Microbial Metabolism Flashcards
Why are two of the phosphates on ATP designated with a “squiggle P”?
high energy bonds
Define oxidation and reduction
oxidation is the loss of an electron
reduction is gain of an electron
What is the net ATP from glycolysis?
2
What occurs at the active site of the enzyme?
Substrates attach
What is meant by “reducing power”? List some molecules that act as reducing power.
Reducing power is the ability of a chemical species to make another chemical substance undergo reduction.
NAD+-> NADH and FAD->FADH2
What effect do enzymes have on activation energy?
lower the activation energy
In glycolysis, how many ATP molecules are utilized?
2
Define exergonic
energy releasing
What is meant by carbohydrate catabolism?
the breakdown of sugars to produce ATP or other carbon-containing macromelecules
Define chemiosmosis
Chemiosmosis is the process of diffusion of ions (usually H+ ions, also known as protons) across a selectively permeable membrane. Chemiosmosis leads to a concentration gradient of the diffusing ion across the membrane. A concentration gradient is a form of potential energy that can do work.
Why is the Kreb’s cycle a cycle?
goes in a circle of 8 reactions twice
How many NADH and FADH2 is created in the Kreb’s cycle per glucose?
6 NADH and 2 FADH2
What is activation energy?
the amount of energy needed for a reaction to occur
How much ATP is generated per glucose molecule in the Kreb’s cycle?
2 ATP per glucose
What are the two differences between chemiosmosis in prokaryotes vs eukaryotes? (hint: where it occurs and the number of ATP generated)
In prokaryotes it takes place on the plasma membrane, in eukaryotes it takes place in the mitochondria membrane
Eukaryotes produce 36 ATP, Prokaryotes produce 38
How much NADH is generated in glycolysis?
2
Briefly describe how enzymes are named. [i.e. what are two common suffixes (endings) that are used?]
named for the reaction they catalyze, end in -ase or -sin
What is the terminal electron acceptor in fermentation?
organic molecule like pyruvate
What is the terminal electron acceptor in anaerobic respiration?
inorganic molecule like carbonate or sulfate
Final electron acceptor in fermentation vs aerobic respiration
fermentation- pyruvate
aerobic- oxygen
What are the main three steps of aerobic respiration and in what order do they occur?
glycolysis, Kreb’s cycle, and electron transport chain
Define metabolism
the sum of all chemical reactions of a living organism
What is the number of ATP generated for each NADH and FADH2 in the electron transport chain?
NADH= 3 ATP
FADH2= 2 ATP
Compare photosynthesis to aerobic respiration
Photosynthesis uses the sun’s energy. Can fix its own carbon.
Define catabolism
breaking down complex molecules to produce energy. Exergonic
In the electron transport chain, what happens to the reducing power generated in glycolysis and the Krebs cycle?
the electrons are passed from electron carrier to electron carrier which moves protons out of the cell
What step happens prior to the Kreb’s cycle? What 2 things happen?
transition step, pyruvate is converted to CoA and NAD+ is reduced to NADH (2 per glucose)
In glycolysis, how many ATP molecules are generated per glucose molecule?
4, 2 used, 2 net
Give some examples of coenzymes (a special type of cofactor)
FAD= flavin adenine dinucleotide
FMN=flavin mononeucleotide
CoA= coenzyme A
Other vitamins
Define reactants/substrates
starting components
substrates are the reactants for enzymes
define anabolism
smaller subunits combine to create macromolecules. Endergonic
Define endergonic
energy absorbing/requiring energy
define electrochemical gradient
a difference in charge and chemical concentration
What are the three types of carriers found in the electron transport chain?
flavoproteins, cytochromes, and ubiquinones (coenzyme Q)
Briefly describe how enzymes function.
substrates attach to the enzyme at the active site and are transformed into a new product
Number of ATP produced in fermentation vs aerobic respiration
fermentation- 2
aerobic- 36-38
O2 requirements in fermentation vs aerobic respiration
fermentation- does not need O2 but O2 can be present
aerobic- needs O2
Briefly describe how feedback inhibition works.
process in which the end product of a reaction inhibits or controls the action of the enzyme that helped produce it. prevents unneccesary product from being made
What gas is being produced in the catalase test?
O2
Describe four properties of enzymes.
biological catalyses
speed up the rate of reaction by lowering activation energy
reusable
are not permanently changed by reaction
made of protein (ribosomes are made of RNA)
specific for a specific substrates
need an optimal pH and temp to work best
Define substrate and turnover number.
a way of expressing the number of substrate molecules converted into products in one second
How and why do the following affect enzyme function?
a. temperature
b. pH
c. substrate concentration
d. inhibitors (competitive and allosteric)
temp: can affect the shape of the enzyme
pH: can affect the shape of the enzyme
substrate concentration: enzyme activity increases with concentration until it hits a plateau
competitive inhibitors: compete with the substrate to fill the active site on the enzyme
allosteric inhibitors: change the shape of the active site
What is the terminal electron acceptor in aerobic respiration?
oxygen
Describe the different parts of an enzyme.
holozyme- whole enzyme
apoenzyme- protein part of the enzyme
cofactor- ion or organic molecule that is required to make the enzyme functional
active site- binding site for substrate
allosteric site- site that allows molecules to either activate or inhibit enzyme activity
What are two ways to speed up a chemical reaction?
increase heat and lower activation energy
In glycolysis what is glucose converted to?
two molecules of pyruvate
define proton motor force
the movement of H+ to the outside of the membrane that creates an electrochemical gradient
What molecule is regenerated in the Kreb’s cycle?
oxaloacetic acid (OAA)
