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Flashcards by Chelsi Souch, updated more than 1 year ago
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Created by Chelsi Souch
over 8 years ago
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| Question | Answer |
| Stroma | Fluid within the chloroplast |
| How many membranes enclose the mitochondrion? | two: 1. Outer smooth membrane 2. Inner membrane, which has cristae and the matrix |
| Describe the endosymbiotic hypothesis on the origin of Chloroplasts and Mitochondria | x |
| Chloroplasts are divided into three major compartments by internal membranes: | 1. the space between the two outermost membranes 2. the stroma, a thick fluid within the chloroplast, and 3. the space within grana, membrane-enclosed discs and tubes. |
| What is central to the processes that make energy available to the cell | Enzymes and membranes are central Chloroplasts carry out photosynthesis, using solar energy to produce glucose and oxygen from carbon dioxide and water Mitochondria consume oxygen in cellular respiration, using the energy stored in glucose to make ATP (chemical energy). Water is a byproduct in these reactions. Note: They are opposite processes! |
| Endosymbiotic hypothesis | Endosymbiont: An organelle considered to be a prokaryote engulfed by an Eukaryote (nucleus already present) -Mitochondria and chloroplasts in eukaryotic cells originated through symbiosis between multiple organisms, where one organism ‘engulfed’ free-living prokaryotes |
| Evidence for endosymbiosis | contain their own DNA, which encodes some of their proteins - small size, similar to the size of a prokaryote - have at least two membranes: inner and outer membranes - are not synthesized in the cell like ribosomes and lysosomes |
| The ingredients for photosynthesis are | • The ingredients for photosynthesis are carbon dioxide and water • CO2 is obtained from the air by a plant’s leaves (organs). - H2O is obtained from the damp soil by a plant’s roots (organs). • Chloroplasts rearrange the atoms of these ingredients to produce sugars (glucose) and other organic molecules. • Oxygen gas is a by-product of photosynthesis. |
| Cellular Respiration | Aerobic Harvest of Food Energy – Is the main way that chemical energy is harvested from food (produced by plants originally) and converted to chemical energy in ATP (usable form) -REQUIRES oxygen |
| The Relationship between Cellular Respiration and Breathing | • Cellular respiration and breathing are closely related. – Cellular respiration requires a cell to exchange gases with its surroundings. – Breathing exchanges these gases between the blood and outside air. |
| Where does cellular respiration occur? | Cellular respiration occurs in mitochondria. – Cellular respiration is a chemical process that harvests energy from organic molecules. • The waste products of cellular respiration, CO2 and H2O, are used in photosynthesis. |
| Equation for cellular respiration | C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP |
| Redox Reactions (Oxydation Reduction Reactions) | Chemical reactions that transfer electrons from one substance to another are called oxidation-reduction reactions or in short: REDOX reactions :REDOX REACTIONS: Definition – Loss of electron(s) from donor and gain of electron(s) by a receiver. |
| Redox reaction | |
| Why does electron transfer to oxygen release energy? | – When electrons move from glucose to oxygen, it is as though they were falling (high E to low E) – This “fall” of electrons releases energy during cellular respiration. – However, this fall is NOT due to gravitational pull but rather due to the FORCE (pull) of attraction by oxygen since it is the most electronegative atom found among biological molecules |
| Metabolism has two parts: | Anabolism: Synthesis Catabolism: Breaking |
| 3 stages of cellular respiration | Glycolysis (breakdown of Glucose) How to generate some ATP and reducing power TCA cycle (Tri Carboxylic Acid cycle, Kreb cycle) How to generate more ATP, generate a variety of C skeletons and more reducing power ETC (Electron Transport Chain) Way more ATP, Water as a by product, regeneration of NAD+ |
