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CELL RESPIRATION AND METABOLISM Chapter 5 CELL RESPIRATION AND METABOLISM

Acetyl coenzyme A enables the products of glycolysis to enter the ___________________ _______________.

Acetyl coenzyme A enables the products of glycolysis to enter the citric acid cycle OR Krebs cycle.

During an enzyme-catalyzed reaction, the substrate binds to the enzyme’s __________________ _______________.

During an enzyme-catalyzed reaction, the substrate binds to the enzyme’s active site.

Fig. 4.3 Describe this graph Enzyme activity 10 20 30 37 40 100 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Enzyme activity 10 20 30 37 40 100 Temperature (°C)

Fig. 4.3 Describe this graph Copyright © McGraw-Hill Education. Permission required for reproduction or display. Enzyme activity This graph shows that an enzyme’s activity is optimal at approximately 37 – 41 degrees C 10 20 30 37 40 100 Temperature (°C)

Glycolysis a) requires the presence of oxygen Glycolysis  a) requires the presence of oxygen.   b) is the first step of cellular respiration.   c) produces carbon dioxide and water.   d) utilizes FAD as an electron acceptor. 

Glycolysis a) requires the presence of oxygen Glycolysis  a) requires the presence of oxygen.   b) is the first step of cellular respiration.   c) produces carbon dioxide and water.   d) utilizes FAD as an electron acceptor. 

Lactic acid a) is produced as a result of aerobic metabolism of glucose.   b) is one of the normal end products of glycolysis.   c) is a common end product of red blood cells.   d) none of the above.

Lactic acid  a) is produced as a result of aerobic metabolism of glucose.   b) is one of the normal end products of glycolysis.   c) is a common end product of red blood cells.   d) none of the above.

CH 4 and 5 What are the roles of NAD and FAD?

CH 4 and 5 What are the roles of NAD and FAD? Electron acceptors

A term often used to describe the electron transport chain is ”oxidative phosphorylation.” Why?

A term often used to describe the electron transport chain is ”oxidative phosphorylation.” Why? The electron transport chain requires oxygen for the phosphorylation of ADP to make ATP

CH 4 and 5 Understand cellular respiration. Where does the Krebs cycle occur?

CH 4 and 5 Understand cellular respiration. Where does the Krebs cycle occur? Mitochondrial matrix

CH 4 and 5 Understand cellular respiration. Where is ATP made?

CH 4 and 5 Understand cellular respiration. Where is ATP made? Mitochondrial matrix

CH 4 and 5 What are the roles of NAD and FAD?

CH 4 and 5 What are the roles of NAD and FAD? Electron acceptors They “couple” oxidation and reduction reactions; ie. Take an electron from one molecule and transfer it to another. Carry the “energy” to the electron transport chain (in the inner mitochondrial membrane).

CH 4 and 5 From which reactions is carbon dioxide produced?

CH 4 and 5 From which reactions is carbon dioxide produced? Carbon dioxide is produced when Pyruvate becomes Acetyl-CoA Also released from the Krebs Cycle (carbon dioxide is not formed from the oxygen that we breathe in) See next slides….

How does ATP form in the mitochondrion? STEP 1: Formation of Acetyl CoA. Click HERE After one 6-carbon glucose molecule breaks down into two 3-carbon pyruvate molecules, pyruvate enters the mitochondrion. A single carbon is removed and breathed out of the body as carbon dioxide. The other two carbons attach to a molecule called Coenzyme A, forming Acetyl Coenzyme A (Acetyl CoA) When carbon dioxide is formed, energy is released in the form of electrons that are captured by NAD to form NADH + H+. Yield 1: NADH per pyruvate.

The Krebs Cycle PRODUCTS: 3 NADH 1 FADH2 1 ATP (per Pyruvate) WASTE PRODUCTS: 2 carbon dioxide For an explanation, Click HERE

CH 4 and 5 What does the cell do with carbon dioxide?

CH 4 and 5 What does the cell do with carbon dioxide? Cells release carbon dioxide as a waste product

What is the primary role of the Krebs Cycle?

What is the primary role of the Krebs Cycle? The primary role of the Krebs Cycle is to make NADH and FADH2, which carry electrons to the electron transport chain. NADH and FADH2 “couple oxidation and reduction reactions. They are formed by reduction from their oxidized counterparts. (Reduction means they have accepted electrons).

Which reactions (metabolic pathways) release carbon dioxide?

Which reactions (metabolic pathways) release carbon dioxide? The breakdown of pyruvic acid into acetyl CoA AND reactions of the Krebs Cycle

What are the reactants and products of glycolysis?

