Chapter 8

Fermentation

•2 ATP

Respiration

•38 ATP

How does a Aerobic respiration differ from anaerobic respiration?

*Aerobic respiration: use of an oxygen molecule as the final electron acceptor of the electron transport system. The final electron acceptor in the electron transport chain is molecular oxygen (O2) *Anaerobic respiration: use of a non-oxygen inorganic molecule, like CO2 nitrate, nitrate, oxidized iron, or sulfate, as the final electron acceptor at the end of the electron transport system. The final electron acceptor in the electron transport chain is not (O2). Anaerobic respiration yields less energy than aerobic respiration because only part of the Krebs cycle operates under anaerobic conditions.

Describe how temperature, pH, substrate concentration,And competitive and noncompetitive inhibition affect enzyme activity.

*Temperature: enzymes become inactive at high temperatures. *pH: causing them to denature (loss of specific conformational shape) and blocking the active site. *substrate concentration: by increasing the enzyme concentration do you rate of a chemical reaction increases as the substrate concentration increases. Enzymes can greatly speed up the rate of reaction. Enzymes become saturated when substrate concentration is high. *competitive inhibition: (drug) compete with the normal substrate for the active site of the enzyme. *non-competitive inhibition: (drug) binds to a site different from the active site(allosteric site). Decreases the ability of normal substrate to combine with the enzyme by bringing about a conformational change in the shape of the enzyme.

What cellular process occurs in the absence of oxygen, oxidizes NADH to NAD+, and reduces cellular organic molecules?

-Fermentation

What is PEP? In which step of glycolysis is PEP involved? Describe the chemical reaction in which PEP is involved in terms of reactants, products, and ATP.

-Phosphoenolpyruvic acid Embden-Meyerhof Pathway. Very last step •2 ADP •2ATP •2 pyruvic acid

Aerobic respiration

-The final electron acceptor in the electron transport chain is molecular oxygen (O2)

Anaerobic respiration

-The final electron acceptor in the electron transport chain is not O2 -Anaerobic respiration yields less energy than aerobic respiration because only part of the Krebs cycle operates under anaerobic conditions

Define the following terms: activation energy, enzyme, active site, and substrate.Describe the role of each of these in enzymes activity

-activation energy: the input energy that is needed to activate or start a reaction. -enzyme: used to control reactions so they are frequent and calculated. They function repeatedly. Each enzyme acts only on a particular type of molecule it is called its substrate. -active site: location within an enzyme where substrate binds. -substrate: each enzyme is specific and acts only on a particular type of molecule. The chemical reactants to which an enzyme binds.

Biosynthesis of carbohydrates,lipids,proteins, and nucleic acids requires so much _______ in the form of ________.

-energy -ATP

A site on an enzyme other than the active site that can bind molecules and influence the shape of the active site is referred to as a(n)

Allosteric site

Which of the following does not occur when aerobic bacteria are deprived of oxygen

Excess acetyl-CoA inhibits the Krebs cycle.

What cellular process occurs in the absence of NADH to NAD+, and reduces cellular organic molecules?

Fermentation

Cellular respiration results in the complete breakdown of________ to ______ and _______.

Glucose; CO2; water

The electron transport chain

• A series of carrier molecules that are, in turn, oxidized and reduced as electrons are passed down the chain. • The energy released can be used to produce ATP by chemiosmosis.

Basically, what process occur during cellular respiration and photosynthesis?

•Cellular respiration: cells harness the chemical energy in glucose transfer it into ATP (Ex: Human cells, most pathogenic bacteria) •photosynthesis: uses light to produce glucose.(Ex. Plants, certain bacteria)

How does the term "conformation" relate to enzyme structure and function? Consider enzyme specificity and how this influences control of metabolism intracellularly.

•Conformation If an enzyme fits the particular shape of its substrate. By controlling the formation of specific enzymes, a cell may exert control over its metabolism and I highly specific manner.

Describe fermentation and contrast it with respiration.

