1. Plasma membrane proteins that actually attach to each other between two neigh

Question

1. Plasma membrane proteins that actually attach to each other between two neighboring cells creating a zip-lock seal is called A. gap junctions B. tight junctions C. adhesion junctions D. plasmodesmata 2. An energy requiring reaction is called A. chemical reaction B. coupled reaction C. endergonic reaction D. exergonic reaction 3. The first law of thermodynamics states A. energy cannot be changed from one form to another without loss of usable energy B. all forms of energy are eventually converted to heat C. the universe's energy is increasing towards entropy D. energy of the universe is constant (energy cannot be created or destroyed) 4. ATP is made up of which 3 types of molecules A adenosine, phosphates, glucose B. C. D. adenine, ribose, phosphate adenine, phosphate, amino acid adenosine, ribose, potassium Molecules that react with the help of enzymes are called A. substrates B. products C. inhibitors D. cofactors 5. 6. When enzymes are exposed to excessive amounts of heat what happens A. B. C. D. the reaction rates speed up the reaction rates slow down denaturation occurs and the enzyme no longer functions the reaction rates stay the same 7. An inhibitor that resemble the normal substrate and compete with substrates for the active site are called A. noncompetitive inhibitors B. allosteric inhibitors C. competitive inhibitors D. none of the above Which stage of cellular respiration takes place in the cytosol? A. Glycolysis B. Formation of AcetylCoA C. Kreb's Cycle D. Oxidative Phosphorylation What is last electron acceptor molecule in the electron transport chain? A. Oxygen B. Carbon Dioxide 8 9. D. FMN

Explanation / Answer

Ans. #1. Correct option- B. Tight junctions form seal the adjoining cell membranes like zip-lock fashion and make the region impermeable to water and solutes.

# Gap junctions are “channels-like” junctions that facilitate transfer of solutes between the two adjoining cells.

# Adhesion junctions are present as narrow bands or spots.

# Plasmodesmata are cytoplasmic connections between two adjacent plant cells.

#2. Correct option- C. Endergonic reaction. A reaction requiring energy input is called an endergonic reaction.

# A reaction that releases energy is called an exergonic reaction.

# A chemical reaction can be endergonic or exergonic.

# Coupled reactions are two reactions – one of which is endergonic and the other is exergonic.

#3. Correct option D. Energy of the universe is constant.

#4. B. Correct option- B. Adenine (base), ribose (pentose sugar), phosphate.

Like other nucleotides, ATP consists of a base (adenine), sugar (ribose) and a phosphate group.

#5. Correct option- A. Substrate.

# An enzyme reacts with substrate to form product.

# A molecule that inhibits/stops enzyme activity is called an inhibitor.

# A non-protein molecule required by the enzyme for catalysis is called a cofactor.

#6. Correct option- C. Denaturation. When excess heat is supplied to enzymes (or, most other proteins), they undergo thermal denaturation and lose their catalytic activity.

# Reaction rates speed up when the enzyme is heated from a lower to the optimum temperature.

# Colling slows down enzyme activity.

#7. Correct option- C. A competitive inhibitor is structurally similar to the normal substrate, competes with the substrate for the active site – thus reduces the overall enzyme activity.

# Neither of a noncompetitive or allosteric inhibitor does not compete with the substrate for the active site of enzyme.

#8. Correct option- A. Glycolysis.

# Rest processes take place in mitochondria.

#9. Correct option- A. Oxygen. O2 acts as the terminal electron acceptor in ETC.

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