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Bio Test 5
Cell Resp. and Photosynthesis
| Question | Answer |
|---|---|
| What are the three metabolic stages of cell respiration? | 1. Glycolysis 2. Citric cycle 3. Oxidative phosphorylation |
| Define Cellular Respiration | A metabolic process that requires oxygen |
| Define Glycolysis: | Cells get energy from glucose through glycolysis to produce starting material for citric acid cycle |
| Does glycolysis require oxygen? | No |
| Glycolysis and Citric Acid clycle break down what? | Breakdown glucose and other organic fuels |
| Where does glycolysis occur? | cytosol |
| How does glycolysis begin the degradation process? | by breakiing down glucose into 2 pyruvates |
| Where does the citric acid cycle occur? | Mitochondiral matrix |
| How does the citric acid cycle complete the breakdown of glucose? | By oxidizing a derivative of pyruvate to CO2. |
| What does the CO2 from the citric acid cycle represent? | fragments of oxidized organic molecules. |
| What kind of reactions are included in the CAC and Glycolysis? | Redox reactions |
| What happens in the reactions of CAC and Glycolysis? | Dehydrogenous enzymes transfer electrons from substrates to NAD+, forming NADH |
| Where does oxidative phosphorylation occur? | In the inner membrane of the mitochondria |
| What are the two processes of oxidative phosprylatioN? | Electron transport and chemiosmosis |
| What percent of the ATP generated by the cell occurs in Oxidative phossphorylatioN? | 90% |
| What about the other percentage of ATP generated by the cell? Where does it come from? | it is made directly in a few reactions of glycolysis and the CAC by substrate level phosphorylation |
| How does the ATP generated by CAC and Glycolysis form? | Direct enzymatic transfer of phosphate group from an organic substrate to ADP |
| Oxidative phos: | Electron transport chain accepts electrons from the breakdown products of the first two stages (mostly NADH) and passes electrons from one molecule to another |
| What happens to the elctrons of oxidative phos at the end of the chain? | Electrons are combined with oxygen and hydrogen ions to form water |
| In each step of the chain, how is the energy output stored? | In a form the mitochondria can use to make ATP |
| What is inputed in glycolysis? | 1. 6 carbone sugar (glucose) split into 2, 3 carbon sugars |
| What happens to the smaller sugars in glycolysis? | oxidized and their remiaining atoms rearrange to form 2 pyruvates |
| What is the output of glycolysis? | 2 molecules of pyruvate |
| What is the energy investment phase of glycolysis? | The cell spends or used ATP- |
| Energy payoff phase? | ATP produced by substrate level phosphorylation and NAD+ is reduced to NADH by electrons relased from oxidation of food |
| What much ATP is outputted per glucose? | 2 ATP and 2 NADH |
| What does phosphorylation do in glycolysis? | Traps glucose inside cell |
| What's another name for pyruvate? | Pyruvic acid |
| summarize the first step of pathways of glycolysis | 2 ATPs are required |
| Second step of glycolysis? | 2 NAD makes 2 NADH |
| Third step | Two ADP+2pyruvates=2 ATP |
| Another name for Citric acid cycle | Kreb's cycle |
| What does cac complete? | Completes oxidation of organic molecules |
| What happens when oxygen is present in glycolysis? | chemical energy in pyruvate and NADH is extracted by the cac and oxidative phos |
| CAC with oxygen | two pyruvate molecules from glycolysis enter the mitochondria via active transport--enzymes of CAC complete oxidation of organic fuel |
| What happens to the pyruvate in the mitochondria? | Converted to Acetyl Coenzyme A |
| What does acetyl CoA do? | links the CAcycle to glycolysis |
| What does the CAC function as? | A metabolic furnace that oxidizes organic fuel made from pyruvate |
| What is the input in CAC? | Acetyl CoA |
| What does CAC produce? | 1 ATP 3 NADH 1 FADH2 |
| What does each step of the CAC require? | catalyzed by a specific enzyme |
| What is the first step of the CAC? | 2 carbons enter in the relatively reduced form of acetyl group |
| What are the second and third steps of CAC? | two different carbons leave in the completely oxidized form of CO2 |
| What is the fourth step of CAC? | The acetyl group joins the cycle by combining with oxaloacetate--citrate |
| What are the last seven steps of CAC? | To decompose citrate back to oxaloacetate |
| How does NADH form/ | In steps 3,4,8, 3 NAD+ reduced to 3 NADH |
| How does FADH2 form? | Step 6, electrons are transferred to FAD to make FADH2 |