Copyright © McGraw-Hill Education Copyright © McGraw-Hill Education. Permission required for reproduction or display. Fig. 5.3 Glucose (C6H12O6) GLYCOLYSIS ATP 1 ADP Glucose 6-phosphate 2 Fructose 6-phosphate ATP 3 ADP Dihydroxy- acetone phosphate Fructose 1,6-biphosphate 4 3–Phosphoglyceraldehyde 3–Phosphoglyceraldehyde Pi Pi NADH NADH 5 5 2 H 2 H NAD NAD 1,3–Biphosphoglyceric acid 1,3–Biphosphoglyceric acid ATP ATP 6 6 ADP ADP 3–Phosphoglyceric acid 3–Phosphoglyceric acid 7 7 2–Phosphoglyceric acid 2–Phosphoglyceric acid 8 8 Phosphoenolpyruvic acid Phosphoenolpyruvic acid ATP ATP 9 9 ADP ADP Pyruvic acid (C3H4O3) Pyruvic acid (C3H4O3)

What are the reactants and products of lactic acid synthesis?

The formation of lactic acid Fig. 5.4 Copyright © McGraw-Hill Education. Permission required for reproduction or display. NADH + H+ NAD H O H OH O O H C C C H C C C OH LDH OH H H H Pyruvic acid Lactic acid The formation of lactic acid

What is the purpose of lactic acid synthesis?

What is the purpose of this reaction? Fig. 5.4 Copyright © McGraw-Hill Education. Permission required for reproduction or display. NADH + H+ NAD H O H OH O O H C C C H C C C OH LDH OH H H H Pyruvic acid Lactic acid To provide NAD to drive glycolysis

What is the first reaction in the mitochondrion where Carbon Dioxide is released?

First step after pyruvate enters the mitochondrion Fig. 5.5 Copyright © McGraw-Hill Education. Permission required for reproduction or display. H H NAD NADH + H+ H C H H H C H C O + S CoA C O + CO2 C S CoA HO O Pyruvic acid Coenzyme A Acetyl coenzyme A First step after pyruvate enters the mitochondrion

What is the purpose of the Krebs Cycle?

To make NADH AND FADH Fig. 5.6 Glycolysis C3 Pyruvic acid CYTOPLASM NADH + H+ Mitochondrial matrix CoA C2 Acetyl CoA Oxaloacetic acid C4 CO2 Fig. 5.6 Citric acid cycle 3 NADH + H+ 1 FADH2 1 ATP C6 Citric acid C5 α-Ketoglutaric acid CO2

What is the purpose of NADH and FADH2?

ELECTRON TRANSPORT CHAIN What is the purpose of NADH and FADH2? Copyright © McGraw-Hill Education. Permission required for reproduction or display. NADH FMN The purpose of NADH and FADH2 is to donate electrons to the electron transport chain. NAD FMNH2 2 H+ 2 e– FADH2 Oxidized Fe2+ CoQ Cytochrome b FAD Reduced Fe3+ Electron energy 2 e– ELECTRON TRANSPORT CHAIN Fe2+ Fe3+ Cytochrome c1 and c Cytochrome a Fe3+ Fe2+ 2 e– Fe2+ H2O Cytochrome a3 Fig. 5.8 Fe3+ 2 e– + 1 – O2 2 2 H+

What is the function of oxygen?

ELECTRON TRANSPORT CHAIN Where is ATP synthesized? Fig. 5.9 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Outer mitochondrial membrane Where is ATP synthesized? Inner mitochondrial membrane OXYGEN IS THE ULTIMATE ELECTRON ACCEPTOR H+ H+ 2 Intermembrane space Third pump Second pump H+ 1 2 H+ ATP synthase H2O First pump 2 H + 1 / O2 3 4 H + 2 e– 1 ADP + Pi H+ ATP 4 H+ NAD+ Matrix NADH

Why does liver (but not skeletal muscle) release glucose into the blood stream?

