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Biomolecules Test Review -KEY

1.  What are the 4 large categories of organic compounds that we call biomolecules?

Proteins Carbohydrates

Lipids Nucleic Acids

2.  What are examples of each biomolecule?

Examples / Biomolecule (polymer)
Starch, glucose, Cellulose, Glycogen / Carbohydrate
Oils, waxes, fats, vitamins, steroids, cell membranes / Lipids
DNA, RNA, ATP / Nucleic Acids
Enzymes, Insulin, Antibodies, Hemoglobin / Proteins

3.  How are monomers and polymers related?

Polymers are long chains of single units called Monomers.

4.  What is the difference in dehydration synthesis and hydrolysis? Use monomer(s) and polymer(s) in your explanation. In which process is water used? Released? – Dehydration Synthesis

During dehydration synthesis monomers are linked together by the removal of a water molecule producing a polymer; which is the opposite of what occurs during hydrolysis. Hydrolysis adds water to a polymer, breaking the bonds holding the polymer together, resulting in individual monomers.

5.  What are the monomers for each biomolecule?

Monomer / Biomolecule (polymer)
Monosaccharide / Carbohydrates
Fatty Acids / Lipids
Nucleotides / Nucleic Acids
Amino Acids / Protein

6.  What elements make up each type of biomolecule? (use the element’s symbol)

Elements / Biomolecule (polymer)
C H O / Carbohydrates
C H O / Lipids
C H O N P / Nucleic Acids
C H O N sometimes S / Protein

7.  How do you know C6H12O6 is a carbohydrate and not a lipid, protein, or nucleic acid?

Because the Hydrogen and Oxygen are in a 2:1 ratio and there is no N or P

8.  Glucose, one type of monosaccharide, is represented by the chemical formula, C6H12O6. If you were to put together 2 glucose molecules, why wouldn’t the molecular formula for the newly made disaccharide be C12H24O12?

In order to link the 2 molecules together a water molecule must be removed (dehydration synthesis) the resulting formula would be:

C6H12O6 + C6H12O6 C12H22O11 + H2O

9.  What is the difference between saturated and unsaturated fatty acid? Which is better for you? Why?

Saturated fatty acid- single bonds, straight and tightly packed. Solid at room temperature. (Bad for us!)

Unsaturated fatty acid- double bonds bend the tails and it’s crooked (not straight). Liquid at room temperature (ex. Olive Oil)

10.  For proteins to function (work) they have to be folded in several conformations

A.  Primary – sequence of amino acids

B.  Secondary – coiled into a helix or pleat

C.  Tertiary – folded into a “glob” that has an active site – it works in this shape

D.  Quaternary – 2 or more tertiaries (globs) that are held together by a metal ion (i.e iron holds hemoglobin together; copper holds myoglobin together)

What (molecule) directs or determines their primary conformation? DNA

11.  When a protein is denatured, what does that mean? What can denature a protein (name 2)?

Denatured means that it changes shape and would no longer function properly.

Temperature and pH are 2 things that can denature a protein.

12.  Which nitrogenous base pairs bond together in deoxyribonucleic acid? Ribonucleic acid? How do they differ?

Base Pairs
DNA / RNA
A – T / A –U
C - G / C - G

13.  What are enzymes? How do they function? Enzymes are a catalyst. Catalysts are used to speed up a reaction by decreasing the amount of energy needed to get the reaction started…Lowers the activation energy.

14.  What factors affect the rate at which enzymes function? Explain how each would affect the enzymes rate of reaction.

Factors that Affect Rate at Which Enzymes Function / How would it affect rate of reaction?
Temperature / To hot or cold reaction would be inhibited
pH / pH to acidic or basic for that enzyme would inhibit reaction
Enzyme Concentration / More enzymes the faster the substrate is acted upon
Substrate Concentration / Higher concentration would slow down total reaction speed

15.  Using the diagrams shown: IDENTIFY and LABEL the active site, substrate, enzyme and product.

Using the illustration above to describe what happens at each step:

Step 1: Substrate attaches to the enzyme at the active site (Like a lock and key it must be the right shape in order to fit…doesn’t fit doesn’t work)

Step 2: Enzyme substrate complex formed – Reaction occurs

Step 3 (What happens to the enzyme?): Products are released from the enzyme. Enzyme remains unchanged and is available to do the reaction again if more substrate is available.

16.  Compare competitive and noncompetitive inhibition and how it affects enzyme function.

A noncompetitive inhibitor - is a substance that interacts with the enzyme, but usually not at the active site. The noncompetitive inhibitor reacts either remote from or very close to the active site. The net effect of a non-competitive inhibitor is to change the shape of the enzyme and thus the active site, so that the substrate can no longer interact with the enzyme to give a reaction. Non-competitive inhibitors are usually reversible, but are not influenced by concentrations of the substrate as is the case for a reversible competitive inhibitor.
A competitive inhibitor - is any compound which closely resembles the chemical structure and molecular geometry of the substrate. The inhibitor competes for the same active site as the substrate molecule. The inhibitor may interact with the enzyme at the active site, but no reaction takes place. The inhibitor is "stuck" on the enzyme and prevents any substrate molecules from reacting with the enzyme. However, a competitive inhibition is usually reversible if sufficient substrate molecules are available to ultimately displace the inhibitor. Therefore, the amount of enzyme inhibition depends upon the inhibitor concentration, substrate concentration, and the relative affinities of the inhibitor and substrate for the active site.

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17.  Complete the following chart:

Protein / Nucleic Acids / Carbohydrates / Lipids
Elements in biomolecule / C, H, O, & N
Sometimes S / C, H, O, N, & P / C, H, O
Hydrogen and Oxygen (2:1) / C, H, O
Hydrogen and Oxygen (greater than 2:1)
Where synthesized in the cell / Ribosome / Nucleus / Chloroplast / Smooth ER
Function(s) of biomolecule / Catalyst, Maintenance, Repair, growth, transport, and metabolism / Genetic Code
Blueprints of DNA
Cellular Energy / Short term energy storage
Structural support
Primary fuel source / Long term energy storage
Cushion
Insulation
Vitamins
Steroids
Plasma Membranes
Monomer / Amino Acids / Nucleotides / Monosaccharides / Fatty Acids
Examples / Meat, cheese, Milk
Insulin, Hemoglobin, Antibodies, and Enzymes / RNA, DNA, & ATP / Potatoes, Rice, sugars (glucose, sucrose, lactose, & Fructose)
Cellulose, and Chitin / Fats, Oils, Waxes, Steroids,
& Vitamins

18.  Identify each of the following molecules