LS7A : Week 1 - 3 PALS + Practice AOL (For Midterm 1)
True
Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X could form an ionic bond with Na+
There will be a net movement of salt from side B to side A and net movement of water from side A to side B.
A beaker contains two solutions of salt dissolved in water. The two solutions have different concentrations of salt (measured by molarity, M) and are separated by a membrane that is permeable to both salt and water. The salt and water will move through the membrane by diffusion. Which statement is true about the diffusion of these solutions? - There will be a net movement of salt from side B to side A and net movement of water from side A to side B. - There will be a net movement of salt from side A to side B and no movement of water. - There will be a net movement of water from side A to side B and no movement of salt. - There will be a net movement of both salt and water from side B to side A.
This reaction is endergonic
A certain chemical reaction has a ∆G° value of +3.8 kcal/mol. Which of the following statements are true about this reaction? (Select all that apply) - This reaction could not occur in a cell unless it were coupled with an exergonic reaction - This reaction is exergonic - This reaction involves a decrease in enthalpy. - This reaction is endergonic
- The reaction is exergonic - Disorder of the molecules increases over the course of the reaction. - The bonds in the products are stronger on average than the bonds in the reactants
A certain chemical reaction involves the breaking of twelve bonds and the formation of twelve new bonds. This reaction has a negative ∆H° and a positive ∆S°. Which of the following statements must be true about this reaction? (Select all that apply) - None of these; more information is needed - The reaction is exergonic - Disorder of the molecules increases over the course of the reaction. - The bonds in the products are stronger on average than the bonds in the reactants
Not Change
Adding an enzyme to this reaction would _________ the size of region Y. - Decrease - Increase - Not change
Decrease
Adding an enzyme to this reaction would _________ the size of region Z. - Decrease - Increase - Not change
The head groups are repelled by the hydrophobic membrane interior.
Although the phospholipid molecules can be in constant lateral movement, they very rarely flip from one side of the bilayer to the other. Which of the answer choices could explain this? - The cholesterol keeps the phospholipids on the correct side. - The head groups are repelled by the hydrophobic membrane interior. - The molecular attraction between the fatty acid tails is too strong. - The head groups are too large to fit between the interior fatty acid tails.
False
Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X is not able to form a hydrogen bond with water:
False
Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X contains at least one ionic bond.
False
Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X could form a hydrogen bond with another Molecule X:
False
Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X could form an ionic bond with Cl-:
an increase in the production of G
If end product E activates enzyme 5, what would you expect to observe as the amount of E increases in the cell? - an increase in the production of B - a decrease in the production of F - an increase in the production of E - an increase in the production of G - an increase in the production of C
- pathway has three endergonic reactions - is an anabolic pathway
In a metabolic pathway, a series of enzymatic reactions catalyzes the conversion of molecule A to molecule E. Several intermediate steps are involved in which the product of one reaction becomes the substrate for the next. The graph illustrates the changes of free energy that occur at each step in the pathway. Overall, this _____ based on the changes in free energy that take place as A is converted to E. (Select all that apply) - pathway has three endergonic reactions - is an anabolic pathway - is a catabolic pathway - pathway has three exergonic reactions
Decrease
Making the value of ΔH more negative for this reaction would _______ the size of region Y. - Decrease - Increase - Not change
This patient's substrate concentration is below 100 uM
Most patients respond well to treatment with the most effective drug. However, one unusual patient responds poorly, and her enzymatic activity decreases even further when she takes the drug. From this observation you can conclude that: - This patient's substrate concentration is below 100 uM - This patient's substrate concentration is over 200 uM - This patient has no enzyme for the drug to interact with
12
Six carbon atoms are linked by single covalent bonds such that those carbon atoms and bonds together form the shape of a hexagon (see below). All of the unshared electrons form covalent bonds with hydrogen. How many hydrogen atoms does this molecule contain? - 10 - 8 - 6 - 12 - 4
False
T/F: Drug A could be working as an allosteric inhibitor at all substrate concentrations:
True
T/F: Drug B could be working as an allosteric inhibitor at all substrate concentrations
False
T/F: Reaction D is endergonic.
False
T/F: Reaction D should occur at a faster rate than reaction C.
diffusion of water from A to B but no diffusion of salt
The beaker in the illustration contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to water but not to salt. What will occur in this container? - diffusion of water from B to A and of salt from A to B - diffusion of salt from B to A, but not of water - diffusion of water from A to B but no diffusion of salt - diffusion of both water and salt from B to A
Decrease
The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. Compared to when the Na+ channel is closed, how will the transport of Waste molecules change when the Na+ channel is open? The rate of Waste transport out of the cell will: - Decrease - Increase - Not change
Lower
The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. The concentration of Waste molecules is ________ inside the cell compared to the outside. - About the same - Lower - Higher
Net movement of Waste out of the cell will continue for some time and then all net movement of Waste in or out of the cell will stop
The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. What will happen to the net movement of Waste molecules if the Na+/K+ Pump stops working? - All net movement of Waste in or out of the cell will stop immediately - Net movement of Waste out of the cell will continue for some time and then all net movement of Waste in or out of the cell will stop - Net movement of Waste out of the cell will stop immediately and then Waste will be transported into the cell - Net movement of Waste out of the cell will continue for some time and then Waste will be transported into the cell - Net movement of Waste out of the cell will continue indefinitely (nothing will change)
There will be net movement of Na+ into the cell through the channel
The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. What will happen when the Na+ channel is open? - There will be net movement of Na+ out of the cell through the channel - There will be no net movement of Na+ through the channel - There will be net movement of Na+ into the cell through the channel
Drug B
The drug you are developing is intended for patients who have enzymatic activity that is too low, so the drug is used to increase enzyme activity. Which drug would be least effective for treatment? - Drug A - Drug B
True
Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 1 is hydrophilic.
