Glycolysis What are Carbohydrates? Carbohydrates are one of the three macronutrients – major nutrients our bodies need. Protein and fat are the other two. Examples of Carbohydrates 1. glucose (monosaccharide) 2. fructose (monosaccharide) 3. galactose (monosaccharide) 4. sucrose (disaccharide) 5. lactose (disaccharide) 6. cellulose (polysaccharide) 7. chitin (polysaccharide) 8. starch (polysaccharide) 9. xylose 10. maltose Table sugar Sucrose is common sugar. It is a disaccharide, a molecule composed of two monosaccharides: glucose and fructose. Sucrose is produced naturally in plants, from which table sugar is refined. It has the molecular formula C12H22O11. Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose. Monosaccharides are the building blocks of disaccharides (such as sucrose and lactose) and polysaccharides (such as cellulose and starch) which are not fully sugar but a concentration of sugar aka concentrated sugar. What is Glycolysis? Glycolysis is an anaerobic reaction, and in low oxygen conditions it is the sole source of ATP. Glycolysis is a series of reactions that helpextract energy from glucose. This is an ancient pathway of metabolism that is present in the majority of living organisms today. It is the foundation of both aerobic and anaerobic cellular respiration. It takes place in the cytosol of a cell and is the foundation of both aerobic and anaerobic cellular respiration. https://teachmephysiology.com/biochemistry/atp-production/glycolysis/ This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses on “Glycolysis”. 1. Which of the following enzyme catalyzes the first step of glycolysis? a) Hexokinase b) Pyruvate kinase c) Glucokinase d) Phosphofructokinase-1 View Answer Answer: a Explanation: The first of glycolysis is irreversible under intracellular conditions and is catalyzed by hexokinase. 2. What is the general term used for the anaerobic degradation of glucose to obtain energy? a) Anabolism b) Oxidation c) Fermentation d) Metabolism View Answer Answer: c Explanation: Fermentation is the general term used for the degradation of glucose to obtain energy in the form of ATP. 3. Whenever the cell’s ATP supply is depleted, which of the following enzyme’s activity is increased? a) Hexokinase b) Pyruvate kinase c) Glucokinase d) Phosphofructokinase-1 View Answer Answer: d Explanation: Phosphofructokinase-1 is a regulatory enzyme; it is the major point of regulation in glycolysis. Its activity is increased whenever the cell’s ATP supply is depleted. 4. Cleavage of Fructose 1, 6-biophosphate yields ___________ a) Two aldoses b) Two ketoses c) An aldose and a ketose d) Only a ketose View Answer Answer: c Explanation: Fructose 1, 6-biophosphate is cleaved to yield glyceraldehyde 3-phosphate, an aldehyde and dihydroxyacetone phosphate, a ketose. 5. Dihydroxyacetone phosphate is rapidly and reversibly converted to ___________ a) Glyceraldehyde 3-phosphate b) 1, 3-bis-phosphoglycerate c) Fructose 1, 6-bisphosphate d) Fructose 6-phosphate View Answer Answer: a Explanation: Dihydroxyacetone phosphate is rapidly and reversibly converted to glyceraldehyde 3-phosphate by triose phosphate isomerase. 6. What is the first step in the payoff phase of glycolysis? a) Reduction of 1, 3-bisphosphoglycerate to glyceraldehyde 3-phosphate b) Oxidation of glyceraldehyde 3-phosphate to 1, 3-bisphosphoglycerate c) Reversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3-phosphate d) Irreversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3-phosphate View Answer Answer: b Explanation: Glyceraldehyde 3-phosphate dehydrogenase catalyzes the first step in the payoff phase, oxidation of glyceraldehyde 3-phosphate to 1, 3-bisphosphoglycerate. 7. Which substrate is used in the last step of glycolysis? a) Glyceraldehyde 3-phosphate b) Pyruvate c) Phosphoenolpyruvate d) 1, 3-bisphosphoglycerate View Answer Answer: c Explanation: The last step in glycolysis is the transfer of phosphoryl group from phosphoenolpyruvate to ADP catalyzed by pyruvate kinase. 8. High concentration of glucose 6-phosphate is inhibitory to ___________ a) Hexokinase b) Pyruvate kinase c) Glucokinase d) Phosphofructokinase-1 View Answer Answer: a Explanation: Hexokinase catalyzes the reaction involving conversion of glucose to glucose 6-phosphate. 9. The product formed in the first substrate level phosphorylation in glycolysis is ___________ a) Pyruvate b) 3-phosphoglycerate c) 1, 3-bisphosphoglycerate d) 2-phosphoglycerate View Answer Answer: b Explanation: Phosphoglycerate kinase transfers phosphoryl group from 1, 3-bisphosphoglycerate to ADP forming ATP and 3-phosphoglycerate. 