What type of solution did you test as your unknown? Did it contain protein? Observe your classmates reactions and describe which unknown solutions contain the most and the least protein.
How can you tell? Lipids Lipids are a class of molecules that are not soluble do not dissolve in water. Figure 4. Saturated and unsaturated fatty acid and a lipid triglyceride Testing for Lipid with Sudan IV Use gloves and avoid contact with Sudan IV as it is considered a possible carcinogen.
Materials Filter paper small enough to fit in the petri dish and pencil with areas labeled for test substances clean empty petri dish solution of 0. Solutions of deionized water, vegetable oil, and test solutions cream, dairy milks, coconut milk, soy milk etc. Procedure Obtain filter paper and on the far edge mark with pencil which solutions will be placed toward the interior of the mark.
Drop a small amount of solution near the appropriate mark. Vegetable oil Test solutions Allow to dry. Use a hairdryer to speed up this process. While the paper is drying, answer the Data Analysis questions below. Soak the paper in the petri dish containing 0. Record the color of the spots in the table below. Observations Sudan IV test for lipid: Reproduce this table in your lab book and complete it with your observations.
Data table 4. Spot Contents Color after reaction Relative amount of lipid? Vegetable oil 3. Instructions to clean up: When your observations are complete, carefully dispose of any remaining Sudan IV solution in the container provided by your instructor.
Your negative control? Hypothesize which solutions will contain the greatest amount of lipid. Why do you believe this to be true? Which solutions contained the greatest amount of lipid? Did your observations support your hypothesis? Were you surprised by some of the results? Part II. The Saga of the Soda Dispenser Enrique was a new employee. Scope of the Problem If the diet soda dispenser did have regular soda, then did the regular soda dispenser have diet?
Questions for your lab book: Does the regular soda have high fructose corn syrup in it? Write your observation in your lab book. Does the diet soda have high fructose corn syrup in it? Determine whether fructose is a monosaccharide, disaccharide or polysaccharide. Can we do a test? More questions for your lab book: Would it be a good idea to include controls?
If so, which solutions? Which detector reagent s will you use? How many test tubes do you need? How will you label them? Testing Unknown Soda Solutions Materials Clean test tubes labeled with the contents you will add to each tube deionized water, and solutions to test Indicator. Procedure Perform the test for monosaccharides: Obtain the needed number of clean test tubes and mark them at 2.
Code them as to the contents numbers corresponding to your solutions- which you record below Obtain the unknown solutions from your instructor. Fill the tubes to the 2. Fill the tubes to the 5 cm mark with indicator and treat was needed.
Reproduce this table in your lab book and complete it with your observations, then answer the questions regarding the soda saga. Observations Perform the Appropriate Test: Reproduce this table in your lab book and complete it with your observations. Data table 5. Tube Contents Color after reaction Presence of fructose? Diet or regular? When your observations are complete, carefully wash and rinse the tubes following the instructions in part 1.
At the end of the lab period be sure all labels are removed from the tubes using a small piece of paper towel and ethanol. Final Conclusion What does Enrique tell his manager? Is the soda dispenser messed up or not? What, if any, soda needs to be changed? Study Questions Why should you always include controls in each procedure? What serves as a good negative control and why? Describe a positive control.
What if only AFTER running your test, you read the label of the lemon-lime soda and notice that the ingredients do not contain fructose but does contain sucrose. Is your test procedure faulty or is there another explanation for your result? Common source: Table sugar. Common source: Rice. Common source: Cooking oils. A joins to T and T to A by two hydrogen bonds.
Note that the DNA molecule shown below is double stranded, and that the two strands run in opposite directions, denoted by the 3' and 5' ends. While nucleic acids are important as information carrying molecules, they are not nutritionally important. The Molecules of Life Proteins Proteins are the primary building materials of the body. Dehydration Synthesis and Hydrolysis: Proteins, fats, and carbohydrates all use these two common reactions involving water to assemble and disassemble the molecule.
When two hydrogens and one oxygen are removed from two separate molecules and the result is a single molecule and a water, this is called a dehydration synthesis reaction.
