Lab 3: Chemical Composition of Cells Flashcards
Atoms
basic units of matter, that all organisms consist of
Biomolecules
proteins, carbohydrates, and lipids
How are macromolecules (biomolecules) formed?
they form during dehydration reactions when smaller molecules bond as water is given off
Hydrolysis reaction
bonds are broken when water is added
A fat (lipid) contains:
one glycerol and three fatty acids
Monomers
smaller molecules
Polymers
made up of multiple monomers
What is the monomer in proteins?
amino acids
How are the amino acids bonded?
by a peptide bond
Monosaccharides in a polysaccharide (carbohydrates)
glucose molecules
Positive control
color change
Negative control
no color change
What benefit is a positive control?
positive controls give you a standard by which to tell if the substance being tested is present (or acting properly) in an unknown sample
What benefit is a negative control?
negative controls ensure that the experiment is giving reliable results
Enzyme
proteins that speed chemical reactions, ex. amaylse
All amino acids differ by:
the R group (remainder group) attached to a carbon atom
Peptide
a chain of two or more amino acids
Polypeptide
a very long chain of amino acids
Dipeptide
the bonding of two amino acids through a dehydration reaction
Biuret reagent tests for:
proteins (purple) and peptides (pinkish-purple)
Biuret reagent contains:
a strong solution of sodium or potassium hydroxide (NaOH or KOH) and a small amount of dilute copper sulfate (CuSO4) solution
Enzymes are composed of what type of organic molecules?
proteins
Is starch a protein?
no
What are carbohydrates?
sugars and molecules that are chains of sugars
What is the monosaccharide in carboyhdrates?
glucose, contains one sugar unit
What is the disaccharide in carbohydrates?
maltose, which has two sugar units
Polysaccharides of carbohydrates:
glycogen, starch, and cellulose
Animals store glucose as:
glycogen
Plants store glucose as:
starch
Starch consists of:
amylose that is nonbranched and amylopectin that is branched
Iodine tests for:
starch
If a solution is positive for starch it turns:
blue/black
If a solution is negative for starch it turns:
brown
What stores glucose as starch? Potatoes or onions?
potatoes
Benedict’s reagent tests for:
sugar molecules
If a solution is positive for sugar it turns:
green (very low), yellow (low), yellow-orange (moderate), orange (high), orange-red (very high)
If a solution if negative for sugar it turns:
blue
What are lipids soluble and insoluble in?
lipids are insoluble in water and soluble in solvents, such as alcohol and ether
Lipids includes:
fats, oils, phospholipids, steroids, and cholesterol
Oils and fats are composed of:
three molecules of fatty acids bonded to one molecule of glycerol
Phospholipids are composed of:
two molecules of fatty acids bonded to one molecule of glycerol and one phosphate group
What are steroids derived from?
cholesterol
Steroids and cholesterol are composed of:
skeletons of four fused rings of carbon atoms, but they differ by functional groups (attached side chains)
Brown paper tests for:
fats and oils
If a solution if positive for fats it turns:
translucent
If a solutions is negative for fats it turns:
solid
What kind of protein if lactase, the biomolecule that speeds up the breakdown of lactose?
enzyme
What is another name for plant fats?
oils
What must be present to successfully break down fats during digestion?
emulsifier
