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Flashcards by Angela Yianni, updated more than 1 year 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 wen chlorophyll absorb light? | Elections are excited to higher energy level,vthese 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 2 3 carbon molecules ATP and reduced NADP are used to produce GP and TP, NADP isreformed and returns to the light dependent reaction whilst 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 to hydrogen ions which can reduce two molecules NAD |
| why is the overall ATP yield only 2 | two molecules of atp are required to phosphorylate glucose, and only for 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, hydrogen ion is accepted by NAD, the resulting acetyl group combines with coenzyme a to produce acetyl coenzyme a and one carbon dioxidedioxide molecule |
| how does the krebs cycle produce to reduced hydron carriers and atp | acetyl coenzyme a combines with a full carbon molecule to produce a 6 carbon molecule this 6 carbon molecule losses 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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