Cellular Respiration PDF

Cellular Respiration  Let’s review! 1. Define active transport. 2. If a water balloon is placed in a solution of 50% salt, which way will water move in relation to the balloon? 3. In the previous question, is the solution inside the balloon hypotonic, isotonic, or hyperto...

Cellular Respiration  Let’s review! 1. Define active transport. 2. If a water balloon is placed in a solution of 50% salt, which way will water move in relation to the balloon? 3. In the previous question, is the solution inside the balloon hypotonic, isotonic, or hypertonic? 4. How are phagocytosis and receptor- mediated endocytosis different?  Pre-lecture video Cellular Respiration and the Mighty Mitochondria https://www.youtube.com/watch?v=4Eo7JtRA 7lg&t=2s  Types of energy Energy causes change and carries out work 1. Kinetic energy: energy of movement/motion 1. Moving objects transfer motion to other objects 2. Example: your legs pedaling a bike to put you in motion 3. Thermal energy is a type of kinetic energy 1. Describes the random movement of atoms or molecules 2. Example: Heat puts water molecules in motion 4. Light is a type of kinetic energy 1. Chloroplasts take in light during photosynthesis  Types of energy 2. Potential energy: energy that matter contains based on its location or structure Example: waiting to go down a hill on your bicycle; you have potential energy Molecules also have potential energy because of the electrons in their bonds Chemical energy: the potential energy in a chemical reaction to do work in the cell  Thermodynamics Thermodynamics is the study of energy transformations I. First law (law of conservation): energy in the universe is constant I. Energy can be transferred or transformed, but cannot be created or destroyed II. Second law: every energy conversion that occurs increases the disorder in the universe I. Disorder (entropy): random arrangement of matter and energy  Cellular respiration In cellular respiration, the cell uses oxygen and glucose to make carbon dioxide and ATP – The cell also gives off heat, increasing entropy – But the cell uses most of the energy it gives off in the form of ATP Chemical energy is an example of: A. Kinetic energy B. Potential energy C. Heat  Two types of chemical reactions Exergonic reactions release energy – Example: Wood burning releases light and heat energy  Types of chemical reactions Endergonic reactions take in energy and their products contain potential energy – Example: photosynthesis: convert light energy to chemical energy  Metabolism All of the chemical reactions in your body are called the metabolism A metabolic pathway is the series of steps taken in a chemical reaction to break down or build complex molecules – Cellular respiration is a metabolic pathway Your metabolism contains many metabolic pathways of chemical reactions  Energy coupling Energy coupling is when energy released from exergonic reactions is used in endergonic reactions  Adenosine triphosphate (ATP) ATP powers almost all forms of work in the cell ATP is made of adenosine and 3 phosphate groups If phosphate groups are negatively charged, that means they are A. Hydrophilic B. Hydrophobic C. Isotonic D. Cannot be determined  Making adenosine diphosphate Although the phosphate groups are all negative charged, they have to be crowded together in ATP – They are repulsed by each other, so any little nudge will break them apart – The bonds can be easily broken by hydrolysis The hydrolysis of ATP is A. Endergonic B. Exergonic C. Isotonic D. All of the above  Hydrolysis of ATP leads to energy coupling The phosphate group that is released during the hydrolysis of ATP is used to power other chemical reactions in the cell – Providing a phosphate group to other molecules for work is called phosphorylation – ATP can help drive chemical, transport, and mechanical work in the cell Chemical work with the help of ATP Reactants are phosphorylated to convert them to products  Transport work with the help of ATP ATP phosphorylates transport proteins to move molecules against their concentration gradient Mechanical work with the help of ATP Phosphorylation of motor proteins in muscle cells cause the protein to change shape. This results in the pulling of the protein filament attached to the motor protein → muscle contraction  Recycle, Renew, Reuse ATP ATP is used and regenerated in a cell to be used again ADP + P → ATP hydrolysis occurs → ADP + P Stages of cellular respiration  Stage 1: Glycolysis Occurs in the cytoplasm, specifically in the cytosol Takes in glucose and converts it to 2 molecules of pyruvate Makes a bit of ATP Provides electrons to the electron transport chain  Stage 2: Pyruvate oxidation and the citric acid cycle Occurs in the mitochondria Pyruvate is oxidized to a 2-carbon compound The citric acid cycle finishes breaking down glucose into carbon dioxide This is where the carbon dioxide you exhale comes from Makes some ATP Provides electrons to electron transport chain Stage 3: Oxidative phosphorylation Electrons