Chapter 5 Review

=Reviewing concepts=

1. Which of the following is not an organic molecule?

a. cellulose

b.surcrose

c.water

d. testosterone

answer= c. water

2. Which of the following terms includes all the other terms on this list?

a. polysaccharide

b. carbohydrate

c. monosaccharide

d. glycogen

answer= b. carbohydrate

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. hydrophilic

4. Cholesterol is an example of what kind of molecule?

a. protein

b. lipid

c. amino acid

d. carbohydrate

answer= b. lipid

5. The 20 amino acids vary only in their

a. carboxyl groups

b. side groups

c. amino groups

d. lipid groups

answer= b. side groups

6. A specific reactant an enzyme acts upon is called the

a. catalyst.

b. sucrase

c. active site

d. substrate.

answer= d. substrate

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.

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

- You need energy before the big race so pasta provides you carbohydrates that will help you run well in the race giving enough energy.

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

-They are all made up of monosaccharides.

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

- Steroid is a lipd molecule in which the carbon skeleton forms four fused rings and the function in circulating in our body as chemical signals and cause the male and female appearances.

11. How are polypeptides related to proteins?

- Polypeptides create all different kinds of proteins.

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

- Denaturation affect proteins to change their shape and proteins do not function well.

*Applying Concepts

14. Analyzing Diagrams The reaction below shows two amino acids joining together.

a. One product of this reaction is represented by a question mark. WHich molecule is it?

- water molecule

b. WHat is this kind of reaction called? Explain

- Dehydration reaction takes place when a water molecule goes off and form a new bond with other polymers

c. If an amino acid were aded to this chain, at what two places could it attach?

- Amino acid can attach to either to the amino group of carboxyl group

15. Analyzing Graphs Use the graph to answer the questions below

a. At which temperature does enzyme A perform best? Enzyme B?

- Enzyme A: 38 degrees    Enzyme B: 78 degrees

b. Knowing that one of these enzymes is found in humans and the other in thermophilic(heat-loving) bacteria, hypothesize which enzyme came from which organism.

- Enzyme A: human             Enzyme B: thermophilic bacteria

c. Propose a hypothesis that explains why the rate of the reaction catalyzed by enzyme A slows down at temperatures above 40 degrees.

- Even though the temperature is above 40 degrees, the rate of the reaction slows down.  That means the product will be shortly released and the reaction is about the end.

Summary 5.5

=Enzymes are proteins that speed up specific reactions in cells=

*Key terms
activation energy: the 'start-up' energy that activates the reactants and triggers a chemical raaction.
catalysts: compounds that speed up chemical reactions
enzymes: the main catalysts of chemical reactions in organisms that are spcialized proteins
substrate: a specific reactant acted upon by and enzyme
active site: a particular region of enzyme where substrate fits into

*Enzymes and Activation Energy

- Reactions all need activation energy to react and produce a product.
-Ways to provide activation energy: -heat up the mixture of molecules.
-cellular reactions depend on the catalysts.
-specialized proteins called enzymes.
-enzymes help cells to react in its normal tempertaure
-not providing activation energy
-lowers the energy requirement barrier

*How Enzymes Work
-Enzyme fits the shape of only particular reactant molecules
-The fit between enzyme and substrate is snug
- tighter grip may also bend the substrate, weakening its bonds
- lower activation energy by accepting two reactant molecules
-temperature, pH, etc affects enzyme works.

*Concept Check 5.5
1. Explain the role of activation energy in a reaction. How does an enzyme affect activation energy?
- Activation energy is the energy that helps reactants to react. Enzymes catalyze the reaction.
2. Describe how a substrate interacts with an enzyme.
-Subscrate fits into an enzyme and get easily reacted

Summary 5.4

=Protenins perform most functions=

*Key Terms
protein: a polymer constructed from a set of just 20 kinds of monomers called amino acids
amino acid: monomer that makes up proteins; contains carboxyl and amino functional groups.
polypeptide: a chain of proteins linked by amino acids together.
denaturation: loss of normal shape of a protein due to heat or other factor.

*The Functions of Proteins

protein: a polymer by set of just 20 kinds of nomonmers(amino acids).
-functioning of organisms in daily life
ex) hair and fur, amke muscles, and provide nutrient storage
-less visible functions ex) circulate in the blood
fend the body from harmful microorganisms
hers that act as signals
-structure of proteins is the key to understanding their elaborate and diverse functions.

*Amino Acids
amino acid: consists central carbon atom bonded to four partners
- 3 parts are all the same

- one part=>hydrogen atom

- two others are a carboxyl group and amino group

+ 'side group' or 'R-group', the fourth bond of the central carbon, cause the difference about amino acids.

ex) leucine, and serine

*Building Protein

polypeptide: cells create proteins by linking amino acids together into a chain.

- the link is created by a dehydration between amino group of amino acid and the carboxyl group of amino acid in the cahin.

- body createds variety of proteins by arranging different amino acids in different orders.

- most polypeptide chains are at least 100 amino acids in length due to the 20 choices for each amino acid.

- each protein has unique sequence of amino acids.

*Protein Shape

- functional protein has one or more polypeptides precisely twisted, folded, and coiled.

- protein's shpe is also influenced by environment, usually aqueous

-> water attracts hydrophilic side groups and rejects hydrophobic

denaturation: changes in shape of protein due to temperatur, pH,or some other qualities

-ex) egg's white liquid part turning into solid while heating up.

