Microbiology - Problem Drill 05: Microbial Metabolism

Transcription

1 Microbiology - Problem Drill 05: Microbial Metabolism No. 1 of Anabolism is a metabolic process where are turned into molecules. (A) Complex, simple (B) Simple, ATP (C) Simple, ATP (D) Simple, complex This would be for catabolism the opposite of anabolism. Anabolism often requires energy to assemble the larger more complex molecules. Since ATP is a form of generated energy this answer is incorrect. The process of anabolism is the process were simple molecules are metabolized into larger or complex molecules. This process usually requires the input of energy. D. Correct! Catabolism is the breakdown of complex molecules into smaller less complex molecules. The process typically generates energy. Anabolism can be thought of as synthesis of biomolecules. The synthesis of biomolecules comes from precursor smaller molecules (many of which have been created through the complementary process of catabolism) and requires energy input. Catabolism is the breakdown of molecules such as glucose, proteins and lipids. This breakdown product releases energy and creates precursors for use in the anabolic pathway.

2 No. 2 of is the breakdown of complex molecules into simpler molecules with the of energy. (Choose the best answers below to fill in the blanks.) (A) Anabolism, input (B) Anabolism, release (C) Catabolism, release (D) Catabolism, input Anabolism is the assembly of complex molecules from simpler molecules. Anabolism usually requires the input of energy. Anabolism is the assembly of complex molecules from simpler molecules. Anabolism usually requires the input of energy. C. Correct! Catabolism is the breakdown of complex molecules into simpler molecules usually releasing energy. D. Incorrect! Catabolism is the breakdown of complex molecules into simpler molecules usually releasing energy not requiring it. In the study of metabolism it is useful to determine if a molecule is becoming more or less complex, i.e. the direction of the reaction. If the direction is toward lower complexity, as a generalization you can make an educated guess that energy will be released. The process of catabolism is associated with the breakdown of complex molecules.

3 No. 3 of Nutrient molecules with high energy electrons are by catabolic reactions and the energy is stored in high energy bonds like. (A) Hydrolyzed and DNA (B) Oxidized and RNA (C) Deaminated and amino acids (D) Oxidized and ATP Hydrolysis is a chemical reaction when a molecule reacts with water. One reactant gets a hydroxyl OH and the other a proton +H (not an election). This answer is partially correct, catabolic reactions do involve oxidation. However RNA is a stable molecule. In order to be a participant in the storage and or transfer of genetic information the bonds of RNA must be relatively stable so not high energy. Deamination is the removal of an amine group from an amino acid. This is a step in breaking down proteins to ultimately be used in Krebs cycle. However amino acids are not high energy molecules. D. Correct! Catabolism is the process of oxidation of nutrient or complex molecules leading to the creation and storage of energy in the form of high energy bonds. The most common high energy bond where energy is stored in the cell is in ATP. Catabolism is the process of oxidation of nutrient or complex molecules leading to the creation and storage of energy in the form of high energy bonds. The most common high energy bond where energy is stored in the cell is in ATP.

4 No. 4 of The breakdown of glucose to produce large amount of energy in the form of ATP is known as. (A) Catabolism (B) Redox (C) Substrate level phosphorylation (D) Respiration Catabolism is the breakdown of complex biomolecules to simple molecules. This is frequently accompanied by energy being produced. However the over all process is not referred to as catabolism. REDOX referees to the reduction and oxidation of a sample. Oxidation refers to the loss of an electron by a molecule. Reduction describes the gain of an electron by a molecule. Substrate level phosphorylation is the direct transfer of a phosphate from an organic molecule to ADP. Cells can do this in glycolysis and a small amount of ATP made in the Kreb's cycle is made this way. D. Correct! A series of metabolic processes that the living cell uses to produce energy. This is done through oxidation of organic molecules. Cellular respiration, weather prokaryote or eukaryote is a oxidative process. The chemical energy of organic molecules is releases in a series of organized steps. The steps are frequently accompanied by use of oxygen (in aerobic respiration) and the release of CO 2 and H 2 O.

5 No. 5 of Carbohydrates are the primary energy source for microbial metabolism typically in the form of glucose. Glucose is metabolized further via fermentation or cellular respiration. Before fermentation or cellular respiration occurs glucose first goes through the. (A) TCA cycle (B) Glycolysis (C) Kreb s cycle (D) Electron transport TCA cycle is also known as the Kreb s cycle. It is a series of reactions involving he oxidative metabolism of biomolecules with the concurrent production of ATP. ATP serves as the main source of cellular energy. B. Correct! Glycolysis the metabolic pathway that occurs in almost all living cells. Glucose is changed in a series of steps to pyruvic acid which releases energy in the process. Glycolysis precedes the other pathways and is therefore the primary pathway. TCA cycle is also known as the Kreb s cycle. It is a series of reactions involving he oxidative metabolism of biomolecules with the concurrent production of ATP. ATP serves as the main source of cellular energy. D. Incorrect! Electron transport chain or system is a series of oxidation-reduction reactions that result in an electron(s) creating the energy that is used in oxidative phosphorylation. The oxidative phosphorylation is used to make ATP. Energy carrying molecules of NADH and FADH2 give their electrons to coenzymes. The enzymes used in electron transport and oxidative phosphorylation are on the inner membrane of the bacteria. However the ETC of bacteria is high variable between species. Membrane invaginations form structures called: mesosomes, respiratory vesicles or lamellar vesicles. Note in the schematic the metabolic processes available including Krebs, TCA etc. all begin after glycolysis.

