Biological Molecules and Enzyme Activity

This video is a condensed review of biochemistry topics relevant to AP Biology exams. It covers the organization of organic molecules, including carbohydrates, proteins, nucleic acids, and lipids. The video explains radioisotopes and their use in experiments, such as the Hershey and Chase experiment. It delves into protein structure, focusing on primary, secondary, tertiary, and quaternary structures, with hemoglobin as a key example. The video also discusses an experiment simulating early Earth conditions to create organic molecules. Enzyme activity, including competitive and non-competitive inhibition, is explained, along with the concept of Gibbs free energy. The session concludes with a call for feedback.

What is the defining characteristic of organic molecules?

• Ability to dissolve in water

• Presence of carbon and hydrogen in a fixed ratio

• Presence of nitrogen

• Presence of oxygen

Which of the following is NOT a type of lipid?

• Steroid

• Phospholipid

• Cellulose

• Triglyceride

What is the role of radioisotopes in biological experiments?

• To trace the incorporation of elements in organisms

• To provide nutrients to cells

• To dissolve organic molecules

• To increase the temperature of reactions

What is the primary structure of a protein?

• A complex of multiple protein units

• A helical loop structure

• A 3D structure formed by folding

• A string of amino acids held by peptide bonds

What causes sickle cell anemia at the molecular level?

• A deficiency in iron

• A mutation in the primary structure of hemoglobin

• A lack of oxygen in the blood

• An excess of red blood cells

What was the main finding of the Miller-Urey experiment?

• Creation of life from inorganic molecules

• Formation of complex organic molecules from simple precursors

• Discovery of new elements

• Synthesis of DNA

What is the induced fit model in enzyme activity?

• The enzyme is permanently altered by the substrate

• The enzyme changes shape to fit the substrate

• The substrate changes shape to fit the enzyme

• The enzyme and substrate do not interact

How does a competitive inhibitor affect enzyme activity?

• It mimics the substrate and blocks the active site

• It permanently deactivates the enzyme

• It binds to the allosteric site

• It increases the enzyme's activity

What is Gibbs free energy?

• Energy stored in chemical bonds

• Energy released by a reaction

• Energy required to start a reaction

• Energy available to do work

What happens to the rate of an enzyme-catalyzed reaction when all substrate is converted to product?

• The rate approaches zero

• The rate increases

• The rate decreases

• The rate remains constant