Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
70 Cards in this Set
- Front
- Back
According to the fluid mosaic model of cell membranes, what is true of membrane phospholipids? |
They can move laterally along the plane of the membrane |
|
What is true of integral membrane proteins? |
They are usually transmembrane proteins |
|
You measure the uptake of a compound into cells and find that in the presence of ATP there is uptake but in the absense of ATP there is not. What is the best explanation of this? |
This process is taken up by active transport |
|
What is true about diffusion? |
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration |
|
What diffuses most easily through the phospholipid bilayer? |
O2 |
|
What diffuses least easily through the phospholipid bilayer? |
CO2 |
|
Mammilian blood contains the equivilant of 0.15M of NaCl. Seawater contains the equivilant of 0.45 M NaCl. What will happen if red blood cells are transferred from the bloodstream to seawater? |
Water will leave the cells causing them to shrivel and collapse. |
|
Solution A is hypertonic compared to solution B. This means that: |
Solution A has a higher concentration of dissolved solutes to solution B |
|
Which of the following is a characteristic feature of a carrier protein in a plasma membrane? |
It exhibits a specificity for a particular type of molecule. |
|
What is a membrane potential? |
A voltage difference across a membrane due to unequal distribution of charged solutes. |
|
A vesicle fuses with a cell membrane, releasing its contents outside of the cell. Which type of transport event is this? |
Exocytosis |
|
Which term most-precisely describes the cellular process of breaking down large, complex molecules into smaller, simpler ones?? |
Catabolism |
|
What is stated in the first law of thermodynamics? |
Energy can be transformed into other forms of energy but energy cannot be created nor destroyed |
|
Which molecule connects with anabolism and catabolism in cells by storing energy from catabolic reactions and providing that energy to anabolic reactions? |
ATP |
|
Characterize this reaction: C6H12O6 |
Catabolic: G=0; exergonic; NADH intermediate; ATP is produced |
|
How do enzymes speed up chemical reactions in cells? |
Enzymes lower the activation energy barrier of reactions |
|
What is the active site of an enzyme? |
The place on the enzyme where the substrate binds. |
|
Zinc is present in the active site of the enzyme carboxypeptidase. The zinc most likely acts as a |
Cofactor necessary for enzyme activity. |
|
How does a competitive inhibitor decrease the rate of an enzyme reaction? |
By binding to the active site of the enzyme |
|
Beta-galactosidase is a multimeric enzyme. If one of its subunits binds one molecule of lactose, the binding of lactose to the other subunits is facilitated. What is the term for this phenomenon? |
Cooperativity |
|
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as |
Feedback inhibition |
|
When a molecule of NADH donates an electron as a part of a redox reaction, the molecule becomes |
Oxidized |
|
Which of the following statements about NAD+ is false? |
NAD+ has more chemical energy than NADH |
|
The primary role of oxygen in cellular respiration is to: |
Act as an acceptor for electrons and hydrogen, forming water. |
|
The ATP made during glycolysis is generated by: |
Substrate level phosphorylation |
|
What happens in glycolysis? |
Glucose is split into two pyruvate molecules, creating 2 NADH and 2 ATP |
|
What happens in the citric acid cycle? |
Acetyl-CoA is converted to 2 CO2, forming 3 NADH, 1 ATP and 1 FADH2 |
|
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the highest energy level? |
NADH |
|
Describe the flow of electrons during cellular respiration? |
Sugars to NADH to electron transport chain to 02 |
|
Feedback regulation coordinates the rate of cellular respiration with the metabolic needs of a cell. which compound inhibits the activity of phosphofructokinase, a key enzyme in glycolysis |
ATP and citrate |
|
The most important function of fermentation is to: |
Recycle NADH to NAD+ so that glycolysis can continue |
|
When oxygen is released as a result of photosynthesis, it is a by-product of which of the following? |
Splitting of water molecules |
|
Photosynthesis requires light. Why? |
Light excites the electrons in pigments, and these high energy electrons are used later to reduce CO2, forming sugars |
|
What is a photosystem? |
A cluster of pigments and proteins that work together to capture light |
|
In the thykaloid membrane, what is the main role of the pigment molecules in the light harvesting complex? |
Absorb photons and transfer light energy to the reduction center chlorophyll |
|
Reduction of NAD+ occurs in |
Photosynthesis |
|
Which of the following statements best represents the relationships between the light reactions and the Calvin Cycle? |
The light reactions provide ATP and NADPH to the calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions |
|
What do oxidative phosphorylation and photophosphorylation have in common? |
A proton pump is coupled to an ATP synthase in the same membrane which uses the proton gradient to produce ATP. |
|
Reactions that require CO2 input occur in the |
Calvin Cycle |
|
What happens in the Calvin Cycle of photosynthesis? |
CO2 is fixed and glyceraldehyde 3-phosphate (G3P) is made using NADPH and ATP |
|
Describe the water flow of electrons during photosynthesis |
Water--> PSII--> ETC --> PSI --> NADPH --> Sugars |
|
Chlorophyll and other pigments involved in photosynthesis are located in: |
Thylakoids |
|
Photorespiration: |
Involves the same enzyme, rubisco, of calvin cycle |
|
CO2 in mesophyll cells of c4 plants condense with: |
phosphoenol pyruvate to make a four carbon product |
|
Calvin cycle in bundle sheath cells |
C4 plants |
|
Calvin cycle in Mesophyll cell |
C3 plants |
|
Calvin cycle during the day time |
CAM plant |
|
Oxygen released during photosynthesis is comes from the splitting of: |
H2O |
|
G3P is produced in the Calvin cycle during |
Reduction phase |
|
A competitive enzyme inhibitor |
appears structurally similar to the substrate |
|
Substances that tend to maintain pH |
buffers |
|
Fermentation in yeast results in |
production of alcohol |
|
Properties associated with an enzyme |
- has an active site - substrate specific - binds to substrate - lowers the activation energy
|
|
Allosteric enzyme oscillates between inactive and active states because: |
of conformation change at a site other than the active site |
|
Which sequence of reactions represents correct flow of electrons in photosynthesis? |
H2O to NADPH ---> Calvin cycle |
|
A Photosystem contains: |
light harvesting systems and reaction center |
|
Chemiosmosis causes |
generation of ATP from ADP |
|
pH will change when OH- ions are added and: |
will become basic |
|
Which of the following proteins is most abundant in the biosphere? |
Rubisco |
|
Which metabolic pathway is common to fermentation and cellular respiration? |
glycolysis |
|
Noncylic electron flow in photosynthesis results in synthesis of: |
ATP and NADPH |
|
Difference between autotrophs and heterotrophs |
Autotrophs but not heterotrophs can nourish themselves starting with CO2 and inorganic chemicals |
|
What is driven by the ETC from light driven reactions? |
Creation of pH gradient by pumping proteins across the thylakoid membranes |
|
Phosphorylation involves generation of: |
ATP from sunlight |
|
In mechanism phosphorylation is most similar to: |
Oxidative phosphorylation in cellular respiration |
|
Fatty acids are oxidized by |
beta oxidation |
|
Net gain of ATP from glycolysis consists of: |
two ATP |
|
Krebs cycle recycles: |
oxaloacetates |
|
Intermediate energy source in the cell that drives reactions is: |
ATP |
|
Energized (excited) electrons from the photosystem are captured by: |
primary electron acceptor |