| NADH and Electron Transport Chains (ETC) | The path that electrons take on their way down from glucose to oxygen involves many steps. |
| Stage 1: Glycolysis | One molecule of glucose (6C) is split into two molecules of pyruvic acid (3C). |
| Describe in detail | |
| Glycolysis makes some ATP directly when .... | enzymes transfer phosphate groups from fuel molecules to ADP. This process is called, Substrate level phosphorylation |
| What are the net molecular products of Glycolysis, for each glucose molecule used? | •2 of ATP •2 of NADH •2 of Pyruvic acid • 2 H20 (waste) |
| Glycolysis Summary | • Is a metabolic pathway each step catalyzed by an enzyme and takes place in the cytoplasmic fluid of the cell • Harvests chemical energy by OXIDIZING 1 glucose (6C) molecule to form 2 pyruvate (3C) molecules. • Glucose is first energized by using ATP • Substratelevel Phospholylation makes ATP: an enzyme transfers phosphate group from a substrate molecule to 2 ADP to form 2 ATP (about 6% of energy of a glucose molecule) • Another source of energy, reducing power, NADH is also produced (provides another 16% of energy of glucose molecule, depending on the availability of O2 • Pyruvate is OXIDIZED prior entering the TCA cycle |
| Stage 2: The Citric Acid Cycle (TCA cycle or Kreb Cycle , Hans Krebs: 1930) | takes place in the Mitochondrial Matrix. • completes the breakdown of Glucose generating many of the two cofactors, NADH and FADH2 • In the citric acid cycle, pyruvic acid from glycolysis is first “groomed” into a usable form: a 2C Acetyl CoA (Acetyl coenzyme A) • “grooming” (oxidizing) also produces 1 NADH molecule per pyruate molecule (i.e. 2 NADH for a glucose molecule) |
| Grooming of Pyruvic Acid to Enter Mitochondria | |
| Stage 3: Electron Transport Chain (ETC) Oxidative Phosphorylation | • Electron transport releases most of the energy your cells need to make most of their ATP. • The molecules of electron transport chains (ETC) are built into the inner membranes of mitochondria. – The chain functions as a chemical machine that uses energy released by the “fall” of electrons to pump hydrogen ions across the inner mitochondrial membrane. – These ions (H+ ) store potential energy (as electrochemical potential gradient) |
| Mitochondrial Electron Transport Chain Oxidative Phosphorylation | |
| When the hydrogen ions flow back by facillitated diffusion through the membrane, they release | energy. – The ions flow through a membrane bound enzyme (protein) called ATP synthase. – ATP synthase takes the energy released from this flow (kinetic energy) and synthesizes ATP (potential energy) . – This process is called Chemiosmosis (Peter Mitchel in 1953 received the Nobel prize for discovering this process) |
| Cellular respiration can “burn” other kinds of molecules besides glucose: | Diverse types of carbohydrates – Fats – Proteins |
| Fermentation: | Some of your cells can actually work for short periods without oxygen. • Fermentation – Is the anaerobic harvest of food energy. • After functioning anaerobically for about 15 seconds, – Muscle cells will begin to generate ATP by the process of fermentation. |
| Evolution Connection: The Oxygen Revolution | The atmospheric oxygen we breathe is a by-product of photosynthesis. • Cyanobacteria were the first organisms to carry out photosynthesis. • The production of oxygen changed the Earth forever. – The “oxygen revolution” was a major episode in the history of life on Earth. |
| Almost all plants are photosynthetic autotrophs, as are some bacteria and protists (algae) | They generate their own organic matter through photosynthesis |
| Chloroplasts: Sites of Photosynthesis | Photosynthesis – Occurs in chloroplasts. • Chloroplasts – Are found in the interior cells of leaves. – Contain stroma, a thick fluid. – Contain thylakoids, membranous sacs |
| The Overall Equation for Photosynthesis | |
| Photosynthesis is composed of two processes: | The light reactions convert solar energy to chemical energy. Water molecules are used as electron donors at this stage – The Calvin cycle (“dark reaction”) makes sugar (Glucose) from carbon dioxide using the chemical energy the light reactio |
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