energy Flashcards
phototroph
organisms that capture energy from the sun
organisms that derive energy from chemical compounds
chemotrophs
autotrophs
organisms that can create their own carbon using inorganic carbon
heterotrophs
rely on other organisms for their organic forms of carbon
set of chemical reactions that break down polymers into monomers, and in the process produce ATP
catabolism
anabolism
chemical reactions that build molecules
kinetic energy
the energy of motion
potential energy
stored energy which is released by a change in an objects structure or function
chemical energy
form of potential energy held in the chemical bonds between pairs of atoms in a molecule
what composes ATP
3 phosphate groups, ribose, adenine
first law of thermodynamics
The universe contains a constant amount of energy- new energy is never formed or never lost. energy only changes in its form (can change from kinetic energy to potential energy)
second law of thermodynamics
energy transformations always result in an increase in disorder in the universe
entropy
degree of disorder in a system
Gibbs free energy (G)
the amount of energy available to do work
If a product of a reaction has more free energy than the reactants, is the ΔG positive or negative?
positive
if a product of a reaction has a negative ΔG, what does this mean?
products have less free energy than the reaction, and energy is released
Exergonic reactions: what are they and are their ΔG value + or - ?
Describes reactions with a negative G that release energy and proceed spontaneously
reactions with a positive G and require an input of energy, are called?
Endergonic reactions
the hydrolysis of ATP is a:
A. Endergonic reaction
B. Exergonic reaction
B
Energetic coupling
a process in which a spontaneous reaction (negative ΔG) drives a non-spontaneous reaction (positive ΔG). It requires that the net ΔG of the two reactions be negative.
Activation energy
energy required to reach the transition state (also known as energy barrier)
Transition state
An intermediate state between reactants and products, and has a high amount of free energy
What role do enzymes have with activation energy?
enzymes lower the activation energy.
they do this by stabilising the transition state and decreasing the free energy
at the end of a reaction, enzymes.. A. Denature B. Temporarily denature C. Are unchanged D. They remain permanently bound to the product
C
enzymes have a 3d shape due to the A. Primary structure B. Quaternary structure C. Secondary structure D. Tertiary structure
D
How do enzymes join to the reactants?
they form a complex with the substrate, called the enzyme-substrate complex
How are enzymes able to reduce activation energy?
they can position two substrates by aligning their reactive chemical groups and limiting their motion relative to each other
if the size of the active site is very small in comparison to the whole enzyme, what is the point of the other parts of the enzyme?
it is required to bring catalytic amino acid into very specific positions in the active site
Types of inhibitors that influence enzyme activity
Irreversible and reversible
Irreversible inhibitors
usually form covalent bonds with enzymes and irreversibly inactivate them
reversible inhibitors
form weak bonds with enzymes and therefore easily dissociate from them
glycolysis outline
begins with a molecule of glucose and ends with two 3-carbon molecules of pyruvate and a net total of two molecules of ATP and two molecules of NADH
First stage of glycolysis
addition of two phosphate groups to glucose
requires an input of energy
second stage of glycolysis
glucose (a 6 carbon molecule) is split into two 3 carbon molecules
third stage of glycolysis
ATP and NADH are produced, and two molecules of pyruvate
what occurs during pyruvate oxidation
pyruvate molecules lose one carbon (which is released as CO2), electrons are picked up by NAD and become NADH. the 2 carbon molecule is known as Acetyl. Acetyl cannot pass through the membrane, so a CoA group attaches and becomes Acetyl-CoA
Where does glycolysis occur?
Cytoplasm
Where does pyruvate oxidation occur?
Mitochondrial membrane
What happens in the citric acid cycle
Acetyl group (has 2 carbons) has a 4 carbon molecule added to it and becomes citrate. The 6 carbon molecule loses 2 carbons, and it is released as CO2. The electrons released from the bonds between carbons splitting are obtained by FAD and becomes FADH2 and NAD becomes NADH
Where does the citric acid cycle occur?
mitochondrial matrix
Citric acid cycle yield
2 ATP
6 NADH
2 FADH2
