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1 Jun 2019

1) Look up the structures of the following molecules. For each carbon atom, indicate its oxidation state. Calculate the average oxidation state of the carbon atoms in each.

Glucose

Pyruvic acid

Citric acid

Oxaloacetic acid

Carbon dioxide

2) Consider the following hypothetical cell. Initially, the cell has an equal number of positive and negative charges (cations and anions) on either side of its plasma membrane (extracellular, intracellular). There are equal concentrations of Na+, K+, and Cl- on either side of the plasma membrane. Consider the effects of the following events, in sequence, upon the ion concentrations and charge distributions (membrane electrical potential).

A. NKA proteins are activated in the plasma membrane. How does this affect the ions and the membrane electrical properties?

B. A small number of K+ channels open in the plasma membrane. How does this affect the ions and the membrane electrical properties?

C. An even larger number of Na+ channels open in the plasma membrane.

D. The Na+ and K+ channels close. Cl- channels open.

3) Pancreatic juice contains approximately 150 mM Na+. How do these Na+ ions contribute to the absorption of amino acids and sugars? Explain how 100% of an amino acid can be absorbed from the small intestines. HINT: intestinal epithelial cells have NKA, numerous cotransporters (symporters) and facilitated diffusion proteins.

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Deanna HettingerLv2

3 Jun 2019

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Related questions

1. The plasma membrane of liver cells contains a glucose uniportthat transports glucose by facilitated diffusion. When the[glucose] is higher inside the liver cell than the [glucose]outside the liver cell, the glucose uniport will

A. couple the transport of glucose out of the cell to thehydrolysis of ATP

B. couple the transport of glucose into the cell to thehydrolysis of ATP

C. switch to a closed conformation, allowing no transport ofglucose

D. transport glucose out of the cell by passive transport

E. transport glucose in of the cell by passive transport

2. Unlike the positive charged ion shown in the middle diagramof figure 11-4B, K+ is higher in concentration inside the cell. Howwill the membrane potential of a cell at rest (shown in both themiddle and right-hand diagrams of Figure 11-4B) affect theelectrochemical gradient for K+?

A. The membrane potential will increase the electrochemicalgradient

B. The membrane potential will decrease the electrochemicalgradient

C. The membrane potential will have no effect on theelectrochemical gradient

3. Which of the following proteins carries out activetransport?

A. gluclose symport

B. Bacteriorhodopsin

C. ABC transporter

D. NA K pump

E. All of the above

4. Aquaporin will not transport Na+ ions because

A. Two asparagine residues in the channel prevent the passage ofNa+ ions by binding the oxygen of each water molecule as it passesby

B. Na+ ions are repelled by the positive charges at the entranceto the channel

C. Na+ ions cannot make contact with the carbonyl (C=O) groupson all four sides of the channel

D. The passage of Na+ ions is energetically unfavorable becauseone side of the channel is hydrophobic in nature

5. The acetylcholine receptor is different from other channelproteins we have discussed, such as the K+ leak channel,because

A. The acetylcholine channel is composed of a single polypeptiderather than multiple subunits

B. The acetylcholine channel transports Na+ ions against theconcentration gradient for sodium

C. The acetylcholine channel has a much smaller diameter thanother channel proteins

D. The acetylcholine channel transports ions with theirassociated shell of water molecules

E. The acetylcholine channel is always open, and never switchesto a closed conformation

6. After opening briefly along the axon of a neuron,voltage-gated ion channels switch to an inactivated conformationthat slowly returns to the original closed conformation of theprotein. This slow change in conformation, requiring about amillisecond, is important because

A. all of the ions that were transported across the membranewhen the ion channels were open must be actively transported backto the other side of the membrane, restoring the originalconcentration gradient, before the ion channels can open again

B. ATP hydrolysis is necessary to drive this energeticallyunfavorable change in conformation

C. it prevents the action potential from reversing direction andtraveling back toward the cell body of the neuron

D. the channel protein must be dephosphorylated in order tocomplete the transport process and return to the originalnonphosphorylated conformation

limeelephant476

Compare the intracellular and extracellularconcentrations for Na and K of a %u201Cgeneral%u201D mammalian cellto that in a squid which lives in the salty ocean. What are thevalues for Na and K out and in? (You can find values by going togoogle and typing in %u201Csquid axon ion concentrations%u201D orgoing to http://faculty.weber.edu/nokazaki/Comparative%20Animal%20Physiology/Tests/Chp%2011%20Essay%20questions.htm). Why are they different? Why is the voltage ofthe squid neuron so very similar to that of a %u201Cgeneral%u201Dmammalian cell (hint: is it the absolute concentrations of ionsthat are important or their ratios across the plasma membrane)?

You will be plotting the flowof ions -
which is an electrical current. When you make yourplots, the y axis
will be the amount of current flow. Make it sothat inward current
(that is, net flow of ions into the cell) isdownward (below zero), and
outward current (that is, the flow of ions out ofa cell) is positive.

Then, Use the Goldman equation and the Goldmanequation simulator to answer the following questions. Whenanswering "Why" questions, do so in one-two sentences.

