Enzymes and Catalysts Quiz

A catalyst is a substance that _______ up the rate of a _______ reaction, without _______ the reaction itself.

• speeds

• slows

• stops

• alters

Answer explanation

A catalyst is a substance that speeds up the rate of a chemical reaction without altering the reaction itself. Therefore, 'speeds' is the correct choice, as it accurately describes the function of a catalyst.

Catalysts can be _______ or _______.

• Inorganic

• Organic

• Metallic

• Synthetic

• Biological

Answer explanation

Catalysts can be classified as inorganic or organic. Inorganic catalysts include metals and metal oxides, while organic catalysts are typically based on carbon compounds. Thus, 'Inorganic' is a correct choice.

Most catalysts are (a)  

• organic

• inorganic

• metallic

• gaseous

Answer explanation

Most catalysts are organic compounds, which play a crucial role in facilitating chemical reactions without being consumed. While inorganic and metallic catalysts exist, organic catalysts are more prevalent in various applications.

What is an enzyme?

• A type of protein that speeds up chemical reactions

• A type of carbohydrate that stores energy

• A type of lipid that forms cell membranes

• A type of nucleic acid that stores genetic information

Answer explanation

An enzyme is a type of protein that catalyzes biochemical reactions, increasing their rate without being consumed in the process. This distinguishes it from carbohydrates, lipids, and nucleic acids, which serve different functions.

Enzymes work by lowering (a)  

• Activation energy

• Temperature

• pH level

• Concentration

Answer explanation

Enzymes lower activation energy, which is the energy required for a reaction to occur. By reducing this energy barrier, enzymes increase the rate of biochemical reactions, making them essential for various cellular processes.

Typically, enzymes are _______ than their substrates.

• larger

• smaller

• equal in size

• more complex

Answer explanation

Enzymes are typically larger than their substrates because they need to accommodate the substrate's shape for binding. This size difference allows enzymes to effectively catalyze reactions, making 'larger' the correct choice.

Match the following models with their descriptions.

• This model is used to describe the structure of cell membranes, not enzyme action.

• Allosteric

• This model describes enzymes as having a specific shape that fits the substrate exactly.

• Fluid Mosaic

• This model involves enzymes having multiple binding sites and can be regulated by molecules binding at sites other than the active site.

• Induced Fit

• This model suggests that enzymes change shape to fit the substrate upon binding.

• Lock and Key

Enzyme ______________

• Helpers

• Catalysts

• Inhibitors

• Substrates

Answer explanation

Enzymes are biological catalysts that speed up chemical reactions in the body. They act as helpers by lowering the activation energy needed for reactions, making them essential for various metabolic processes.

Match the following biological molecules with their types.

• Enzyme

• Nucleic Acid

• Starch

• Lipid

• DNA

• Protein

• Cholesterol

• Carbohydrate

Enzyme action is similar to the action of a key fitting into a lock because:

• Enzymes are made of metal like keys.

• Enzymes can open any lock.

• Enzymes have a specific shape that fits into a substrate.

• Enzymes are used to lock cells.

Answer explanation

Enzymes have a specific shape that fits into a substrate, similar to how a key fits into a lock. This specificity allows enzymes to catalyze particular reactions, making them essential for biological processes.