Chapter 6: Learning Curve

As a cat pounces on a mouse, her muscles burn 10 units of potential energy (which the cat previously gained from eating). However, the pounce itself only required 4 units of kinetic energy. How many units of energy were dissipated as heat? 2.5 6 14 10 4

6

Consider the refrigerator in your kitchen. Based on what you know about the first and second laws of thermodynamics, how does a refrigerator most likely work? A refrigerator removes heat from its interior and transports this energy outside, into the kitchen. A refrigerator destroys any heat in its interior, or in the food it contains. A refrigerator creates new energy, although it is in the form of cold rather than heat. A refrigerator removes the potential energy contained within food. A refrigerator both destroys any heat in its interior, or in the food it contains, and creates new energy in the form of cold.

A refrigerator removes heat from its interior and transports this energy outside, into the kitchen.

Which of the following is considered a form of kinetic energy? a rolling ball light heat wind All of these choices are correct.

All of these choices are correct.

Imagine that several atoms bond to form a carbohydrate, creating a more orderly system. Which of the following statements is true regarding the universe after this carbohydrate forms? The energy of the universe increases. The energy of the universe decreases. The entropy of the universe increases. The entropy of the universe decreases. Both the energy and entropy of the universe increases.

The entropy of the universe increases.

Phosphofructokinase is an allosteric enzyme in the pathway that breaks down glucose to produce ATP. Regulation of glycolysis is directly related to the level of ATP and citrate. If ATP or citrate levels are high, phosphofructokinase is inhibited. What will happen to this enzyme when ATP levels drop? Phosphofructokinase is activated. Metabolism of citrate is inhibited. Phosphofructokinase is inhibited. Metabolism of phospholipids is activated. Metabolism of phospholipids is inhibited.

Phosphofructokinase is activated.

_____ are organisms that derive energy from sunlight. Heterotrophs Phototrophs Chemotrophs Autotrophs

Phototrophs

Imagine that you walk out of your warm house on a cold winter's day. What is different between the air inside and outside of your house in this scenario? The molecules in the cold air outside of your house have more kinetic energy than those inside. The molecules in the cold air outside of your house are moving faster than those inside. The molecules in the warm air of your house are moving faster than those outside. The molecules in the warm air have more potential energy than those outside. The molecules in the warm air inside of your house have less entropy than those outside.

The molecules in the warm air of your house are moving faster than those outside.

Oak trees are categorized as: chemoautotrophs. photoheterotrophs. chemoheterotrophs. photoautotrophs.

photoautotrophs

Organisms that derive their energy from the sun and carbon from carbon dioxide are: photoheterotrophs. chemoheterotrophs. photoautotrophs. chemoautotrophs. chemolithotrophs.

photoautotrophs

Organic molecules store _____energy in their _____ bonds. potential; covalent kinetic; ionic kinetic; covalent kinetic; hydrogen potential; ionic

potential; covalent

Enzymes are most often: sterols. proteins. carbohydrates. triglycerides. nucleotides.

proteins

Converting glucose to glycogen: releases energy. requires energy. requires sunlight. requires diffusion of glycogen into a muscle cell. requires cellulose.

requires energy.

ATP is a nucleotide composed of adenine, _____, and three phosphate groups.

ribose

You have entered a 5K race. As you finish the last 50 yards, you are breathing harder than at the start of the race and sweating profusely. This is an example of the _____ law of thermodynamics because _____ is increasing. first; entropy second; entropy first; body temperature second; body temperature None of the other answer options is correct.

second; entropy

Gibbs free energy is defined as: the amount of energy lost as heat. the amount of entropy. the amount of energy available to do work. spontaneous energy. the amount of potential energy in a system.

the amount of energy available to do work.

Nearly all cells use ATP as their primary energy source. This is evidence that: ATP evolved recently (in the last 100 years) as a potential source of energy. life continues to evolve and use novel energy sources. the use of ATP by cells began eons ago and has been conserved over time. only eukaryotic cells can produce ATP. fossil fuels are composed of ATP.

the use of ATP by cells began eons ago and has been conserved over time.

The second law of thermodynamics states that: energy cannot be created or destroyed. there is an increase in disorder in the universe over time. only eukaryotic cells can produce ATP. combustion engines are 100% efficient. the universe becomes more orderly over time.

there is an increase in disorder in the universe over time.

An energy input is necessary for both endergonic and exergonic reactions. true false

true (exergonic supplies energy: endergonic requires energy. Nevertheless, all chemical reactions require an input of energy to proceed, even exergonic reactions that release energy. For an exergonic reaction, the energy released is more than the initial input of energy, so there is a net release of energy.)

