Exam 3 Flashcards
Name the two major types of Metabolic Reactions.
- Anabolic
* Catabolic
An Anabolic reaction usually requires energy.
True or False?
true
Are Anabolic Reactions building reactions or break down reactions?
Building Reaction
What is Cell Metabolism in simple terms?
The sum of both building up reactions and breaking down reactions
What does synthesis mean?
Process is making something (building)
What does -lysis mean?
break down/burst
What are Biological Catalysts?
Enzymes found in living things
What are enzymes predominantly made up of?
Proteins
Define Catalyst
a substance that speeds up chemical reactions without being permanently altered
When heat is used as a catalyst, what does it do to the molecules?
It speeds them up causing them to bump into eachother and react
Are all Proteins enzymes?
no
Living systems depend on reactions that occur spontaneously, but at very ____ rates.
slow
No Catalyst makes a reaction occur that cannot otherwise occur.
true or false
true
Most Biological Catalysts are proteins (enzymes), but other than those, a few are RNA molecules called _________.
ribozymes
What is another name for a Substrate?
Reactant
A Reactant is usually a monomer or a macromolecule.
true or false
true
What will put reactants into a Transition State
hint: an input of energy
the activation energy
What type of reaction is an exergonic reaction?
a reaction where energy is released
“building blocks” refers to what?
monomers
If we used heat as a catalyst for ourselves instead of enzymes, we would die. Why is this true?
we are composed primarily of proteins and extreme heat would denature the proteins.
What is activation energy?
The amount of energy required by certain chemicals for them to have a reaction
Enzymes enable us to do the same reaction that we could do without them, but effects the amount of energy needed to do the reaction. How?
It enables us to do the reaction with far Less energy
What do enzymes do to the energy of activation?
enzymes lower the energy of activation
Is the beginning of a reaction considered stable or unstable?
Stable
Is the Transition State of a reaction considered stable or unstable?
Unstable
Activation energy _________ reactions
initiates
Define Hydrolyze
to undergo hydrolysis
When you see -ase at the end of a word, what does it mean?
its probably an enzyme
Is a Catabolic reaction a building reaction or a break down reaction?
break down reaction
Enzymes are highly specific. What does this mean?
each enzyme catalyzes only one chemical reaction
Name the specific site on the enzyme that a substrate binds to?
the active site
The makes the active site specific?
Its exact 3-D shape and chemical properties
An enzymes name can tell you one of two things, what can it tell you?
*the substrate it works on
or
*the reaction that it can catalyse
What is being referred to when you hear Lock and Key?
When a substrate and an enzyme bind (their shapes fitting together perfectly)
Name the broader, less specific enzyme we discussed in class. (named for the reaction it works on)
dehydrogenase
What does dehydrogenase do?
catalyzes (accelerates) the removal of Hydrogens
What is amylose?
Starch
What is protease?
a digestive enzyme that breaks down (processes) proteins (polypeptides)
How does the diet pill Alli work?
it’s an enzyme inhibitor
lipase inhibitor
What two monosaccharides together make sucrose?
glucose+fructose
What is the enzyme-substrate complex?
A non-covalent complex composed of a substrate bound to the active site of an enzyme
How is an enzyme-substrate complex (ES) held together
3 possible ways
- Hydrogen Bonding
- Electrical attraction
- temporary covalent bonding
At the end of a reaction, what two things are left?
- the product
* we get the enzyme back
Does the enzyme change shape when a substrate binds ?
yes
Enzymes can assist in chemical reactions in several different ways.
true or false
true
Enzymes may use one or more mechanisms to catalyze a reaction. Name three ways
- Inducing Strain: stretching substrate
- Substrate Orientation: enzyme that brings them together (anabolic)
- Adding Chemical Groups: R-groups may be involved in reaction
What does the catchers mitt analogy refer to?
Binding of a substrate to an enzyme and the enzyme changing shape to make the binding tight- “induced fit”
An enzyme can add a chemical group to the substrate.
True or False?
True
Hemoglobin won’t work without which cofactor?
Iron
Some enzymes require Ions or other molecules in order to function.
True or false
true
What are cofactors known as?
