Human Physiology Exam 4

first law of thermodynamics,(law of conservation of energy

energy can be transformed (changed from one form to another), but it can neither be created nor destroyed. Ex. mechanical energy can be transformed into electrical energy.

Reactions that release energy are called __________ reactions.

exergonic

An enzyme can only bind one substrate at a time. An enzyme speeds up a chemical reaction in the cell, but can only be used once.

false false

Blood sugar refers to what molecule circulating in blood?

glucose

transaminases (ALT/AST) diseases

hepatitis muscular dystrophy

Oxidation-reduction reactions in cells often involve the transfer of ___ atoms rather than free ___. A hydrogen atom contains 1 electron and 1 proton; therefore a molecule that loses hydrogen becomes ____, and one that gains hydrogen becomes ___. NAD is an example of a____that transfers pairs of ____ atoms from one molecule to another. In the reaction shown on the left, NAD is ___ (it acts as a oxidizing agent); whereas in the reaction on the right, NAD is ____ (it acts as a reducing agent).

hydrogen oxygen oxidized reduced coenzyme hydrogen reduced oxidized

As temperature increases, enzyme activity ____ up to a point, a characteristic ____, after which activity ____________ . Looking at the graph, enzyme activity peaks at around ____________ C and is lowest around ____________ C. The peak corresponds to ____ temperature and the decrease reflects an altered ____________ structure of enzymes at ____________ temperatures.

increases plateau decreases 40 0 body tertiary higher

Energy flow through organisms

is inefficient because energy is lost to heat as it is converted

Enzyme (catalyst)

is not used up in a chemical reaction, lowers the activation energy in a reaction, is a protein or ribozyme, will react with a substrate at the active site Enzymtic reactions are not dependent on amount of energy, but affected by temperature, PH, and the amount of the enzme.

Entropy

is the degree of disorganization of a system's total energy.

Different organs can make slightly different "models" of the enzyme that differ in one or a few amino acids. These different models of the same enzyme are called isoenzymes.

isoenzymes: enzymes, usually produced by different organs that catalyze the same reaction but that differ from each other in amino acid composition Ex. If a enzyme normally functions in the liver cells but can also be found in muscle tissure catalyzing reactions, the form found in the muscle tissue would be considered a isoenzyme.

How often can a sucrase molecule be used to hydrolyze sucrose?

many times

When an atom or molecule gains electrons it is said to be ___; when it loses electrons it is ___. Oxidation-reduction reactions always occur in ____reactions, because an atom or molecule cannot become ______ unless there is a molecule to which it can donate its electrons. The atom or molecule that donates electrons is known as a _____ agent and the one that accepts electrons is the _____ agent. The term oxidation does not mean that oxygen has to be involved. Rather it arises from the fact that oxygen readily _____ electrons and therefore acts as a strong ____ agent.

reduced oxidized coupled oxidized reducing oxidizing accepts oxidizing

Bioenergetics

refers to the flow of energy in living systems.

Some enzymatic reactions can move both forward and backward, which means they are ____________ . For example, the enzyme carbonic anhydrase catalyzes the following reaction:

reversible

The second law of thermodynamic

states that the amount of entropy increases in every energy transformation. Because only energy in an organized state—called free energy—is available to do work, this means that the free energy of a system decreases as its entropy increases. . But the second law dictates that the process cannot simply be reversed and continued indefinitely.

In a metabolic pathway, the product of one enzyme subsequently becomes the ____________ of the next. In a branched metabolic pathway, the product of an intermediate becomes the substrate for ____________ enzyme. ____________ metabolic pathways are branched. End-product inhibition acts on the ____________ enzyme. In the pathway shown, if the product F exhibited allosteric inhibition, then the pathway leading to product F' would be ____________ .

substrate more than one most branch-point favored

The energy released by most exergonic reactions in the cell is used, either directly or indirectly, to drive one particular endergonic reaction:

the formation of adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate (abbreviated Pi).

ATP

the universal energy carrier of a cell

It is ___ that many enzymes are inactive without the presence of cofactors or coenzymes. Cofactors include _____ In figure (a), the cofactor ____ the active site of the enzyme. In figure (b), the cofactor participates in the bond between the enzyme and the _____.

true metal ions is changing substrates

What occurs if liver cells are damaged and can not produce the bilirubin derivatives?

-Conjugated bilirubin levels increase in the blood -Jaundice occurs -AST and ALT blood levels increase

In the cells of the pancreas, for example, many digestive enzymes are produced as inactive zymogens, which are activated after they are secreted into the intestine.

. Activation of zymogens in the intestinal lumen (cavity) protects the pancreatic cells from self-digestion. The activation/inactivation of the enzyme, zymogens is achieved by the process of phosphorylation/dephosphorylation. (add or remove phosphate)

Reversible reactions are governed by the law of_____, the principle that the reaction will be driven from the side of the equation where the concentration is ___ to the side where it is___. In the tissues, where CO2 is ___, the reaction will move to the___. In the lungs where CO2 is ___ and H2CO3 is ___, the reaction will move to the ___. In other words, the ____ of the reaction depends on the relative ______ of the molecules on each side of the equation.

...law of law of mass action high low high right low high left direction concentrations

1. What happens to the globin part of hemoglobin that is released from old red blood cells? 2. What happens to the heme group once the iron is released? 3. What happens to the iron that is released from old red blood cells? 4. How is bilirubin transported to the liver?

