Biology Chapter 2b: Enzymes Quiz

Enzymes are proteins that catalyze and accelerate chemical reactions within the body.
The specific shape of an enzyme is crucial for its function.
Enzymes return to their original state post-reaction, allowing them to be reused multiple times.
Lactase is an example of an enzyme that breaks down lactose into glucose and galactose for energy.

Activation energy is the minimum energy required to initiate a chemical reaction.
Enzymes reduce activation energy, acting as catalysts, which accelerates reactions.
Mechanisms by which enzymes lower activation energy include:
- Stressing, bending, or stretching critical chemical bonds.
- Directly participating in the reaction.
- Creating a favorable microhabitat for the reaction.
- Orienting or holding substrate molecules in place.
Lactase catalyzes lactose breakdown via:
- Bending covalent bonds between sugars.
- Direct interaction in the reaction.
- Establishing a conducive microhabitat.
- Reorienting molecules spatially.
Reaction rates can be influenced by various factors:
- Increased enzyme amounts raise reaction rates until all substrate is bound.
- Higher temperatures generally increase rates up to the enzyme's optimum; beyond that, enzymes can denature.
- pH levels near the enzyme's optimum enhance reaction rates; extreme pH can hinder function.
Competitive inhibitors block the active site, preventing substrate binding.
Noncompetitive inhibitors bind elsewhere on the enzyme, altering its shape and affecting substrate binding.

Prokaryotic cells are simple in structure yet exhibit extreme diversity.
All cells are categorized into two main types:
- Eukaryotic cells contain a nucleus that houses DNA and various organelles.
- Prokaryotic cells lack a nucleus and organelles; their DNA is located centrally within the cell.
Basic structures present in all prokaryotes:
- Plasma membrane encloses cell contents, including DNA, ribosomes, and cytoplasm.
- Cytoplasm is a jelly-like fluid maintaining internal cell environment.
- DNA consists of circular loops carrying genetic information.
- Ribosomes are structures converting genetic information into protein.
Additional prokaryotic structures:
- Cell wall, providing protection and shape.
- Capsule, a protective outer layer.
- Pili, hair-like structures aiding in attachment and potentially DNA transfer.
- Flagellum, a whip-like structure that facilitates movement.

Eukaryotic cells feature enclosed DNA within a nucleus and are significantly larger, generally at least ten times the size of prokaryotic cells.
Eukaryotic cytoplasm contains specialized organelles, enhancing its functionality, unlike the simpler structure of prokaryotic cells lacking organelles.

Enzymes are proteins that catalyze and accelerate chemical reactions within the body.
The specific shape of an enzyme is crucial for its function.
Enzymes return to their original state post-reaction, allowing them to be reused multiple times.
Lactase is an example of an enzyme that breaks down lactose into glucose and galactose for energy.

Activation energy is the minimum energy required to initiate a chemical reaction.
Enzymes reduce activation energy, acting as catalysts, which accelerates reactions.
Mechanisms by which enzymes lower activation energy include:
- Stressing, bending, or stretching critical chemical bonds.
- Directly participating in the reaction.
- Creating a favorable microhabitat for the reaction.
- Orienting or holding substrate molecules in place.
Lactase catalyzes lactose breakdown via:
- Bending covalent bonds between sugars.
- Direct interaction in the reaction.
- Establishing a conducive microhabitat.
- Reorienting molecules spatially.
Reaction rates can be influenced by various factors:
- Increased enzyme amounts raise reaction rates until all substrate is bound.
- Higher temperatures generally increase rates up to the enzyme's optimum; beyond that, enzymes can denature.
- pH levels near the enzyme's optimum enhance reaction rates; extreme pH can hinder function.
Competitive inhibitors block the active site, preventing substrate binding.
Noncompetitive inhibitors bind elsewhere on the enzyme, altering its shape and affecting substrate binding.

Prokaryotic cells are simple in structure yet exhibit extreme diversity.
All cells are categorized into two main types:
- Eukaryotic cells contain a nucleus that houses DNA and various organelles.
- Prokaryotic cells lack a nucleus and organelles; their DNA is located centrally within the cell.
Basic structures present in all prokaryotes:
- Plasma membrane encloses cell contents, including DNA, ribosomes, and cytoplasm.
- Cytoplasm is a jelly-like fluid maintaining internal cell environment.
- DNA consists of circular loops carrying genetic information.
- Ribosomes are structures converting genetic information into protein.
Additional prokaryotic structures:
- Cell wall, providing protection and shape.
- Capsule, a protective outer layer.
- Pili, hair-like structures aiding in attachment and potentially DNA transfer.
- Flagellum, a whip-like structure that facilitates movement.

Eukaryotic cells feature enclosed DNA within a nucleus and are significantly larger, generally at least ten times the size of prokaryotic cells.
Eukaryotic cytoplasm contains specialized organelles, enhancing its functionality, unlike the simpler structure of prokaryotic cells lacking organelles.