•Fermentation: Process that uses an organic molecule as a final electron acceptor or to regenerate NAD+ from NADH such that glycolysis can continue. •Respiration: A process in living organisms involving the product of energy, typically within the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances.

The three stages of aerobic glucose catabolism are glycolysis, The Krebs cycle,and an electron transport chain. In general terms, describe glycolysis - the first stage of aerobic glucose catabolism - including substrates, products, and net energy production.

1. Glycolysis: first step in the breakdown of glucose, the most common example of which is the Embden- Meyerhoff-Parnas pathway, producing two pyruvates, tow NADH molecules,and two (not yield) ATP per starting glucose molecule -Preparatory stage glycolysis: 2ATP are used Glucose is split to form 2 glyceraldehyde-3-phosphate -Energy-Conserving Stage of Glycolysis: 2 glyceraldehyde-3-phosphate are oxidized to 2 pyruvic acid 4ATP are produced 2NADH are produced

Identify where (spatially) within the cells of eukaryotes and prokaryotes each of the following processes takes place: glycolysis, intermediate step, Krebs cycle, electron transport chain.

1. Glycolysis: takes place in the cytoplasm of prokaryotic and eukaryotic cells. 2. Intermediate step: the transition reaction occurs in the mitochondrial matrix of Eukaryotes; in the prokaryotes,lack membrane-enclosed organelles. 3. Krebs cycle: occurs in the cytoplasm of prokaryotes along with glycolysis and transition reaction, but it takes place in the mitochondrial membrane in eukaryotic cells , in prokaryotes occurs in their cell membrane.

List three useful (to humans) end products of fermentation and explain how fermentation reactions are used to identify bacteria.

1. Lactic acid 2. Carbon dioxide 3. Ethanol •Morphological (shapes) characteristics •Differential staining: Gram staining, acid fast stain •Biochemical tests: determines presence of bacterial enzymes. For example, fermentation test is used to differentiate between intestinal bacteria (enterics).

Name the three types of ATP phosphorylation. Compare and contrast the three types of ATP phosphorylation.

1. Substrate-level phosphorylation: energy from the transfer of high energy PO4 to ADP generates ATP C-C-C~P+ADP->C-C-C+ATP 2. Oxidative phosphorylation: energy released transfer of electrons (oxidation) of one compound to another (reduction) is used to generate ATP in the electron transport chain. ATP is formed indirectly through chemosynthesis. 3. Photophospholyperation: light causes chlorophyll to give up electrons. Energy release from transfer of electrons (oxidation) of chlorophyll through a system of carrier molecules is used to generate ATP through chemosynthesis.

Antioxidants

:in extreme cases like schizophrenia, for example, drugs (if proven or potentially so) should be used to alleviate suffering.

Oxidative phosphorylation

ATP is formed indirectly through chemiosmosis.

Discuss the roles of acetyl-CoA in the so called "Intermediate step" , the Krebs cycle, and electron transport in carbohydrate catabolism.

In the transition reaction, electrons are also transferred to NAD to form NADH. To proceed to the next stage of this metabolic process,The comparatively tiny two carbon acetyl must be attached to a very large carrier compound called coenzyme A (CoA). The transition reaction occurs in the mitochondrial matrix of eukaryotes, in prokaryotes, it occurs in the cytoplasm because prokaryotes lack membrane enclosed organelles. The Krebs cycle transfer remaining electrons from the acetyl group produced during transmission reaction to electron carrier molecules, thus reducing them.

In general terms, describe the Krebs cycle, including substrates, products, and net energy production.

Oxidation of citric acid (formed from acety CoA-oxaloacetic acid reaction) produces NADH, FADH2, and ATP Oxidation of molecules liberates electrons for an electron transport chain (ETC) Using as ETC, ATP is generated by oxidative phosphorylation.

Intermediate step

Pyruvic acid( from glycolysis) is oxidized and decarboxylated

Describe the way in which drugs known as PABA structure analogs (eg. the sulfonamides) inhibit folic acid(=folate) synthesis.

