AY Honors/Biochemistry/Answer Key
1. Define the following terms:
a. Carbohydrates
A carbohydrate is a molecule that is present in living organisms consisting of carbon, hydrogen, and oxygen atoms.
b. Lipid
Lipids are a group of molecules that include fats, waxes, sterols, Vitamin A, Vitamin D, Vitamin E, Vitamin K, monoglycerides, diglycerides, triglycerides, phospholipids. Lipids store energy, used in binding protein targets, and structural components of the cell membrane.
c. Fatty acid
Fatty Acids are carboxylic acids with a long hydrocarbon chain. They can be saturated or unsaturated.
d. Protein
Proteins consist of one or more long chains of amino acid residues. They are large biomolecules. Proteins have a lot of functions in organisms such as DNA replication, catalyzing metabolic reactions, responding to stimuli, and transporting molecules from one to another.
e. Peptide
A peptide is a compound consisting of two or more amino acids that are linked in a chain. They are short chains of amino acids.
f. Enzyme
Enzymes are biological molecules that act as catalysts. They accelerate the chemical reactions.
g. Amino acid
Amino Acids are used by cells in the body to build proteins.
h. Nucleic acid
Nucleic acids can be DNA, RNA, mRNA, and TRNA. They help replicate cells, and build proteins.
i. Hydrophilic and hydrophobic
j. Triglyceride
A triglyceride is an ester which is a formation of carboxylic acid and alcohol. Triglycerides are the main body fat in mammals and vegetable fat.
k. Monosaccharide
2. What is the importance of water in organisms? What are the main physical and chemical characteristics of the water molecule?
3. What does metabolism mean?
4. Biochemically, why do we feel hungry?
5. Explain how the glucose pathway occurs.
6. Which human cells depend only on this pathway for energy?
7. Which molecule links the glucose pathway and the Krebs Cycle?
8. What is the importance of the Krebs Cycle?
9. What is the function of lipids?
10. Why are lipids insoluble in water?
11. Why are lipids, and not glucose, used for energy storage?
12. What is beta oxidation? Why does this pathway receive this name?
13. What are essential and non-essential amino acids?
Amino Acids forms proteins. They are organic compounds when combined that help build cells. When proteins from the Amino Acids break down they leave Amino Acids. The body uses the amino acids to break down food, grow, repair cells and skin cells. They can be stored and used for energy.
Essential Amino Acids
There are amino acids that cannot be made by the human body. They only come from food. There are 9 types of Essential Amino Acids. They are isoleucine, leucine, histidine, lysine, methionine, phenylalanine, threonine, valine, tryptophan
Non-Essential Amino Acids
Our bodies make these amino acids. They are: asparagine, alanine, glutamic acid, aspartic acid.
14. What are ketone bodies, where are they produced, and what are the consequences of excess production?
15. What compounds are formed by the binding of amino acids? What are the main functions of these compounds?
16. What is the importance of nucleic acids? What is its structure like and what are its components?
17. Draw a DNA molecule, with four nucleotides, naming its components.
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