Biology Chapter on Enzymes and Cell Structure

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What type of inhibitor binds to the active site of an enzyme and resembles the substrate?

Noncompetitive inhibitor

Competitive inhibitor (correct)

Allosteric inhibitor

Substrate inhibitor

Which characteristic applies to coenzymes?

They are always inorganic.

They do not include any vitamins.

They are a type of organic cofactor. (correct)

They act as permanent enzyme inhibitors.

What is the potential effect of mutations in enzyme-encoding genes?

They result in only harmful changes that decrease fitness.

They have no impact on enzyme performance.

They always lead to loss of enzyme activity.

They can create new enzyme functions or alter substrate specificity. (correct)

Which type of inhibitor causes a change in the enzyme's shape without binding to the active site?

Noncompetitive inhibitor Signup and view all the answers

Which of the following best describes the role of cofactors in enzyme activity?

They can assist in the catalytic process by binding to enzymes. Signup and view all the answers

What is the role of allosteric regulation in enzyme activity?

It can both inhibit and stimulate enzyme activity. Signup and view all the answers

How do cells regulate enzyme activity to avoid chemical chaos?

By switching genes on or off and regulating enzyme activity. Signup and view all the answers

What happens when an inhibitor binds to an allosteric site on an enzyme?

It stabilizes the enzyme's inactive form. Signup and view all the answers

What are the two states in which each enzyme exists due to allosteric regulation?

Active and inactive. Signup and view all the answers

What is the result of an activator binding to an enzyme?

It stabilizes the active form of the enzyme. Signup and view all the answers

What is the primary function of the plasma membrane in a cell?

To act as a selective barrier for the exchange of materials Signup and view all the answers

What is a key characteristic that differentiates prokaryotic cells from eukaryotic cells?

Location of DNA Signup and view all the answers

Why is a higher surface area to volume ratio advantageous for cells?

It enhances metabolic processes by allowing efficient material exchange Signup and view all the answers

Which organelle is responsible for housing the genetic instructions of a eukaryotic cell?

Nucleus Signup and view all the answers

What structural feature is common in both prokaryotic and eukaryotic cells?

Selectively permeable plasma membrane Signup and view all the answers

In eukaryotic cells, what is the role of ribosomes?

To assemble proteins according to genetic instructions Signup and view all the answers

What component of eukaryotic cells allows for incompatible processes to occur simultaneously?

Organelles created by internal membranes Signup and view all the answers

Which of the following features is NOT characteristic of prokaryotic cells?

Nucleus Signup and view all the answers

What generally happens to the surface area to volume ratio as a cell increases in size?

It decreases Signup and view all the answers

What distinguishes the cytoplasm of eukaryotic cells from prokaryotic cells?

Presence of organelles Signup and view all the answers

What happens to an enzyme's activity when the temperature exceeds its optimal level?

The speed of the enzyme reaction drops sharply. Signup and view all the answers

Which of the following factors can affect an enzyme's activity?

General environmental factors, including pH, temperature, and substrate concentration. Signup and view all the answers

What role do cofactors play in enzyme function?

They are non-protein molecules or ions required for proper enzyme function. Signup and view all the answers

How do substrates bind to the active site of an enzyme?

By weak interactions such as hydrogen bonds. Signup and view all the answers

What is the effect of variations in pH on enzymes?

They can disturb hydrogen bonding or ionic interactions and change the active site shape. Signup and view all the answers

What role does phosphorylation play in the function of the sodium-potassium pump?

It triggers a shape change that releases Na+ outside the cell. Signup and view all the answers

Which statement best describes the nature of the electrochemical gradient?

It comprises both chemical and electrical forces acting on ions. Signup and view all the answers

Which type of transport occurs when cells engulf large particles or small organisms?

Phagocytosis Signup and view all the answers

In a spontaneous process, which of the following must occur regarding the universe's entropy?

Entropy must increase for the process to be spontaneous. Signup and view all the answers

What is the primary function of ATP in cellular processes?

It powers cellular work by providing energy. Signup and view all the answers

Which of the following statements about enzymes is true?

Enzymes lower activation energy without altering ΔG. Signup and view all the answers

What is the primary outcome of hydrolysis reaction involving ATP?

It releases energy for cellular work. Signup and view all the answers

What happens to the free energy during an endergonic reaction?

Free energy is absorbed, resulting in a higher ΔG. Signup and view all the answers

How does enzyme specificity benefit metabolic processes?

It ensures that specific substrates are transformed efficiently. Signup and view all the answers

Which of the following best describes catabolic pathways?

They release energy by breaking down complex molecules. Signup and view all the answers

What is the role of the active site in an enzyme?

It is where substrates bind and reactions catalyze. Signup and view all the answers

What is one effect of an electrogenic pump?

It generates voltage across the membrane. Signup and view all the answers

What describes the significance of the ΔG in a reaction?

It indicates whether the reaction requires energy input. Signup and view all the answers

Which process involves the uptake of specific molecules by cell membrane vesicles?

Receptor-mediated endocytosis Signup and view all the answers

What is the primary function of ribosomes in a cell?

Translate mRNA into polypeptides Signup and view all the answers

Which component is primarily responsible for the synthesis of ribosomal RNA within the nucleus?

Nucleolus Signup and view all the answers

What distinguishes rough endoplasmic reticulum (RER) from smooth endoplasmic reticulum (SER)?

RER has ribosomes on its surface, while SER does not. Signup and view all the answers

What is the primary role of the Golgi apparatus in the endomembrane system?

Modify and package proteins Signup and view all the answers

Which of the following best describes the function of lysosomes?

Digest larger molecules and recycle cell material Signup and view all the answers

What defines the unique structure of mitochondria?

Contains cristae for increased surface area Signup and view all the answers

In plant cells, what is the function of the central vacuole?

Store water and maintain turgor pressure Signup and view all the answers

What is the main advantage of the endosymbiont theory concerning mitochondria and chloroplasts?

They evolved from a single prokaryotic ancestor. Signup and view all the answers

Which structures are found in both cilia and flagella?

Microtubule triplets Signup and view all the answers

What role do integrins play in the extracellular matrix (ECM)?

Connect the ECM and cytoskeleton, signaling changes Signup and view all the answers

What is the primary function of the nuclear envelope in eukaryotic cells?

Regulate the exchange of molecules between nucleus and cytoplasm Signup and view all the answers

Which type of vacuole is responsible for maintaining water balance in freshwater protists?

Contractile vacuole Signup and view all the answers

How do chloroplasts optimize the conversion of solar energy during photosynthesis?

By utilizing thylakoids for increased surface area Signup and view all the answers

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