Bio 110 test 2
describe the importance of activation energy and how it can be altered
activation energy: an initial input of energy in a chemical reaction that allows the molecules to get close enough to cause a rearrangement of bonds
explain the various ways in which enzymes increase the rate of biological reactions
-enzymes, which are proteins that act as catalysts lower the activation energy in a reaction, which speeds it up -enzymes lower the activation energy is by straining the bonds of the substrates (reactants), which is like stretching them to change the shape to make it easier for the reaction to take place. -enzymes provide a place for two or more substrates to meet so that when they get together they can react (straining the reactants and bringing them close together are two commons ways that enzymes lower the activation energy barrier. also enzymes may facilitate a chemical reaction by changing the local environment of the reactants.
1.Explain the general reaction for photosynthesis in terms of water, light, oxygen and carbon dioxide and carbohydrate
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10.Explain how the Calvin cycle produces glucose.
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11.Explain the action of rubisco in oxidizing RuBP.
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12.Compare and contrast major variations in photosynthesis, including the conditions under which these variations are most likely encountered.
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13.Describe the path of energy from sunlight to covalent bonds formed during the light reactions of photosynthesis.
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14.Describe the path of energy from the light reactions through the Calvin Cycle
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3.Explain the difference between the light reactions and the Calvin cycle
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4.Explain how pigments are important to photosynthesis
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5.Relate the absorption spectrum of a pigment to its color
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7.Explain how the light reactions generate ATP and NADPH.
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8.Explain the molecular basis of energy generated as a result of electron transport
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9.Describe what is meant by the term 'carbon fixation.' What portion of photosynthesis is used for carbon fixation ?
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Compare the overall amount of ATP produced by the complete metabolic breakdown of one molecule of glucose under aerobic conditions with the ATP produced from the breakdown of one glucose molecule under anaerobic conditions.
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Describe fermentation in plant and animal cells and explain the importance of this process in terms of energy harvest and ATP production.
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Describe glycolysis in general terms, including the molecules that exist at its start and its end, as well as its net versus total ATP production.
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Describe how the NADH molecules produced during glycolysis are oxidized back to NAD+ under aerobic and anaerobic conditions and explain why this oxidation is important to glucose metabolism and ATP production.
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Describe the chemical relationship between the glucose molecules used by cells as fuel and the carbon dioxide generated by the same cells as waste.
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Describe the structure of ATP and explain how ATP makes a wide variety of thermodynamically unfavorable cellular process possible
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Explain how the electron transport chain uses the high energy electrons harvested originally from glucose to provide the direct source of energy used by ATP synthase to make ATP.
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Explain the difference in the Calvin Cycle and Hatch-Stack Pathway in C3 & C4 plants.
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Explain why the NADH produced in glycolysis and the NADH and FADH2 produced in the Krebs cycle differ from one other in the amount of energy they provide for the production ATP by oxidative phosphorylation.
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Trace the path of high-energy electrons from glucose to water in aerobic respiration
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compare the function of the two photosystems in green plants.
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Explain where the specific locations of the (above) pathways in a generalized eukaryotic cell.
1. glycolysis: glucose is broken down to two pyruvate molecules. occurs in the cytosol 2. Breakdown of the pyruvate: two pyruvate molecules enter the mitochondrial matrix where each one is broek down to the acetyl group and one CO2 molecule (one NADH molecule is made by the reduction of NAD+) 3. Citric acid cycle: each acetyl group is incorporated into an organic molecule... (occurs in the mitochondrial matrix) 4. oxidative phosphorylation: the overall process of electron transport and ATP synthesis is called oxidative phosphorylation because NADH or FADH2 have been oxidized and ADP had become phosphorylated to make ATP (occurs in the cristae which are invaginations of the inner mitochondrial membrane)
Explain how oxidation and reduction are interrelated in chemical reactions p 139
First, remember OIL RIG (oxidation is loss, reduction is gain). oxidation: a process that involves the removal of electrons; occurs during the breakdown of small organic molecules (has less energy) reduction: a process that involves the addition of an atom or a molecule (has more energy) When one thing is oxidized, some of its electrons are lost, but they don't just disappear. They are gained by another substance, meaning that one is reduced. So oxidation and reduction always happen together.