GLYCOGENESIS AND GLYCOGENOLYSIS Why does liver (but not skeletal muscle) release glucose into the blood stream? ANSWER: Only the liver has the enzyme, glucose-6-phosphatase. GLYCOGEN Pi Pi 1 2 Glucose 1-phosphate Pi ADP ATP Glucose (blood) Glucose (blood) Glucose 6-phosphate Liver only Many tissues Fructose 6-phosphate Fig. 5.10 Fig. 5.10 GLYCOLYSIS GLYCOGENESIS AND GLYCOGENOLYSIS

Describe the Cori Cycle? (and its purpose)

Describe the Cori Cycle and its purpose Skeletal muscles Liver Fig. 5.11 Glycogen Glycogen Exercise Rest 1 9 Blood Glucose 6-phosphate Glucose Glucose 6-phosphate 8 7 2 6 Pyruvic acid Pyruvic acid 3 5 Blood Lactic acid Lactic acid 4 During exercise, skeletal muscle glycogen serves as a source of glucose-6-phosphate for the lactic acid pathway. The lactic acid is transported to the liver, where it is used for the synthesis of glucose

An adequate amount of all 20 amino acids is required to build proteins for growth and to replace the proteins that are turned over. However, only 8 of these (9 in children) cannot be produced by the body and must be obtained in the diet. These are the ____________ amino acids.

An adequate amount of all 20 amino acids is required to build proteins for growth and to replace the proteins that are turned over. However, only 8 of these (9 in children) cannot be produced by the body and must be obtained in the diet. These are the essential amino acids.

When amino acids are needed in the body, our bodies often make their own amino acids through a process called _____________ in which the NH2 group is transferred from one amino acid to a keto acid of the Krebs Cycle.

When amino acids are needed in the body, our bodies often make their own amino acids through a process called __transamination_ in which the NH2 group is transferred from one amino acid to a keto acid of the Krebs Cycle.

If there are more amino acids than are needed for protein synthesis, the amine group from glutamic acid may be removed and excreted as urea in the urine. This is known as ____________ deamination.

If there are more amino acids than are needed for protein synthesis, the amine group from glutamic acid may be removed and excreted as urea in the urine. This is known as oxidative deamination.

Which organ has an almost absolute requirement for blood glucose as its energy source?

Which organ has an almost absolute requirement for blood glucose as its energy source? brain

Oxygen is __________________ by the action of the electron transport chain. Choose: oxidized or reduced

Oxygen is __________________ by the action of the electron transport chain. Choose: oxidized or reduced

The transport of protons from the intermembrane space to the mitochondrial matrix occurs via ________________________ enzyme.

The transport of protons from the intermembrane space to the mitochondrial matrix occurs via ________________________ enzyme. ATP synthase

Fatty acid metabolism occurs via which metabolic pathway?

Fatty acid metabolism occurs via which metabolic pathway Fatty acid metabolism occurs via which metabolic pathway? Beta-oxidation

Ketone bodies are produced by excessive _______________ breakdown.

Ketone bodies are produced by excessive ____fat________ breakdown.

The process in which an amine group is transferred from one amino acid to another is called

The process in which an amine group is transferred from one amino acid to another is called transamination.

The conversion of glucose into glycogen and fat Glucose 1-phosphate glycogenesis Occurs when _____________? Glucose Glucose 6-phosphate Fructose 6-phosphate Fructose 1,6-biphosphate Glycerol 3-Phosphoglyceraldehyde Fat Pyruvic acid Fatty acids Acetyl CoA C4 C6 Oxaloacetic acid Citric acid Citric acid cycle Fig. 5.12 C5 -Ketoglutaric acid

The conversion of glucose into glycogen and fat Glucose 1-phosphate glycogenesis Occurs when there are adequate amounts of ATP Glucose Glucose 6-phosphate Fructose 6-phosphate Fructose 1,6-biphosphate Glycerol 3-Phosphoglyceraldehyde Fat Pyruvic acid Fatty acids Acetyl CoA C4 C6 Oxaloacetic acid Citric acid Citric acid cycle Fig. 5.12 C5 -Ketoglutaric acid

Name four divergent metabolic pathways for the involvement of Acetyl CoA

DIVERGENT METABOLIC PATHWAYS FOR ACETYL COENZYME A Copyright © McGraw-Hill Education. Permission required for reproduction or display. Bile acids Steroids Cholesterol Citric acid (Krebs cycle) Ketone bodies Acetyl CoA CO2 Fatty acids Fig. 5.13 Triacylglycerol (triglyceride) Phospholipids

Describe beta oxidation and its purpose

BETA OXIDATION PRODUCES ATP FROM FATTY ACID BREAKDOWN Copyright © McGraw-Hill Education. Permission required for reproduction or display.   H H O Fatty acid C C C H H OH CoA BETA OXIDATION PRODUCES ATP FROM FATTY ACID BREAKDOWN 1 ATP AMP + PPi H H O Fatty acid C C C CoA H H FAD 2 FADH2 1.5 ATP H H O Fatty acid C C C CoA H H2O Fig. 5.14 3 CoA HO H O Fatty acid C C C CoA H H NAD Fatty acid now two carbons shorter 4 NADH + H+ 2.5 ATP O H O Fatty acid C C C CoA 5 Acetyl CoA Citric acid cycle 10 ATP

Which molecules undergo transamination?