carried by NADH and FADH2 help provide electrons to electron transport chain Energy released from electron transport chain is used to make ATP in oxidative phosphorylation Electrons are passed to oxygen to make water The connection between the electron transport chain (ETC) and ATP Energy moving down the ETC by electrons also pumps hydrogen ions across the inner membrane of the mitochondria A concentration gradient of hydrogen ions results Chemiosmosis makes ATP by using the potential energy from the hydrogen concentration gradient Which stage of cell respiration does not occur in the mitochondria? A. Glycolysis B. ETC C. Oxidative phosphorylation D. Citric acid cycle  Glycolysis Stage 1 of cellular respiration  Glycolysis 1 glucose → 2 pyruvate 6 carbons in glucose → 3 carbons in each pyruvate 9 steps in glycolysis 2 NAD+ → 2 NADH 2 ATP produced  The production of ATP ATP is produced by substrate-level phosphorylation – Phosphate group from substrate → ADP → ATP  Energy is made during glycolysis The oxidation of glucose to pyruvate creates energy in the form of ATP and NADH ATP can be used by the cell immediately NADH electrons must pass through the ETC Pyruvate will be further oxidized in the citric acid cycle Molecules formed between the reactant and product in a chemical reaction are called intermediates Details in glycolysis Steps 1-4 1-3: ATP adds 2 phosphate groups to a glucose intermediate 4: The intermediate is then split into 2 three- carbon molecules These molecules are called glyceraldehyde-3- phosphate (G3P) Details in glycolysis Steps 5-9 occur twice: 5: NAD+ is reduced to NADH – Phosphate group is added to each G3P 6-9: 4 ATP produced, water is also produced in step 8 – 2 pyruvate formed For each molecule of glucose at the beginning of glycolysis, 2 pyruvate are formed  Details in glycolysis An enzyme is involved in each step of glycolysis Steps 1-4 consume energy Steps 5-9 produce energy Because 2 ATP were used during steps 1-4 and 4 ATP were made during steps 5-9, the net gain is 2 ATP -2ATP + 4 ATP = 2 ATP  Review of glycolysis Occurs in the cytosol Consists of 9 steps each involving an enzyme Starts with 1 glucose molecule Glycolysis produces: – 2 ATP – 2 pyruvate – 2 NADH Pyruvate oxidation and the Citric acid cycle Step 2 of cellular respiration  Pyruvate oxidation and the Citric acid cycle Pyruvate is transported to a mitochondrion for pyruvate oxidation and the citric acid cycle Pyruvate itself does not enter  Pyruvate oxidation Step 1: carboxyl group removed as CO2 Step 2: Pyruvate oxidized and reduction of NAD+ → NADH Step 3: Coenzyme A joins to form Acetyl CoA 2 Acetyl CoA enter the citric acid cycle because 2 pyruvate from glycolysis  Citric acid cycle (Krebs cycle) Coenzyme A splits of from Acetyl CoA and is recycled For each pyruvate, this is produced: – 2 CO2 – 3 NADH – 1 ATP – FADH2 (an electron carrier) ***Remember, for each glucose molecule, there are 2 pyruvate produced, that means these products in Krebs cycle are doubled*** Citric acid cycle (Krebs cycle) Oxidative phosphorylation Step 3 of cellular respiration  Most ATP is produced by oxidative phosphorylation NADH and FADH2 contribute electrons to the ETC Oxygen accepts those electrons Electrons in the ETC allow hydrogen ions to be released into the intermembrane space of the mitochondrion Flow of hydrogen ions in chemiosmosis with the help of ATP synthase Oxidative phosphorylation makes about 28 ATP Cellular respiration review Fermentation  Fermentation produces energy without Oxygen Aerobic respiration utilizes oxygen to make ATP energy – Example: Oxidative phosphorylation in cellular respiration Anaerobic respiration does not require oxygen to make ATP – Example: Glycolysis and Fermentation  Lactic acid fermentation Regeneration of NAD+ Step 1: Glycolysis – Glucose is broken down to 2 pyruvate molecules – Makes 2 ATP – 2 NAD+ reduced to 2 NADH Step 2 – NADH oxidized back to NAD+ – Pyruvate reduced to lactate  When do we use lactic acid fermentation? When our bodies cannot deliver enough O2 to the bloodstream, muscle cells switch to lactic acid fermentation Example: intense exercise Within an hour, lactate is carried by blood to the liver → lactate converted to pyruvate  Real-life lactic acid fermentation Dairy industry – Lactic acid fermentation by bacteria to make cheese and yogurt Other types of fermentation – Soybeans → soy sauce  Alcohol fermentation Used in brewing, winemaking, and baking Yeast can carry out both aerobic and anaerobic respiration NADH reduced to NAD+, pyruvate converted to CO2 and ethanol – CO2 provides bubbles that appear in beer and champagne – CO2 causes bread to rise  Types of anaerobes Facultative anaerobes – Yeast and bacteria that can make ATP with or without O2 Example: our muscle cells Obligate anaerobes – Only carry out anaerobic respiration – Are poisoned by O2 How many NADH molecules are made during lactic acid fermentation? A. 1 B. 2 C. 3 D. None  https://www.youtube.com/watch?v=4Eo7JtRA 7lg https://www.youtube.com/watch?v=uixA8ZXx 0KU