Cellular Respiration
Role of Oxygen in CR:
it acts as the final receptor of electrons in the electron transport chain and chemiosmosis process, the final step of cellular respiration
Name the 3 main stages of cellular respiration and state the specific region in the cell where each stage occurs
1. Glycolysis: cytosol 2. Citric acid cycle: mitochondrial matrix 3. Electron transport chain: within inner mitochondrial membrane
Electron transport chain overview
1st part of stage 3 of cellular respiration Location: inner membrane What happens: NADH and FADH2 are shuttled along the ETC to oxygen, the final electron acceptor. Proteins in the ETC use energy from released electrons to shuttle H+ against concentration gradient into the inner membrane space
Where/how is ATP produced?
ATP can be produced by various cellular processes, most typically in mitochondria by oxidative phosphorylation under the catalytic influence of ATP synthase or in the case of plants in chloroplasts by photosynthesis.
Structure of ATP
ATP consists of adenosine and three phosphate groups. It has the empirical formula C10H16N5O13P3
role of ATP in metabolism
ATP transports chemical energy within cells for metabolism. It is one of the end products of photophosphorylation, cellular respiration, and fermentation and used by enzymes and structural proteins in many cellular processes, including biosynthetic reactions, motility, and cell division.
What does ATP stand for?
Adenosine Tri Phosphate
Stages of cellular respiration
Glycolysis - The Citric Acid Cycle-Electron Transport Reactions- Creation of ATP
relationship between photosynthesis and cellular respiration
Althought not directly reversible reactions, celllular respiration and photosynthesis share many of the same key players and similar concepts. Both pathways have many redox reactions as electrons are taken from some molecules and given to others. In general, photosynthesis is an anabolic pathway that builds up more complex organic molecules from simpler ones, storing energy in the bonds of those complex molecules that originally came from the sun. Oxygen is produced as a byproduct. Cellular respiration is a catabolic pathway that breaks down the complex molecules into smaller ones and in the process, liberates the large amount of bond energy of glucose and banks it into smaller, usable molecules (ATP). It requires oxygen produced in photosynthesis to complete this process the most efficiently.
What is the electron transport chain?
An electron transport chain (ETC) is a series of compounds that transfer electrons from electron donors to electron acceptors via redox reactions, and couples this electron transfer with the transfer of protons (H+ ions) across a membrane.
Where does cellular respiration occur?
In eukaryotes, glycolysis occurs in the cytosol.. The remaining processes take place in mitochondria.
Chemical Formula of ATP
C10H16N5O13P3
Chemical equation for cellular respiration
C6 H12 O6 + 6O2 ------> 6CO2 + 6H2O + ATP + Heat
Goal of cellular respiration
Cell respiration is a series of chemical reactions in which the overall goal is to break down large, energy rich macromolecules and release the stored energy in order to make many ATP molecules which can each be used to power cell jobs
Summary of cellular respiration
Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water.The energy released is trapped in the form of ATP for use by all the energy-consuming activities of the cell. C6H12O6 + 6O2 + 6H2O → 12H2O + 6 CO2
What is cellular respiration?
Cellular respiration is the set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
Heterotrophs
Consume other energy
Function of ATP
Energy is released by hydrolysis of the third phosphate group. After this third phosphate group is released, the resulting ADP (adenosine diphosphate) can absorb energy and regain the group, thus regenerating an ATP molecule; this allows ATP to store energy like a rechargeable battery.
Write the summary equation for cellular respiration.
Glucose + oxygen ----> carbon dioxide + water + energy (ATP & heat)
Glycolysis
Glycolysis (from glycose, an older term for glucose + -lysis degradation) is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+.
What occurs in the citric acid cycle?
In glycolysis, the glucose was oxidized to pyruvate. In the citric acid cycle, the pyruvate will be further broken down to carbon dioxide. And it will result in more prize tickets (ATP), but we'll also end up with two other compounds that can be converted to ATP: NADH and FADH2.
Chemisomosis
Location: inner membrane space, inner membrane, matrix What happens: energy from H+ concentration in inner membrane space drives H+ through ATP synthase, which activates catalytic sites that attach a phosphate group to ADP to form ATP
Autotrophs
Make their own food
Function of mitochondria in cellular respiration
Mitochondria are membrane-enclosed organelles distributed through the cytosol of most eukaryotic cells. Their number within the cell ranges from a few hundred to, in very active cells, thousands. Their main function is the conversion of the potential energy of food molecules into ATP.