| How does ATP form in CAC? | GTP is formed by substrate level phosphorylation of GDP (step 5), which is used to make ATP |
| How does the Electron transport chain get electrons? | After NADH and FADH2 are produced by CAC, they relay electrons extracted from food to it |
| NADH and FADH2 supply what? | Energy to phophorylate ADP to make ATP |
| Chemiosmosis? | Couples ETC to ATP synthesis in oxidative phophorylation |
| What happens to the electrons from NADH and FADH2? | Lose nergy in several steps |
| What happens at the end of the ETC? | Electrons passed to oxygen to make water |
| Where does the ETC occur and what is it made of? | Linked series of proteins in the cristea of mitochondria |
| What are the protiens made of? | FMN, coenzyme Q, and cytochromes |
| What happens to the proteins as they accept electrons? | They are reduced, As it gives electrons to next protein, it is oxidized; exothermic reaction |
| Does ETC make ATP? | NO, not directly? |
| What is ETC's function? | To ease the fall of electrons from food to oxygen |
| How does it ease the fall of electrons? | Breaking a large free-energy drop into a series of smaller steps that release manageble amounts of free energy |
| What does the mitochondria do after ETC? | Couples ET and energy release to ATP synthesis by chemiosmosis |
| ATP Synthase | Enzyme that makes ATP from ADP and inorganic phosphates |
| how does ATP synthase work? | Uses existing ion gradient to power ATP synthesis |
| what is the gradient in ATP synthase? | difference in proton gradient |
| What does electron transfer cause in chemiosmosis? | protein complexes to pump hydrogen ion from the mitochondrial matrix to the intermembrane space |
| What about the resulting hydrogen ion gradient? | Stores energy, drives chemiosmosis in ATP synthase, is refered to as a proton motive force |
| How does ETC work? What is the first step? | A rotor within the membrane spins clockwise when H+ flows past it down the gradient |
| Second step of ETC? | stator anchored in the membrane holds the knob stationary. |
| 3rd ETC step? | A rod (for “stalk”) extending into the knob also spins, activating catalytic sites in the knob. |
| 4th ETC Step? | Three catalytic sites in the stationary knob join inorganic |
| Chemiosmosis? | Energy coupling mechanism that uses energy in the form of H+ gradient across a membrane to drive cellular work |
| What powers Chemiosmosis? | flow of H+ back across membrane |
| In which sequence does cell respiration flow? | Glucose, NADH, ETC (oxidative phosphorylation), Proton pump, and then to ATP |
| How much ATP is produced by oxidative phospohyrlatioN? | 32-34 |
| What is the maximum amount of ATP produced per glucose? | 36-38 |
| Fermentation? | Enables some cells to produce ATP without oxygen |
| What does fermentation consist of? | Reactions that regenrate NAD+, and glycolysis |
| What happens in alcohol fermentation? | pyruvate is converted to ethanol in two steps, one of which releases carbon dioxide |
| What happens in lactic acid fermentation? | pyruvate reduced directly to NADH to form lactate, occurs when we breakdown sugar faster than we can get oxygen from blood to go through cellular respiration |
| What is a similarity between fermentation and cellular respiration? | use glycolysis to oxidize glucose and other organic fuels to make pyruvate |
| How do they differ? | In their final electron accepter |
| What is the key juncture that determines what happens after glucose is broken down? | pyruvate |
| Does the oxidative breakdown of glucose occur seperatly? | No |
| Where do most of our calories come from? | fats, proteins, sucrose, and startch(polysachrides) |
| Catobolic pathways do what for electrons? | funnel electrons from many kinds of organic molecules into cellular respiration |
| What happens in the digestive tract? | starch is hydrolyzed to glucose--->glycolysis--->CAC |
| What happens in liver and muscle cells? | glycogen is hydrolyzed to glucose between meals-->glycolysis-->CAC |
| how does sucrose get broken down? | Gets broken down into glucose and other monosachs-->glycolysis-->CAC |
| When can proteins be used for fuel in cell respiration? | they must be digested to their building blocks, amino acids |
| What happens to the amino acids we consume in our diet? | are used by our cells to build new proteins |
| What happens when too many amino acids exist? | They are converted by enzymes into intermediates of glycolysis and CAC |
| Deamination: | A process where the amino groups (nitrate) of amino acids are removied |
| How is the amino group extreted? | Urea, ammonia |
