Understanding Enzymes and Metabolic Reactions

What organelle is responsible for photosynthesis in plants?

• Chloroplast

• Nucleus

• Mitochondria

• Ribosome

Which of the following is NOT a factor that can speed up chemical reactions?

• Presence of food

• Decreasing temperature

• Increasing temperature

• Stress or nerves

What is the primary reason high temperatures are dangerous to cells?

• They can melt lipids in cell membranes.

• They increase metabolic rate excessively.

• They cause cells to freeze.

• They reduce the effectiveness of enzymes.

What is the role of enzymes in biological reactions?

• To serve as reactants

• To speed up reactions without being consumed

• To act as substrates

• To increase the temperature

What happens to enzymes after a reaction?

• They are permanently altered

• They become substrates

• They remain unchanged and can be reused

• They are consumed

What determines the specificity of an enzyme to its substrate?

• The pH level only

• The shape of the enzyme's active site

• The enzyme's color

• The substrate's temperature

What is meant by 'enzyme turnover'?

• The process of producing enzymes

• The number of substrates an enzyme can process per minute

• The degradation rate of enzymes

• The recycling of enzymes

How do enzymes lower the activation energy of a reaction?

• By increasing the temperature

• By changing the pH

• By physically altering the substrate's structure

• By binding to substrates at the active site

Which factor does NOT affect the activity of an enzyme?

• The enzyme's 3D shape

• The color of the substrate

• The substrate's shape

• The presence of cofactors

What is activation energy?

• Energy required to stop a reaction

• Energy released during a reaction

• Energy stored in the substrate

• Energy required to start a reaction