Unit 1 - Enzymes and Chemical Reactions

Question 1

What is a chemical reaction?

Answer 1

• Process that changes one set of molecules into a new set of substances
• Occurs when chemical bonds b/w atoms are either broken or formed, resulting in the production of one/more new substances

Question 2

Why do all chemical reactions need an initial investment energy?

Answer 2

• In order for products to form from a reaction, existing reactants must first be broken down, requiring energy

Question 3

What is activation energy?

Answer 3

• Energy needed by reactants to break existing chemical bonds and “activate” a chemical reaction

Question 4

Describe an energy absorbing reaction

Answer 4

• Reactants have less energy than the products
• Bonds in the reactant molecules are broken down and new ones are formed during the formation of products
• Requires more energy than it gives off
• Ex: Photosynthesis

Question 5

Describe an energy releasing reaction

Answer 5

• Reactants have more energy than products
• Energy investment is still required to break reactant bonds
• Gives off more energy than required
  -Ex: Respiration in cells

Question 6

How do reactant molecules obtain activation energy?

Answer 6

• Activation energy is usually in the form of heat that reactant molecules absorb from their surroundings
• The bonds of the reactant break only when the molecules have absorbed enough energy to become unstable

Question 7

What is an enzyme?

Answer 7

• Organic molecule (protein) that acts as a catalyst
• Essential for cell function, help reactions happen faster

Question 8

What are catalysts?

Answer 8

• Substances that help a reaction take place more rapidly at a lower temp

Question 9

What are some factors that affect enzyme functioning?

Answer 9

1. Temperature: every enzyme has an optimum temp, and an enzyme may become denatured without it
2. pH: every enzyme has an optimum pH range at which it functions the best, pH outside of this range can cause it to denature