| What can catabolism do in the cell (harvesting?) | can harvest energy stored in fasts from food or from storage cells in the body |
| What are fats digested into? | glycerol-->glyceraldehyde-3phosphate (which can enter glycolysis as an intermediate) |
| What else are fats digested into? | Fatty acids--most of energy in fat comes from fatty acids |
| Beta oxidation: | Breaks down the fatty acids into 2 carbon fragments that enter CAC as Acetyl CoA |
| Which is the best type of fuel that enters the body? | Fats, (it makes twice as much energy as 1 gram Carbs) |
| Do all organic molecules of food become oxidized to make ATP? | NO |
| What else does food provide? | A carbon skeleton that cells need to make their own molecules |
| What are anabolic pathways also known as? | Biosynthesis |
| What is an example of when organic monomers obtained from digestion are used to synthesize molecules? | Amino acids from hydrolysis of proteins in food--into a cell's own proteins |
| Where doe the small molecules the body builds on come from? | food, or glycolysis or CAC |
| What is an example of an intermediate formed in CAC that is diverted inrto anabolic pathways? | Humans make about half of the 20 amino acids in proteins by modifying compounds shuttled out of the CAC |
| Feedback mechanisms: | Regulate cellular respiration |
| Feedback inhibition: | The end product inhibits at starting step of pathway |
| How does the cell control catabolic pathways? | if a cell is working hard and its ATP concentration drops, respiration speeds up to make more ATP |
| What is regulation mainly based upon? | Controling the activity of enzymes at strategic points in the catabolic pathway |
| Phsphofructokinase | An important switch that controls catabolism speed (pacemaker) Enzyme that catalyzes step 3 of glycolysis, |
| Photosynthesis: | process that converts solar energy into chemical energy |
| Producers of biosphere: | Self feeders like plants and autotrophs |
| Photoautotrophs: | use energy of sunlight ot make organic molecules from water and Carbon Dioxide |
| Photosynthesis: | occurs in plants, algae, protists, prokaryotes |
| Heterotrophs: | Consumers, obtain materia from other organisms |
| Chloroplasts: | Sites of photosynthesis in lants |
| Chlorophyll: | Green pigment located within chloroplasts--give color |
| Mesophyll: | Tissue in the interior of the leaf |
| Stomata: | Microscopic poers that allow CO2 to enter the leaf and allow oxygen to exit |
| Veins: | Water absorbed by the roots is delivered to the leaves by the veins |
| what are the major sites of Photosynthesis: | leaves of plants |
| Chloroplasts and what do they contain? | Organelles in which photosynthesis occurs, and contain thylakoids and grana |
| What is the overall equation of photosynthesis? | 6CO2+6H20+light energy-->C6H12O6+6 O2 |
| What is important to note about the photosynthesis equation, in relation to the cellular respiration equation? | they are opposites |
| In plant cells: | Both cell respiration and photosynthesis occurs |
| Chloroplasts split water into: | Into hydrogen and oxygen, incorporating the electrons of hydrogen into sugar molecules |
| Cell respiration: | energy is released from sugar when electrons associated with hydrogen are transported by carriers to oxygen--forming water as a by-product |
| Water is split: | Electrons are transfered along with hydrogen ions (h+) from water to CO2, reducing itto sugar |
| What happens to the electrons as they more from water to sugar? | Increase in potential energy |
| The transfer of electrons from water to sugar requires... | Energy, provided by light |
| Photosynthesis is what sort of a process (reaction) | Redox, water is oxidized, carbon dioxide is reduced |
| What is the first stage of photosynthesis? | Light reactions--occur in thylakoids of chloroplasts |
| What is the second stage of photosynthesis? | Calvin cycle--occurs in stroma |
| Light reactions: | The steps that convert solar energy to chemical energy |
| What are the steps involved in light reactions: | Split water, relase oxygen, produce ATP, and form NADPH |
| Light absorbed by chlorophyll drives | a transfer of electrons and hydrogen from water (H2O) to an acceptor called NADP+ |
| NadP+: | Nicotinamide adenine dinucleotide phosphate--temporarily stores the energized electrons |
| Light reactions of photosynthesis | give of O2 as a byproduct |
| Light reactions use solar energy...to? | Use solar energy to reduce NADP+-->NADPH, by adding a pair of electrons along with H+ |