The molecules are "dehydrated" because water is removed, and they are synthesized joined into one large molecule. When one large molecule is split lysis means splitting into two molecules with the addition of water and energy, the reaction is called hydrolysis. In each of the illustrations, these reactions, which are opposites, are shown in red. Fats lipids Fats are the primary long-term energy storage molecules of the body.
Fats are made of a glycerol left and up to three fatty acids. Heart health and fats : Saturated fatty acids have no double bonds and therefore hold the maximum number of hydrogens. In other words, the carbons are "saturated" with hydrogen. Unsaturated fatty acids have some double bonds and therefore hold fewer hydrogens.
Saturated fats are not as good for you as unsaturated fats. Saturated fats are long straight molecules that can clog your arteries, whereas more unsaturated fats, because of the additional double bonds, are more bendy and less likely to clog up the small blood vessels. It's like the difference between trying to swallow an uncooked spaghetti stick and a cooked spaghetti noodle. The orientation of the double bonds affects the chemical properties of the fat.
Margarine, some types of peanut butter, and shortening are examples of artificially hydrogenated trans -fats. Many fast food restaurants have recently eliminated the use of trans -fats, and U. Essential fatty acids are fatty acids that are required but not synthesized by the human body.
Consequently, they must be supplemented through the diet. Omega-3 fatty acids fall into this category and are one of only two known essential fatty acids for humans the other being omega-6 fatty acids.
They are a type of polyunsaturated fat and are called omega-3 fatty acids because the third carbon from the end of the fatty acid participates in a double bond. Salmon, trout, and tuna are good sources of omega-3 fatty acids.
Omega-3 fatty acids are important in brain function and normal growth and development. They may also prevent heart disease and reduce the risk of cancer. Like carbohydrates, fats have received a lot of bad publicity. However, fats do have important functions. Fats serve as long-term energy storage.
They also provide insulation for the body. Phospholipids are the major constituent of the plasma membrane. Like fats, they are composed of fatty acid chains attached to a glycerol or similar backbone. Instead of three fatty acids attached, however, there are two fatty acids and the third carbon of the glycerol backbone is bound to a phosphate group.
The phosphate group is modified by the addition of an alcohol. A phospholipid has both hydrophobic and hydrophilic regions. The fatty acid chains are hydrophobic and exclude themselves from water, whereas the phosphate is hydrophilic and interacts with water.
Cells are surrounded by a membrane, which has a bilayer of phospholipids. The fatty acids of phospholipids face inside, away from water, whereas the phosphate group can face either the outside environment or the inside of the cell, which are both aqueous. Because fat is the most calorie dense food and having a storable, high calorie compact energy source would be important to survival. The nature of its fat also made it an important trade good.
Like salmon, ooligan returns to its birth stream after years at sea. Its arrival in the early spring made it the first fresh food of the year.
As you learned above all fats are hydrophobic water hating. To isolate the fat, the fish is boiled and the floating fat skimmed off.
Importantly it is a solid grease at room temperature. Because it is low in polyunsaturated fats which oxidize and spoil quickly it can be stored for later use and used as a trade item.
Its composition is said to make it as healthy as olive oil, or better as it has omega 3 fatty acids that reduce risk for diabetes and stroke. It also is rich in three fat soluble vitamins A, E and K. Unlike the phospholipids and fats discussed earlier, steroids have a ring structure. Although they do not resemble other lipids, they are grouped with them because they are also hydrophobic.
All steroids have four, linked carbon rings and several of them, like cholesterol, have a short tail. Cholesterol is a steroid. Cholesterol is mainly synthesized in the liver and is the precursor of many steroid hormones, such as testosterone and estradiol.
It is also the precursor of vitamins E and K. Cholesterol is the precursor of bile salts, which help in the breakdown of fats and their subsequent absorption by cells.
Although cholesterol is often spoken of in negative terms, it is necessary for the proper functioning of the body. It is a key component of the plasma membranes of animal cells. Waxes are made up of a hydrocarbon chain with an alcohol —OH group and a fatty acid.
Examples of animal waxes include beeswax and lanolin. Plants also have waxes, such as the coating on their leaves, that helps prevent them from drying out. Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective; they may serve in transport, storage, or membranes; or they may be toxins or enzymes.
