lab exam 1

• A lengthwise cut through any type of specimen is called a longitudinal section (Is).
• A crosswise cut through any type of specimen is called a cross section (cs).
• The metric system is the standard system of measurement in the sciences, including biology, chemistry, and physics.
• To do this properly, you have to make sure that the lowest margin of the water level, or the meniscus, is at the 20 mI mark.
• The stereomicroscope (dissecting microscope) is designed to study entire objects in three dimensions at low magnification.
• The compound light microscope is used for examining small or thinly sliced sections of objects under higher magnification than that of the stereomicroscope.
• The term compound refers to the use of two sets of lenses: the ocular lenses located near the eyes and the objective lenses located near the object.
• The transmission electron microscope is analogous to the compound light microscope.
• The object is ultra-thinly sliced and treated with heavy metal salts to improve contrast.
• The scanning electron microscope is analogous to the dissecting microscope, it gives an image of the surface and dimensions of an object.
• Resolution is the minimum distance between two objects at which they can still be seen, or resolved, as two separate objects.
• The stereomicroscope (dissecting microscope) allows you to view objects in three dimensions at low magnifications.
• When viewing an object on a slide under high power, the depth of field is the area- -from top to bottom--that comes into focus while slowly focusing up and down with the microscope's fine-adjustment knob.
• When a specimen is prepared for observation, the object should always be viewed as a wet mount.
• In phospholipids, the phosphate group and glycerol are polar and hydrophilic ("water-loving").
• The fatty-acid chains are nonpolar and hydrophobic ("water-fearing").
• Such molecules with two different affinities are amphipa-thie, and amphipathic phospholipids have a natural tendency to self-assemble into a double-layered sheet.
• To effectively regulate the flow of materials moving into and out of cells, membranes must be selectively permeable.
• In healthy cells, betacyanin remains inside the vacuoles, surrounded by a vacuolar membrane called the tonoplast.
• Monosaccharides and some disaccharides will react with Benedict's reagent after being heated in a boiling water bath.
• Enzymes are proteins that speed chemical reactions.
• Roots of beet contain large amounts of a reddish pigment called betacyanin localized almost entirely in the large central vacuoles of cells.
• Typically, fat, such as in the adipose tissue of animals, and oils, such as the vegetable oils from plants, are composed of three molecules of fatty acids bonded to one molecule of glycerol.
• All organisms consist of basic units of matter called atoms.
• Carbolydrates include sugars and molecules that are chains of sugars.
• Steroids are derived from cholesterol.
• A polypeptide is a very long chain of amino acids.
• Proteins and some carbohydrates (called polysaccharides) are polymers because they are made up of smaller molecules called monomers.
• Phospholipids have the same structure as fats, except that in place of the third fatty acid there is a phosphate group (a grouping that contains phosphate.
• Biuret reagent changes color in the presence of proteins or peptides.
• An emulsifier can cause a fat to disperse in water.
• A chain of two or more amino acids is called a peptide, and the bond between the amino acids is called a peptide bond.
• Glucose, which has only one sugar unit, is a monosaccharide; maltose, which has two sugar units, is a disaccharide.
• Bile salts (emulsifiers found in bile produced by the liver) are used in the digestive tract.
• Proteins are made up of amino acids (the subunits) joined together.
• The fluid mosaic model of membrane structure is composed of elaborate molecular elements.
• An emulsifier contains molecules with both polar and nonpolar ends.
• Lipids are compounds that are insoluble in water and soluble in solvents, such as alcohol and ether.
• What solution tests for carbohydrates?

  Benedict's solution
• What solution is used to test for proteins?

  Biuret Reagent