Allosteric inhibitors of an enzyme bind: a site on the enzyme that is not the active site. to the substrate. to the active site of the enzyme. a site on the substrate that is not the active site. to co-factors that accelerate the reaction.

a site on the enzyme that is not the active site.

As atmospheric carbon dioxide levels increase, the oceans become more: salty. acidic. aqueous. basic. dense.

acidic

Chemical reactions that have a positive ΔG are _____.

endergonic

The synthesis of ATP from ADP and Pi is a(n) _____ reaction with ____ ΔG. endergonic; a positive exergonic; a negative exergonic; a positive reversible; zero endergonic; a negative

endergonic; a positive

As plant cells rely on energy obtained directly from the sun to carry out cellular processes, sugars are only used as backup energy sources for plants on cloudy days. true false

false (Plants use the energy of sunlight to convert carbon dioxide and water into sugar and oxygen. Sugars, such as glucose, contain energy in their chemical bonds that can be used to synthesize ATP, which in turn can power the work of the cell. Plants still power most cellular processes by breaking down the sugar they make.)

Of the following molecules, which has the greatest potential energy? water sodium chloride carbon dioxide glucose alanine

glucose

In chemical reactions, most of the entropy increase occurs as: chemical energy. heat. glycolysis. electrical energy. ATP production.

heat.

Enzymes are typically: polysaccharides. most active at 65°C. highly specific. most active at 0°C. multipurpose—one enzyme catalyzes multiple pathways.

highly specific.

An avalanche is an example of _____ energy. kinetic potential chemical metabolic anabolic

kinetic

The entire set of chemical reactions that sustain life is called: metabolism. catabolism. anabolism. hydrolysis. plasmolysis.

metabolism.

Which of the following organisms are considered heterotrophs? most bacteria plants dogs most bacteria and dogs hydrogen bacteria

most bacteria and dogs

Spontaneous reactions have a _____ ΔG. positive zero negative

negative

Imagine that you are talking with one of your friends. He states that evolution has actually violated the second law of thermodynamics because complex living organisms are more ordered than the nucleic acids, amino acids, and other molecules that compose them. Why doesn't evolution contradict the second law of thermodynamics? Because evolution takes place over millions of years, the loss of entropy is negligible and thus the laws of thermodynamics are not violated. Evolution is a biological process, and biological processes do not have to conform to the laws of physics. Evolution doesn't affect entropy, as living organisms eventually die and become "disordered." Even though evolution may decrease the entropy of living organisms, it increases the entropy of the Earth (or the universe) as organisms release heat. Evolution actually does violate the second law of thermodynamics, and this fact is problematic for scientists.

Even though evolution may decrease the entropy of living organisms, it increases the entropy of the Earth (or the universe) as organisms release heat.

_____ are organisms that derive carbon from organic compounds. Phototrophs Heterotrophs Autotrophs Chemotrophs

Heterotrophs

Carbon dioxide dissolves in water to form _____.

carbonic acid

You have entered a 5K race. As you finish the last 500 yards, your body has converted _____ energy to _____ energy with the loss of _____. heat; kinetic; chemical potential energy chemical potential; kinetic; heat heat; chemical potential; kinetic energy kinetic; chemical potential; heat chemical potential; heat; kinetic energy

chemical potential; kinetic; heat

Imagine that you discover a microbial deep-sea organism that can derive energy from (inorganic) hydrogen gas (H2). However, this microbe can also synthesize organic compounds from carbon-containing inorganic molecules in the ocean. This microbe is a: chemoheterotroph. phototroph. photoautotroph. chemoautotroph. photoheterotroph.

chemoautotroph.

Imagine that you discover a carnivorous deep-sea fish that cannot utilize the carbon in carbonic acid (or any other inorganic molecule) present in seawater to form glucose (or other organic molecules). Living so far beneath the water's surface, this fish is also incapable of harnessing energy from the sun. This fish would be considered a: photoheterotroph. chemoheterotroph. photoautotroph. phototroph. chemoautotroph.

chemoheterotroph

Escherichia coli bacteria in your colon are categorized as: photoheterotrophs. chemoheterotrophs. photoautotrophs. chemoautotrophs.

chemoheterotrophs

Organisms that derive both their energy and carbon from organic compounds are: photoheterotrophs. chemoautotrophs. chemolithotrophs. chemoheterotrophs. photoautotrophs.

chemoheterotrophs