1. Broken down into amino aicds 2. Converted to biliverdin and then bilirubin 3. Transported to red bone marrow, liver, and spleen 4. Bonded to albumin

1. Elevated levels of acid phosphatase in the blood would indicate: 2. Isoenzymes released from damaged tissue include MM, BB, and: 3. What condition does Tom's elevated MB isoform of creatine phosphate suggest? 4. Prostate cancer can lead to difficult with urination due to: 5. What additional test can be done for prostate cancer?

1. cancer of the prostate 2. MB 3. heart attack 4. enlarged prostate compresses the urethra 5. PSA

metabolic pathway.

A sequence of enzymatic reactions that begins with an initial substrate, progresses through a number of intermediates, and ends with a final product

Enzymes exhibit peak activity in a_____ pH range called the _____. If the pH is not in this range the reaction rate will ____. The pH optimum of an enzyme corresponds to the _____in which it is found. For instance ____________ has a pH optimum around ____________ to allow it to work in the extremely ____________ gastric juice; whereas trypsin has a pH optimum around ____________ to allow it to work in the ____________ pH of the pancreatic juice.

narrow PH optimum decrease body fluid pepsin 2 acidic 9 alkaline

endergonic reactions.

Chemical reactions that require an input of energy

Which of the following correctly represents the mechanism of enzyme function (S = substrate, P = product, E = enzyme)?

E+S ->E-S _>E-P ->E+P

1. Adds water to split molecules 2. Removes phosphate groups 3. Removes water to join molecules 4. Removes hydrogens 5. Adds phosphate groups 6. Rearranges the atoms in a molecule

Hydrolase Phosphatase Synthase Dehydrogenase Kinase Isomerase

Alkaline Phosphatase disease

obstructive jaundice pagets disease carcinoma of bone

Where is sucrase found in the human body?

on the microvilli of the small intestine

An inherited defect in one of these genes may result in a disease known as an inborn error of metabolism.

In this type of disease, the quantity of intermediates formed prior to the defective enzymatic step increases, and the quantity of intermediates and final products formed after the defective step decreases. Diseases may result from deficiencies of the normal end product or from excessive accumulation of intermediates formed prior to the defective step. The effects of an inborn error of metabolism on a branched metabolic pathway. The defective gene produces a defective enzyme, indicated here by a line through its symbol.

Heat is measured in units called calories.

One calorie is defined as the amount of heat required to raise the temperature of 1 cubic centimeter of water 1 degree on the Celsius scale.

In what condition would a diet low in phenylalanine be recommended for a young child?

PKU

amylase diseases

pancreatitis perforated peptic ulcer

Enzymes are a subclass of+___ The amount of energy required for a reaction to occur is called the It is ___ that most reactions in the body occur without the need for catalysts. Enzymes act as____ Catalysts ____ the activation energy needed for a reaction to occur.

proteins activation energy false catalyst lower do not change

-Enzymes are __ -The active site of an enzyme binds to which of the following?__

proteins substrates

Coupled reactions

provide the cell the energy it needs for reactions and are inefficient and result in heat loss

Exergonic reaction

Reactions that convert molecules with more free energy to molecules with less—and, therefore, that release energy as they proceed. Ex, breaking glucose into carbon dioxide and water denoting chemical reactions that liberate energy.

There are a few special cases in which RNA demonstrates enzymatic activity; in these cases they are called ribozymes.

Ribozymes function as enzymes in reactions involving remodeling of the RNA molecules themselves, and in the formation of a growing polypeptide in ribosomes.

Why is it that damaged tissue changes the levels of enzymes in the blood? Why is it that damaged tissue, such as in the case of a myocardial infarction, changes the levels of enzymes in the blood?

The dead cells release enzymes into the blood. Dead or damaged cells release enzymes into the blood.

allosteric inhibition.

The mechanism by which a final product inhibits an earlier enzymatic step in its pathway or the active site changes shape to inhibit the reaction. The allosteric inhibitor combines with a part of the enzyme at a location other than the active site. This causes the active site to change shape so that it can no longer combine properly with its substrate.

Coenzymes NAD and FAD are found in the vitamins niacin and riboflavin. Why is it that excess amounts of these vitamins are removed from the body in the urine?

They are water-soluble vitamins and therefore not stored in the body.

The effect of substrate concentration on the rate of an enzyme-catalyzed reaction.

When the reaction rate is at a maximum (plateau), the enzyme is said to be saturated.

FAD

a coenzyme derived from riboflavin that participates in electron transport within the mitochondria.

NAD

a coenzyme derived from the vitamin niacin that functions to transport electrons to oxidation-reduction reactions, It helps to transport electrons to the electron transport chain within mitochondria.

Gene therapy

a method where scientists use viruses to insert a defective gene into a patient in order to treat severe combined immunodeficiency disease

A catalyst

a substance/chemical that increases the rate of a chemical reaction without changing the nature of the reaction or being changed by the reaction

Energy-liberating reactions

are coupled to energy-requiring reactions. This relationship is like that of two meshed gears; the turning of one (the energy-releasing exergonic gear) causes turning of the other (the energy-requiring endergonic gear).

ATP is able to store and release large amounts of energy because of its ________.

bond with phosphate groups and its ability to couple to exergonic and endergonic reactions

In simple terms sucrase

breaks sucrose into glucose and fructose.

How does sucrose change the configuration of sucrase?

by binding to the active site