The Living World 9th Edition by George Johnson - Test Bank

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Objects that are not actively moving but have the capacity to do so are said to possess potential energy.

Reactions that tend to proceed on their own, releasing energy, are called exergonic.

Enzymes are catalysts because they function to lower activation energy.

The site on the surface of an enzyme where a substrate binds is called the binding site.

Relative humidity does not influence the action of enzymes.

Movement of water across the cell membrane down the concentration gradient does NOT require cellular energy.

ATP is composed of a sugar, the organic base adenine, and three phosphate groups.

In reference to enzyme activities, repressors disrupt the active site, while activators restore it.

The site on the enzyme surface where the reactant binds is referred to as the active site.

Objects that are moving are said to possess kinetic energy.

The making and breaking of chemical bonds is called chemical reactions.

Diffusion of oxygen into the blood does not use ATP.

A boulder perched on a hill has potential energy, not kinetic energy.

The first law of thermodynamics states that energy can be changed from one form to another, but cannot be created or destroyed.

Chemical reactions that release energy are called exergonic reactions.

A competitive inhibitor interferes with the active site of the enzyme so a substrate cannot bind.

The extra energy required to destabilize existing chemical bonds and to initiate a chemical reaction is called activation energy.

Energy flows into the biological world from the sun.

Most human enzymes work best within the range of pH 6 – 8.

A competitive inhibitor of enzymes interferes with the active site of the enzyme; a noncompetitive inhibitor of enzymes indirectly interferes by changing the shape of the active site of the enzyme.

The components of an ATP molecule are ribose, 3 phosphates, 1 adenine.

All cells convert the potential energy found in food molecules into ATP through cellular respiration.

allosteric

The site where a signal molecule binds to the surface of an enzyme is the allosteric site.

thermodynamics

The study of energy is called thermodynamics.

potential

A ball sitting on a table top has potential energy because of its position.

coupled

When an endergonic reaction is driven by the splitting of ATP molecules, such that both these reactions occur simultaneously, the two-part reaction is called a coupled reaction.

potential, kinetic

If a ball begins to roll down an incline, its potential energy is converted into kinetic energy.

Energy can be converted from one form to another, but cannot be created or destroyed.

The first law of thermodynamics states that energy can be converted from one form to another, but cannot be created or destroyed.

entropy

A measure of the degree of disorder in a system is called entropy.

catalysis

The process of lowering the activation energy of a chemical reaction is called catalysis.

endergonic

In endergonic reactions, the products contain more energy than the reactants.

No, different types of cells have different enzymes, depending on the needs of the cells. Every kind of cell contains thousands of different kinds of enzymes.

The enzyme becomes denatured. Chemical bonds that maintain the enzyme’s shape and configuration are too weak to hold the peptide chains in their proper position.

Enzymes can be regulated by a mechanism called feedback inhibition, where the product of the reaction acts as the repressor. Enzyme inhibition can occur in two ways. Competitive inhibitors compete with the substrate for the same binding site. Noncompetitive inhibitors can bind to the enzyme at the allosteric site, changing the shape of the enzyme and making it unable to bind to the substrate.

An ATP molecule is composed of three subsections. First, there is a ribose sugar molecule that serves as a backbone to which the other two subsections are attached. Next, there is adenine, one of the four nitrogenous bases found in a DNA molecule. Finally, there is a chain of three phosphates.

Reactants are sometimes called substrates and are the molecules that enter a chemical reaction. Products are the results of a chemical reaction.

Biosynthesis, contraction, importing metabolites, active transport, flagellar movements, cell crawling, chemical activation, cytoplasmic transport, and heat production.