False
Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 2 could form a hydrogen bond with another Molecule 2.
True
Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 2 only contains nonpolar covalent bonds.
True
Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 3 is unable to form a hydrogen bond with water.
Drug A
Which drug causes the enzyme to reach saturation at the highest substrate concentration? - Drug B - Drug A
C6H12O6
Which molecule would most likely require a transport protein to cross the plasma membrane of a red blood cell? - O2 - C6H12O6 - CO2 - H2O
- synthesis of new DNA copies prior to cell division - fat cells growing bigger during times of ample nutrition
Which of the examples are considered anabolism? Select all that apply - a person losing weight on a calorie restriction diet - synthesis of new DNA copies prior to cell division - fat cells growing bigger during times of ample nutrition - hydrolysis of glycogen (a glucose polymer) during physical activity - use of fat (triglyceride) stores as a cellular energy source
glutamic acid + NH3 → glutamine, ΔG + 3.4 kcal/mol
Which of the reactions would you predict could be coupled to ATP hydrolysis in the cell? Select all that apply. (Note: the ∆G of ATP hydrolysis is -7.3 kcal/mol) - glucose 1-phosphate + H2O → glucose + Pi, ΔG − 5.0 kcal/mol - phosphoenolpyruvate + H2O → pyruvate + Pi, ΔG − 14.8 kcal/mol - glucose 6-phosphate + H2O → glucose + Pi, ΔG − 3.3 kcal/mol - glutamic acid + NH3 → glutamine, ΔG + 3.4 kcal/mol - creatine phosphate + H2O → creatine + Pi, ΔG − 10.3 kcal/mol
Reaction A
Which reaction could be coupled with reaction B? - Reaction C - Reaction A - More than one of these - Reaction D - None of these - Reaction E
Isotonic
You are trying to do some experiments on red blood cells, so you place red blood cells in a beaker filled with an aqueous solution. This solution consists of salts and sugars that are similar to those found in the cytosol of a red blood cell. However, you do not know the concentration of the salts and sugars in the beaker. The red blood cell membrane is semipermeable and only water can pass through it. After two hours (Beaker B), your experimental system has reached equilibrium. You notice that your red blood cells have decreased in volume and become floppy. To fix the problem, you add more liquid from an unlabeled beaker to your cells (you do not know the composition of this liquid). You wait two more hours and notice that your red blood cells have swollen and burst. In beaker B, the cytosol of your red blood cells is ________ compared to the solution in your beaker. - Hypotonic - Hypertonic - Isotonic
False
You are trying to do some experiments on red blood cells, so you place red blood cells in a beaker filled with an aqueous solution. This solution consists of salts and sugars that are similar to those found in the cytosol of a red blood cell. However, you do not know the concentration of the salts and sugars in the beaker. The red blood cell membrane is semipermeable and only water can pass through it. After two hours (Beaker B), your experimental system has reached equilibrium. You notice that your red blood cells have decreased in volume and become floppy. To fix the problem, you add more liquid from an unlabeled beaker to your cells (you do not know the composition of this liquid). You wait two more hours and notice that your red blood cells have swollen and burst. T/F: In beaker B, there is no longer any water moving in or out of your red blood cells. - True - False
Hypertonic
You are trying to do some experiments on red blood cells, so you place red blood cells in a beaker filled with an aqueous solution. This solution consists of salts and sugars that are similar to those found in the cytosol of a red blood cell. However, you do not know the concentration of the salts and sugars in the beaker. The red blood cell membrane is semipermeable and only water can pass through it. After two hours (Beaker B), your experimental system has reached equilibrium. You notice that your red blood cells have decreased in volume and become floppy. To fix the problem, you add more liquid from an unlabeled beaker to your cells (you do not know the composition of this liquid). You wait two more hours and notice that your red blood cells have swollen and burst. The observation above suggests that at the beginning of the experiment, the solution in the beaker was _______ compared to the cytosol of your red blood cells. - Hypotonic - Hypertonic - Isotonic
Pure water
You are trying to do some experiments on red blood cells, so you place red blood cells in a beaker filled with an aqueous solution. This solution consists of salts and sugars that are similar to those found in the cytosol of a red blood cell. However, you do not know the concentration of the salts and sugars in the beaker. The red blood cell membrane is semipermeable and only water can pass through it. After two hours (Beaker B), your experimental system has reached equilibrium. You notice that your red blood cells have decreased in volume and become floppy. To fix the problem, you add more liquid from an unlabeled beaker to your cells (you do not know the composition of this liquid). You wait two more hours and notice that your red blood cells have swollen and burst. The observations above suggest that the extra liquid you added to your beaker could have been: - More of the solution that was in your beaker to start - Pure water - A highly concentrated solution of salt and sugar
