BIO 103: Practice Quiz (Unit 3)

Allosteric regulation controls reaction rate by ____. producing excess substrates 1. Binding regulatory molecules at a site other than the active site 2. Changing in the temperature of the system 3. Binding regulatory molecules to the active site 4. Alternately oxidizing and reducing the substrate

Binding regulatory molecules at a site other than the active site.

For each six atoms of carbon derived from CO2 fixed in the light-independent reactions, how many molecules of PGAL (phosphoglyceraldehyde) are produced? 1. 2 2. 3 3. 6 4. 12 5. 15

12

How many ATP molecules (net yield) are produced per molecule of glucose during glycolysis? 1. 1 2. 2 3. 4 4. 36 5. 38

2

According to the accompanying diagram, which letter indicates the chloroplast membrane? 1. A 2. B 3. C 4. D 5. E

A

In order to use the energy stored in sugars, cells must first convert it to energy stored in ____, which is synthesized during aerobic respiration. 1. Carbon 2. Oxygen 3. ATP 4. NAD+ 5. carbon dioxide

ATP

In the accompanying figure, letter F represents ____, a product of light-dependent reactions in both the cyclic and noncyclic reactions. 1. ATP 2. Oxygen 3. carbon dioxide 4. Water 5. hydrogen ions

ATP

When fats are broken down as energy sources, the fatty acids are converted to ____ and enter ____. 1. Pyruvate; Glycolysis 2. Acetyl-CoA; Substrate Level Phosphorylation 3. PGAL; the Citric Acid Cycle 4. Acetyl-CoA; the Citric Acid Cycle 5. NADH and FADH2; the Electron Transfer Chain

Acetyl-CoA; the Citric Acid Cycle

ATP contains ____. 1. Adenine 2. Cytosine 3. Uracil 4. Thymine 5. Guanine

Adenine

A molecule that gives up an electron becomes ____. 1. ionized only 2. oxidized only 3. reduced only 4. both ionized and oxidized 5. both ionized and reduced

Both ionized and oxidized

In the accompanying figure, which letter(s) corresponds to the location where the citric acid cycle takes place? 1. A only 2. B only 3. C only 4. A and B 5. B and C

C only

Which type(s) of plants have adapted to hot, dry conditions by minimizing photorespiration? 1. C3 only 2. C4 only 3. CAM only 4. C3 and CAM 5. C4 and CAM

C4 and CAM

Methane (CH4) is a natural gas that is often used as a fuel. When it burns in the presence of oxygen, carbon dioxide and water are produced. Replace the "X" in the following reaction of methane combustion to balance the equation. CH4 + 2O2 → CO2 + XH2O 1. lCH4 + 2O2 → CO2 + 0H2O 2. CH4 + 2O2 → CO2 + 1H2O 3. CH4 + 2O2 → CO2 + 2H2O 4. CH4 + 2O2 → CO2 + 32O 5. CH4 + 2O2 → CO2 + 4H2O

CH4 + 2O2 → CO2 + 2H2O

Which gas is released into the environment when organic material is burned? 1. O2 2. CO2 3. N2 4. H2 5. Cl2

CO2

In order for glycolysis to proceed ____. 1. glucose must enter the mitochondria 2. an input of energy from ATP is required 3. oxygen must be available 4. heat must be supplied 5. carbon dioxide must be available

An input of energy from ATP is required

In the accompanying figure, the reactions at letter B ____.​ ​1. are driven by ATP 2. ​generate water ​3. produce NADPH ​4. are dependent on light ​5. produce O2

Are dependent on light

Glucose enters a cell via a glucose transporter. What prevents glucose molecules from moving back through the transporter and leaving the cell? 1. Phosphorylation 2. charge differences 3. closed transporters 4. gated transporters 5. concentration gradient

Phosphorylation

The electrons that are accepted by NADP+ to form NADPH during the noncyclic pathways of the light-dependent reactions are emitted by ____. 1. photosystem I 2. hydrogen ions 3. Glucose 4. Sunlight 5. ATP synthase

Photosystem I

What is a key feature of autotrophs? 1. Autotrophs harvest energy directly from the environment. 2. Autotrophs do not require carbon. 3. Autotrophs obtain carbon from organic compounds. 4. Autotrophs harvest energy from decomposing organisms. 5. Autotrophs are consumers.

