that numerous minerals are
insoluble at acidic pH, such as iron. Insoluble means the mineral is no longer dissolved
in water, so difficult for roots to absorb. So the low pH can cause deficiencies due to
minerals being insoluble)
How is the H+-ATPase so important for nutrient transport across the plasma
membrane? - Answers - The H+-ATPase pumps protons across the plasma membrane,
which generates a proton motive force - an electrochemical gradient of protons, high
potential outside relative to low potential inside. The favorable flow of protons down their
gradient can be coupled, by transport proteins, to the active transport of a nutrient, such
as nitrate (NO3-). Coupling transport of a proton with another nutrient is called
secondary active transport.
What does it mean to say an ion channel is gated? - Answers - Some types of ion
channels open and close at random. Other types of ion channels are closed, but open in
response to signals, such as a change in membrane potential (voltage-gated) or binding
to another protein or small molecule (ligand gated). So saying a channel is gated,
means the channel does not open at random, but only in response to a signal.
State your favorite ion channel, carrier or pump and explain why it's your favorite. -
Answers - Many possible answers
True/false, if false explain why.
If a plant is deficient in a mineral that is phloem mobile, then the plant will show
symptoms in older leaves before younger leaves. - Answers - True - if phloem mobile,
then the mineral, if deficient in the soil, can be moved from old leaves to young leaves,
and then the old leaves will show deficiency symptoms. If the mineral is phloem
immobile, then symptoms will appear first in younger leaves.
VERIFIED ANSWERS
List four essential mineral elements. For each, state a function and a deficiency
symptom. - Answers - Lots of possible answers
State two ways a decrease in soil pH may cause mineral deficiency symptoms. -
Answers - A decrease in soil pH means an increase in proton (H+) concentration. An
increase in soil H+ can result in cation exchange where H+ replace other cations, such
as Ca2+, from the surface of negatively charged soil particles. The Ca2+ is then
dissolved in water and can potentially leach out of the soil resulting in a calcium
deficiency.
The other way low pH could cause a mineral deficiency is that numerous minerals are
insoluble at acidic pH, such as iron. Insoluble means the mineral is no longer dissolved
in water, so difficult for roots to absorb. So the low pH can cause deficiencies due to
minerals being insoluble)
How is the H+-ATPase so important for nutrient transport across the plasma
membrane? - Answers - The H+-ATPase pumps protons across the plasma membrane,
which generates a proton motive force - an electrochemical gradient of protons, high
potential outside relative to low potential inside. The favorable flow of protons down their
gradient can be coupled, by transport proteins, to the active transport of a nutrient, such
as nitrate (NO3-). Coupling transport of a proton with another nutrient is called
secondary active transport.
What does it mean to say an ion channel is gated? - Answers - Some types of ion
channels open and close at random. Other types of ion channels are closed, but open in
response to signals, such as a change in membrane potential (voltage-gated) or binding
to another protein or small molecule (ligand gated). So saying a channel is gated,
means the channel does not open at random, but only in response to a signal.
State your favorite ion channel, carrier or pump and explain why it's your favorite. -
Answers - Many possible answers
True/false, if false explain why.
If a plant is deficient in a mineral that is phloem mobile, then the plant will show
symptoms in older leaves before younger leaves. - Answers - True - if phloem mobile,
then the mineral, if deficient in the soil, can be moved from old leaves to young leaves,
and then the old leaves will show deficiency symptoms. If the mineral is phloem
immobile, then symptoms will appear first in younger leaves.