Structure of mitochondria
Mitochondria have: an outer membrane that encloses the entire structure an inner membrane that encloses a fluid-filled matrix between the two is the intermembrane space the inner membrane is elaborately folded with shelflike cristae projecting into the matrix. a small number (some 5-10) circular molecules of DNA
Steps of Glycolysis
Occurs in cytoplasm Breaks glucose into 2 molecules of pyruvate Initial series of endergonic reactions requiring ATP Second series of exergonic reactions makes a net 2 molecules of ATP for every glucose ATP is made by substrate level phosphorylation Some electrons from glucose are also transferred to electron shuttle NAD+,, reducing it to NADH with the help of dehydrogenase
In overall terms, describe what is occuring in cellular respiration and why it is so vital for organisms.
Organisms have countless energy needs in their cells such as building larger molecules from smaller, pumping ions against their concentration gradients in and out of cells, contracting muscle proteins, etc. Each of these activities requires only a small bit of cellular energy. Large complex food molecules such as glucose have a great deal of chemical energy in their bonds. To use one of these molecules to power each cell's jobs would be overkill and would waste most of the bond energy. Cellular respiration is a process that allows the gradual breakdown of all the bond energy in glucose and turns it into many, smaller packets of more usuable energy (ATP molecules).
Explain why the citric acid cycle is called a cycle.
Overall, it is a cycle because the sugar that begins the cycle by combing with acetyl CoA will eventually be made again by the end of the cycle. Several steps occur in which carbon dioxide is produced and high enegy electrons are given to electron shuttles (NAD+ and FAD) for use in the ETC and ATP is made by substrate level phosphorylation. Eventually, the products of these steps regenerates the same sugar to be used again as the cycle turns again.
Define oxidation and reduction and gives examples of a redox reaction.
Oxidation is the loss of electrons from a molecule. Reduction is the gaining of electrons. In cellular respiration, glucose is oxidized to carbon dioxide as electrons are taken away from it and given to oxygen which is reduced.
Role of Carbon Dioxide in CR:
Product of CR
Glycolysis Overview
Stage 1 of cellular respiration Location: cytoplasm What happens: glucose is broken down into 2 molecules of pyruvate (2 3-carbon compounds) Reactant: 1Glucose Products: 2Pyruvates Produces: 2 ATP, 2 NADH (net)
Citric Acid Cycle Overview
Stage 2 of cellular respiration Location: matrix of mitochondria What happens: completes breakdown of carbon dioxide, makes small amounts of ATP, provides electrons
Oxidative Phosphorylation Overview
Stage 3 of cellular respiration Location: inner membrane and inner membrane space of mitochondria What happens: electron transport chain, chemiosmosis; energy from electrons--> produces 32 ATP
Role of Glucose in CR:
Starting molecule for CR: Provides the Energy
Role of water in CR:
The hydrogen atoms come from water to make glucose
Fuel of ATP
The main fuels for ATP synthesis are glucose and fatty acids. Initially glucose is broken down into pyruvate in the cytosol. Two molecules of ATP are generated for each molecule of glucose. The terminal stages of ATP synthesis are carried out in the mitochondrion and can generate up to 34 ATP.
Process of cellular respiration
The process occurs in two phases: glycolysis, the breakdown of glucose to pyruvic acid the complete oxidation of pyruvic acid to carbon dioxide and water
Function of The Citric Acid Cycle aka the Krebs Cycle
The tricarboxylic acid cycle (TCA cycle) is a series of enzyme-catalyzed chemical reactions that form a key part of aerobic respiration in cells. This cycle is also called the Krebs cycle and the citric acid cycle.
Describe the role of NAD+ and FAD in cellular respiration.
These molecules serve as electron shuttles or carriers. They oxidize more complex molecules such as glucose and take those electrons to the electron transport chain in order to allow the extraction of energy in a slow, controlled manner which makes the maximum amount of ATP molecules.
Products of Each Stage in Cellular Respiration
glycolysis: 2 ATP (produces 4 but uses 2), 2 Pyruvate, 2 NADH Formation of Actyl CoA: 2 Acytl CoA, 2 Carbon Dioxide Citric Acid (Krebs) Cycle: 2 ATP, 6 NADH, 2 FADH2, 4 CO2 Electron Transport Chain: 32 ATP and H2O
Citric Acid Cycle Steps
takes in acetlyl co-A (manufactured from glucose) and oxaloacetate to form citric acid (aka citrate), which is very high in energy. The citric acid gradually loses that energy, partly as CO2 (a waste product) and partly as GTP and NADH and FADH2, which go on to produce ATP, which is used to power many of the actual operations in the body.
All the energy in ATP is stored in:
the bonds of atp molecule