Inorganic ions
Name something that can add or remove chemical groups from the substrate and can also participate in many different reactions.
coenzymes
coenzymes are almost always ________.
vitamins
Prosthetic groups are also known as what?
non-amino acid groups
Name something that is permanently bound to their enzyme that also helps the enzyme have functionality.
Prosthetic groups
What are the B-Vitamins known as?
energy vitamins
Is NAD a coenzyme?
yes
Does NAD have anything to do with Niacin?
yes
All cofactors are vitamins.
true or false
false, all cofactors are ions
Name 3 cofactors.
- Iron
- Copper
- Zinc
Name 5 Coenzymes
- Biotin
- Coenzyme A
- NAD
- FAD
- ATP
Name 3 Prosthetic groups
- Heme
- Flavin
- Retinal
Being deficient in Retinal means you’re deficient in what vitamin?
vitamin A
If you have a retinal deficiency , the ____ in your retina will not work efficiently and you will have night blindness
Rods ( help you see in dimmer light)
Which 2 or the 3 cofactors (Ions)play a role in oxidation/reduction?
- Iron
* Copper
Which cofactor (Ion) helps bind NAD?
Zinc
Which coenzyme provides/extracts energy in catalyzed reactions?
ATP
Which two of the coenzymes on the chart carry electrons?
NAD and FAD
Which of the 3 separate molecules in the prosthetic group converts light energy?
Retinal
The less enzyme we have, the ______ the reaction rate
slower
In a catalyzed reaction is there usually more enzyme than substrate present or less enzyme than substrate present?
less enzyme than substrate
What does the reaction rate do when the enzyme becomes saturated?
the reaction rate levels off/stops
What has to happen for an enzyme to be saturated?
all enzyme molecules are bound to substrate molecules
What is used to calculate enzyme efficiency?
Maximum rate
How many molecules of substrate can convert to product per second? (turnover)
1 to 40 million molecules per second
The amount of enzyme and the amount of _________ both effect the rate of reaction.
substrate
What is the substrate for alcoholdehydrogenase?
alcohol
What happens with the liver if you don’t drink often?
the liver doesn’t make as much alcohol dehydrogenase (the enzyme used in processing alcohol)
What group of people are genetically predisposed to being alcoholics because they do not produce much alcoholdehydrogenase?
Native Americans
Enzyme-catalyzed reactions are part of metabolic pathways.
true or false?
true
In a metabolic pathway, the product of one series of chemical reactions, modified by enzymes, becomes the substrate for the next.
true or false?
true
Define homeostasis
the maintenance of stable internal conditions
Cells can regulate metabolism by controlling the amount of what?
an enzyme
What can chemical inhibitors do to enzymes to slow reaction rates?
bind to them
What do Natural inhibitors do?
regulate metabolism
What are artificial inhibitors used for?
- to treat diseases
- kill pests
- to study enzyme function
When an inhibitor covalently binds to a side chain in the active site and the enzyme is permanently inactivated, what is this referring to?
irreversible inhibition
Rat poison is an enzyme inhibitor, what does it inhibit?
the ability to make ATP
Which is more common in cells, reversible inhibition or irreversible inhibition?
reversible inhibition
What does a competitive inhibitor do concerning the enzyme?
It competes with the substrate for the active site
What does a noncompetitive inhibitor do concerning the enzyme?
It binds to a site distinct from the active site
A noncompetitive inhibitor does not keep the substrate from bonding to the active site, therefore it does not disrupt the shape or function of the enzyme.
True or False?
False. The noncompetitive inhibitor binds to the enzyme at a site distinct from the active site which causes change in the shape and function of the enzyme.
What happens if the competitive inhibitor gets to the active site before the substrate?
the reaction can’t happen
If a noncompetitive inhibitor binds to the enzyme, can the reaction still happen?
no
When a non-substrate molecule binds to a site on an enzyme other than the active site, what is this called?
Allosteric regulation
When a noncompetitive inhibitor binds to a site on the enzyme that isn’t the active site, what is this site called?
the allosteric site
What type of regulation can activate or inactivate enzymes?
Allosteric regulation