WHAT MAJOR CATEGORY OF MOLECULE IS UNDERGOING TRANSMINATION? Fig. 5.15 OH O HO O AMINO ACIDS OH O OH O C C C C H H N C H C O C O N C H H + AST + H H C H H C H H C H H C H H C H C H C H C HO O H O O C C H O O H O O Glutamic acid Oxaloacetic acid α-Ketoglutaric acid Aspartic acid OH O OH O OH O OH O C C C C H H N C H C O C O N C H H + ALT H + H C H H C H H C H H C H H C H H H C H H C C HO O HO O Glutamic acid Pyruvic acid -Ketoglutaric acid Alanine

What does the body do with excess ammonia?

OXIDATIVE DEAMINATION Copyright © McGraw-Hill Education. Permission required for reproduction or display. Amino acid α-Ketoglutaric acid NH3 + CO2 Amino transfer Urea cycle in liver Keto acid Glutamic acid Urea Also - Ammonia is produced by intestinal bacteria Carried to the liver Converted to glutamic acid Removed from glutamic acid by transfer to urea O H H N C N H H Fig. 5.16

Describe how amino acids are catabolized for energy

AMINO ACID CATABOLISM Alanine, cysteine, glycine, serine, threonine, tryptophan They are converted (by deamination) to molecules of cellular respiration Pyruvic acid NH3 Urea Fig. 5.17 Leucine, tryptophan, isoleucine Acetyl CoA NH3 Urea Asparagine, aspartate Citric acid Arginine, glutamate, glutamine, histidine, proline Urea NH3 Oxaloacetic acid –Ketoglutaric acid NH3 Urea Citric acid cycle Phenylalanine, tyrosine Isoleucine, methionine, valine Urea NH3 Fumaric acid Urea Succinic acid NH3

How do the different organs vary in their use of substrates as energy sources?

How do the different organs vary in their use of substrates as energy sources?

DEFINE: Glycolysis Glycogenesis Glycogenolysis Gluconeogenesis Lipogenesis Lipolysis Ketogenesis

Table 5.2

Which organs provide glucose to the bloodstream?

Fig. 5.1 Glycogen in liver Glucose Glucose from digestive tract Copyright © McGraw-Hill Education. Permission required for reproduction or display. Fig. 5.1 Glycogen in liver Glucose from digestive tract Glucose from liver Capillary Glucose in blood plasma Interstitial fluid Plasma membrane Glucose in cell cytoplasm Glycolysis Anaerobic Cytoplasm Pyruvic acid Lactic acid Metabolism in skeletal muscle into mitochondrion Aerobic Citric acid cycle Electron transport CO2 + H2O Mitochondrion Respiration

Describe the energy cost and benefits of glycolysis

Fig. 5.2 GLYCOLYSIS 1 ATP ADP ATP 2 NADH ADP 2 NAD Glucose 2 Copyright © McGraw-Hill Education. Permission required for reproduction or display. GLYCOLYSIS 1 ATP ADP ATP 2 NADH ADP 2 NAD Glucose 2 Free energy 2 ATP 2 ADP + 2 Pi 3 2 ATP 2 ADP + 2 Pi Pyruvic acid

Describe the main products of glycolysis Knowing each metabolic step is not required.

Copyright © McGraw-Hill Education Copyright © McGraw-Hill Education. Permission required for reproduction or display. Fig. 5.3 Fig. 5.3 Glucose (C6H12O6) GLYCOLYSIS ATP 1 ADP Glucose 6-phosphate 2 Fructose 6-phosphate ATP 3 ADP Dihydroxy- acetone phosphate Fructose 1,6-biphosphate 4 3–Phosphoglyceraldehyde 3–Phosphoglyceraldehyde Pi Pi NADH NADH 5 5 2 H 2 H NAD NAD 1,3–Biphosphoglyceric acid 1,3–Biphosphoglyceric acid ATP ATP 6 6 ADP ADP 3–Phosphoglyceric acid 3–Phosphoglyceric acid 7 7 2–Phosphoglyceric acid 2–Phosphoglyceric acid 8 8 Phosphoenolpyruvic acid Phosphoenolpyruvic acid ATP ATP 9 9 ADP ADP Pyruvic acid (C3H4O3) Pyruvic acid (C3H4O3)

The carbon dioxide that we breathe out comes from …

The carbon dioxide that we breathe out comes from … citric acid cycle (Krebs Cycle)