2217494
Description
Flashcards by Charlotte Lloyd, updated more than 1 year ago
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Created by Charlotte Lloyd
almost 10 years ago
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| Question | Answer |
| Define energy: | The ability to do work |
| Why are the units of energy? | Joules, J |
| What does the body need energy for? | Metabolism Movement Active transport Maintenance, repair, division Production of substances (enzymes etc.) Maintainance of body themperature |
| How does energy flow through living systems? | Light energy converted by plants to chemical energy (glucose) by photosynthesis Chemical energy is converted into ATP during respiration ATP used to do work |
| Word equation for then hydrolysis of ATP | Adenine triphosphate + water = Andenine disphosphate + inorganic phosphate (+ energy) |
| Decribe how ATP is converted into ADP and ADP is converted into ATP | ATP is hydrolysed into ADP and inorganic phosphate, the ADP is then condensened (phosphorylated) into ATP |
| Name the three types of phosphorylation | Photophosphorylation Oxidative phosphorylation Substrate level phosphorylation |
| How are leaves adapted for photosynthesis | Large surface area Thin (short diffusion pathway) Transparent cuticle Long upper mesophyll with lots of chloroplasts Stomta (gas exchange) Xylem (transport water to leaf) |
| General equation for photosynthesis | 6carbon dioxide + 6water = Glucose + 6oxygen |
| How are the chloroplasts structured? | Grana = stacks of discs called thylakoids, connecting tubular extensions = lamellae. Stroma = fluid filled matrix, contain starch grains |
| What occurs when chlorophyll absorb light? | Elections are excited to higher energy level, these electrons leave the molecule and are taken up by an electron carrier |
| When the chlorophyll loses electrons is it oxidised or reduced? | Oxidised |
| How does the excitation of chlorophyll lead to ATP production? | Electrons pass along a number of electron carriers, in a series or redox reactions, each carrier is at a lower energy level so the electrons lose energy at each stage this energy is used to synthesis ATP |
| How is reduced NADP produced in the light dependent reaction? | The photolysis of water produces the electrons needed to replace those lost in the chlorophyll, this also produces hydrogen ions which reduce NADP |
| Equation for the photolysis of water: | 2Water (+light) = 4Hydrogen ions + 4Electrons + Oxygen |
| Why is the photolysis of water needed during the light dependant reaction? | To produce the electrons needed to replace those lost by the chlorophyll, also produces hydrogen ions to reduce NADP and oxygen |
| Where does the light dependant reaction take place? | Grana/Thylakoids of the chloroplasts |
| How are the thylakoids adapted for their function (light dependant reaction)? | Large surface area - for the attachment of chlorophyll, electron carriers and enzymes. Network of proteins, to hold chlorophyll in a way to maximise light absorption. Granal membranes contain enzymes for ATP synthesis. DNA and ribosomes - so chloroplasts can manufacture proteins needed |
| How does carbon dioxide enter the chloroplast? | Through the stomata of the leaf then into the stroma the chloroplast |
| How is carbon dioxide used to produce organic molecules (glucose) and regereratec RuBP in the calvin cycle | Carbon dioxide combines with a 5 carbon compound called RuBP producing two 3 carbon molecules; ATP and reduced NADP are used to produce GP and TP; NADP is reformed and returns to the light dependent reaction; some TP is converted to organic substances most is regenerated RuBP using ATP |
| Where does the light independent reaction take place? | In the stroma of the chloroplast |
| Why does the light independent reaction not take place in the absence of light? | The light independent reaction uses the products of the light dependent reaction |
| What is the law of limiting factors? | At any given moment the rate of a physiological process is limited by the factor that is at its least favourable value |
| What are two ways of measuring the rate of photosynthesis? | Measuring the volume of oxygen released by the plant; Or the volume of carbon dioxide taken up by the plant |
| If light intensity is the limiting factor how is it related to the rate of photosynthesis? | Rate of photosynthesis is directly proportional to intensity of light |
| What is the compensation point? | The point where the volume of oxygen produced and volume of carbon dioxide used by the plant is exactly balanced; no net production or loss of gas |