Start with the default conditions in thesimulator.

PK = 100 Ko = 10mM Ki = 100

PNa =1 Nao =100 Nai = 1

PCl =10 Clo= 100 Cli = 10

What is the voltage of a cell that has thesevalues? Why

If the relative potassium permeability waschanged to 1, what would be the voltage of the cell? Why?

Change the permeability of K back to 100. Ifthe permeability to chloride is changed from 10 to 100, will therebe a voltage change? Why?

Change the permeability of chloride back to10. Now, change the extracellular concentration of potassium to 90mM. What is the voltage of the cell? Why?

Now change the extracellular concentration ofpotassium to 200. What is the voltage of the cell? Why? Now changethe permeability to potassium to 9999. Is there a further largechange in the voltage of the cell? Why?

amaranthjackal220

________30. If you are investigating the inner structure of a new cell and see that it has a significantly larger amount of RER than other cells. You would conclude the cell does a great deal of____?
A. ATP synthesis

B. protein synthesis
C. DNA synthesis
D. active transport
E. polysaccharide hydrolysis

________31. If a cell comes in contact with a toxic substance such as H2O2, it could survive as long as it has a ___ to digest it.
A. DNA
B. peroxisome

C. mitochondria
D. phospholipids
E. intermediate filaments

________32. Some cells have structures to help them withstand osmotic pressure. For example,
A. Plant cells due to their walls
B. Animal cells due to the sodium/potassium pumps

C. Bacterial cell due to their swimming

D. Viruses due to their protein coats

________33. Evolution occurs only as a cell ____.

A. They undergo mitosis
B. Change in their gene pool
C. They move from one habitat to another

D. They begin to eat different foods

________34. Ribosomes are produced in the

A. nucleoli.
B. chromatin.
C. nuclear envelopes.

D. Golgi complex. E. cisternae.

________35. Algae are often green, but there are red and brown species also. What accounts for this difference in color?
A. The chlorophyll of chloroplasts
B. The pigments in other plastids

C. The presence of a mitochondria
D. The accumulation of cellular wastes

________36. The chloroplast and other like prokaryotes have which of the following that helps with photosynthesis?
A. They live in water based environments
B. They have chloroplasts in their cytoplasm

C. Change color in the dark vs. the sun
D. They have photoreceptor proteins in their membranes or mesosomes.

________37. Located in the membrane, we see a set of proteins called receptors that only connect with or bind to specific substances. This is called __.
A. ligand specificity.
B. hormone selectivity.

C. cell tonicity.
D. water saturation. E. signal resolution.

________38. Of the following statements, we could say that ___ is false.
A. All organisms are composed of cells and cell products.
B. An organism's structure and all of its functions are due to the activities of cells.
C. The cellular organelles are the simplest structural and functional unit of life.
D. Cells come from preexisting cells.
E. Cells are made from nonliving components including the nucleus, cell membrane and cytoplasm.

________39. If it is really true that our cells are the smallest anatomical unit that meets all of the properties of life, then which of the following could imply otherwise?
A. vacuoles
B. centrioles

C. Golgi apparatus
D. mitochondria
E. endoplasmic reticulum

________40. Oxygen is an absolute need for animal and plant cells alike due to the ___.

A. RER
B. Mitochondria
C. Lysosomes

D. DNA

________41. In a plasma membrane, we expect to see the carb/protein structures to extend into the ___, but the secondary messengers to move within the __.
A. extracellular fluid; cytosol
B. cytosol; extracellular fluid

C. intracellular fluid; cytosol

D. cytosol; intracellular fluid

E. extracellular fluid; plasma

________42. Bacteria are found in all of the following habitats:

A. Caves
B. Oceans
C. Animals

D. Everywhere on Earth

________43. Two solutions are separated by a selectively permeable membrane. Solution A has a higher concentration of an impermeable solute compared to solution B. Which of the following do you expect would happen?
A. solute will move from solution A to solution B

B. solute will move from solution B to solution A

C. water will more from solution A to solution B

D. water will move from solution B to solution A E. no movement of solute or water will occur

________44. In the kidney, we notice that almost all of the cells involved in the production of urine have high concentrations of the Na+/K+ pump. Which typically works to push Na+ ___ its concentration gradient by using ___.
A. up; active transport

B. up; facilitated transport
C. up; cotransport
D. down; active transport
E. down; facilitated transport

________45. In the charts of a patient recently admitted to the hospital noted that he was taking a medication called lithium and high doses of calcium supplements. Given this, we would expect the patientâs liver to have a higher than normal amount of __ to purify out the lithium and calcium.

A. lysosomes.
B. centrosomes.
C. mitochondria.
D. peroxisomes.
E. rough endoplasmic reticulum.

________46. We have long observed that our neural cells in the brain cannot replicate or replace themselves due to the lack of ____.
A. produce ATP.
B. divide.

C. produce enzymes.
D. secrete material across their plasma membrane E. conduct electrical signals.

________47. An organismâs structure and function is ultimately due to the structure and function of itâs __.
A. Organs
B. Tissues

C. Cells

D. Nuclei