Describe the distinct metabolic pathways used by cells to harvest the energy stored in glucose under aerobic conditions.
Process by which living cells obtain energy from organic molecules primary aim to make ATP and NADH Aerobic respiration uses oxygen O2 is consumed and CO2 is released
Explain the First and Second Laws of Thermodynamics and describe how they reflect the existence and behavior of energy in the universe.
The first law of thermodynamics (conservation of energy) states that energy cannot be created or destroyed. However, energy can be transferred from one place to another and can be transformed from one type to another. The second law of thermodynamics states that any energy transfer or transformation from one form to another increases the degree of disorder of a system called entropy (measure of the randomness of molecules in a system) when a physical system becomes disordered the entropy increases. as the energy becomes more evenly distributed that energy is less able to promote change or do work. when energy is converted from one form to another some energy may become unusable by living organisms.
Explain the relationship between anabolic and catabolic pathways in metabolism and describe the storage and release of energy in the forms of ATP and NADH
catabolic reactions: result in the breakdown of larger molecules into smaller ones, usually releasing energy. results in the breakdown of macromolecules into smaller ones anabolic reactions: a metabolic pathway that involves the synthesis of larger molecules from smaller precursor molecules. such reactions usually require an input of energy (usually endergonic) and must be coupled with exergonic reactions. to obtain the energy for the proton gradient you have to break the hydrogen and electron from NADH and then use the H to make ATP. You are breaking down a molecule and in turn using the energy to build a molecule (ATP) Chemical reactions are often coordinated with each other and occur in sequences called metabolic pathways, each step of which is catalyzed by a specific enzyme. These pathways are categorized according to whether the reactions lead to the breakdown or synthesis of substances.
2.Describe the structure of the chloroplast.
chloroplasts are organelles found in plant and algal cells that carry out photosynthesis; these organelles contain large quantities of chlorophyll (pigment that gives plants their green color).. all green parts of a plant contain chloroplasts and ca.,n perform photosynthesis (although a majority of photosyn. occurs in the leaves.
Explain the energy requirements of endergonic and exergonic reactions.
endergonic: a reaction that has a positive free-energy change requiring the addition of free energy from the environment exergonic:spontaneous; if a chemical reaction has a negative free-energy change, the products have less free energy that the reactants and free energy is released during product formation
Define enthalpy, entropy, and free energy and describe how these concepts affect the fate of chemical reactions.
enthalpy(H): the total energy of a system entropy(S): the degree of disorder in a system free energy(G): in living organisms, the amount of available energy that can be used to do work - G=H-TS (T=absolute temperature in Kelvins)
Describe the three major ways cells regulate metabolic pathways. p 130
gene regulation: the ability of cells to control their level of gene expression (turn off genes needed to do something with something that is not available but when it comes available and the gene is needed then it will turn on) Cellular Regulation: ells integrate signals from their environment and adjust their chemical reactions to adapt to those signals Biochemical Regulation: the noncovalent binding of a molecule to an enzyme directly regulates its function (feedback inhibition in which the product of a metabolic pathway inhibits an enzyme that acts early in the pathway which prevents the over accumulation of the product
define competitive inhibition, noncompetitive inhibition, and activation and explain how each relates to the active and allosteric sites
inhibition: a mechanism for succession in which early colonists exclude subsequent colonists competitive inhibition: a molecule that binds (noncovalently) to the active site of an enzyme and inhibits the ability of the substrate to bind.. competing with the substrate for the ability to bind to the substrate; usually have a structure or a portion of their structure that mimics the structure of the enzyme's substrate. noncompetitive inhibition: a molecule that binds (noncovalently) to an enzyme that is outside the active site (which is called the allosteric site) and inhibits the enzyme's functions active site: is the location in an enzyme where the chemical reaction takes place allosteric site: a site on an enzyme where a molecule can bind noncovalently and affect the function of the activation site
Differentiate between kinetic and potential energy
kinetic energy: energy of motion. something that is currently in motion potential energy: the energy of state or position something that is not in motion that could be set into motion
