Chapter 8: Microbial Metabolism

Which three of the following are characteristics of most enzymes?

-act as organic catalysts -function in low concentration -have a unique shape and specificity

Which suffix denotes an enzyme?

-ase

How many ATP molecules are produced by oxidative phosphorylation for each glucose that enters glycolysis?

34

What term is used to describe the minimum amount of energy required for a reaction to proceed?

Activation energy

What do the letters of ATP represent?

Adenosine triphosphate

Which term is used to describe the integration of anabolic and catabolic pathways?

Amphibolism

Which two of the following are correct about the catalytic function of enzymes?

An enzyme binds to its substrate. An enzyme participates in changes to the substrate.

What term refers to a biological catalyst that lacks an essential cofactor?

Apoenzyme

Which of the following can synthesize all the macromolecules from CO2 and minerals?

Autotrophs

The term "metabolism" includes which type(s) of cellular reactions?

Both anabolic and catabolic

_____________ is a set of reactions needed to break down organic molecules into materials while ___________ is the set of reactions that use these materials to build larger, more complex molecules.

Catabolism, anabolism

What term is also used to describe an active site?

Catalytic site

Which of the following can act as an electron carrier?

Coenzymes

Which identifies the correct relationship among components of coenzymes?

Coenzymes = organic / Metals = inorganic

Which is NOT a method of overcoming activation energy in any reaction?

Decreasing the substrate concentration

Common electron carriers include

FAD, NAD

True or false: Coenzymes are inorganic cofactors.

False

True or false: Most enzymes are named based on their molecular composition.

False

Which four of the following could INCREASE the rate of an enzymatic reaction which is currently not at optimal conditions.

Increase temperature slightly Increase enzyme concentration Decrease temperature slightly Increase substrate(s) concentration

What is the typical "next step" for pyruvate at the end of glycolysis following normal aerobic or anaerobic respiration?

Krebs cycle

Which model is sometimes used to describe enzyme-substrate interactions?

Lock-and-key

Which of the following macromolecules can commonly act as a catalyst?

Macromolecules

What name is given to the compound which an enzyme will act upon?

Substrate

Most enzymes are named to reflect which of the following?

The action of the enzyme

Which describes the primary function of a coenzyme?

Transient carrier in reactions

True or false: Cofactors are either coenzymes or metal ions.

True

True or false: Cofactors participate directly in chemical reactions with the enzyme-substrate complex.

True

True or false: In strict aerobes and some anaerobes, pyruvic acid enters the Krebs cycle after it is converted to acetyl CoA.

True

Vitamin deficiency results in the inability to form ______.

a complete holoenzyme

Electron carriers like NAD and FAD repeatedly ______.

accept and release electrons

The minimum amount of energy required for a reaction to proceed is termed the ___________ energy.

activation

The _______ site is the region on an enzyme that binds substrate.

active

Which feature of an enzyme is the "most" unique?

active site

lyase

add or remove groups from double-bonded substrates add or remove groups from double-bonded substrates

A series of reactions that converts glucose to CO2 and allows the cells to recover significant energy in the form of ATP is known as ______.

aerobic respiration

pathways couple catabolic metabolic pathways with anabolic metabolic pathways.

amphibolism

In ___________ respiration, oxygen is not the terminal electron acceptor.

anaerobic

A non-functional enzyme which needs a cofactor is called a(n)

apoenzyme

polymerase

bonds small molecules with larger ones

Ribozymes ______ and ______.

can inhibit gene expression may have served as the first genetic material within ancient cells

Glycolysis is a(n) ______ process, which breaks down glucose into smaller molecules.

catabolic

An enzyme acts as a ________ that alters the rate of a reaction without being changed by the reaction.

catalyst

hydrolase

cleave bonds with the addition of water

Often, ______ will bind within an enzyme's active site and produce a unique active site for the substrate.

cofactors

Which three of the following are characteristics of most enzymes?

composed of protein are larger in size than their substrate lower the activation energy for a reaction

isomerase

convert a substrate to its isomeric form

carbohydrase

digests a carbohydrate substrate

lipase

digests fats

A(n) ______ is a biological catalyst.

enzyme

Composed principally of amino acids, ______ act as biological catalysts, facilitating metabolic activities of the cell.

enzymes

A reaction that releases energy is termed ______.

exergonic

True or false: Both aerobic and anaerobic respiration use oxygen as the final electron acceptor.

false

In the presence of an enzyme catalyst, a chemical reaction will proceed ______ than if the enzyme were not present.

faster

The incomplete breakdown of glucose in the absence of oxygen that yields only a small amount of ATP and produces a variety of byproducts is a process called

fermentation

Which term describes the incomplete breakdown of glucose due the absence of an electron acceptor for the electron transport system?

fermentation

ligase

form bonds using water and the energy in ATP form bonds using water and the energy in ATP

Aerobic respiration includes the following three pathways:

glycolysis Krebs cycle respiratory chain

nuclease

hydrolyzes nucleic acids

protease

hydrolyzes peptide bonds

Enzyme-substrate interactions are sometimes referred to as a "_______ and key" interaction.

lock

The combination of all reactions (catabolic + anabolic) within a cell is termed

metabolism

The Krebs cycle occurs in the ______ of eukaryotic cells and the ______ of bacteria.

mitochondria; cytoplasm

The location of the Krebs cycle enzymes in eukaryotes is in the ____________matrix, while in prokaryotes the enzymes are found in the ____________________

mitochondria; cytoplasm

The final step in the electron transport chain transports electrons to ______ to generate water.

molecular oxygen

Enzymes can have ______ active site(s).

multiple

During aerobic respiration of one molecule of glucose, 34 ATP are generated by _____________ phosphorylation in the electron transport system.

oxidative

In aerobic respiration, ___________ serves as the final electron acceptor.

oxygen

A series of metabolic reactions is termed a ______.

pathway

Which best defines an active site?

region on an enzyme where the substrate binds

During exergonic reactions, energy is ______.

released

are a class of RNA molecules that catalyze reactions on other RNA, and their discovery serves as evidence to support the RNA hypothesis.

ribozymes

In cells, the biosynthesis of carbohydrates involves ______.

several alternative pathways

The is the term for a specific molecule on which an enzyme acts.

substrate

In a metabolic pathway, ______ and ______.

the product of one reaction is often the substrate for another branches provide alternate methods for nutrient processing

oxidoreductase

transfer electrons from one substrate to another transfer electrons from one substrate to another

transferase

transfer functional groups from one substrate to another

True or false: An enzyme can have more than 1 active site.

true

A ______ is an organic component of coenzymes.

vitamin

The final step in the electron transport chain produces ______.

water