The structure labeled X on a single-celled organism is most similar to the A
skin of a multi-celled organism.
B
brain of a multi-celled organism.
veins of a multi-celled organism.
stomach of a multi-celled organism

What are two reasons for why a species might disappear from the fossil record?

1. environmental factors, such as ph and temperature, can affect the function of an enzyme. a. true b. false 2. which of the following is an organic molecules (ex. vitamins) that an enzyme? a. coenzyme b. product c. active site d. substrate 3. how do enzymes effect the speed of a chemical reaction? a. they speed it up b. they slow it down c. they have no effect on the speed of a reaction 4. during a chemical reaction, an enzyme is used up so that it can only be used one time. a. true b. false 5. which of the following results from a chemical reaction that is catalyzed by an enzymes? a. active site b. product c. substrate d. coenzyme

4. rat liver is able to metabolize glucose by both the glycolytic and the pentose phosphate pathway. which of the following are properties of both the glycolytic and pentose phosphate pathway? a. nad+ is involved b. co2 is liberated c. phosphate esters are intermediates d. glyceraldehyde 3-phosphate is an intermediate e. fructose 6-phosphate is an intermediate4. rat liver is able to metabolize glucose by both the glycolytic and the pentose phosphate pathway. which of the following are properties of both the glycolytic and pentose phosphate pathway? a. nad+ is involved b. co2 is liberated c. phosphate esters are intermediates d. glyceraldehyde 3-phosphate is an intermediate e. fructose 6-phosphate is an intermediate