Enzymes

The enzyme is specific for the substrate that it works on. This is called the ________________

"Lock and Key Model"

Enzyme names end in _____, the beginning of the name is the substrate that it works on.

-ase; Ex: lactose ----> lactase protein ----> protease

For many enzymes in the human body, denaturation occurs around ___________, just above normal body temp of ___________

40 degrees C ; 37 degrees C

Meat tenderizer contains an enzyme that interacts with meat. If meat is coated with tenderizer and then placed in a refrigerator, how would the enzyme be affected? It would be broken down. It would no longer act as an enzyme. Its shape would change. Its activity would slow down.

Its activity would slow down.

Which of the following is a characteristic of an enzyme? * a) It is an inorganic catalyst. b) It regulates the rate of a specific chemical reaction. c) It provides energy for any chemical reaction. d) It is destroyed after each chemical reaction.

b) It regulates the rate of a specific chemical reaction.

An enzyme-substrate complex may result from the interaction of molecules of: a) sucrose and maltase b) protein and protease c) fat and amylase d) glucose and lipase

b) protein and protease

The pH at which an enzyme works best is referred to as its __________ pH. Each enzyme works best at its own pH.

optimum

Co-enzymes

non-protein parts Ex: vitamins

Enzyme Saturability

As concentration (amount) of substrate or enzyme increases, the enzyme rate increases up until the point where the rate levels off because the enzyme molecules are working at their maximum rate.

Under which conditions is the enzyme most effective?

At its optimum point

"Lock and Key Model"

where the shape of the active site of the enzyme is specific for only one substrate (like a key is specific for a lock).

Organic Catalysts that speed up the rate of a chemical reaction

Enzymes

Which statement about enzymes is NOT correct? Enzymes are destroyed when they are used and must be synthesized for each reaction. Enzymes are specific because of their shape and catalyze only certain reactions. Enzymes are composed of polypeptide chains. Enzymes form a temporary association with a reactant.

Enzymes are destroyed when they are used and must be synthesized for each reaction.

Describe the characteristic of enzymes that prevents ptyalin and trypsin from digesting the same type of food. (Ptyalin breaks down carbohydrates and trypsin breaks down protein.)

Enzymes are specific to their substrate. Every enzyme has an active site designed for a substrate to fit perfectly into the enzyme, in order to have chemical reaction occur. The enzyme has a specific substrate that will fit perfectly into the active site and cause a chemical reaction. Ptyalin breaks down carbohydrates and trypsin breaks down protein. They each react for a specific type of food based on what is included in these foods. If a steak is consumed trypsin will digest the steak and if pasta is consumed, ptyalin will digest the pasta.

State how a fever of 40°C would most likely affect the activity of enzymes lower than 40°C and support your answer.

Human body temperature is normally 37C, so at 40C the enzymes will begin to denature the substrates won't fit, and the enzymes will be ineffective. This will lower the rate of enzyme activity.

State how the activity of pepsin will most likely change after it moves with the food from the stomach to the small intestine.

The activity of pepsin will change after it moves from the stomach to the small intestine because the pepsin is being moved into a more basic environment. Pepsin does it's best job at breaking down food in the stomach in an acidic environment, but when moved to the small intestine, the activity of pepsin will slow down because it is moving into a more basic environment.

Optimum

The best or highest (temperature) you can hit

Which statement describes all enzymes? They control the transport of materials. They absorb oxygen from the environment. They provide energy for chemical reactions. They affect the rate of chemical reactions.

They affect the rate of chemical reactions.

enzyme-substrate complex

When the enzyme and substrate bond, and the reaction occurs

Catalyst

a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change

If figure B represents a disaccharide and then the disaccharide is split in two, each must represent a molecule of: a) an amino acid b) a monosaccharide c) a polysaccharide d) a fatty acid

a) a monosaccharide

The part of the enzyme molecule into which the substrate fits is called the: a) active site b) coenzyme c) protease d) polypeptide

a) active site

Which term describes the changes in the active site of an enzyme due to high temperatures? * a) denaturation b) dehydration c) hydrolysis d) alteration

a) denaturation

Which group of organic compounds includes enzymes? a) proteins b) sugars c) carbohydrates d) lipids

a) proteins

An enzyme that hydrolyzes starch usually will not act upon sucrose. This fact is an indication that enzymes are: a) specific b) catalytic c) synthetic d) oxidative

a) specific

Pepsin digests protein in the stomach. Pepsin works best in which type of environment? basic, only sometime acidic, sometimes basic neutral acidic, only

acidic, only

For example, enzymes that work in the human stomach have an optimum pH which is very ________, and enzymes in the intestines have an optimum pH that is _______

acidic; basic

Which statement best describes the relationship between substrate concentration and the rate of enzyme activity? a) Substrate concentration has no effect on the rate of enzyme activity. b) The rate of enzyme activity varies directly with the substrate concentration. c) The rate of enzyme activity becomes stabilized when a certain substrate concentration is reached. d) As the substrate concentration is increased, the enzyme activity increases constantly.

c) The rate of enzyme activity becomes stabilized when a certain substrate concentration is reached.

