microbiology exam 2 Lec 3 pt 1 Flashcards
metabolism definition
the sum of the chemical reactions in
an organism
catabolism definition
provides energy and building blocks for
anabolism
anabolism definition
uses energy and building blocks to build
large molecules
A ___________ is a sequence of
enzymatically catalyzed chemical reactions in a cell
metabolic pathway
Metabolic pathways are determined by ______
enzymes
Enzymes-Collision Theory states—
that chemical reactions can occur when
atoms, ions, and molecules collide
Activation energy is needed to
disrupt electronic configurations
Reaction rate is the
frequency of collisions with
enough energy to bring about a reaction
how can reaction rate be increased
Can be increased by enzymes or by increasing temperature or pressure
Prosthetic groups means
permanent component of
enzyme
Cofactor means
transient nonprotein component of
enzymes
Enzymes are
biological catalysts
what are coenzymes
organic cofactors (examples: NAD+, NADP+, FAD, Coenzyme A)
components of a haloenzyme
Apoenzyme(protein portion),inactive + (coenzyme) Cofactor (nonprotein portion),activator+substrate=Holoenzye
(whole enzyme),active
substrate binds to the
active site
the mechanism of enzyme action has to do with its ability to
increase the rate of chemical reactions by lowering the activation energy, or energy toll, required for the reaction to occur
enzyme classificiations
Oxidoreductase
Transferase
Hydrolase
Lyase
Isomerase
Ligase
Ligase
joining of molecules; uses ATP
isomerase
rearrangement of atoms
Lyase
removal of atoms without hydrolysis
Hydrolase
hydrolysis
Transferase
transfer functional groups
oxidoreductase
oxidation-reduction reactions
what Factors Influencing Enzyme Activity
Temperature(possible denaturing), pH (possible denaturing), substrate concentration, inhibitors
types of enzyme inhibition
Competitive inhibition. Noncompetitive inhibition
noncompetitive inhibition is normally a ____ thing
good
competitive inhibition
phenomenon in which a substrate molecule is prevented from binding to the active site of an enzyme by a molecule that is very similar in structure to the substrate
noncompetitive inhibition
whena. substrate binds to an enzyme at a different location which changes the active site for another
Ribozymes are
RNA that cuts and splices RNA
Oxidation
removal of electrons
Reduction
gain of electrons
an oxidation reaction paired with
a reduction reaction is known as
Redox reaction
Biological oxidations are often
dehydrogenations
Dehydrogenation
a chemical reaction where hydrogen atoms are removed from a molecule, resulting in a more unsaturated molecule
ATP is generated by the ___________ of ADP
phosphorylation
phosphorylation
the addition of a phosphoryl (PO3) group to a molecule
different types of phosphoylation that generates ATP
Substrate Level Phosphorylation, Oxidative Phosphorylation, Photophosphoylation
Photophosphoylation
Light causes chlorophyll to give up electrons. Energy released from transfer of electrons (oxidation)
of chlorophyll through a system of
carrier molecules is used to generate AT
Oxidative Phosphorylation
Energy released from transfer of electrons (oxidation) of one compound to another (reduction) is used to generate ATP in the electron transport chain
Substrate Level Phosphorylation
Energy from the transfer of a high-energy PO4– to ADP
generates ATP
generation of atp formula
Adenosine–p~p+energy+p=ADP
this goes to
Adenosies–P~P~P= ATP
Carbohydrate Catabolism
The breakdown of carbohydrates to release energy
What are the products of glycolysis?
Glycolysis produces ATP, NADH, and pyruvic acid.
What is the Embden-Meyerhof Pathway?
The Embden-Meyerhof Pathway, also known as Glycolysis, is the oxidation of glucose to pyruvic acid, producing ATP and NADH.
What happens after glycolysis
After glycolysis, the cell undergoes one of three processes:
Aerobic Cellular Respiration
Anaerobic Cellular Respiration
Fermentation
What is the role of oxygen in the fate of pyruvic acid after glycolysis?
If oxygen is present, pyruvic acid undergoes Aerobic Cellular Respiration; if oxygen is not present, it undergoes Anaerobic Cellular Respiration or Fermentation.
What is the main difference between aerobic and anaerobic cellular respiration?
Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration occurs without oxygen and produces less ATP.
What happens during fermentation?
