Biology CSF Chapter 6 HW

Which of the following examples describe an energy transformation:

- A child runs and bumps into her brother, knocking him over. - A plant uses solar energy to construct carbohydrates in photosynthesis. - A hot cup of coffee transfers heat to the air as it cools - An oven uses electrical energy to generate heat to bake a cake. - An individual uses energy obtained from eating a hamburger to run a marathon.

Select the statements that describe the energy cells use to drive cell processes:

- ATP and carbohydrates are reservoirs of chemical energy -Animals use ATP to generate carbohydrates for quick energy -The energy stored in chemical bonds is a form of potential energy -Plants use the energy in sunlight to power cell processes when ATP is not available

Which of the following is an example of the potential energy in adenosine triphosphate (ATP) being turned into work?

- ATP synthase transfers a phosphate to ADP - ATP is spontaneously hydrolyzed to ADP - ATP hydrolysis induces a conformational change in a protein that moves ions across a membrane - ATP is bound by an enzyme but is not hydrolyzed - A phosphate group is transferred from ATP to glucose during glycolysis.

How do organisms use energy according to the first law of thermodynamics?

- Animal movement produces heat, which is the form energy takes when it is destroyed. - Plants transformed light energy into chemical energy by photosynthesis. - Plants are more energy efficient than animals because plants trap heat from the sun. - Photosynthesis organisms, such as plants, create their own energy by photosynthesis. - Animals eat to obtain chemical energy that they convert into kinetic energy.

Feedback inhibition is important for the regulation of many metabolic pathways. Which of the following are examples of feedback inhibition?

- Arsenic binds to pyruvate dehydrogenase and inhibits the enzyme. - The beginning of glycolysis is inhibited by high levels of ATP in the cell. - The lac operon is not transcribes when there is no lactose present. - An intermediate of glycolysis activates an enzyme downstream in the pathway. - The production of tryptophan is halted by presence of excess tryptophan.

How do enzymes recognize their substrates?

A binding site that fits the shape and complements the charge of the substrate.

Identify whether the examples describe anabolic or catabolic pathways:

Anabolic: - photosynthesis generates storage carbohydrates from CO2 and H2O -A protein molecule is constructed from amino acid subunits. Catabolic: -Glycosis converts one molecule of glucose to two molecules of pyruvate -A nucleic acid molecule is broken down into nucleotide subunits

When a muscle moves, a phosphate is removed from ATP. Breaking a bond in ATP allows the chemical energy stored in the bond to disperse in a muscle cell in the form of mechanical energy and heat energy. How does the second law of thermodynamics apply to this process?

As the confirmed energy in ATP is released, some of the energy does work and some escapes as thermal energy.

The second law of thermodynamics states that entropy, or disorder, in a system constantly increases. How do biological systems remain highly ordered?

Biological systems require an input of energy to remain highly order.

Classify the following examples of enzymatic regulation as competitive inhibition or allosteric inhibition:

Competitive Inhibition: - Ethanol out-competes thylene glycol for binding to the enzyme alcohol dehydrogenase. -Ibuprofen binds tightly to the active sight of COX enzymes instead of the natural substrate. Allosteric Inhibition: -Isoleucine inhibits an enzyme by binding to a protein domain that does not include the active site. -Adenosine triphosphate (ATP) prevents the synthesis of additional ATP by binding to a regulatory domain that is separate from its catalytic domain.

Identify the examples below as being endergonic or exergonic:

Endergonic: (requires energy) -generating carbohydrates in photosynthesis in photosynthesis -pedaling bike up steep hill - constructing DNA from nucleotides Exergonic: -A ball rolling down a hill -metabolizing a protein into amino acids -breaking down glucose in cellular respiration

What does the first law of thermodynamics state about energy.

Energy cannot be wither created or destroyed, but it can be transformed.

A specialized protein in the small intestine breaks up DNA molecules into individual nucleotides. In this reaction, which molecule is the enzyme, which is the substrate, and which is the product? One of the our answer choices will not be used.

Enzyme: the specialized protein Substrate: the DNA molecules Product: the nucleotides

Both photosynthesis and cellular respiration are cellular processes that involve glucose. How do these two processes differently affect the metabolism of glucose?

Glucose is produced during photosynthesis to hold the energy gathered from light, whereas glucose is broken down during cellular respiration to release stored cellular energy.

An enzyme catalyzes a reaction in a way that results in a lower activation energy. What is the significance of a lower activation energy?

It increases the rate of cellular reaction.

Where is energy stored in adenosine triphosphate (ATP), as shown below?

The phosphate groups that repel each other due to the multiple negatively charged atoms.

Why does the body use chemical energy?

The potential energy stored in chemical bonds can be released to perform work within a cell.

What change occurs when an enzyme binds to a substrate with induced fit?

The shape of the enzyme's active site changes to better fit the substrate.

Which of the following describes an anabolic pathway?

a) A pathway that generates ATP b) A pathways that breaks down molecules into smaller subunits c) A pathway that transmits signal within a cell D) A pathway that generates molecules from smaller subunits

Enzymes take part in nearly all metabolic reactions. What is an enzyme's impact on the activation energy of chemical reaction?

decrease the activation energy of a reaction

Activation energy is best defined as the energy that...

is required to bring the reactant molecules to a transition state