Enzymes influence chemical reactions in living things by: a) providing the substrate required for the reactions to occur b) combining with excess hydrogen to form gaseous wastes c) affecting the rate at which the reactions occur d) absorbing water released when polymers are formed

c) affecting the rate at which the reactions occur

Enzymes do NOT _________ during a chemical reaction. When the reaction ends the enzyme separates from the product and can then bond with another substrate. Enzymes are _________.

change; reusable

At high temperatures, the rate of enzyme action decreases because the increased heat * a) neutralized the acids and bases in the system b) changes the pH of the system c) increases the concentration of the enzyme d) alters the active site of the enzyme

d) alters the active site of the enzyme

Which of the following variables has the least direct effect on the rate of an enzyme-regulated reaction?: a) enzyme concentration b) pH c) temperature d) carbon dioxide concentration

d) carbon dioxide concentration

The "lock-and-key" model of enzyme action illustrates that a particular enzyme molecule: a) reacts at identical rates under all conditions b) may be destroyed and resynthesized several times c) forms a permanent enzyme-substrate molecule d) interacts with a specific type of substrate molecule

d) interacts with a specific type of substrate molecule

Any substance that is acted upon by an enzyme is called a: a) vitamin b) polypeptide c) glycerol d) substrate

d) substrate

Denaturations: when the shape of the active site changes and the substrate no longer fits. This causes the enzyme rate to _________ because now the enzyme is ineffective.

decrease

The change in shape of enzyme molecules which occurs at high temperatures is known as replication specificity synthesis denaturation

denaturation

If an enzyme is not within its optimal range, it will _________ and _________ the rate of activity.

denature ; decrease

Hydrogen peroxide (H2O2) is a toxic by-product of cellular metabolism in organisms. The reaction below occurs within the cells to prevent the accumulation of hydrogen peroxide. In this reaction, catalase functions as an 2H2O2 ---(catalase)---> 2H20 + O2 indicator in the detection of hydrogen peroxide enzyme in the breakdown on hydrogen peroxide enzyme in the synthesis of hydrogen peroxide emulsifier in the digestion of hydrogen peroxide

enzyme in the breakdown on hydrogen peroxide

All cells of an organism are engaged in many different chemical reactions. This fact is best supported by the presence in each cell of thousands of different kinds of nucleic acids chloroplasts enzymes polysaccharides

enzymes

Lipase, maltase, protease, are members of a group called catalysts known as carbohydrates enzymes hormones fats

enzymes

Which class of molecules is responsible for speeding up chemical reactions? fats nucleic acids sugars enzymes

enzymes

Shrimp that live in the cold waters off Alaska will die if introduced into warm water. One likely reason these shrimp do not survive is that enzymes in the shrimp function at a low optimum temperature start to replicate break down into small starch molecules are composed of fat molecules that melt

function at a low optimum temperature

Enzyme molecules normally interact with substrate molecules. Some medicines work by blocking enzyme activity in viruses. These medicines are effective because they have a shape that fits into the enzyme are the same size as the enzyme are the same size as the substrate molecules have a shape that fits into all cell receptors

have a shape that fits into the enzyme

As temperature increases, the rate of enzyme action ________ until it reaches the temperature at which it is most ________

increases; efficient

The rate of enzyme activity is increased by __________ the concentration of substrate molecules.

increasing

The enzyme salivary amylase will act on starch, but not on protein. This action illustrates that salivary amylase is not reusable lacks protein contains starch is chemically specific

is chemically specific

In the chemical equation shown below, what does the letter A represent? maltose + water ---A---> glucose + glucose maltase lipase protease hydrolase

maltase

Enzymes

proteins made of amino acids

With The Induced Fit Model of Enzyme Action the active site slightly changes its _________ to fit the substrate perfectly.

shape

Organic catalysts that _________ the rate of chemical reactions by ___________________________.

speed up; lowering the activation energy

Three factors that affect the rate of enzyme action are:

temperature, pH, enzyme/substrate concentration

the activation energy

the energy needed to get a reaction started

Denaturations

when the shape of the active site changes and the substrate no longer fits