Autotrophs harvest energy directly from the environment

In the accompanying diagram, ATP synthase pumps hydrogen ions into which space? 1. A 2. B 3. C 4. D 5. E

B

The analogy of a key fitting into a lock is descriptive of the ____. 1. random collision between substrate molecules 2. binding of coenzymes to enzymes 3. binding of substrate to the enzyme's active site 4. regeneration of ATP from ADP 5. stepwise cascade of electrons in the oxidation-reduction reactions

Binding of substrate to the enzyme's active site.

A car uses the energy stored in the organic molecules of gasoline to propel the vehicle forward. In this scenario, the ____ energy in the gasoline is converted to ____ energy of motion. 1. potential; chemical bond 2. Chemical; activation 3. Kinetic; potential 4. Potential; kinetic 5. Activation; kinetic

Potential; Kinetic

Which reaction is endergonic? 1. protein synthesis 2. Digestion 3. Fire 4. aerobic respiration 5. muscle contraction

Protein synthesis

Chlorophyll a absorbs which color(s) of light? 1. red only 2. green only 3. violet only 4. red, violet, and orange 5. red, violet, and green

Red. violet, and orange

NAD+ and NADH are coenzymes that carry electrons during glycolysis according to the accompanying reaction. In the accompanying figure, NAD+ is ____ to form NADH and NADH is then ____ to form NAD+. 1. reduced; Oxidized 2. Oxidized; reduced 3. ionized ; reduced 4. oxidized; ionized 5. altered; not altered

Reduced; Oxidized

Which enzyme catalyzes the process of carbon fixation? 1. RuBP 2. ATP synthase 3. PGAL 4. Rubisco 5. thylakoid kinase

Rubisco

All of these substances assist enzymes during the catalysis of biochemical reactions. Which one is a cofactor (that is, not a coenzyme)? 1. ATP 2. Heme 3. vitamin B7 (biotin) 4. flavine adenine dinucleotide (FAD) 5. nicotine adenine dinucleotide phosphate (NADP)

Vitamin B7 (biotin)

During times of high sugar production, some PGAL molecules that remain in the chloroplast ____. ​1. undergo carbon fixation by ATP synthase ​2. are assembled into lipid molecules ​3. are assembled into starch molecules ​4. are used to produce sucrose ​5. are exported to the plant's vascular tissue

are assembled into starch molecules

What are the molecular reactants for photosynthesis in plants? 1. H2O only 2. CO2 only 3. O2 only 4. both CO2 and O2 5. both CO2 and H2O

both CO2 and H2O

Why is pyruvate reduced to lactate during fermentation? 1. to produce more ATP only 2. to produce CO2 only 3. to regenerate NAD+ from NADH 4. to produce both ATP and CO2. 5. to produce ATP and regenerate NAD+ from NADH

to regenerate NAD+ from NADH

In the formation of ATP from ADP and Pi, ADP is ____. 1. Reduced 2. Oxidized 3. Phosphorylated 4. Denatured 5. inactivated

Phosphorylated

For each molecule of CO2 that enters the Calvin-Benson cycle, ____ NADPH molecules are reduced and ____ molecules of ATP are split into ADP and Pi. 1. Two; Two 2. Two; Six 3. Six; Two 4. Six; Six 5. Five; One

Two; Two

How is the process of carbon fixation necessary for plant growth? 1. Carbon fixation extracts carbons from organic plant sugars to be used for energy. 2. Carbon fixation incorporates carbon from PGAL into sugar molecules. 3. Carbon fixation extracts carbon from an inorganic source (CO2) and uses it to build sugars. 4. Carbon fixation extracts carbon from an inorganic source (CO2) to produce O2 needed for plant growth. 5. Carbon fixation regenerates carbon to be used in the light-dependent reactions for ATP production.