6 No. 6 of In the preparatory stage of glycolysis glucose is energized by adding phosphate groups. Two molecules of ATP are in this step resulting in two molecules of glyceraldehyde 3 phosphate. compounds. (A) 4 and produced (B) 2 and produced (C) 4 and used (D) 2 and used Clue is in the question. It states that Two molecules of ATP are involved. The most likely scenario then is that two phosphates are added. The question does state that two molecules of ATP are used in the preparatory step so the first half of this answer is correct. However remember that in the preparatory step ATP is used not produced. Clue is in the question. The question states that Two molecules of ATP are involved. The most likely scenario then is that two phosphates are added. In the preparatory step ATP is used not produced. Production of ATP will occur in the following steps D. Correct! The question does state that two molecules of ATP are used in the preparatory step so the answer 2 is correct. In the preparatory step ATP is used not produced. Production of ATP will occur in the following steps. Glycolysis has four main steps (although it has 10 distinct chemical reactions). These key events occur during glycolysis: 1. Preparatory stage, glucose is energized by adding two phosphate groups. Two molecules of ATP are used in this step and results in two, three-carbon compounds. 2. Substrate level phosphorylation makes 2 molecules of ATP from ADP. During the formation of the two phosphorylated 3-carbon molecules 4 molecules of ATP are made. This results in a net gain of 2 ATP per glucose. 3. For every glyceraldehyde 3-phosphate molecule a molecule of NAD+ is reduced to NADH. NADH can enter the electron transport system generating more ATP by oxidative phosphorylation. 4. Two molecules of pyruvate are made. Pyruvate may be fermented or enter the Krebs cycle depending on the bacterium.

7 No. 7 of The end product of glycolysis includes: 2 ATP, 2 NADH and 2. (A) Urea (B) Lactic acid (C) Galactose (D) Pyruvate Urea is a product of the urea cycle which is involved in protein breakdown. Lactate or lactic acid is formed under aerobic conditions. Pyruvate is reduced to lactate. pyruvate + NADH + H + lactate + NAD + Galactose is a carbohydrate that is used as a metabolite not a product. D. Correct! A single molecule of glucose gives rise to 2 molecules of pyruvate. Step by step complete solution (the long version). This can be any format, whatever you can type in Word.

8 No. 8 of In REDOX reactions molecules are either oxidized or reduced. Which of the following statements is true of oxidation reduction processes? Reduction reactions trap chemical energy. In reduction the substrate gains electrons and hydrogens. (A) A molecule that has undergone reduction is energy rich. (B) Reduction reactions release chemical energy. (C) A molecule that has undergone oxidation is energy rich. (D) Reduction is the releasing of electrons by a molecule. A. Correct! REDOX reactions are involved in the energy release or generation (storage) of chemical energy. As a rule of thumb it should be remembered that when a molecule is reduced it has acquired an electron and hydrogens and traps energy. Reduction reactions trap chemical energy. In reduction the substrate gains electrons and hydrogens. A molecule that has undergone reduction is energy rich. Oxidation reactions release energy. In biological systems, oxidation involves the loss of hydrogen atoms from a substrate, electrons are usually lost with hydrogen atoms. An oxidized molecule has given up energy. D. Incorrect! Reduction is the acquisition of electrons. The basics of oxidation and reduction are presented. It is in oxidation reduction that high energy molecules are created and utilized. Oxidation reactions release energy. In biological systems, oxidation involves the loss of hydrogen atoms from a substrate, electrons are usually lost with hydrogen atoms. An oxidized molecule has given up energy. Reduction reactions trap chemical energy. In reduction the substrate gains electrons and hydrogens. A molecule that has undergone reduction is energy rich.

9 No. 9 of The breakdown products of glucose to glucose-6 phosphate and fructose-6-phospate enter the anabolic pathway to make glycogen and peptidoglycan, both of which are polysaccharides. This is an example of. (A) Catabolism (B) Anabolism (C) Fermentation (D) Electron Transport Chain Catabolism is the breakdown of molecules into simpler one usually releasing energy. The pathway described is making the molecule more complex and uses energy. B. Correct! This is anabolism because a simple starting molecule is assembled into more complex molecules. Fermentation is the production of energy under anaerobic conditions. D. Incorrect! Electron transport is the process where the greatest amount of energy in the form of ATP is created. To answer this question consider the complexity of the starting molecules, glucose and glucose-6- phosphate and fructose-6-phospate and then look at the products. The starting molecules are simple carbohydrates and the end products are more complex. This is therefore and example of anabolism.

10 No. 10 of NAD is used in glycolysis and the Kreb s cycle during cellular respiration and is converted to NADH. The potential of NADH can be used to convert ADP to ATP in the electron transport chain. (A) Oxidizing (B) Hydrolyzing (C) Reducing (D) Fermenting The H (hydrogen) is a clue that the NADH is not an oxidizing molecule. Hydrolyzing is the addition of an OH. C. Correct! The hydrogen from NADH is released as a reducing agent. This is used in the electron transport chain to make ATP. D. Incorrect! Fermentation is the process of energy creation without oxygen and in the absence of the ETC. The mechanism for oxidative phosphorylation is the gradient of H+ across the cell membrane. This is called chemiosmotic coupling. NADH enters the ETS chain at the beginning and yields 3 ATP per NADH.