Exam 2 review Flashcards
What is catabolism (decomposition)
A chemical pathway that RELEASES energy (EXERGONIC REACTION) from BREAKING down more complex REACTANTS into less complex PRODUCTS
What is anabolism (synthesis)
A chemical pathway that USES up energy (ENDERGONIC REACTION) to CREATE more complex PRODUCTS from less complex REACTANTS
What is the difference between exergonic and endergonic
-exergonic reactions release energy
-endergonic reactions uses up energy
What is oxidation
-lose electrons
-electron donor
What is reduction
-gain electrons
-electron acceptor
What is hydrolysis
-Breaking of a chemical bond using a water molecule
What is phosphorylation
-Addition of a phosphate group to any molecule
what is a catalyst
-speeds up reaction without being consumed by the reaction
-stays the same
NOTES:
-enzymes are proteins that act as catalysts for chemical reactions inside the cells
-all enzymes are catalysts
-enzymes may combine molecules, separate the components or rearrange them
-The molecules that is changed by the enzyme is a substrate
-the pocket in the enzyme that binds the substrate is active site
Which enzyme is responsible for the
following reaction?
What is the purpose of this reaction?
Is this catabolism or anabolism?
-amylase
-breaks down bigger pieces into smaller pieces so that the cell can use it
-catalyst
How do enzymes help with a reaction
enzymes facilitate chemical reactions by lowering the ACTIVATION ENERGY
What is activation energy
the energy requires to initiate a chemical reaction
-Which of the following labeled arrows shows the amount of energy saved going from reactants to products by using a catalyst?
-Which is the activation energy with no enzyme?
-Is this reaction exergonic or endergonic?
-b
- A
-endergonic
Enzymes bind to their substrate and facilitate chemical reactions and change the substrate without being altered themselves
What is the induced fit model
the shape of the enzyme changes as the substrate binds creating a perfect alignment and ideal microenvironment for the reaction to occur
what are coenzymes or cofactors
-non-protein helpers that bind enzymes and are required for the function of some enzymes
-interact with the active site of an enzyme to improve its performance
EX: cofactors: Fe^2+ and Mg^2+ (inorganic)
EX: coenzymes: vitamis, ATP, and NADH (organic)
What is competitive inhibitors
They mimic the substrate and by binding to the active site, they block the binding of the substrate
What is allosteric inhibition and activation
When the enzyme’s activity is inhibited or activated by binding of the regulatory molecule to a site separate from the active site
What is metabolic pathway
A set of enzymatically controlled reactions that result in a final product
What is a peptide bond
-covalent bonds that join amino acids together
-between the amine group of one amino acid and the carboxyl group of the next amino acid
What are the factors that affect enzymatic activity
TEMPERATURE
-molecules move faster as temperature increase
-DENATURATION: the unfolding of a protein’s secondary or higher structure
pH
-too basic or too acidic environments can also cause denaturation
SUBSTRATE CONCENTRATION
-SATURATION POINT: the point at which the rate of enzymatic activity does not increase with increased substrate concentration
In an enzymatic reaction, the ______ binds to the _______.
A. Substrate; active site
B. Active site; catalyst
C. Catalyst; active site
D. Activation energy; substrate
A. substrate; active site
How is this enzyme regulated?
Sulfanilamide is an antimicrobial drug used to treat yeast and bacteria infection. It is Structurally similar to PABA which is the substrate of the enzyme responsible for of folate. Sulfanilamide binds to the same active site on the enzyme as the substrate and inhibits the enzyme.
A. Allosteric Inhibition
B. Competitive Inhibition
C. Feedback Inhibition
D. Allosteric Activation
B competitive inhibition
How is production of tryptophan regulated
C feedback inhibition
How does penicillin work
B competitive inhibition
What kind of enzyme regulation
1) D. allosteric activation
2) A. Allosteric inhibition
what pathway does most microbes use
embden-meyerhof-parnas (EMP) (glycolysis)
What is enter-doudoroff pathway
- Alternative to glycolysis
- Produces NADPH and ATP
- Produces Pyruvate
- Occurs in Pseudomonas, Rhizobium, and Agrobacterium
What is Pentose phosphate pathway
- Operates simultaneously with glycolysis
- Produces NADPH (electron carrier molecule)
- No ATP is produced
- Produces Ribose 5-phosphate which is the precursor for DNA/ RNA
How is ATP generated in Glycolysis?
A. Substrate Level Phosphorylation
B. Oxidative Phosphorylation
C. Photophosphorylation
What are the products of Glycolysis?
Where does it occur in prokaryotes
and eukaryotes?
-A
-the end products are 2 ATP ,2 NADH, 2 pyruvates
PYRUVATE OXIDATION
What is oxidized and what is reduced?
What are the products?
Where does it occur in prokaryotes and eukaryotes?