Fermentation occurs in the absence of oxygen and converts pyruvic acid into products like ethanol or lactic acid, regenerating NAD+ but producing less ATP than respiration.
What is the route to Aerobic and Anaerobic Cellular Respiration after glycolysis?
After glycolysis, pyruvic acid can either undergo:
Aerobic Cellular Respiration (with oxygen)
Anaerobic Cellular Respiration (without oxygen)
What is the general equation for glycolysis?
Glucose + 2 ATP + 2 ADP + 2 PO₄³⁻ + 2 NAD⁺ → 2 pyruvic acid + 4 ATP + 2 NADH + 2H⁺
What happens during glycolysis?
Glycolysis is the oxidation of glucose to pyruvic acid, producing 2 ATP, 2 NADH, and 2 pyruvic acid molecules.
What is the intermediate reaction in carbohydrate catabolism?
In the intermediate reaction, pyruvic acid from glycolysis is oxidized and decarboxylated (loses a carbon dioxide molecule).
What is the role of acetyl CoA in cellular respiration?
Acetyl CoA is formed from the decarboxylation of pyruvic acid and enters the Krebs cycle for further oxidation.
What happens to the electron carriers from glycolysis and the Krebs cycle?
The electron carriers (NADH and FADH₂) from both glycolysis and the Krebs cycle donate electrons to the electron transport chain.
What happens during the Krebs cycle?
In the Krebs cycle, acetyl CoA is oxidized, producing NADH, FADH₂, and ATP
What is the function of the electron transport chain?
The electron transport chain oxidizes molecules and liberates electrons, which are used to generate ATP by oxidative phosphorylation.
What are the key products of the Krebs cycle?
The Krebs cycle produces:
Some ATP by substrate-level phosphorylation
Reduces electron carriers NAD+ to NADH and FAD to FADH₂
Gives off CO₂ (carbon dioxide
What is oxidative phosphorylation?
Oxidative phosphorylation is the process by which ATP is produced through the electron transport chain and chemiosmosis.
What is the role of the electron transport chain in cellular respiration?
In the electron transport chain, the energy of electrons is used to produce a large amount of ATP by oxidative phosphorylation.
What is the main function of glycolysis in cellular respiration?
Glycolysis produces ATP, reduces NAD+ to NADH, and oxidizes glucose to pyruvic acid.
How does pyruvic acid fit into cellular respiration?
In respiration, pyruvic acid is converted to acetyl CoA, the first reactant in the Krebs cycle.
What happens to pyruvic acid in fermentation?
In fermentation, pyruvic acid and the electrons carried by NADH from glycolysis are incorporated into fermentation end-products, regenerating NAD+.
What are the end-products of fermentation?
Fermentation produces various end-products such as ethanol (in yeast) or lactic acid, depending on the organism and conditions.
What happens to the electrons carried by NADH and FADH₂ in respiration?
NADH and FADH₂ donate their electrons to the electron transport chain, which uses the energy to produce ATP.
What is the role of oxygen in respiration
Oxygen acts as the final electron acceptor in the electron transport chain, forming water (H₂O).
What are the major differences between respiration and fermentation?
Respiration involves the complete oxidation of glucose, including the Krebs cycle and electron transport chain, producing a large amount of ATP.
Fermentation occurs without oxygen, regenerating NAD+ and producing end-products like ethanol or lactic acid, but yields much less ATP.
What is the significance of chemiosmosis in the electron transport chain?
Chemiosmosis is the process by which protons (H⁺) are pumped across the mitochondrial membrane, creating a proton gradient that drives the production of ATP via ATP synthase.
What happens after fructose 1,6-diphosphate is formed in glycolysis?
An enzyme cleaves fructose 1,6-diphosphate into two three-carbon molecules: dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (GP).
What happens when glucose enters the cell during glycolysis
Glucose is phosphorylated using one ATP molecule, forming glucose 6-phosphate.
What happens to glucose 6-phosphate in glycolysis?
Glucose 6-phosphate is rearranged to form fructose 6-phosphate.
What happens to fructose 6-phosphate in glycolysis?
Fructose 6-phosphate is phosphorylated using another ATP molecule to form fructose 1,6-diphosphate. This is the second ATP investment.
What happens to DHAP and GP in glycolysis?
DHAP is readily converted into GP, and vice versa, so both products are present in equal amounts
How is ATP produced from PEP in glycolysis?
