Questions 1-12

Reviewing Concepts
Multiple Choice
Choose the letter of the best answer.

1. Which of the following is not an organic molecule?
a. cellulose
b. sucrose
c. water
d. testosterone

Answer: c

2. Which of the following terms includes all the other terms on this list?
a. polysaccharide
b. carbohydrate
c. monosaccharide
d. glycogen

Answer: B

3. Which term is most appropriate to describe a molecule that dissolves easily in water?
a. hydrocarbon
b. hydrophobic
c. hydrophilic
d. organic

Answer: C

4. Cholesterol is an example of what kind of molecule?
a. protein
b. lipid
c. amino acid
d. carbohydrate

Answer: B

5. The 20 amino acids vary only in their
a. carboxyl goups.
b. side groups.
c. amino groups.
d. lipid groups.

Answer: B

6. A specific reactant an enzyme acts upon is called the
a. catalyst.
b. sucrase.
c. active site.
d. substrate.

Answer: C

7. An enzyme does which of the following?
a. adds heat to a reaction, speeding it up
b. lowers the activation energy of a reaction
c. cools a reaction, slowing it down
d. raises the activation energy of a reaction

Answer: B

Short Answer
8. Besides satisfying your hunger, why else might you consume a big bowl of pasta the night before a race?

Answer: You need the carbohydrate to keep you're energy up during the big race.

9. How are glucose, sucrose, and starch related?

Answer: Sucrose and starch are related because they are all Saccharides.

10. What are steroids? Describe two functions they have in cells.

Answer: A steroid is a lipid characterized by a carbon skeleton with four fused rings. Two functions they have in cells would be: circling you're body with chemical signals, and make the appearance of a male and a female different.

11. How are polypeptides related to proteins?

Answer:Polypeptides build up the structure of the protein

12. How does denaturation affect the ability of a protein to function?

Answer: Denaturation affect the ability of a protein to function because it changes their shape so they might not function properly.

5.5

• Enzymes- specialized proteins that are the main catalysts of chemical reactions in organisms.
• Catalysts- compounds that speed up the chemical reaction.
• Activation energy- the energy needed to start up a chemical reaction
• Substrate- a specific reactant acted upon by an enzyme.
• Active site- a particular region of the enzyme where the substrate fits into.
• Hot molecules are strong enough to overcome the weak bonds
• An enzyme doesn't supply the activation energy to the reacting molecules but they lower the requirements for it to happen.
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Concept Check 5.5

• Explain the role of activation energy in a reaction. How does and enzyme affect activation energy?

• The activation energy provides the amount of energy needed to start a chemical reaction. An enzyme lowers the requirement of energy that is needed to activate the chemical reaction.

• Describe how a substrate interacts with an enzyme.

• A substrate is a specific reactant acted upon by an enzyme. It helps the enzyme to fit into a specific area.

5.4

• Protein- a polymer constructed with a set of 20 kinds of monomers that are called amino acids.

• Amino Acid- a monomer that has a central carbon that is then bonded with 4 partner in a covalent bond. Amino acids make up protein. there are only about 20 kinds of amino acids that make up the proteins.

• Polypeptide- a chain formed by amino acids that make proteins.
  
  

• Denaturation- an unnatural change in nature that causes the protein to change it's normal shape.

• Proteins form objects like hair, fur and muscles.

• The amino acids make up all the protein in the world with 20 types.

• polypeptide chains are mostly 100 amino acids long

• A protein in the form of amino acids linked together cannot function correctly

• A protein consists of more than 1 polypeptide twisted and folded together

• 1) Give at least two examples of proteins you can "see" in the world around you. What are their functions?

• Hair and fur are two types of protein that you can see in the world around you.
  

• 2) Relate amino acids, polypeptides, and proteins
• Amino acids make proteins and it makes a polypeptide chain which is usually more than 100 amino acids long.
  
  
• 3) Explain how heat can destroy a protein.
  
• Heat causes denaturation, a process when the protein breaks apart, making it malfunction. Protein is held together by weak side bonds or side bonds with water. Hot molecules can destroy this force because of the force it has.
  
• 4) Which parts of an amino acid's structure are the same in all amino acids? Which part is unique?
  all amino acids share the same 3 bonds. The center bond with the carbon, one to an hydrogen molecule, another to an amino acid and lastly, one to a carboxyl group. The part that is unique is the side group which determines what the protein would be like.