*Concept Check 5.4

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

- Hair protects our head to be warm.
- Egg's white part is very nutrient

2. Relate amino acids, polypeptides, and proteins.

- Protein is made out of lots of amino acids and polypeptide is a chain that cells created by linking amino aicds. Therefore, amino acid is just a building blocks of these.

3. Explain how heat can destroy a protein.

- Heating up a protein is a change in temperature and that causes protein to unravel and change its shapes

4. Which parts of an amino acid's structure are the same in all amino aicds? Which part is unique?

- All amino acid has centeral carbon and side groups is the unique part where determines the property of proteins.

5.3 Summary

5.3: Lipids include fats and steroids
*Key terms
-lipids: the compounds that water avoid to be mixed together
-hydrophobic: Water-avoiding molecules

-fat: organic compound consisting of a three-carbon backbone (glycerol) attached to three fatty acids.

-saturated fat: a fat in which all three fatty acid chains contain the maximum possible number of hydrogen atoms

-unsaturated fat: a fat that contains less than the maximum number of hydrogen atoms in one or more of its fatty acid chains.

-steroid: a lipid molecule in which the carbon skeleton forms four fused rings

-cholesterol: an essential molecue found in the membranes that surround our cells.

*Characteristics of Lipids

lipids= water-avoiding compounds ex) fat, oil

hydrophobic= water-avoiding molecules

-other types of lipids 1)stored as fats

2)circulate in our body as chemical signals to cells

*Fats

-three-carbon backbone(glycerol) with three fatty acids

-fats have solid and liquid

-tissues cushion your organs and provide body insulation

-saturated contains maximum possible hydrogen atoms bonded with carbons

ex) butter and animal fats

-unsaturated is less than the maximum # hydrogen atoms cuz of double bonds with carbons

ex) fruiths, vegetables, fish, corn oil, olive oil

*Steroid

- a lipid molecule in which the carbon skeleton forms four fused rings

- hydrophobic like lipids

- steroid estrogen and testosterone functions cause the appearance of male and female.

- the different structure of molecules of testosterone and estrogen

+ Cholesterol: an essential molecule found in the membrances that surround our cells. A tlpe of steroid

- high-level cholesterol increase risk for cardiovascular disease.

Concept Check 5.3

1. WHat property do lipids share?

- Lipids do not want to mix with water. Therefore, lipids act as a boundary that surrounds and contains watery cells.

2. WHat are the parts of a fat molecule?

- Fats consist of a three-caron backbone called glycerol attached to three fatty acids on each part. Fatty acids have long hydrocarbon chains.

3. Describe two ways that steroids differ from fats.

- Steroids differ in structure and function. Steroids circulate in our body as chemical signals. Their estrogen and testosterone cause male and female appearance. In structure, these two types of steroids differ in the location of molecules.

4. What does the term unsaturated fat on a food label mean?

- Unsaturated fat means that there are some double bonds on hydrocarbons.

5.1 summary

=Carbon is the main ingredient of organic molecules=

*organic molecule=most carbon-bases molecules
*Inorganic molecule=Non-carbon-based molecules ex)H2O, O2, NH2

*Hydrocarbon=organic molecule that are composed of only carbon & hydrogen
*functional groups=group of atoms within a molecule that interacts in predictable ways with other molecules

*hydrophilic=functional group that attracts water

*monomers=large molecules that are built from many similar, smaller molecular units
*polymers=linked monomers together into long chains.

a polymer

Note=!

*Carbon skeletons and functional groups

-carbon> very common, has four partly-filled electrons in its highest energy level.
-Functional groups are important because carbon skeleton and the attached functional groups determine the properties of organic molecule

-Hydrocarbon=organic molecule that are composed of only carbon & hydrogen

-Hydrocarbons molstly used as fuel, gas.

ex) Methane(CH4).

-hydrophilic molecules(attract water molecules) such as hydroxyl groups tend to become surrounded by water molecules.

*Monomers and Polymers

-Bimolecules> composed of hundreds or even millions of atoms. Monomers create these.
-Polymers: the chains with monomers linked together.

-All different polymers are built from a collection of fewer than 50 kinds of monomers.

-Classification for life's large molecules: carbohydrates, lipid, proteins, and nuclei acids.

ex) spider's web is an example of polymer that is made out of protein

*Building and breaking polymers

Dehydratiion: two monomers bond to each other, making a polymer chain longer.

-Each time a monomer is added to a chain, a water molecule is released.

Ex) Hydroxyl group of one monomer reacts with a hydrogen atom from the other monomer releasing a water molecule eventually.

Hydrolysis: the addition of a water molecule breads the polymer chain.

-Our cells break down the monomers to obtain energy by adding a water molecule into it.

-Basicully water molecule has been removed to build a polymer

*Concept Check 5.1

1. Draw a molecule that has a three carbon skeleton and a hydroxyl group on the middle carbon (Hint: The molecule's fromula is C3H8O.)

-

2. Explain the connection between monmomers and polymers

-Polymers are the chain that is made of lots of monomers linked together and monomers are just one molecular units.

3.What molecule is released during constrcution of a polymer? What is this reaction called?

- a water molecule will be released and this reaction is called dehydration reaction

4.Draw at least three ways in which five carbon atoms could be joined to mke different carbon skeletons.