Chapter 5 - Self-quiz

The following statements about enzyme characteristics are true:

-enzymes generally exhibit a high degree of specificity for one particular substrate and -enzymes have a region called the active site, which provides an area where it can form a loose association with its substrate

All of the following statements about competitive and non-competitive inhibitors are true:

-competitive inhibitors work by competing with a substrate for binding to an enzyme's active site -noncompetitive inhibitors can bind at sites other than the active site of an enzyme, distorting the tertiary protein structure, which alters the shape of the active site, rendering it ineffective for substrate binding -some noncompetitive inhibitors bind reversibly while some bind irreversibly to their enzyme

The principal energy-exchange molecule in living cells is:

ATP

The typical end products of complete aerobic cell respiration are carbon dioxide, water, and:

ATP

The energy source that drives the photosynthetic reactions in cyanobacteria is:

Light

Define metabolism and distinguish between anabolism and catabolism

Metabolism is the sum of all chemical processes carried out by living organisms. A subdivision of metabolism is anabolism which are reactions that require energy to synthesize complex molecules from simpler ones. Catabolism is the other subdivision of metabolism and involves reactions that release energy by breaking complex molecules into simpler ones, which in turn, can be reused as building blocks.

photoautotrophs

They are a subdivision of autotrophs They require CO2 and light They synthesize organic molecules from inorganic molecules

Enzyme cofactors are usually inorganic ions that enhance enzymatic activity by improving the "fit" between an enzyme and its substrate. True or False?

True

Metabolic pathways rely on many enzymes to synthesize or catabolize substrates to an end product. Within a given metabolic pathway, a product can become another enzymes' substrate. True or False?

True

during aerobic cell respiration most of the energy is produced during:

electron transport chain reactions

Anabolic reaction

formation of macromolecules

Reduction

gain of electrons

The end products of photosynthesis in cyanobacteria and plant cells are:

glucose and oxygen

Parts of an enzyme: (pg. 144) 1. 2. 3. 4. 5. 6. 7.

list of answers: a-apoenzyme b-Cofactor c-substrate d-active site e-coenzyme f-allosteric site g-holoenzyme

Oxidation

loss of electrons

The following statements about glycolysis are true:

-glycolysis can occur under aerobic or anaerobic conditions and is a metabolic pathway by which glucose is oxidized to pyruvic acid -glycolysis depends on the expenditure of two ATPs in substrate-level phosphorylations of the glucose molecule to initiate the metabolic pathway -energy from glycolysis is captured in the form of ATP at the substrate level when released energy from substrate molecules (late in the process) is used to form high-energy bonds between ADP and Pi. -glycolysis is a metabolic process that splits glucose (a six carbon molecule) into two three-carbon molecules of pyruvic acid that captures a relatively small amount of energy in the form of ATP compared to electron transport and oxidative phosphorylation

The following are characteristics of fermentation:

-produces acids, gases, and alcohol -occurs in the absence of oxygen -starts with the breakdown of pyruvic acid -occurs following glycolysis and produces NAD

Which of the following would influence the rate of an enzyme reaction?

-temperature -pH -concentration of substrate molecules -concentration of product molecules

What is feedback inhibition?

-when an end product accumulates, it often binds to and inactivates the first enzyme that catalyzes the first reaction in the pathway and -it is a reversible noncompetitive inhibition that regulates the rate of many metabolic pathways

How are fats and proteins used for energy?

Fats are hydrolyzed to 3 fatty acids and glycerol. The glycerol is metabolized in glycolysis. Fatty acids are broken down into two-carbon pieces by a metabolic pathway called beta oxidation. This results in the formation of acetyl-CoA which enters the Krebs cycle and is oxidized to obtain additional energy.

Many microorganisms in this group can carry out photosynthesis

a-autotrophs

Members of this group synthesize organic compounds to obtain energy

a-autotrophs

Members of this group usually do not cause disease

a-autotrophs

Phosphorylation

addition of phosphate group

Matching: Chemiosmosis--> Glycolysis--> Electron Transport Chain--> Fermentation--> Photosynthesis--> Krebs Cycle-->

answers: b-ATP production from a proton gradient across the plasma membrane a-Pathway that begins the breakdown of glucose f-Flavoproteins, cytochromes, and quinones c-Anaerobic pathway that uses an organic final electron acceptor d-Pathway that uses carbon dioxide, light, and chlorophyll to produce carbohydrates e-also is known as the tricarboxylic acid cycle (TCA) or the citric acid cycle

Many microorganisms in this group are infectious

b-chemoheterotrophs

Members of this group break down organic compounds to obtain energy

b-chemoheterotrophs

Members of this group carry out the same metabolic processes as man

b-chemoheterotrophs

catabolic reaction

breakdown of nutrients

Chemoautotrophs

use inorganic chemical reactions for energy production

Chemoheterotrophs

use organic compounds for energy production

Photoautotrophs

use sunlight and carbon dioxide

Photoheterotrophs

use sunlight as a source of energy, and organic compounds as a carbon source