Biology Test 1 Chapter 5

A chemical reaction that uses ATP to build cellular components is a. catabolic. c. photosynthetic. b. anabolic. d. respiration.

b. anabolic.

Which of these carries the most energy? a. ADP c. NADH b. ATP d. NAD+

b. ATP

Which of the following is a similarity between photosynthesis and respiration? a. Neither is a metabolic process. b. They are both metabolic processes. c. Neither is an anabolic process. d. They are both mainly anabolic processes.

b. They are both metabolic processes.

As an energy carrier, ATP differs from NADPH in that a. ATP transfers energy through phosphorylation, whereas NADPH donates electrons and hydrogen ions. b. ATP transfers energy through redox reactions, whereas NADPH uses phosphorylation. c. NADPH is involved in a larger variety of chemical reactions than ATP. d. NADPH is made by Photosystem I, whereas ATP is made by Photosystem II.

a. ATP transfers energy through phosphorylation, whereas NADPH donates electrons and hydrogen ions.

________ reactions release energy by breaking down complex molecules. a. Catabolic c. Photosynthetic b. Anabolic d. Respiration

a. Catabolic

The image below diagrams the action of an enzyme. Notice that the enzyme is depicted as being more tightly wrapped around the substrates in step 2 than it is in step 1. Why is this? a. When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around the substrates. b. Generally, the size of a substrate is larger than the size of the active site into which it must fit. When the substrate enters the active site, the active site must stretch to fit. c. Before catalysis can occur, a substrate must change its shape so that it fits into the active site of the enzyme more precisely. d. Most active sites are only designed to hold one substrate. In this image, two substrates enter the active site, creating a tighter fit.

a. When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around the substrates.

Chemical reactions that break down lipids are a. catabolic. c. metabolic. b. anabolic. d. respiration.

a. catabolic.

Some kinds of drain cleaners use enzymes rather than strong, more dangerous chemicals. These enzymes must be able to a. catalyze a catabolic reaction. b. raise the energy of the reaction that clears the clog. c. create energy that can be used to break up the clog. d. catalyze an anabolic reaction.

a. catalyze a catabolic reaction.

The capture and use of energy by living organisms involves numerous chemical reactions. Collectively these processes are known as a. metabolism. c. anabolic reactions. b. respiration. d. catabolic reactions.

a. metabolism.

Photosynthetic organisms capture energy from sunlight and convert it into chemical bonds by forming a. sugars. c. work. b. enzymes. d. substrates.

a. sugars.

What should the arrow in the following equation be labeled? Sugar + oxygen --> carbon dioxide + water + ATP. a. photosynthesis c. Krebs cycle b. cellular respiration d. Calvin cycle

b. cellular respiration

When ATP breaks down into ADP and a phosphate group, a. energy is absorbed by ADP and transferred to enzymes. b. energy is released and can power cellular activities. c. ADP becomes the active site in an enzyme. d. the energy in the broken bond is transferred to the phosphate group.

b. energy is released and can power cellular activities.

The energy required for life processes must be extracted from an organism's a. nucleus. c. predators. b. environment. d. biosynthesis.

b. environment.

In a human cell, a. one enzyme usually catalyzes no more than five different chemical reactions. b. nearly all chemical reactions are catalyzed by enzymes. c. enzymes have to be constantly replaced as they are used up in the reactions that they catalyze. d. some enzymes are specialized to store activation energy.

b. nearly all chemical reactions are catalyzed by enzymes.

In the reaction C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O, the 6 CO2 molecules are some of the a. substrates. c. enzymes. b. products. d. reactants

b. products

Plants and animals use different energy storage molecules, yet they both use the same mechanism to "burn" their stored energy. How can plants and animals both be successful, even though they "burn" different energy storage molecules? a. The internal components of plant and animal cells are identical. b. The second law of thermodynamics says that all cells have the same energy transfer system. c. The breaking of the chemical bonds of a storage molecule transfers energy, no matter what molecule is stored. d. All organisms have the same enzymes to catalyze their energy-producing reactions.

c. The breaking of the chemical bonds of a storage molecule transfers energy, no matter what molecule is stored.

The first law of thermodynamics states that a. metabolic reactions must be balanced. b. the flow of energy connects living things to their environments. c. energy cannot be created nor destroyed. d. systems tend to become more disorderly.

c. energy cannot be created nor destroyed.

In the reaction H2O + CO2 + carbonic anhydrase --> H+ + HCO3-+ carbonic anhydrase, carbonic anhydrase is a(n) a. reactant. c. enzyme. b. product. d. active site.

c. enzyme.

Carbon dioxide is one product of a metabolic process, which occurs in both plants and animals. This process is called a. catalysis. c. respiration. b. glycolysis. d. photosynthesis.

c. respiration.

Photosynthesis and cellular respiration are both complementary and relatively balanced, but early history of life on Earth showed increasing oxygen concentrations. This indicates that a. both photosynthesis and respiration were occurring at approximately the same levels. b. neither photosynthesis nor respiration were occurring. c. the amount of photosynthesis occurring exceeded the amount of cellular respiration. d. the amount of cellular respiration occurring exceeded the amount of photosynthesis.

c. the amount of photosynthesis occurring exceeded the amount of cellular respiration.

In many organelles, groups of different enzymes are located on membranes in close proximity to each other because a. attaching enzymes to the membrane prevents the cell from losing them to the surrounding environment. b. when enzymes are in close proximity, each one can catalyze more than one type of reaction. c. these enzymes are involved in the same metabolic pathway and keeping them closer together increases the efficiency of the pathway. d. all enzymes must act in groups to position substrates in the proper orientation to produce the product.

c. these enzymes are involved in the same metabolic pathway and keeping them closer together increases the efficiency of the pathway.

Which of the following is either consumed or synthesized in virtually every cellular reaction? a. sugars c. DNA b. enzymes d. ATP

d. ATP

What is the importance of photosynthesis to organisms other than plants? a. All other organisms require carbon dioxide for life processes. b. The sugars made during photosynthesis are building blocks of DNA. c. All cells must have chloroplasts in order to survive. d. Photosynthesis captures energy that other organisms access when they eat either plants or organisms that eat plants.

d. Photosynthesis captures energy that other organisms access when they eat either plants or organisms that eat plants.

Cells contain the molecule GTP (guanosine triphosphate). Would this molecule be useful as an energy carrier (similar to ATP)? a. No, because it does not contain the adenosine necessary for storing energy. b. No, because it contains fewer phosphates than ATP. c. Yes, because it contains a nitrogenous base just like ATP. d. Yes, because it contains the same number of phosphates as does ATP.

d. Yes, because it contains the same number of phosphates as does ATP.

The enzyme rubisco is important to the process of a. catabolism. c. glycolysis. b. fermentation. d. carbon fixation.

d. carbon fixation.

A given enzyme a. can be used for many different kinds of chemical reactions. b. is permanently changed during a chemical reaction. c. has a special site where the products bind before the reaction begins. d. increases the rate of a particular reaction.

d. increases the rate of a particular reaction.

Enzymes can catalyze a reaction only if a. they encounter a molecule of ATP. b. their active site is sufficiently oxidized. c. they have both products in their active site at the same time. d. they encounter a substrate that fits their active site.

d. they encounter a substrate that fits their active site.