Life 102 Exam 2

Front 1

According to the fluid mosaic model of cell membranes, what is true of membrane phospholipids?

Back 1

They can move laterally along the plane of the membrane

Front 2

What is true of integral membrane proteins?

Back 2

They are usually transmembrane proteins

Front 3

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?

Back 3

This process is taken up by active transport

Front 4

What is true about diffusion?

Back 4

It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration

Front 5

What diffuses most easily through the phospholipid bilayer?

Back 5

O2

Front 6

What diffuses least easily through the phospholipid bilayer?

Back 6

CO2

Front 7

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?

Back 7

Water will leave the cells causing them to shrivel and collapse.

Front 8

Solution A is hypertonic compared to solution B. This means that:

Back 8

Solution A has a higher concentration of dissolved solutes to solution B

Front 9

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

Back 9

It exhibits a specificity for a particular type of molecule.

Front 10

What is a membrane potential?

Back 10

A voltage difference across a membrane due to unequal distribution of charged solutes.

Front 11

A vesicle fuses with a cell membrane, releasing its contents outside of the cell. Which type of transport event is this?

Back 11

Exocytosis

Front 12

Which term most-precisely describes the cellular process of breaking down large, complex molecules into smaller, simpler ones??

Back 12

Catabolism

Front 13

What is stated in the first law of thermodynamics?

Back 13

Energy can be transformed into other forms of energy but energy cannot be created nor destroyed

Front 14

Which molecule connects with anabolism and catabolism in cells by storing energy from catabolic reactions and providing that energy to anabolic reactions?

Back 14

ATP

Front 15

Characterize this reaction: C6H12O6
+ 6 O2 ---> 6 CO2 + 6 H20

Back 15

Catabolic: G=0; exergonic; NADH intermediate; ATP is produced

Front 16

How do enzymes speed up chemical reactions in cells?

Back 16

Enzymes lower the activation energy barrier of reactions

Front 17

What is the active site of an enzyme?

Back 17

The place on the enzyme where the substrate binds.

Front 18

Zinc is present in the active site of the enzyme carboxypeptidase. The zinc most likely acts as a

Back 18

Cofactor necessary for enzyme activity.

Front 19

How does a competitive inhibitor decrease the rate of an enzyme reaction?

Back 19

By binding to the active site of the enzyme

Front 20

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?

Back 20

Cooperativity

Front 21

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as

Back 21

Feedback inhibition

Front 22

When a molecule of NADH donates an electron as a part of a redox reaction, the molecule becomes

Back 22

Oxidized

Front 23

Which of the following statements about NAD+ is false?

Back 23

NAD+ has more chemical energy than NADH

Front 24

The primary role of oxygen in cellular respiration is to:

Back 24

Act as an acceptor for electrons and hydrogen, forming water.

Front 25

The ATP made during glycolysis is generated by:

Back 25

Substrate level phosphorylation

Front 26

What happens in glycolysis?

Back 26

Glucose is split into two pyruvate molecules, creating 2 NADH and 2 ATP

Front 27

What happens in the citric acid cycle?

Back 27

Acetyl-CoA is converted to 2 CO2, forming 3 NADH, 1 ATP and 1 FADH2

Front 28

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the highest energy level?

Back 28

NADH

Front 29

Describe the flow of electrons during cellular respiration?

Back 29

Sugars to NADH to electron transport chain to 02

Front 30

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

Back 30

ATP and citrate

Front 31

The most important function of fermentation is to:

Back 31

Recycle NADH to NAD+ so that glycolysis can continue

Front 32

When oxygen is released as a result of photosynthesis, it is a by-product of which of the following?

Back 32

Splitting of water molecules

Front 33

Photosynthesis requires light. Why?

Back 33

Light excites the electrons in pigments, and these high energy electrons are used later to reduce CO2, forming sugars

Front 34

What is a photosystem?