The high-energy phosphate from PEP is transferred to ADP, forming ATP. Since two molecules of PEP are produced per glucose molecule, two ATP molecules are formed.
What happens to 3-phosphoglyceric acid in glycolysis? (GP)
An enzyme relocates the phosphate group from 3-phosphoglyceric acid to form 2-phosphoglyceric acid in preparation for the next step.
What happens to 2-phosphoglyceric acid in glycolysis?
A water molecule is removed from 2-phosphoglyceric acid, converting it into phosphoenolpyruvic acid (PEP). This step creates a high-energy bond in PEP.
What are the final products of glycolysis?
The final products of glycolysis are two molecules of pyruvic acid and a net gain of 2 ATP molecules and 2 NADH molecules for each glucose molecule.
What is the Pentose Phosphate Pathway?
The Pentose Phosphate Pathway is an alternative to glycolysis that operates simultaneously with it. It can use glucose and pentoses and produces 1 ATP per glucose.
What are the main products of the Pentose Phosphate Pathway?
The Pentose Phosphate Pathway produces:
Pentoses (used in nucleic acids)
Glucose from CO₂ (important in photosynthesis)
Certain amino acids
NADPH (used in anabolic reactions)
Which organisms utilize the Pentose Phosphate Pathway?
Bacillus subtilis, Escherichia coli, and other organisms use the Pentose Phosphate Pathway.
What is the Entner-Doudoroff Pathway?
The Entner-Doudoroff Pathway is an alternative to glycolysis and the Pentose Phosphate Pathway. It produces NADPH and ATP without involving glycolysis or the Pentose Phosphate Pathway.
Which bacteria use the Entner-Doudoroff Pathway?
The Entner-Doudoroff Pathway is used by certain Gram-negative bacteria, including:
Pseudomonas
Rhizobium
Agrobacterium
What are the main products of the Entner-Doudoroff Pathway?
The Entner-Doudoroff Pathway produces:
1 ATP
2 NADPH per glucose
What occurs in Steps 3 and 4 of the Krebs cycle?
In Steps 3 and 4, oxidations and decarboxylations combine to remove two carbon atoms from the original acetyl group. The carbon atoms are released as CO₂, and NADH is generated from NAD+.
What is the result of the oxidations in Step 2 of the Krebs cycle?
rearangment of molecules to form NADH
What is formed in Step 4 of the Krebs cycle?
During the second oxidation in Step 4, CoA is added into the cycle, forming succinyl CoA.
What happens in Step 8 of the Krebs cycle?
oxidation generates NADH and converts malic acid to oxaloacetic acid, which is ready to enter another round of the Krebs cycle.
How is ATP produced in the Krebs cycle?
ATP is produced by substrate-level phosphorylation in Step 5 of the Krebs cycle, when CoA is removed from succinyl CoA, leaving succinic acid
What happens in Step 6 of the Krebs cycle?
In Step 6, an oxidation reaction occurs, producing FADH₂.
What is the overall goal of the Krebs cycle?
The Krebs cycle generates high-energy molecules like NADH, FADH₂, ATP, and CO₂ while regenerating oxaloacetic acid to continue the cycle.
What is the Electron Transport Chain (ETC)?
the Electron Transport Chain is a series of carrier molecules that are alternately oxidized and reduced as electrons are passed down the chain.
What happens as electrons are passed down the Electron Transport Chain?
As electrons move down the Electron Transport Chain, energy is released, which can be used to produce ATP by chemiosmosis.
What is chemiosmosis?
Chemiosmosis is the process by which energy from the electron transport chain is used to pump protons (H⁺) across a membrane, creating a proton gradient that drives ATP production via ATP synthase.
electrons can enter the ETC how
from a primary election donor either at complex I or complex H
how do electrons exit the chain
by reducing the terminal electron acceptor O2
What is aerobic respiration?
Aerobic respiration is a type of respiration where molecular oxygen (O₂) is the final electron acceptor in the electron transport chain.
What is anaerobic respiration?
Anaerobic respiration is a type of respiration where the final electron acceptor in the electron transport chain is not oxygen (O₂).
why does anaerobic respiration yield less energy than aerobic respiration?
Anaerobic respiration yields less energy than aerobic respiration because only part of the Krebs cycle operates under anaerobic conditions, limiting the energy produced.