Each cell in a living system may contain thousands of different proteins, each with a unique function. Their structures, like their functions, vary greatly. They are all, however, polymers of amino acids, arranged in a linear sequence.
The functions of proteins are very diverse because there are 20 different chemically distinct amino acids that form long chains, and the amino acids can be in any order.
For example, proteins can function as enzymes or hormones. Enzymes , which are produced by living cells, are catalysts in biochemical reactions like digestion and are usually proteins. Each enzyme is specific for the substrate a reactant that binds to an enzyme upon which it acts.
Enzymes can function to break molecular bonds, to rearrange bonds, or to form new bonds. An example of an enzyme is salivary amylase, which breaks down amylose, a component of starch. Hormones are chemical signaling molecules, usually proteins or steroids, secreted by an endocrine gland or group of endocrine cells that act to control or regulate specific physiological processes, including growth, development, metabolism, and reproduction.
For example, insulin is a protein hormone that maintains blood glucose levels. Proteins have different shapes and molecular weights; some proteins are globular in shape whereas others are fibrous in nature. For example, hemoglobin is a globular protein, but collagen, found in our skin, is a fibrous protein.
Protein shape is critical to its function. Changes in temperature, pH, and exposure to chemicals may lead to permanent changes in the shape of the protein, leading to a loss of function or denaturation to be discussed in more detail later. All proteins are made up of different arrangements of the same 20 kinds of amino acids. Amino acids are the monomers that make up proteins.
Each amino acid has the same fundamental structure, which consists of a central carbon atom bonded to an amino group —NH 2 , a carboxyl group —COOH , and a hydrogen atom. Every amino acid also has another variable atom or group of atoms bonded to the central carbon atom known as the R group. The R group is the only difference in structure between the 20 amino acids; otherwise, the amino acids are identical.
The chemical nature of the R group determines the chemical nature of the amino acid within its protein that is, whether it is acidic, basic, polar, or nonpolar. Each amino acid is attached to another amino acid by a covalent bond, known as a peptide bond, which is formed by a dehydration reaction.
The carboxyl group of one amino acid and the amino group of a second amino acid combine, releasing a water molecule. The resulting bond is the peptide bond.
The products formed by such a linkage are called polypeptides. While the terms polypeptide and protein are sometimes used interchangeably, a polypeptide is technically a polymer of amino acids, whereas the term protein is used for a polypeptide or polypeptides that have combined together, have a distinct shape, and have a unique function.
The Evolutionary Significance of Cytochrome cCytochrome c is an important component of the molecular machinery that harvests energy from glucose. For example, scientists have determined that human cytochrome c contains amino acids. For each cytochrome c molecule that has been sequenced to date from different organisms, 37 of these amino acids appear in the same position in each cytochrome c.
This indicates that all of these organisms are descended from a common ancestor. On comparing the human and chimpanzee protein sequences, no sequence difference was found.
When human and rhesus monkey sequences were compared, a single difference was found in one amino acid. In contrast, human-to-yeast comparisons show a difference in 44 amino acids, suggesting that humans and chimpanzees have a more recent common ancestor than humans and the rhesus monkey, or humans and yeast.
As discussed earlier, the shape of a protein is critical to its function. To understand how the protein gets its final shape or conformation, we need to understand the four levels of protein structure: primary, secondary, tertiary, and quaternary.
The unique sequence and number of amino acids in a polypeptide chain is its primary structure. The unique sequence for every protein is ultimately determined by the gene that encodes the protein. Any change in the gene sequence may lead to a different amino acid being added to the polypeptide chain, causing a change in protein structure and function. What is most remarkable to consider is that a hemoglobin molecule is made up of two alpha chains and two beta chains that each consist of about amino acids.
The molecule, therefore, has about amino acids. The structural difference between a normal hemoglobin molecule and a sickle cell molecule—that dramatically decreases life expectancy in the affected individuals—is a single amino acid of the This can lead to a myriad of serious health problems, such as breathlessness, dizziness, headaches, and abdominal pain for those who have this disease.
0コメント