Carbon fixation extracts carbon from an inorganic source (CO2) to produce O2 needed for plant growth

Some enzymes require inorganic or organic molecules for proper function. These molecules are known as ____. 1. coenzymes only 2. cofactors only 3. antioxidants only 4. coenzymes and cofactors 5. coenzymes, cofactors, and antioxidants

Coenzymes and cofactors.

According to the accompanying diagram, where are hydrogen ions sequestered? 1. A 2. B 3. C 4. D 5. E

D

Which type of molecular movement is a passive process? 1. sodium-potassium pump 2. Endocytosis 3. Exocytosis 4. Diffusion 5. active transport

Diffusion

NADH transfers electrons to oxygen during ____. 1. Glycolysis 2. acetyl-CoA formation 3. the citric acid cycle 4. electron transfer phosphorylation 5. substrate-level phosphorylation

Electron transfer phosphorylation

What do NADH and FADH2 deliver to electron transfer chains? 1. electrons only 2. hydrogen ions only 3. Oxygen 4. electrons and hydrogen ions 5. phosphate

Electrons and hydrogen ions

Which subatomic particles of a pigment absorb light? 1. electrons only 2. protons only 3. neutrons only 4. electrons and protons 5. protons and neutrons

Electrons only

The first law of thermodynamics states that ____. 1. one form of energy cannot be converted into another 2. entropy is increasing in the universe 3. energy can be neither created nor destroyed 4. energy cannot be converted into matter 5. energy is the capacity to do work

Energy can be neither created nor destroyed.

Suppose that it takes three pounds of feed to generate one pound of chicken meat. What happens to the other two pounds of feed? 1. Energy is only lost in portions of feed that are indigestible. 2. Energy is lost only as heat. 3. Energy is both lost in substances that are indigestible and as heat. 4. Energy is only lost to maintain constant entropy in the system. 5. Energy is destroyed during the process of energy conversion.

Energy is both lost in substances that are indigestible and as heat.

During alcoholic fermentation, electrons and hydrogen ions are transferred from NADH to acetaldehyde, forming ____. 1. lactate and ethanol 2. NAD+ only 3. ethanol only 4. NAD+ and ethanol 5. lactate NAD+

Ethanol Only

Pyruvate is the end product of ____. 1. Glycolysis 2. acetyl-CoA formation 3. Fermentation 4. the citric acid cycle 5. the electron transport chain

Glycolysis

When blood glucose levels decrease (for example, between meals), which energy reserves are tapped first? 1. Glycogen 2. Fats 3. Proteins 4. Ethanol 5. amino acids

Gylcogen

When O2 accepts electrons in aerobic respiration, it is converted to ____. 1. O3 2. CO2 3. OH− 4. H2O 5. CO

H2O

During electron transfer phosphorylation ____, ions accumulate in the intermembrane space of the mitochondria. 1. Calcium 2. Hydrogen 3. Oxygen 4. Phosphorus 5. Sodium

Hydrogen

During light-dependent reactions, ____ accumulates inside the thylakoid compartment. 1. Glucose 2. hydrogen ions 3. O2 4. CO2 5. ATP

Hydrogen Ions

The flow of electrons through the electron transfer chain generates a(n) ____ gradient that drives ____ by ____. 1. oxidative; Oxidation of Coenzymes; Redox Reaction 2. Hydrogen ion; ATP synthesis; Electron Transfer Phosphorylation 3. Electron; ATP Synthesis; Electron Transfer Phosphorylation 4. Hydrogen ion; Regeneration of coenzymes; Substrate-level of Phosphorylation 5. Electron; ATP Synthesis; redox reactions

Hydrogen ion;ATP synthesis; Electron transfer Phosphorylation

The transport of ____ across the thylakoid membrane powers ATP production. 1. Electrons 2. hydrogen ions 3. Oxygen 4. carbon dioxide 5. phosphate ions

Hydrogen ions

The red blood cells shown in the middle micrograph of the accompanying figure are immersed in a(n) ____ solution. 1. Hypotonic 2. Isotonic 3. Hypertonic 4. enzymaticturgor

