Ch 3: Chemical Composition of Cells

What type of bond joins amino acids to make peptides?
peptide bonds
What type of protein speeds chemical reactions?
What group is different between types of amino acids?
R group
If iodine solution turns blue-black, what substance is present?
If Benedict's reagent turns red, what substance is present?
What is the function of starch in plant cells?
stores glucose
Is starch a monosaccharide or a polysaccharide?
What is the function of fat in animal cells?
long time energy
What molecules are released when fat undergoes a hydrolysis reaction?
Fatty acids
What type of organic molecule requires the action of emulsifiers to be successfully digested?
Are fats polar or nonpolar?
If Biuret reagent turns purple, what substance is present?
A student adds iodine solution to egg white and waits for a color change. How long will the student have to wait?
It never changes
To test whether a sample contains glucose, what reagent should be used?
Benedict's reagent
Why is it necessary to shake a bottle of salad dressing before adding it to a salad?
To mix oil and water
An unknown sample is tested with both Biuret reagent and Benedict's reagent. Both tests result in a blue color. What has been learned?
No protein or sugar
starch and water are mixed together as ingredients for making gravy. Why doesn't starch react with water to yield monosaccharides?
No amylase
Based on your study of organic molecules in this lab, why do plants benefit from nitrogen fertilizer?
Proteins need nitrogen