Metabolism and energyThe cell theory is that the basic structural and functional unit of life is a cell. Each of you began as a cell from a zygote. Even a whale starts as a single microscopic cell. From that original zygote you just increase identify a hydrolysis reaction is anabolic or catabolic number of cells. An amoeba is a single celled protozoa that lives in pondwater. The rounder identify a hydrolysis reaction is anabolic or catabolic on the right is a typical human cell taken from inside someones cheek. Despite hydrolydis drastically different they look and the different environments they live in, there are a lot of similarities between all living cells.
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BioChem Exam 2. Describe the meaning of the term metabolism in the context of biochemistry. How is this definition different from the way the word metabolism is used in "every day life"? Metabolism is the sum of all the catabolic anabolic or biosynthesis pathways that exist at the cellular level. People think metabolism is the rate at which your body digests food.
The reaction is unfavorable. It also suggest that the cell must have a way of making this reaction occur through coupling or regulation of concentrations of the products and the reactants. If two reactions are coupled, what does that mean?
When reactions are coupled, it indicates that an unfavorable reaction is joined in a simultaneous process of a more favorable reaction. Describe the relationship between anabolic and catabolic pathways. Anabolic pathways are also known as biosynthetic pathways which build up.
Anabolic reactions create complex compounds which require energy. Catabolic reactions break down and release energy. Catabolic reactions provide the energy for anabolic reactions to occur.
Some athletes take creatine supplements. Explain how taking creatine could potentially improve someone's athletic ability without providing this energy directly. This allows athletes to train for long periods of time without becoming fatigued. Look at the standard free energies of hydrolysis fro glucosephosphate and phosphoenolpyruvate. Explain why neither of these molecules is well suited to be the main energy currency in cells.
Both release larger amount of energy when hydrolyzed but they require more energy to reform compared to ATP. ATP doesn't get as much energy out, but it also doesn't require much energy to make. Be able to identify oxidizing and reducing agents in reactions given the necessary information. Why does every oxidation reaction require a reduction reaction and vice versa? The oxidizing agent in a redox reaction is always reduced and the reducing reagent is always oxidized.
This of course assumes that both half cell reactions are written as reduction reactions which generally they are. The reason that reduction reactions are coupled to oxidation reactions is that they involve the transfer of electrons. Electrons are never found free in the environment they must be surrounding a nucleus. The reduction potential for molecule X is Which molecule has a higher affinity for electrons?
What's the role of electron carriers in metabolism? Which form will be generated by anabolic pathways? Electron carriers are critical in metabolism especially in the central metabolic pathways. They allow for a variety of chemical reactions to take place aside from oxidation and reduction. What determines whether a reaction is classified reversible or irreversible? Why are enzymes that catalyze irreversible reactions key regulatory enzymes?
Given the free energy changes of reactions in a pathway, describe how you would predict the key regulatory steps. Relative concentrations of the reactions and products. Whenever the concentrations of either decreases, it shirts proportionally. Explain why reversible reactions can be spontaneous in either direction based on the conditions in a cell.
Explain why irreversible reactions can ONLY be spontaneous in one direction in a cell. Explain how a hormone can be "broadcast" throughout the body, but only have an effect on certain cells. Only particular cells contain a protein receptor that recognizes and responds to a specific hormone. Use a hypothetical or real example to describe two ways a single hormone could cause different responses in different cells.
Specific cells in the brain have protein receptors for Melatonin which decrease blood pressure. Other cells that are involved in production of leptin contains receptors that recognize melatonin and decrease production of leptin.
Only a small amount of hormone is necessary to generate a significant response in a cell. Explain how that is possible and why it is beneficial. A receptor changes shape upon binding the hormone and activates second messengers that then in turn bind and regulate enzymes.
This allows one hormone molecule to initiate a cascade of reactions and amplify the initial signal. Are there any conditions in which both glucagon and insulin would be release in a person? If so, under what conditions? What about glucagon and epinephrine? Glucagon low blood sugar and Insulin high blood sugar are released in response to opposite conditions. Glucagon and insulin are not expected to be released in high amounts at the same time.
Epinephrin meditates high stress. If low blood sugar, glucagon. If high blood sugar, insulin. Thinking about the conditions under which each hormone signal is released, why does it make sense that both glucagon and epinephrine signaling lead to activation of protein kinase A, while insulin signaling results in the activation of protein phosphatase 1?
What does that tell you about the phosphorylation states of metabolic enzymes phosphorylated or dephosphorylated in response to glucagon, epinephrine, and insulin signaling?
The metabolic enzymes responsible for breaking down glycogen into glucose are active after being phosphorylated by protein kinase A and are required when blood glucose concentrations are low.
When blood glucose levels are high, catabolism of glycogen is not necessary and dephosphorylation of the metabolic enzymes causes them to lose their activity. Both binding events cause conformational changes. Both use secondary messengers.
Both are turned off by the dissociation of the hormone. Pathway will remain active and glycogen would constantly broken down eventually overwhelming the bloodstream with glucose.