Back 34

A cluster of pigments and proteins that work together to capture light

Front 35

In the thykaloid membrane, what is the main role of the pigment molecules in the light harvesting complex?

Back 35

Absorb photons and transfer light energy to the reduction center chlorophyll

Front 36

Reduction of NAD+ occurs in

Back 36

Photosynthesis

Front 37

Which of the following statements best represents the relationships between the light reactions and the Calvin Cycle?

Back 37

The light reactions provide ATP and NADPH to the calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions

Front 38

What do oxidative phosphorylation and photophosphorylation have in common?

Back 38

A proton pump is coupled to an ATP synthase in the same membrane which uses the proton gradient to produce ATP.

Front 39

Reactions that require CO2 input occur in the

Back 39

Calvin Cycle

Front 40

What happens in the Calvin Cycle of photosynthesis?

Back 40

CO2 is fixed and glyceraldehyde 3-phosphate (G3P) is made using NADPH and ATP

Front 41

Describe the water flow of electrons during photosynthesis

Back 41

Water--> PSII--> ETC --> PSI --> NADPH --> Sugars

Front 42

Chlorophyll and other pigments involved in photosynthesis are located in:

Back 42

Thylakoids

Front 43

Photorespiration:

Back 43

Involves the same enzyme, rubisco, of calvin cycle

Front 44

CO2 in mesophyll cells of c4 plants condense with:

Back 44

phosphoenol pyruvate to make a four carbon product

Front 45

Calvin cycle in bundle sheath cells

Back 45

C4 plants

Front 46

Calvin cycle in Mesophyll cell

Back 46

C3 plants

Front 47

Calvin cycle during the day time

Back 47

CAM plant

Front 48

Oxygen released during photosynthesis is comes from the splitting of:

Back 48

H2O

Front 49

G3P is produced in the Calvin cycle during

Back 49

Reduction phase

Front 50

A competitive enzyme inhibitor

Back 50

appears structurally similar to the substrate

Front 51

Substances that tend to maintain pH

Back 51

buffers

Front 52

Fermentation in yeast results in

Back 52

production of alcohol

Front 53

Properties associated with an enzyme

Back 53

- has an active site

- substrate specific

- binds to substrate

- lowers the activation energy

Front 54

Allosteric enzyme oscillates between inactive and active states because:

Back 54

of conformation change at a site other than the active site

Front 55

Which sequence of reactions represents correct flow of electrons in photosynthesis?

Back 55

H2O to NADPH ---> Calvin cycle

Front 56

A Photosystem contains:

Back 56

light harvesting systems and reaction center

Front 57

Chemiosmosis causes

Back 57

generation of ATP from ADP

Front 58

pH will change when OH- ions are added and:

Back 58

will become basic

Front 59

Which of the following proteins is most abundant in the biosphere?

Back 59

Rubisco

Front 60

Which metabolic pathway is common to fermentation and cellular respiration?

Back 60

glycolysis

Front 61

Noncylic electron flow in photosynthesis results in synthesis of:

Back 61

ATP and NADPH

Front 62

Difference between autotrophs and heterotrophs

Back 62

Autotrophs but not heterotrophs can nourish themselves starting with CO2 and inorganic chemicals

Front 63

What is driven by the ETC from light driven reactions?

Back 63

Creation of pH gradient by pumping proteins across the thylakoid membranes

Front 64

Phosphorylation involves generation of:

Back 64

ATP from sunlight

Front 65

In mechanism phosphorylation is most similar to:

Back 65

Oxidative phosphorylation in cellular respiration

Front 66

Fatty acids are oxidized by

Back 66

beta oxidation

Front 67

Net gain of ATP from glycolysis consists of:

Back 67

two ATP

Front 68

Krebs cycle recycles:

Back 68

oxaloacetates

Front 69

Intermediate energy source in the cell that drives reactions is:

Back 69

ATP

Front 70

Energized (excited) electrons from the photosystem are captured by:

Back 70

primary electron acceptor