CHAPTER 3 Flashcards
What is ATP?
energy currency of cells
capacity to do work.
energy
Two classes of energy
potential, kinetic
where is chemical energy stored?
in a molecule’s chemical bonds
molecules that function in chemical energy storage
Triglycerides
Glucose
ATP
describe electrical energy.
movement of charged particles
energy exhibited by objects in motion due to applied force
mechanical energy
sound energy
molecule compression caused by vibrating object
energy of electromagnetic waves is called
radiant energy
kinetic energy from movement of atoms, ions, molecules is also called
heat
is heat available to do work?
not usually
What is the first law of thermodynamics?
Energy can neither be created nor destroyed; it can only
change in form
What is the second law of thermodynamics?
When energy is transformed, some energy is lost to heat.
Both the movement of Na+ from an area of higher
concentration to an area of lower concentration and the
movement of an electron from a higher energy to a lower
energy state are examples of (a) potential energy or (b)
kinetic energy?
B kinetic energy
Muscle contraction is an example of what form of energy?
mechanical
Energy can neither be created nor destroyed. However,
according to the first and second laws of
thermodynamics, what can happen to it, and what is
always generated?
it can transform, but some is lost and heat is generated
define metabolism
All biochemical reactions in living organisms
Occur when chemical bonds in existing molecular
structures are broken
chemical reactions
- Substances present prior to start of a chemical reaction
- Written on left side of equation
reactants
Substances formed by the reaction.
* Written on right side of equation
Products
Chemical reactions are classified based on three criteria.
changes in chemical structure, changes in chemical energy, and whether the reaction is reversible or irreversible
True or False : all decomposition reactions in the body are referred to as catabolism or catabolic reactions
True
What Happens in a decomposition reaction?
initial molecule is broken down into smaller structures
Two or more structures have combined to form a larger structure. What type of reaction took place?
synthesis reaction
What is the collective term for all
synthesis reactions in the body?
anabolism
What is an exchange reaction?
Groups exchange between two chemical structures
True or False? Exchange reactions have both decomposition and synthesis components.
True.
What is the most prevalent reaction type in the human body?
exchange reactions.
Production of ATP in muscle tissue is an example of what type of reaction?
exchange reaction
Reaction where energy is released with a net decrease in potential energy
Exergonic
reaction where energy is supplied with a net increase in potential energy
endergonic reaction
most enzymes are ____ proteins
globular
What is an enzyme’s active site?
where it can bind to a substrate
how do enzymes and substrates join?
the positions, sequences, structures, and properties of these residues create a very specific chemical environment within the active site. A specific chemical substrate matches this site like a jigsaw puzzle piece and makes the enzyme specific to its substrate
true or false? active sites have specificity.
true
where can enzymes be located?
within cells (dna polymerase), embedded in plasma membrane (lactase in walls of small intestines), secreted from cells (pancreatic amylase)
Mechanism of action for an enzyme in a decomposition reaction
substrate: lactose. enzyme: lactase)
1) the substrate lactose binds to the enzyme
2)enzyme changes shape, resulting in an induced fit between substrate and enzyme.
3) the bond is broken between glucose and galactose
4) glucose and galactose are released. the enzyme can now bind to other substances
mechanism of action for an enzyme in a synthesis reaction
substrate: glucose monomers enzyme: glycogen synthetase
they fit together and stay together the product is glycogen, and the enzyme is free to bind other substrates
What is a cofactor?
a molecule or “helper” ion required to ensure that a reaction occurs.
difference between organic and inorganic coenzymes
inorganic cofactors attach to enzyme (i.e zinc ion required for carbonic anhydrase to function). Organic factors are called coenzymes. like vitamins or modified nucleotides
Where do enzyme names come from?
name of substrate/product, subclass, suffix-ase
so much substrate is present that all enzyme molecules are engaged in reaction
saturation
true or false : severe increases in temperature cause protein denaturation with loss of function
True
where does glycolysis occur?
cytosol
where does the intermediate stage of cellular respiration take place?
mitochondria
What determines the number of ATP molecules generated?
entry point of electrons into the transport chain
Electrons from NADH enter at top
passed through 3 H+ pumps, generates 3 ATP molecules
electrons from FADH2 enter at second pump
generates 2 ATP molecules
how does cyanide cause cyanide poisoning?
inhibits electron transport and ATP production, electrons unable to reach oxygen
why is energy conversion always less than 100%?
some of the energy is released as heat
true or false? chemical energy is a form of kinetic energy.
False. potential energy.
where does ATP come from?
nutrients we eat
