Chapter 5: Cell Processes and Applications (Enzymes)

Question 1

metabolism

Answer 1

the sum of all chemical reactions that occur in a cell

Question 2

enzyme

Answer 2

types of protein that function as catalysts to speed up chemical reactions

Question 3

substrates

Answer 3

reactants in an enzymatic reaction

Question 4

coenzyme

-what type of molecule and definition

Answer 4

organic, non-protein molecule helpers required by enzymes to function properly

Question 5

activation energy/ energy of activation

Answer 5

the energy that must be added to cause molecules to react with one another

Question 6

identify the source gland for thryroxin and relate the function of thyroxin to metabolism

Answer 6

Thyroxine comes from the thyroid gland. Thyroxine increases the metabolic rate by stimulating most cells of the body to metabolize more glucose and use more energy

Question 7

explain how enzymes work

Answer 7

An enzyme binds to a substrate at its active site. An active site is a small part of the enzyme that complexes with the substrate(s). The enzyme and the substrate fit together like a key fits a lock and form an enzyme substrate complex. To achieve optimum fit and accommodate the substrate(s), the active site of the enzyme undergoes a slight alteration. This is called the induced fit model as it makes the active site best fit to the substrate. After the induced fit model and the enzyme-substrate complex forms, the actual facilitating reaction occurs. The product is released and the active site returns to normal.

Question 8

explain the role of vitamins in biochemical reactions

Answer 8

relatively small organic molecules that are required in trace amounts in diets for synthesis of coenzymes that affect health and physical fitness

Question 9

contrast the roles of enzymes and co-enzymes in biochemical reactions

Answer 9

Enzymes function to speed up chemical reactions while coenzymes are helpers that enable enzymes to function properly.

Question 10

explain how enzyme activity is impacted by: pH

Answer 10

• optimum pH promotes enzyme activity as it provides the most suitable environment for each specific enzyme. At optimum pH, an enzyme will have their normal configurations as it’s globular structure is dependent on its interactions (such as hydrogen bonding between R groups). Changes in pH can alter ionization of R groups and disrupt normal interactions. Denaturation can eventually occur if the enzyme is under extreme pH conditions. When the enzyme shape is altered or completely denatured it is no longer functional

Question 11

explain how enzyme activity is impacted by: temperature

Answer 11

• warm temperatures promote enzyme activity as higher temperatures cause more effective collisions between the enzyme and the substrate. If heat is too high, the enzyme becomes denatured

Question 12

explain how enzyme activity is impacted by: substrate/enzyme concentration

Answer 12

• an increase in substrate or enzyme concentrations generally promotes enzyme activity as there are more collisions between the substrate molecules and the enzyme. If more substrate can fill the active sites then there will be more product results per unit time. However, if we add too much substrate and the enzyme sites are filled continuously with substrate, the enzyme activity rate will not increase anymore. It will have reached its maximum rate.

Question 13

explain how enzyme activity is impacted by: competitive inhibitors

Answer 13

• competitive inhibitors resemble normal substrates and bind to enzyme, usually at the active site, this prevents the substrate from binding and inhibits enzyme activity

Question 14

explain how enzyme activity is impacted by: heavy metals

Answer 14

• excess heavy metal exposure can be toxic to enzymes: they bind to the active site of each enzyme that is exposed and deactivate them, inhibiting enzyme activity

Question 15

Explain what must be included in an experiment that uses the scientific method. Include an example.

Answer 15

To make an experiment using the scientific method you must include a question, hypothesis, procedure, test, analysis, and conclusion
Example: The Effect Catalase has on Different Concentrations of H2O2
Questions - What will happen if different concentrations of H202 are added to a living tissue
Hypothesis - If 1.5%, 3& and 10% concentrations of H202 are added to potato tissue extract, then the extract with the 10% concentration of H202 will produce the highest height of bubbles/foam in centimeters.