Lab Practical Exam 1 Review Flashcards
Benedict reagent
is used to identify simple sugars.
The reaction requires heat to take place.
Benedict reagent
Glucose
six-carbon sugar molecule in starch and glycogen. A common monosaccharide.
Disaccharide
A carbohydrate made up of two sugar molecules linked together.
Maltose
A disaccharide consisting of two glucose molecules bound together.
Simple sugar
Monosaccharides and disaccharides.
Oligosaccharide
A carbohydrate made up of more than two sugar molecules linked together.
Polysaccharide
A carbohydrate made up of hundreds to thousands of sugar molecules linked together.
Starch
A plant-based polysaccharide.
Glycogen
An animal-based polysaccharide.
- Benedict test for sugar
A light blue solution that tests for many types of simple sugars, including maltose and glucose.
Light blue (original color) = no simple sugars. The color then progresses through green, yellow, orange, red, and brown as the amount of simple sugars increases.
Iodine
A solution that turns from brown to purple in the presence of starch.
Positive control
Any procedure that is known to produce the desired result. A positive test result means what you are looking for is present.
Negative control
Any procedure that is known to NOT produce the desired result. A negative test result means what you are looking for is NOT present.
How to interpret the starch test
A positive test result for starch occurs when iodine turns color. Medium blue is a small amount of starch, dark blue indicates a medium amount of starch, and blue-black indicates a large amount of starch. A negative test result for starch occurs when iodine stays yellow.
Lipid
A macromolecule made up of dozens to hundreds of molecules of mostly carbon and hydrogen.
Cholesterol
A lipid with a structure containing over 20 carbon atoms configured into four rings.
+ Phospholipid
A lipid made up of a three-carbon glycerol molecule with a phosphate group and two fatty acids attached.
Triglyceride
A lipid made up of a three-carbon glycerol molecule with three fatty acid chains attached to it.
Fatty acids
Long chains of carbon with hydrogen attached, making them nonpolar molecules.
Saturated fatty acid
A chain of carbon atoms using only single carbon-to-carbon bonds with hydrogen atoms attached to the carbon atoms.
Unsaturated fatty acid
A chain of carbon atoms that contain one (monounsaturated) or more (polyunsaturated) double bonds between carbons with hydrogen atoms attached to the carbon atoms.
How to interpret the paper test:
A positive result for a lipid will result in an evenly distributed oily stain remaining on paper after 15 minutes. Water will completely evaporate, and nonlipid substances mixed with water will leave a circular stain.
A fatty acid with three double bonds.
This is a polyunsaturated fatty acid.
Biuret reagent
A light blue reagent that tests for protein.
How to interpret the Biuret test:
A positive result for the Biuret test occurs anytime the reagent changes from its original blue color to a pink or purple color. Any tube that is blue, no matter which shade of blue, does not contain protein.
turns from light blue to pink if a low concentration of protein is present. Dark purple indicates a high protein concentration.
polymers consisting of long chains of amino acid monomers.
Proteins
Two amino acids form a .
dipeptide
Multiple amino acids folded to form a
functional structure make up a protein.
Magnification
the apparent increase in image size.
Resolution
the ability to distinguish fine detail.
Contrast
the ability to distinguish objects, such as cells, from the background.
advantages of a wet mount may include
Fast preparation.
Requires no special equipment other than a transfer pipette, slide, and cover slip.
Organisms may be viewed in their living state.
Movement of motile microorganisms can be observed.
Diffusion
the net movement of a solute from an area of higher concentration to an area of lower concentration.
Diffusion is the result of
the random movement of molecules.
The rate of diffusion may be influenced by
density of media, concentration gradient, temperature, molecular size, and membrane permeability.
Media
Substance through which diffusion occurs, such as water and air.
Hypertonic
A solution with a higher concentration of nonpermeable solutes in comparison to another solution.
Hypotonic
A solution with a lower concentration of nonpermeable solutes in comparison to another solution.
Osmosis
Osmosis is the movement of water across a selectively permeable membrane from a hypotonic solution into a hypertonic solution.
Osmotic pressure
The pressure applied to a selectively permeable membrane to prevent osmosis.
What effect does corn syrup concentration have on the movement of water in this simulation?
More water is drawn up into the thistle tube with higher concentrations of corn syrup.
When experimenting with a selectively permeable membrane, Diffusion occurred based on
molecular size. Iodine and glucose are much smaller molecules than starch; therefore, they were able to diffuse.
Tonicity
The ability of a solution to change the volume of a cell through osmosis.
