Chemical Reactions & Enzymes

Multiple Choice

These are the substances that are changed during a chemical reaction.

• reactants
• products

Open Ended

Using the article displayed for citation, answer the following question.

Why do you think you need to know about chemistry in Biology?

Fill in the Blanks

Multiple Choice

Covalent bonds form when

• the electronegativity difference between two atoms is very large.

• electrons are completely transferred between two atoms.

• pairs of electrons are shared between two atoms.

• ions are held together by opposite charges.

Multiple Choice

When a chemical reaction happens

• bonds must be broken and reformed
• chemicals don't collide
• atoms keep their arrangements
• chemicals keep their same properties

Open Ended

In this chemical equation label the Yield, Coefficent, Subscript, products, reactants & Chemical Formula.

$$6CO_2+6H_2O→\ C_6H_{12}O_6+6O$$  

Multiple Choice

What is the role of the chemical reaction in the bloodstream as described in the image?

• To enable oxygen absorption

• To remove carbon dioxide

• To transport nutrients

• To regulate body temperature

Multiple Choice

What is produced when carbon dioxide reacts with water in the blood?

• Oxygen

• Carbonic acid

• Hydrogen

• Nitrogen

Multiple Choice

When hydrogen and oxygen combine to form water, water is

• product
• reactant
• enzyme
• catalyst

Multiple Choice

Which of the following is the correct chemical equation for producing water?

• H₂ + O₂ --> H₂O

• 2H₂ + 2O₂ --> 2H₂O

• 2H₂ + O₂ --> 2H₂O

• H₂ + 2O₂ --> 2H₂0

Multiple Choice

Carbon dioxide and seawater combine to form

• calcium carbonate
• carbon monoxide
• carbonic acid 

Multiple Choice

What is the chemical equation for the reaction of hydrogen and oxygen to produce water vapor?

• H2 + O2 -> H2O

• 2H2 + O2 -> 2H2O

• H2 + 2O -> H2O2

• 2H + O2 -> H2O

Multiple Choice

What is the reverse reaction of water changing into hydrogen and oxygen gas?

• It absorbs energy

• It produces energy

• It requires no energy

• It occurs spontaneously

Multiple Choice

What are the different sources of energy for organisms?

• Sunlight

• Food

• Water

• Air

Multiple Choice

Which of the following diagrams correctly shows the reaction pathway of a reaction that absorbs energy?

• reactants, high curve, low products
• reactants high, low dip, little higher products
• reactants, low dip, really high products
• low reactants, high curve, lower products

Open Ended

What role do enzymes play in living things and what affects their function?

Multiple Choice

In living cells, enzymes act as catalysts, which may reduce the amount of activation energy required for a chemical reaction to occur.  In the graphs below, pathway x is a solid line representing the uncatalyzed reaction. The dotted line shows the catalyzed reaction. Which graph best illustrates the changes in a reaction when the catalyst reduces the amount of energy required?

• A

• B

• C

• D

Multiple Choice

What is the role of carbonic anhydrase in the reaction between carbon dioxide and water?

• To slow down the reaction

• To speed up the reaction

• To remove carbon dioxide from the blood

• To produce carbonic acid

Multiple Choice

Use the information in the image to select the statement that BEST describes whether lactase can help break down sucrose into glucose and fructose.

• Lactase can help break down sucrose because sucrose is a disaccharide.

• Lactase can help break down sucrose because sucrose contains glucose.

• Lactase cannot help break down sucrose because sucrose can break down without an enzyme.

• Lactase cannot help break down sucrose because the shape of sucrose does not match the shape of lactase.

Multiple Choice

What is the role of enzymes in chemical reactions?

• To increase the energy of reactants

• To provide a site for reactants to collide

• To change the reactants into products

• To prevent reactions from occurring

Multiple Choice

What analogy is used to describe the fit between the active site and substrates in the enzyme-substrate complex?

• A puzzle

• A lock and key

• A magnet

• A glove

Multiple Choice

The "lock and key hypothesis" attempts to explain the mechanism of?

• Vacuole formation

• any substrate can bind to any enzyme

• Sharing of electrons

• Enzyme specificity (specific substrate bind to a specific enzyme)

Multiple Choice

Enzymes and substrates can be called "locks and keys" because...

• Substrates can block active sites on enzymes

• Enzymes need substrates in order for a chemical reaction to occur

• Enzymes can interact with multiple substrates because the shape of the active site changes

• Enzymes and substrates fit together perfectly due to the specific shape of the active site

Multiple Choice

The "lock and key hypothesis" attempts to explain the mechanism of?

• Vacuole formation
• Pinocytosis
• Sharing of electrons
• Enzyme are specific to a substrate

Open Ended

PREDICT what would happen to the activity of an enzyme that usually is found at pH of 3.5-3.2 and then its placed in a solution of pH 11. JUSTIFY your answer.