Hypertonic

A cell placed in a(n) ____ solution will ____. 1. isotonic; swell 2. hypotonic; swell 3. hypotonic; shrink 4. hypertonic; remain the same size 5. hypertonic; swell

Hypotonic; shrink

What is the correct operational sequence of the processes of aerobic respiration? I. glycolysis II. electron transfer III. citric acid cycle IV. acetyl-CoA formation 1. I → II → III → IV 2. II → IV → I → III 3. IV → III → I → II 4. II → III → IV → I 5. I → IV → III → II

I → IV → III → II

A teacher at the front of a classroom sprays a mist of perfume into the air. After a few minutes, the students in the back of the room are able to smell the perfume. This is an example of ____. 1. increasing entropy only 2. diffusion only 3. decreasing entropy only 4. increasing entropy and diffusion 5. decreasing entropy and diffusion

Increasing entropy and diffusion

A car uses the energy stored in the organic molecules of gasoline to propel the vehicle forward. However, not all the energy contained in the fuel molecules is used for propulsion instead, some is lost as heat. In this scenario, entropy is ____, illustrating the ____ law of thermodynamics. 1. Increasing; Second 2. Decreasing; Second 3. Increasing; First 4. Decreasing; Second 5. Staying the same; Second

Increasing; Second

Substrate level phosphorylation ____. 1. involves the direct transfer of a phosphate group from a substrate 2. requires the presence of oxygen 3. requires the presence of NADH 4. produces most of the ATPs yield during aerobic respiration 5. involves the generation of a hydrogen ion gradient to produce ATP

Involves the direct transfer of a phosphate group from a substrate

Figure 5.19 The red blood cells shown in the top micrograph of the accompanying figure are immersed in a(n) ____ solution. 1. Hypotonic 2. Isotonic 3. Hypertonic 4. Enzymatic 5. turgor

Isotonic

When intense exercise depletes oxygen in muscle cells faster than it can be replenished, these cells will produce ____ by ____. 1. Ethyl alcohol; Alcoholic fermentation 2. Acetaldehyde; Glycolysis 3. Pyruvate; Glycolysis 4. Lactate; Lactate Fermentation 5. Citrate; Citric acid cycle

Lactate; Lactate fermentation

During endergonic reactions, reactants with ____ free energy are converted to molecules with ____ free energy; therefore, they require a net input of energy in order to proceed. 1. more; less 2. less;more 3. zero;low 4. high levels of; no 5. potential; kinetic

Less;more

Glycolysis depends on a continuous supply of ____. 1. Oxygen 2. Pyruvate 3. NAD+ 4. NADH 5. H2O

NAD+

The final step of both alcoholic and lactate fermentation regenerate 1. Glucose 2. ADP 3. NAD+ 4. NADH 5. Electrons

NAD+

Figure 5.3 The accompanying figure illustrates the ____ biological systems. 1. destruction of energy in 2. dispersion of chemical bond energy throughout 3. decrease in entropy in 4. one-way flow of energy through 5. bidirectional flow of energy through

One-way flow of energy through

The removal of electrons from a compound is known as ____. 1. Dehydration 2. Oxidation 3. Reduction 4. Phosphorylation 5. allosteric regulation

Oxidation

Before photosynthesis evolved, ____ was a very small component of Earth's early atmosphere. 1. carbon dioxide 2. Nitrogen 3. Water 4. Oxygen 5. argon

Oxygen

How does a high environmental pH affect an enzyme's activity? 1. High pH decreases the activity of all enzymes. 2. High pH increases the activity of all enzymes. 3. High pH changes the shape of all enzymes. 4. High pH does not affect the enzyme, but does lower the availability of substrate. 5. Some enzymes work well at a high pH, some work well at low pH.

