Carbs, Lipids, and Proteins
Terms
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- What are carbohydrates?
- Molecules that have the genereal molecular formula of CnH2nOn which may also be written as (CH20)n. They usually have the ending -ose.
- Disaccharides
- Formed when 2 monosaccharides are joined together with the elimination of a water molecule, a dehydration, condensation, or synthesis reaction.
- Polysaccharides
- Formed from the combining of many monosaccharides, after dehydration. Polysaccharides are a major storage form of carbs, such as the starch in plants and glycogen in animals.
- Benedict's test
- Used to detect the presence of all monosaccharides and those disaccharides that contain a potentially free aldehyde or ketone group and are commonly called reducing sugars.
- Reducing Sugars
- Disaccharides that can donate electrons.
- What happens in a Benedict's Test?
- The blue cupric ions (Cu++) of the Benedict's Solution are reduced to red cuprous ions (Cu+) or a red copper oxide precipitate (Cu2O).
- Does a Benedict's Test require heat?
- Yes.
- What does an Iodine Test test for?
- It is used to detect the presence of the polysaccharide starch.
- What happens in an Iodine Test?
- The iodine solution (IKI), which is typically an amber-brown color, complexes with the polysaccharide, it becomes a blue-black color.
- What color is a positive Iodine test?
- Blue-black.
- What color is a positive Benedict's test?
- Red.
- How is the polysaccharide starch broken down?
- Hydrolysis -- it's done by your digestive system, using the enzyme (amylase) in your saliva and pancreatic secretions. 3M HCl and heat work, also.
- What are lipids?
- Complex organic molecules that tend to be insoluble in water because they are nonpolar.
- What are the 4 groups of lipids?
- Neutral fats, phospholipids, steroids, and other lipoid substances.
- What are phospholipids?
- Similar to neutral lipids except that they contain a phosphate group in place of one of the fatty acids chains.
- Lipoid Substances
- Include the fat soluble vitamins, A, E, and K, the eicosanoids (most of which are derived from arachidonic acid), such as prostaglandins, leukotrienes, and thromboxanes, and the lipoproteins.
- Sudan IV dye
- A simple way to demonstrate the presence of fats.
- What color is the Sudan IV dye in the first place?
- It is a dark red brown powder that is insoluble in water.
- What color is the Sudan IV dye when in a fat?
- Bright red.
- Proteins
- A group of organic molecules that are both structurally and functionally important in the human body.
- What are the building blocks of protein?
- Amino acids.
- How many naturally occurring amino acids are there?
- About 20.
- What are amino acids linked by?
- Peptide bonds.
- Ninhydrin test
- Used to detect the presence of amino acids.
- What color will amino acids turn when ninhydrin is present?
- Purple.
- Which amino acid turns yellow?
- Praline.
- What is the Biuret test?
- Used to detect the presence of polypeptides and proteins.
- What color is the Biuret solution before mixing?
- Blue.
- What color is the biuret test in the presence of polypeptides?
- Pink or purple. Solutions containing proteins will turn violet with the biuret, solutions of smaller peptides will turn pink, and solutions of amino acids alone will not show a color change and will remina blue. An exception is cysterine, which turns yellow.
- The Ninhydrin Test will not be positive until protein is broken into _____ ____
- amino acids