Consider the possibility that we discover a gene that regulates both the amount of root hairs and where root hairs grow on a root tip. Since the surface area provided by root hairs is so critical to their uptake of water and nutrients, expanding their growth area seems a great advantage. However, which of these might be a problem?
A. Growth of root hairs in the root cap would cause them to be shredded off since this area takes substantial abrasion.
B. Growth of root hairs in the zone of cell division would interfere with root cell proliferation.
C. Growth of root hairs in the zone of elongation would cause them to be shredded off as they anchored in soil and the root lengthened.
D. All of these choices pose a problem.
Answer: D
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Which of the following would be a monohybrid cross?
a) aa x Aa b) AA x aa c) Aa x Aa d) Aa x aa
Insulin stimulates an increase in number of glucose carrier proteins at a cell membrane's surface. What effect will insulin have on cell function? Choose all that apply.A) An increase in insulin, which will increase the diffusion rate.B) ATP amounts needed for this transport will increase.C) Low insulin levels will decrease the number of available carrier proteins.D) Lack of membrane receptors for insulin will decrease amount of glucose taken in.
What will be an ideal response?
What governs the opening of the potassium channels, which establish the resting membrane potential in the plasma membrane of a neuron?
A) The potassium channels open in response to an influx of sodium ions (Na+) into the neuron. B) The potassium channels open in response to an increase in the membrane potential. C) The potassium channels open after binding a neurotransmitter. D) The potassium channels are always open. E) The potassium channels open in response to a decrease in the membrane potential.
Prokaryotes that harvest both energy and carbon atoms from organic molecules are called
A. photoautotrophs. B. chemolithoautotrophs. C. photoheterotrophs. D. chemoheterotrophs. E. nitrogen fixers.