| Light reactions also generate ATP, How? | By using chemiosmosis to power the addition of a phosphate group to ADP--phosphorylation |
| Light energy is initially converted to chemical energy in the form of two compounds, what are they? | NADPH: A source of energized electrons, and ATP: Energy Source of all cells |
| Galvin Cycle: | Forms sugar from carbon dioxide using ATP for energy and NADPH for reducing power |
| How does the calvin cycle begin? | by incorpporating CO2 from the air--> into organic molecules already present in chloroplasts |
| Carbon fixation: | Initial incorporation of carbon into organic compounds |
| What happens after carbon fixation? | The calvin cycle reduces the fixed carbon to carbohydrate by the addition of electrons--power for this is provided by NADPH from light reactions |
| How can the calvin cycle make sugar? | With the help of NADPH and ATP produced by light reactions |
| Calvin cycle is a light requiring one? | No, it's a dark reaction |
| Chloroplasts use light energy to make.. | sugar by coordinating the two stages of photosynthesis |
| Light reactions convert | solar energy to the chemical energy of ATP and NADPH |
| Light: | A form of energy known as electromagnetic energy or electromagentic radiation |
| Electromagentic energy travels in: | Rythmic waves like thos created by dropping a pebble into a pond |
| Wavelength: | Is the distance between the crests of waves and determines the type of electromagnetic energy |
| The visible spectrum includes what two things/ | Includes the colors of light we can see, and the wavelengths that drive photosynthesis |
| Pigments: | Are the substances that absorb visible light (Light receptors) |
| Chlorophyll A: | Main photosynthetic pigment |
| Chlorophyll b: | An accessory pigment |
| Other pigments: | Absorb different pigments of light and pass the enrgy to chloro A |
| What happens when a pigment absorbs light? | Goes from a ground state to an unstable, excited state |
| When a solution of chlorophyll is illuminated? | It will fluoresce, giving off light and heat |
| When light is broken, we get a: | Photon |
| A photosystem is composed of a: | Reaction center surrounded by a number of light harvesting complexes |
| Each light harvesting comples consists of | Pigments( chlrophyll a and b and carotenolds bound to proteins |
| In a diagram, the light complexes are: | The little circles in the cell |
| A photosystem: | A light harvesting complex consisting of pigment molecules bound to particular proteins that funnel energy of photons of light to the reaction center |
| When a reaction center's chlorophyll molecule absorbs energy: | one of its electrons gets bumped up to a primary electron acceptor |
| The thylakoid membrane: | Is populated by two types of photosystems: PS1 and PSII |
| Which functions first? PSI or II? | II |
| what is the characteristic reaction center? | A particular kind of primary electron acceptor next to a pair of special chlorophyll a molecules associated with specific proteins |
| Noncyclic electron flow? | Primary pathway of energy transformation in the light reactions |
| Chloropyhll A: | Will get absorption of e-will be absorbed here, and O2 will be given off |
| Chain of proetins will join | PSII to I |
| A Photon of light strikes a pigment molecule in a | light harvesting complex and is relayed to other pigment molecules until it reaches 1 of the 2 p680 chlorophyll a molecules in the PSII reaction center--It excited one p680 e-s to a higher energy state |
| primary electron acceptor | captures excited electron |
| Water is split into | two electrons, 2 hydrogens, and one oxygen |
| How does the photoexcited electron pass from the primary electron acceptor? | Via the ETC |
| Light harvesting complex to the PSI reaction center get light energy, and this does what? | Excited the electron of one of the 2 p700 chlorophyll a molecules |
| What happens to the photoexcited E-: | Gets captured by PS I's primary electron acceptor, creating a hole in p700 |
| How is the hole filled? | Electron reached bottom of ETC |
| The protein ferredoxin(fd) | serves to help pass photoexcited electrons through second electron transport chain |
| NADP+ serves to: | Transport electrons from Fd to NADP+ |
| To make NADPH | Two electrons are required to reduce NADP+ |
| Light reactions use solar power to generate ATP and NADPH, and they provide, | chemical energy and reducing power to the sugar making reaction so fthe calvin cycle |
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talkglitter2486
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