Some enzymes work well at a high pH, some work well at low pH

Openings in leaves through which gases enter and exit are called ____. 1. Mesophylls 2. Stroma 3. Rubiscos 4. Stomata 5. photosystems

Stomata

The transfer of a phosphate group (Pi) from an intermediate in the glycolysis pathway to ADP is an example of harvesting energy by ____. 1. electron transfer phosphorylation 2. acetyl-CoA formation 3. Reduction 4. Oxidation 5. substrate-level phosphorylation

Substrate-level phosphorylation

In Engelmann's 1882 experiment, why did bacteria cluster in areas of red or blue wavelengths of light? 1. The bacteria used light of those wavelengths for photosynthesis. 2. Algae photosynthesized most efficiently at those wavelengths, producing needed oxygen. 3. The bacteria produced oxygen most efficiently using red and blue light. 4. Algae photosynthesized most efficiently at those wavelengths, producing needed carbon dioxide. 5. The bacteria were attracted to bright light.

The bacteria produced oxygen most efficiently using red and blue light

How does the cyclic pathway of light-dependent reactions differ from noncyclic reactions? ​1. Photolysis is performed by photosystem II in the cyclic pathway, but by photosystem II in the noncyclic pathway. 2. ​The noncyclic pathway uses electrons from water to produce ATP, while the cyclic pathway uses electrons from water to produce sugars. ​3. The noncyclic pathway evolved before the cyclic pathway and does not produce sugars. 4. The cyclic pathway evolved before the noncyclic pathway and does not produce oxygen. 5. Although the noncyclic reactions evolved first, carbon fixation occurs in both cyclic and noncyclic reactions.

The cyclic pathway evolved before the noncyclic pathway and does not produce oxygen.

What occurs when glucose molecules are broken apart during cellular respiration? 1. The heat produced is used to drive biological reactions. 2. Oxygen is released and used as an energy source. 3. The energy released is used in ATP synthesis. 4. ATP is converted into ADP. 5. ADP is released as a waste product.

The energy released is used in ATP synthesis

The ultimate source of energy for living organisms is ____. 1. the citric acid cycle 2. fossil fuels 3. the sun 4. Oxygen 5. aerobic respiration

The sun

Activation energy is the energy required to bring the bonds in reactant molecules to ____. 1. the active site 2. their strongest conformation 3. a reducing agent 4. their breaking point 5. an oxidizing agent

Their breaking point

Twelve PGAL molecules form when six carbon dioxide molecules are attached to six RuBP molecules. Only two of these PGAL molecules are needed to form a 6-carbon sugar. What is the fate of the 10 remaining PGAL molecules? 1. They are degraded. 2. They are converted back to carbon dioxide. 3. They are stored as extra PGAL molecules. 4. They are used during photorespiration. 5. They are converted to RuBP molecules.

They are used during photorespiration

When protein molecules are used as energy sources, the amino groups of the amino acids are ____ and the carbon backbones enter ____. 1. excreted as free amino groups (-NH2); glycolysis 2. build new proteins; the electron transfer chain 3. excreted as ammonia (NH3); the citric acid cycle 4. used to synthesize nucleic acids; glycolysis 5. converted to glycogen; citric acid cycle

excreted as ammonia (NH3); the citric acid cycle

Chlorophyll is found ____ of a plant cell. 1. on the outer chloroplast membrane 2. inside the mitochondria 3. in the stroma 4. in the thylakoid membrane 5. in the plant cell wall

in the thylakoid membrane

During glycolysis, glucose is first phosphorylated twice, and then split into two three-carbon compounds called ____. 1. phosphoglyceraldehyde (PGAL) 2. Pyruvate 3. acetyl CoA 4. Lactate 5. acetaldehyde

phosphoglyceraldehyde (PGAL)

Why is photorespiration an inefficient way to produce sugars? ​1. Photorespiration produces 7-carbon carbohydrate molecules instead of 6-carbon sugars. ​2. The increased production of O2 during photorespiration generates excess dangerous free radicals. ​3. Photorespiration only occurs during the night, when the light-dependent reactions are inactive. ​4. CO2 is lost instead of being fixed and ATP is required to detoxify the ammonia that is produced. ​5. Carbon fixation requires an extra turn of the Calvin-Benson cycle for each molecule of sugar produced.

​Photorespiration only occurs during the night, when the light-dependent reactions are inactive.