| How does carbon dioxide concentration affect the rate of photosynthesis? | Carbon dioxide concentration affects the enzyme activity thus increasing rate of photosynthesis |
| How does temperature affect the rate of photosynthesis? | Plants have an optimum temperature above this rate will decrease as the enzymes will become denatured |
| How and why is glucose phosphorylated? | Glucose is phosphorylated to make it more reactive the phosphate comes from the hydrolysis of ATP |
| How does phosphorylated glucose two molecules of pyruvate? | Phosphorylated glucose is split into two 3 carbon molecules of triose phosphate; the 2 triose phosphate molecules are oxidised; hydrogen ions are removed and transferred to a hydrogen ion carrier NAD; enzymes convert triose phosphate pyruvate producing 2 atp molecules |
| How are two molecules of reduced NAD produced? | Two molecules of triose phosphate are oxidised producing two hydrogen ions which can reduce two molecules NAD |
| Why is the overall ATP yield of glycolysis only two? | Two molecules of ATP are required to phosphorylate glucose, only four molecules of ATP are produced when two molecules of triose phosphate are converted into two molecules of pyruvate |
| Where does glycolysis take place? | In the cytoplasm of the cell |
| Why is glycolysis the only source of ATP in the absence of oxygen (anaerobic conditions)? | Glycolysis does not require oxygen to occur whilst all the other stages of respiration do require oxygen |
| Give the equation for the link reaction | Pyruvate + NAD + coenzyme A = acetyl coenzyme A + reduced NAD + carbon dioxide |
| Explain how the link reaction produces 2 molecules of carbon dioxide | First pyruvate is oxidised; two hydrogen ions are accepted by NAD; the resulting acetyl group combines with coenzyme a to produce acetyl coenzyme a; and one carbon dioxide molecule |
| How does the krebs cycle produce two reduced hydrogen carriers and ATP? | Acetyl coenzyme a combines with a four carbon molecule to produce a 6 carbon molecule; this 6 carbon molecule loses carbon dioxide and hydrogen to give the 4 carbon molecule these hydrogen ions are used to produce reduced hydrogen carriers, ATP is formed by substrate level phosphorylation |
| what is the overall yield for the link reaction and krebs cycle for one molecule of glucose | two reduced NAD molecules, two reduced FAD molecules, two ATP molecules and 6 carbon dioxide molecules |
| explain the significance of the krebs cycle | breaks down macromolecules into smaller ones produces hydrogen ions letter carried to the electron transport chain by oxidative phosphorylation leading to ATP production regenerate the 4 carbon molecule that combines with acetyl coenzyme a and isa source of intermediate compounds used by cells in the manufacture of other substances |
| why are hydrogen acceptors oxidised where do the protons and electrons | hydrogen atoms are released from the hydrogen carriers the atom split in two protons and electrons the electrons move along the electron transport chain |
| how is the energy lost at each electron acceptor used | To pump electrons from the matrix intuothe inter membrane space |
| how is an electrochemical gradient established | the concentration of protons in the intermembrane space is higher in the matrix |
| how does protons moving back into the matrix produce atp | protons move down at the electrochemical gradient back into the matrix via atp synthase this drive theory synthesis of atp from adp and inorganic phosphate |
| what is the name of the process which generates atp | chemo osmosis |
| how is water produced in the electron transport chain | in a matrix at the end of the electron transport chain the protons and electrons and oxygen combine to form water |
| why is oxygen described as the final proton accepter in the electron transport chain | oxygen combines with the protons to form water |
| what process can occur in anaerobic conditions | glycolysis |
| what is the equation for anaerobic respiration in plants and some microbe? | Pyruvate + reduced NAD = ethanol + carbon dioxide + NAD |
| how is ethanol produced from pyruvate in plants and some microbes | Pyruvate loses carbon dioxide and accepts hydrogen from reduced NAD to produce ethanol |
| What is the equation for anaerobic respiration in animals? | Pyruvate + reduced NAD = lactate + NAD |
| How is lactate produced from pyruvate in animals? | Pyruvate takes up two hydrogen atoms from the reduced NAD forming lactate |
| Why is lactate build up bad in humans? | Lactate is harmful,causes muscle cramps and fatigue |
| What is the energy yield from aerobic respiration? | Two molecules of ATP from every one molecule of glucose |
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