10. Glycolysis converts ___________ a) Glucose into pyruvate b) Glucose into phosphoenolpyruvate c) Fructose into pyruvate d) Fructose into phosphoenolpyruvate View Answer Answer: a Explanation: Glycolysis is a metabolic pathway that converts glucose into pyruvate. Fates of Pyruvate Pyruvate is a versatile molecule which feeds into numerous pathways. After glycolysis, it can be converted to acetyl-CoA, which has numerous metabolic destinations, including the TCA cycle. It can also be converted into lactate, which enters the Cori cycle in absence of mitochondria or oxygen. Glycolysis 1. Where does glycolysis take place in cells? ?Cytoplasm ?Mitochondrion ?Endoplasmic Reticulum ?Ribosomes A:Cytoplasm 2. The first step of glycolysis results in the formation of: ?Glucose-6-Phosphate ?Fructose-6-Phosphate ?ATP ?1,6 Bis-PhosphoGlycerate A:Glucose-6-Phosphate 3. The enzyme that produces G3P & DHAP is: ?Hexokinase ?Aldolase ?PhosphoFructoKinase ?Enolase A:Aldolase 4. Glycolysis results in the net gain of: ?2 ATP ?4 ATP ?4 NADH ?2 Acetyl CoA A:2 ATP 5. Glycolysis results in the total production of: ?2 ATP ?4 ATP ?4 NADH ?2 Acetyl CoA A:4 ATP 6. If Fructose-1,6-BisPhosphate is put through glycolysis the net result would be: ?2 ATP ?4 ATP ?4 NADH ?2 FADH2 A:2 ATP 7. Glucose enters cells and is committed to glycolysis with the addition of: ?PFK Enzymes ?-PO4 from ADP ?-PO4 from ATP ?Electrons from ATP A:PO4 from ATP 8. Glucose molecules commonly enter cells through ?GLUT4 Transporters ?Symports with Sucrose ?Antiports with Na+ ?Na/K Pump action A:GLUT4 Transporters 9. Which is not part of the net products of Glycolysis? ?2 ATP ?2 NADH ?2 Pyruvate ?2 CO2 A:2 CO2 10. Glycolysis occurs during aerobic or anaerobic conditions. ?True ?False A:True 11. In the final step of glycolysis ATP is made through the process of: ?Substrate Level Phosphorylation ?Oxidative Phosphorylation ?Photo-Phosphorylation ?RedOx Reactions A:Substrate Level Phosphorylation 12. Which of the following is not a requirement for glycolysis? ?Oxygen ?ATP ?NAD+ ?Glucose A:Oxygen 13. Which of the following is not a product of glycolysis? ?FADH2 ?NADH ?ATP ?Pyruvate A:FADH2 14. NADH is produced by the oxidation of: ?G3P ?DHAP ?PEP ?1,3 BPG A:G3P 15. Which enzyme adds a phosphate to F-6-P? ?PhosphoFructoKinase ?Hexokinase ?Aldolase ?Pyruvate Kinase A:PhosphoFructoKinase 16. Which molecule is an isomer of Glyceraldehyde-3-Phosphate (G3P)? ?DHAP ?PEP ?Pyruvic Acid ?1,3 BPG A:?DHAP Krebs Cycle Multiple Choice 1. The number of ATP molecules produced out of Krebs Cycle is: ?2 ?3 ?4 ?0 A:2 2. How many FADH2 molecules are produced by 1 molecule of glucose? ?1 ?2 ?3 ?4 A:2 3. Krebs Cycle takes place in the: ?Cytoplasm ?Matrix ?Ribsome ?InterMembrane Space A:Matrix (Mitochondria) Function of Mitochondria Mitochondria produce ATP through process of cellular respiration—specifically, aerobic respiration, which requires oxygen. The citric acid cycle, or Krebs cycle, takes place in the mitochondria. This cycle involves the oxidation of pyruvate, which comes from glucose, to form the molecule acetyl-CoA. Acetyl-CoA is in turn oxidized and ATP is produced. 4. Krebs Cycle is part of_______________ respiration. ?Aerobic ?Anaerobic A:Aerobic 5. After the Krebs Cycle only a small portion of the energy of glucose has been converted to ATP. At this point the majority of usable energy is contained in ?NADH and FADH2 ?Carbon Dioxide ?Acetyl-CoA ?Citrate A:?NADH and FADH2 6. The first step in getting energy in the cell by breaking down glucose is known as ?the Krebs cycle ?electron transport ?fermentation ?glycolysis A:glycolysis 7. NADH and FADH2 ?carry electrons to the ETC. ?bind with Acetyl CoA. ?supply energy for the cell. ?make water. A:carry electrons to the ETC 8. Which of the following is not an end product of the Kreb's cycle? ?FADH2 ?CO2 ?pyruvate ?ATP A:pyruvate Types of Cells in the Human Body Key facts about the cell types in the human body Stem cells Embryonic stem cells Adult stem cells Red blood cells Erythrocytes White blood cells Granulocytes (neutrophils, eosinophils, basophils) Agranulocytes (monocytes, lymphocytes) Platelets Fragments of megakaryocytes Nerve cells Neurons Neuroglial cells Muscle cells Skeletal Cardiac Smooth Cartillage cells Chondrocytes Bone cells Osteoblasts Osteoclasts Osteocytes Lining cells Skin cells Keratinocytes Melanocytes Merkel cells Langerhans cells Endothelial Lining blood vessels Epithelial cells Lining body cavities Fat cells White adipocytes Brown adipocytes Sex cells Spermatozoa Ova