Essay about Ch. 04 Study Guide

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Chapter 4 – Cellular Metabolism Study Guide

1. Define the following word parts. an-without mut-change ana-up -zym causing to ferment cata-down de-undoing sub-under -strat spread out

2. Define
Enzyme- Protein that catalyzes a specific biochemical reaction
Metabolism-The combined chemical reactions in cells that use or release energy
Anabolism-Synthesis of larger molecules from smaller ones; anabolic metabolism
Catabolism-Breakdown of large molecules; catabolic metabolism
3. A disaccharide is formed when two monosachharides (simple sugars) come together while water is removed. This is an example of a __dehydration synthesis reaction.

4. When water is added to break the disaccharide into the smaller monosachharides we call this a __hydrolysis reaction.

5. What is the relationship between an enzyme and a substrate? Explain how this relationship works.
Enzymes are specific and only act on their corresponding substrate. The ability of an enzyme to recognize its substrate depends on the enzymes shape. Each enzyme’s polypeptide chain twists and coils into a unique three dimensional shape that fits the particular shape of its substrate molecule. During an enzyme-catalyzed reaction, regions of the enzyme molecule called active sites temporarily combine with specific parts of the substrate, forming an enzyme-substrate complex. This interaction strains chemical bonds in the substrate in a way that makes a particular chemical reaction more likely to occur. When the reaction occurs, the enzyme is released in its original form.
6. What are coenzymes and cofactors? Why are they important?
Coenzymes are small organic molecules which are cofactors which help the active site attain its appropriate shape or helps bind the enzyme to its substrate. Other cofactors are ions such as copper, iron, or zinc. Many coenzymes are composed of vitamin molecules or incorporate altered forms of vitamin molecules.
7. Describe metabolic pathways and how they are regulated.
Metabolic pathways are sequences of enzyme-controlled reactions, and they lead to the synthesis or breakdown of different types of enzymes. Metabolic pathways are controlled via rate-limiting enzymes and negative feedback. Rate-limiting enzymes become ineffectual at catalyzing one of the steps in the metabolic pathway when there is saturation of that particular enzyme. These enzymes are usually first in the series to prevent an intermediate product of the pathway from accumulating. Negative feedback controls the metabolic pathways when the product inhibits the rate-limiting regulatory enzyme. Accumulation of product inhibits the pathway, therefore synthesis falls. Once the concentration of that product decreases synthesis resumes.
8. What is energy?
Energy is the capacity to change something; it is the ability to do work. Energy is recognized by what it can do.
9. List 6 common forms of energy. light, heat, sound, electrical energy, mechanical energy, and chemical energy
10. The form of energy used by cells is _Adenosine triphosphate_(ATP)____. Adenosine
11. Draw an ATP molecule.

12. Describe oxidation.
Oxidation is the process of cells “burning” the glucose molecules of an eaten substance and the energy released by this process is then harnessed to promote cellular metabolism.

13. Cellular Respiration is made up of three distinct, yet interconnected series of reactions. Describe what happens during each of the following stages (including how many ATP are gained)
Glycolysis-“the breaking down of glucose”; Series of ten enzyme-catalyzed reactions that break down the 6-carbon glucose molecule into two separate 3-carbon pyruvic acid molecules. This process takes place in the cytosol; does not require oxygen therefore is referred to as the anaerobic phase of cellular respiration.
3 main events:
1. Two phosphate groups are added to a glucose molecule, one at each end(phosphorylation). This step requires energy