CFA #2 Corrections

Overheating or changing the pH of an enzyme results in the enzyme’s loss of —

• net electrical charge

• ability to catalyze a reaction

• storage of a large amount of chemical energy

• storage of inherited information

Fireflies emit light. The production of light by an organism is called bioluminescence. To generate visible light, cells in a firefly’s tail produce thousands of luciferase enzymes. Luciferase binds to a chemical called luciferin. Once bound, the luciferase enzyme speeds up a chemical reaction that combines an oxygen molecule and luciferin to produce oxyluciferin. This reaction requires energy and releases light. Which of the following best describes how the luciferase enzyme speeds up the chemical reaction?

• Luciferase increases the amount of time the light is visible.

• Luciferase decreases the amount of energy required for the reaction to start.

• Luciferase increases the number of sites on luciferin that must bind to oxygen.

• Luciferase decreases the temperature of the environment inside the body of the
  firefly.

Both euglena and cyanobacteria are photosynthetic unicellular organisms found in pond water. The feature that distinguishes euglena from cyanobacteria is the -

• ability to maintain homeostasis

• presence of ribosomes

• ability to reproduce

• presence of nuclear membrane

When reading a graph, the optimal condition for an enzyme to perform will always be at the -

• Top of the graph

• Bottom of the graph

What is the function of enzymes in biological systems?

• Enzymes act as substrates when the necessary proteins are unavailable.

• Enzymes act as products to create new chemical reactions.

• Enzymes act as catalysts to drive chemical reactions forward.

• Enzymes bond with substrates to create the new reaction products.

According to the graph, addition of the enzyme amylase causes the reaction to —

• slow down

• speed up

• give off heat

• take in heat

Which characteristic of prokaryotic organisms makes them different from eukaryotes?

• Prokaryotic cells do not have a membrane-bound nucleus.

• Prokaryotes do not have chromosomes.

• Prokaryotes are made of cells.

• Prokaryotes have DNA.

Which of the following statements is true regarding the relationship between enzymes and substrates?

• substrates have a specific activation site for enzyme attachment

• substrates can only use a specific ionic bond with the enzyme

• substrates destroy its specific enzyme

• substrates actively interfere with other substrates around it

The diagram represents Trichodina.

Trichodina is a eukaryotic organism that attaches itself to fish and eats bacteria. Which of the following distinguishes Trichodina from all prokaryotes?

• Trichodina is unicellular.

• Trichodina has cytoplasm.

• Trichodina has a nucleus.

• Trichodina is heterotrophic.