The antibiotic trimethoprim- sulfamethoxazole (brand name Bactrim, Septra)inhibits the action of a bacterial enzymes involved in the synthesis of folate. The microorganism is "starved" of folate and dies PABA— enzyme-> Dihydrofolic acid-enzyme—-> Tetrahydrofolic acid (THF) — enzyme—> Purine and pyrimidine nucleotides—enzymes-> DNA and RNA.

In extreme cases like schizophrenia should drugs be used to alleviate suffering

Yes in extreme cases if proven to be effective, or potentially so we should

Describe the role of chemo osmosis and oxidative phosphorylation of ATP.

•It accepts electrons and picks up protons to form water. If oxygen isn't there to accept electrons (for instance, because a person is not breathing in enough oxygen)the electron transport chain will stop running, and ATP will no longer be produced by chemiosmosis. Without enough ATP, cells can't carry out the reactions they need to function, and after a long enough period of time, may even die.

Photophosphorylation

•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 ATP through Chemiosmosis.

Briefly discussed how lipids and proteins can be catabolized for energy and metabolite production.

•Lipids: lipase hydrolyze simple lipids (triglycerides) into glycerol and fatty acids. Fatty acids and other hydrocarbons are catabolized by beta oxidation. Catabolic products can be further broken down into glycolysis and the crib cycle. •Proteins:Before amino acids can be catabolized, they must be converted into various substances that enter the Krebs cycle. Transaminatiom, decarboxylation, and dehydrogenation reactions convert the amino acids to be catabolized.

Distinguish among metabolism, anabolism , and catabolism.

•Metabolism: refers to all of the chemical reactions that happen in living organisms to sustain life. •Anabolism: to "build up" (synthesize) Larger molecules from smaller ones. Example: amino acid ->polypeptide •Catabolism: to "break down" (decompose) larger molecules into smaller ones. Example: Protein digestion->amino acids

Identification methods:

•Morphological shapes) characteristics ⬇️ •Differential staining: gram staining, acid fast stain ⬇️ •Biochemical tests: determine presence of bacteria enzymes

The Kreb's cycle

•Oxidation of citric acid (formed from acetyl CoA-oxaloacetic acid reaction) produces NADH,FADH2 and ATP. •Oxidation of molecules liberates electrons for an electron transport chain (ETC). •Using an ETC, ATP is generated by oxidative phosphorylation.

Make a table listing the six basic types of enzymes discussed in lecture and the activities of each type.

•Oxidoreductase: Oxidation-reduction reactions. •Transferase: Transfer functional groups. •Hydrolase: Hydrolysis •Lyase: Removal of atoms •Isomerase: Rearrangement of atoms. •Ligase: Joining of molecules;uses ATP.

Contrast reduction and oxidation reactions. What is meant by the term "redox"?

•Reduction reactions: Chemical reactions that adds electrons to accepter molecules, leaving them reduced. •Oxidation reactions: Chemical reaction that removes electrons (often as part of H atoms) from donor molecules, leaving them oxidized. *Redox= A process in which one substance or molecule is reduced and another oxidized: oxidation and reduction considered together as complementary processes.

Give an example of a drug that competitively inhibit the HIV viral enzyme reverse transcriptase. Why does this drug have overall antiviral affects(ie. What crucial molecular conversion does this drug prevent)?

•Tenofvir, emtricitabine Specific drugs have been designed to block HIV enzymes reverse transcriptase. Competitive inhibitor's to suppress viral growth

Define photosynthesis, and provide its general summary equation. What types of organisms can photosynthesize?

•process whereby phototropic organisms convert solar energy into chemical energy that can then be used to build up carbohydrates. Takes place in the chloroplasts of plants, algae and in thylakoids or the cell membrane of certain bacteria (chromatophores). Pigments that are molecules that absorb light. -summary equation: 6CO2+6H2O->C6H12O6+6O2 •plants, algae, Blue-green bacteria (Cyanobacteria)