-pyruvate is being oxidized
-NAD+ is being reduced
-products from glycolysis of 2 molecules of pyruvate are 2 acetyl CoA +2 NADH + 2 CO2
-occurs in mitochondrial matrix in eukaryotes and in cytoplasm in prokarytoes
What are the products of the KREBS cycle and where does it occur in prokaryotes and eukaryotes
-2 molecules of acetyl CoA -> 6 NADH + 2 FADH2 + 2 ATP + 4 CO2 + 2 CoA
-occurs in the cytoplasm in prokaryotes and mitochondrial matrix in eukaryotes
True or False? Coenzyme A is consumed whenever pyruvate is fully oxidized.
false
What are the two stages of oxidative phosphorylation
-electron transport chain (ETC)
-chemiosmosis
What is the ELECTRON TRANSPORT CHAIN
A series of complexes (proteins and others) that use redox reactions to transfer electrons down
a chain, coupling those reactions to move protons (H+ ions) across a membrane
What is chemiosmosis mechanism
the use of facilitate diffusion of protons to synthesize ATP
In the ETC,
-where does it occur in prokaryotes and eukaryotes
-what is the electron donor
-what is the final electron acceptor
-eukaryotes, occurs in inner mitochondria membrane
-prokaryotes, occurs in cell membrane
-NADH is the electron donor
-final electron acceptor is oxygen
glycolysis uses 2 ATP and creates 4 ATP, NET ATP is 2
Thiobacillus denitrificans produce ATP with no oxygen. By using NO3-
and producing NO2- which is eventually converted into N2.
This an example of
A. Aerobic respiration
B. Anaerobic respiration
C. Fermentation
B. anaerobic respiration
-How is NAD+ generated in fermentation, aerobic and anaerobic respiration?
-Why is this important?
-How many ATPs are produced in fermentation?
-What is the final electron acceptor?
-oxidation of NADH
-required for glycolysis
-2 ATPs
-organic molecule usually pyruvate
What can be used as fuels for cellular respiration
-glucose, carbohydrates, proteins, and fats
Noncyclic Photophosphorylation
-what is the electron donor
-what is the electron acceptor
-what are the products
-water is the electron donor
-NADP is the electron acceptor
-the products are O2, ATP, and NADPH
what is the difference between oxygenic and anoxygenic photosynthesis
-oxygenic photosynthesis: water is the electron donor and it produces glucose, oxygen, and water
-anoxygenic photosynthesis: produces carbohydrate and water
What RuBisCo
The enzyme ribulose biphosphate carboxylase used in fixation for the Calvin Cycle.
What is fixation in the calvin cycle
RuBisCo is used to catalyze the addition of CO2 to ribulose biphosphate and results in the production of 3 phosohoglycerate
what is reduction in the Calvin cycle
ATP and NADPH from the light dependent reactions are used to convert 3 PGA into glyceraldehyde 3- phosphate
what is regeneration in the Calvin cycle
ATP is used to convert the remaining G3P to RuBP
what is the nitrogen cycle an what are the steps
-transfer of nitrogen from the atmosphere to the soil and living things and back to the atmosphere
steps
1. fixation (converts N2 gas to ammonium)
2.ammonification (converts organic nitrogen into ammonium)
3.nitrification (converts ammonium into nitrite then to nitrate)
4.denitrification (converts nitrogen in the form of NO3- back into N2 gas)
What is substrate level phosphorylation
when phosphate group on one molecule is transferred to ADP to product ATP
What is kinase
an enzyme which phosphorylates ADP and make ATP
How is ATP generated in living cells
-substrate level phosphorylation
-oxidative phosphorylation
-photophosphorylation
-Which molecule is an electron donor and which is the electron acceptor?
-Which is oxidation and which is reduction reaction?
-NADH is the electron donor
-NAD+ is the electron acceptor
-from left to right, it is an oxidation reaction
-from right to left, it is a reduction reaction
-Which reaction is exergonic and endergonic? –Which reaction is spontaneous and which is not?
-The left reaction is exergonic and spontaneous
-The right reaction is endergonic and not spontaneous
What is metabolic diversity
classification of microbes based on carbon, electron, and energy sources
What are the energy sources of metabolic diversity
Phototroph: energy obtained from light
Chemotroph: energy obtained from breaking chemical bonds
What are the electron sources of metabolic diversity
Organotroph: electrons and/or hydrogen ions from organic compounds
Lithotroph: electrons and/or hydrogen ions from inorganic source
What are carbon sources from metabolic diversity
Autotrophs: convert inorganic CO2 from the atmosphere into organic carbon compounds (EX plants and cyanobacteria)
Heterotroph: carbon obtained from organic molecules in other organisms (EX humans Ecoli)
What does this result mean?
-obligate aerobe
-requires oxygen
What does this result mean?
-obligate anaerobe
-killed by oxygen
What does this result mean?
-facultative anaerobe
-prefer oxygen but can survive without it
What does this result mean?
-areotolerant anaerobe
-indifferent to oxygen
What does this result mean?
-microaerophiles
-require a certain oxygen concentration
For standard plate counting what numbers are acceptable
30-300
A plate has 72 colonies with a total dilution factor of 10-7. 0.1 mL was pipetted onto the plate. What was the original CFU/mL concentration of the sample
72 cells/ 0.1mL=720 CFU
720(10/7)=1,028 or 1.03 x 10^3
What is the purpose of the starch hydrolysis test and what do the results mean
-used to determine if bacteria produced amylase
-halo means positive, no halo means negative
What is the purpose of the caseinase test and what do the results mean
-to detect is caseinase is present
-positive result will show clearing around bacteria growth
-negative result will show now clearing
What is the purpose of the gelatinase test and what do the results mean
-To determine if the bacteria is able to secrete gelatinase
-positive will show liquid in test tube
-negative will show no liquid/will be solid in test tube
What is the durham test tubes used for and how do you interpret the results
-used to detect carbohydrate fermentation
-bubbles mean positive for fermentation and acidic
- red to yellow means positive for fermentation
what are coliforms
bacteria used to detect fecal contamination in water