5.3

• Lipids- water avoiding compounds as found in oil.
• Hydrophobic- basically means "water fearing"
• Fat- made of three-carbon backbone called glycerol attached to three fatty acids which contain long hydrocarbon chains.
• Saturated Fat- fat in which all three fatty acid chains contain the maximum possible number of hydrogen atom.
• Unsaturated Fat- fat that contains less than the maximum number of hydrogen atoms in one or more of its fatty acid chains because some of its carbon atom are double-bonded to each other.
• Steroid- a lipid molecule in which the carbon skeleton forms four fused rings.
• Cholesterol- an essential molecule found in the membranes that surround your cells.
• Diets that consists of large amounts of saturated fats are unhealthy. These kind of diets have bad effects like the increasing amount of lipid-containing deposits in the blood vessels called plaques. This can slow down blood flow and cause heart disease.
  
• Steroids are classified as lipids because they are hydrophobic.
• Too much cholesterol can lead to heart and blood vessel disease.
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Concept Check 5.3

1) What property do lipids share?
They are all hydrophobic and stay away from water.
2)What are the parts of a fat molecule?
A fat molecule consist of a glycerol, fatty acids and a hydrocarbon chain.
3) Describe two ways that steroids differ from fats. Steroids travel around the body like chemical signals and steroids are made of four fused rings.
4) What does the term unsaturated fat on a food label mean? Unsaturated fat means that the food has fat that has less than the maximum amount of hydrogen atoms. Usually found in vegetables and fruits.

5.2

• Carbohydrate is compound made out of sugar

• Sugar made up of 1 Carbon 2 Hydrogen and 1 Oxygen.

• CH2O is the basic formula of any carbohydrate.

• Mono saccharides- sugars that contain one sugar unit

• Simple sugars are usually sweet like candy

• Glucose exists in straight chain and ring shaped forms

• Sugar molecules especially glucose are the main power source for you're body.

• Cells break down glucose and stores their energy

• Glucose usually makes fat molecules.

• Disaccharides- double sugar made from the dehydration reaction

• Sucrose is one of the most common disaccirides.

• Sucrose is a major carbohydrate found in plants

• Table sugar is processed from sugarcane which is broken down to glucose and fructose once in the body

• Polymer chains made up of simple sugar monomers are called polysaccharides.

• Starch is a polysaccharide found in plants and made of entirely glucose.

• Glycogen- a polysaccharide that is found in animals

• Cellulose- a polysaccharide found mostly in plants.

• Many people cannot digest cellulose because they lack the molecule necessary to break the bonds between the glucose monomers in cellulose.

• 
  

  Concept Check 5.2

  Explain the difference between a monosaccharide and a disaccharide.

• A monosaccharide is basically a simple sugar with one sugar unit. Glucose and fructose is a good example of a monosaccharide. A disaccharide is two or more monosaccharides combined and sucrose is a example.
  

  Compare and contrast starch, glycogen, and cellulose.

• All of the starch, glycogen and cellulose are basically polysaccharides that store energy. Starch (can only be found in plants) and glycogen store the energy that the body needs. Cellulose are basically the same thing but they are found in plants. They make plants stronger.
  

  How do animals store excess glucose molecules

• Animals store exess energy from glycogen. When needed, the glycogen breaks down and forms glucose. This would be a source of energy for animals.
  

5.1

• Organic molecules- the classification of carbon based molecules
• Inorganic molecules- the classification for non carbon based molecules
• Functional Group- A group of atoms within a molecule that interacts in predictable ways with other molecules.
  
• Hydrophilic- the ability to attract water molecules
• Monomers- creates polymers
• Polymers- a line of monomers
• Carbon has
  only 4 electrons in it's highest occupied energy level.
• Each time a monomer is added to a chain, a water molecule is released
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  Concept Check 5.1
  Draw a molecule that has a three carbon skeleton and a hydroxyl group on the middle carbon.


• 
  Explain the connection between monomers and polymers.
  A chain of monomers make up a polymer.
  What molecule is released during construction of a polymer? What is this reaction called?
  A water molecule is released during the construction of a polymer. This reaction is called dehydration reaction
  Draw at least three ways in which five carbon atoms could be joined to make different carbon skeletons.
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