Lab 5 Review Flashcards (w/ exercise and module)
Names of enzymes typically end with:
-ase
The ___________ states that the concentration of a light absorbing solute is directly proportional to its absorbance
Beer-Lambert Law
_________ in its reduced form is colorless; in its oxidized form, it takes on a brown color.
Guaiacol
Peroxidases can oxidize _________ (compounds that have free hydroxyl groups) and form water
H2O2
___________ are relatively rare in animal cells, but quite common in all higher plant cells.
Peroxidases
_________, the substrate of the enzyme peroxidase, can be a product of oxidation reactions that take place in the cell.
Peroxide
__________ means that all of the enzyme active sites are occupied by substrate
Saturation
_________ is the process of inducing bond strains in a substrate.
Substrate activation
Proteins and nucleic acids absorb ___________ at wavelengths of 240 to 300 nm.
UV light
energy that must be invested for a reaction to occur; to make the reactant unstable and convert it to product, some energy (in the form of this) must be invested
activation energy
The ___________ is typically made up of a few amino acid residues and their respective side chains.
active site
The location on an enzyme that binds substrate is its:
active site
Which of the following activities would result in an increase the rate of a chemical reaction?
adding a catalyst
Which of the following explains the concept of saturation?
all of the active sites of the enzymes are occupied
The strain imposed by physical forces/electron re-distribution, creates a strain on a covalent bond within the substrate molecule, resulting in ____________
bond breakage
How does an enzyme catalyze a reaction?
by decreasing the energy of activation for a chemical reaction
The organic nonprotein portion of an enzyme that is required for proper function is an:
coenzyme
Organic cofactors, also known as ____________, are nonprotein organic molecules that are required for enzyme function. Vitamins can serve as ___________
coenzymes
Vitamins are essential to the survival of organisms because vitamins usually function as:
coenzymes
inorganic ions, called ____________, are necessary for enzyme function.
cofactors
Optical density is proportional to the _____________
concentration of solute
What device is inserted into the chamber of the spectrophotometer (tip of yellow arrow)?
cuvette
Control of enzyme activity is an important aspect of regulating cell metabolism. Which of the following is LEAST likely to be a mechanism of controlling enzyme activity?
denaturation
changes with independent variable
dependent variable
varies with variation in the independent variable (absorbance); graphed on y-axis
dependent variable
a chemical reaction that requires energy investment or expenditure-a reaction that absorbs energy--the chemical energy of the products is higher than the chemical energy of the reactants
endergonic
energy required; nonspontaneous
endergonic reaction
Hydrogen peroxide (H2O2) is a toxic byproduct of aerobic respiration in cells. The reaction shown helps prevent hydrogen peroxide buildup in cells. In this reaction, catalase functions as an:
enzyme in the breakdown of hydrogen peroxide
Which of the following statements regarding enzymes is true?
enzymes increase the rate of reaction
a chemical reaction in which the products are at a lower energy level than reactants--energy is released by the reaction (products are at a LOWER energy level than the reactants)
exergonic
energy released; spontaneous
exergonic reaction
Most catabolic reactions are _________, and most anabolic reactions are __________.
exergonic; endergonic
Each reaction within _________ (the breakdown of glucose) is catalyzed by a different enzyme.
glycolysis
If substrate concentrations are low, and many of the existing enzymes are idle because of a lack of substrate, then adding enzyme will ___________on reaction rate.
have no effect
peroxidase activity of cabbage
high
peroxidase activity of celery
high
peroxidase activity of potatoes
high
peroxidase activity of sweet potatoes
high
peroxidase activity of turnip
high
Substrates are held in the active site of an enzyme by:
hydrogen and ionic bonds
Enzymes recognize and bind to their substrates through ?
hydrogen bonds, ionic bonds, and hydrophobic interactions.
In the experiment conducted in lab, what was the substrate used?
hydrogen peroxide
reaction rate _________ as temperature increases until the point of denaturation.
increases
If the concentration of enzyme is low, and there is a great deal of substrate, then increasing enzyme concentration results in more molecules available to convert substrates to products, thus?
increasing enzyme concentration can increase reaction rate
If the substrate concentration is limiting, how does increasing enzyme concentration affect reaction rate?
increasing enzyme concentration has no effect on reaction rate
the variable that undergoes a constant, continual change whether or not the dependent variable changes
independent variable
usually time (graphed on x-axis); changes whether or not dependent variable changes
independent variable
Other organic compounds absorb ___________.
infrared energy
__________ is a statistical tool to evaluate or establish a relationship between an independent variable and a dependent variable.
linear regression
best-fit line that shows the relationship between an independent variable and a dependent variable
linear regression
Which of the following enzymes would be important in fat digestion?
lipase
What happens to an enzyme when it denatures?
loss of three dimensional shape of the molecule
peroxidase activity of carrots
low
peroxidase activity of onions
low
peroxidase activity of spinach
low
peroxidase activity of zucchini
low
In the degradation of maltose to two glucose molecules:
maltose is the substrate
Cells must produce many different enzymes because:
most cellular reactions require a specific, unique enzyme
peroxidase activity of cooked potatoes
none
Living organisms carry out multiple series of chemical reactions to:
obtain energy for cellular function and activities and grow and reproduce
__________ (OD) is used when a sample is scattering light rather than absorbing it.
optical density
loss of electrons
oxidation
When guaiacol reacts with peroxide and peroxidase, it is __________ to tetraguaiacol, resulting in the formation of a color compound that can be detected spectrophotometrically
oxidized
The experimental setup for your lab involved the extraction of an enzyme from turnip, and observing its reaction rate under a variety of conditions. What is the enzyme?
peroxidase
Peroxidases are present in ___________ of liver cells, kidney cells, leukocytes, and __________ of animals.
peroxisomes; erythrocytes
stored energy
potential energy
produced from substrate through an enzyme-catalyzed reaction
product
Absorbance is ____________ to concentration
proportional
the starting molecule for a chemical reaction
reactant
If all enzyme molecules are working at maximum capacity, then adding substrate will have no effect on ____________
reaction rate
a measure of changes in enzyme activity
reaction rate
the rate at which a chemical reaction takes place; typically linear
reaction rate
Peroxide is ___________ to water, and guaiacol is oxidized to __________.
reduced; tetraquaiacol
gain of electrons
reduction
mathematical quantification of how steep a line is
slope
The shape and properties of the active site determine enzyme __________
specificity.
a reaction that is exergonic--where the products are at a lower energy level than reactants
spontaneous chemical reaction
the molecule that is recognized by, and binds to enzyme-to be changed or altered by the enzyme
substrate
Enzymes are ___________, meaning a different enzyme is involved in each chemical reaction that takes place in a cell.
substrate-specific
The function of an enzyme is to convert _________ to ________
substrate; product
Explain why the cooked potato had no peroxidase activity
the heat caused the enzyme, peroxidase, to denature
Pigments and dyes absorb ___________ between wavelengths of 320 to 660 nm.
visible light
The inactive form of an enzyme if an:
zymogen