p.106 (1-12,14,15)

1. (c) water

2. (b) carbohydrate

3. (c) hydrophillic

4. (b) lipid

5. (b) side groups

6. (d) substrate

7. (b)Lower  the activation energy of a reaction

8. You might consume pasta the night before a race because pasta has carbohydrates which can 

store energy for later use. 

9. Starch, glycogen, and cellulose are all polysaccharides and all three are made from glucose monomers.

10. Steroids are lipid molecules with four fused carbon rings. Steroids circulate y0ur body as chemical signals and are a starting point for which the body produces other steroids (cholesterol) 

11. Proteins are made out of polypeptides linked to amino acids. 

12. Denaturation causes the protien to lost its shape and lose its ability to function properly.

14. 

a) Water molecule

b) This is called dehydration. Dehydration happens when a monomer is added to the polymer chain and a water molecule is released. 

c) It could attach to the Leucine's OH and Serine's H.

15.

a) Enzyme A performs best at about 37-38 degrees anc enzyme B performs best at about 77-78 degrees. 

b) Enzyme A i found in humans. and enzyme B is thermophilic.

c) It slows down at 40 degrees because a human enzyme cannot be higher than that or else the the human would die. 

Summary of Section 5.5 ;))

-=Enzymes=-

Enzymes and Activation Energy

-to start a chemical reaction:

-it is necessary to weaken chemical bonds in reactant molecules

-this requires for the molecules to absorb energy

activation energy-minimum amount of energy required to start up a chemical reaction

-one way to provide activation energy: heat up the mixture of molecules

-hotter molecules may collide with enough energy to weaken bonds

-cooler molecules collide with less energy

-heating up a cell would cause many unnecessary reactions to occur at once, including reactions that destroy the cell's structures

-instead, cellular reactions depend on the assistance of catalysts

catalysts: compounds that speed up chemical reactions

enzymes

definition-specialized proteins that are main catalysts of chemical reactions in organisms

-provide a way for reactions to occur at cell's normal temperature

-doesn't supply activation energy to the reacting molecules

BUT

-lowers the energy requirement barrier so that the reaction can proceed at normal cell temperature

-each enzyme catalyzes a specific kind of chemical reaction

-at any moment's of a cell's life, the specific enzymes that are present and active determine which reactions occur

How do enzymes work?

-the shape of each enzyme fits the shape of the particular reactant molecules

substrate-a specific reactant acted upon by an enzyme 

active site-region of an enzyme into which a particular substrate fits

-the fit between substrate and enzyme is not rigid

-as the substrate enters, the active site changes slightly which fits the substrate more comfortably

-this places certain function groups of the active site in position to catalyze the reaction

-the tighter grip may also bend the substrate which bends its bonds

Another way that an enzyme can lower activation energy

-by accepting two substrates into adjacent sites

-holding the reactant together helps them to react more easily

So...

enzymes can catalyze the formation of larger molecules into smaller molecules 

-an enzyme's structure and shape is essential to its function

also...

-an enzyme's shape is sensitive to changes in its surrounding environment

So....

-factors of pH and temperature can greatly affect: 

-how well an enzyme works

-or if it can work at all

this is one reason why cells can only survive within certain conditions

Concept Check:

1.Explain the role of activation energy in a reaction. How does an enzyme affect activation energy?

The activation energy activates the reactants and triggers the chemical reaction. An enzyme lowers the activation energy to a normal temperature. 

2.Describe how a substrate interacts with an enzyme. 

A substrate enters into the active site of the enzyme, the active site changes shape slightly to fit the substrate more snugly. Then the substrate is converted into products.  

Summary of Section5.4 ;)

-=Proteins=-

protein: a polymer constructed from a set of just 20 kinds of monomers called amino acids.

-are responsible for almost day-to-day fuctioning of organisms

-proteins form structures such as hair and fur, make up muscles, and provide long-term nutrient storage 

-other proteins circulate in blood defend the body from harmful microorganisms

-act as signals, sending messages from one cell to another

-another group of proteins control chemical reactions in a cell

-=Amino Acids=-

definition: a monomer that makes up proteins

-consists of a central carbon bonded to four partners 

-the difference about the each type of amino acid is the "side group" that attaches the fourth bond of the central carbon.

-the side group is responsible for the particular chemical properties of each amino acid

-=Building a Protein=-

polypeptide: chain of linked amino acids 

-cells create protein by making polypeptides

-each link is created by a dehydration reaction between the amino group and the amino acid and the carboxyl group of the next amino acid

-proteins are composed of one or more polypeptide chains

-the body can make a variety of acids in different orders 

-most polypeptides are at least 100 amino acids in length 

-there is a very large number of possible polypeptides

-each protein has a unique sequence of amino acids 

-=Protein Shape=-

-a protein in a single form of amino acids linked together cannot fuction properly

-a fuctional protein consists of one or more polypeptides precisely twisted, folded, and coiled into a unique shape

-some side groups form bonds with each other

-these forces help to fold a polypeptide and keep it folded 

-a protein's shape is also influenced by the surrounding environment, which is usually aqueous

-water attracts hydrophillic side groups

-and rejects hydrophobic groups

-s0o...hydrophillic amino acids are on the outside edges of the protein while the hydrophobic amino acids are clumped in the center of the protein

denaturation: the loss of the normal shape protein due to heat, quality of the environment, or another factor

example: occurs when frying an egg (the egg white changes from a clear liquid to a white solid 

-this is because the polypeptide chains became tangled with one another 

-heating unfolds proteins because...

-most of the forces that keep the folding are weak attractions between pairs of side groups and between side groups and water.

-a protein's function depends on its shape so...

-if a protein loses it shapes (denatures) it won't be able to work properly :( 

Concept Check 

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

Y0u can see the protein that forms fur which keeps animals warm and the protein that forms muscles which keeps the body strong and being able to move. 

2.Relate amino acids, polypeptides, and proteins.

Cells create protein by making polypeptides, which are long chains of amino acids. 

3.Explain how a heat can destroy a protein.

Heat can destroy a protein because most of the folding are weak attractions between pairs of side groups and between side groups and water. The hot molecules collide with enough force to overcome the weak attractions. 

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

One hydrogen atom, an atom in a carboxyl group and and an atom in an amino group are the same in all amino acids. The uniqueness of each amino acid if the side groups that attaches the fourth bond of the central carbon.

Summary of Section 5.3 ;)

unsaturated fat

saturated fat

-=Fats, Lipids and Steroids=-

-=Lipids=-

definition: one of a class of water-avoiding compounds

-lipids act as a wall that surrounds and contains aqueous contents in your cells 

-other lipids molecules circulate in your body as chemical signals to cells 

-some other lipids can be known as fat, which stores energy in your body

hydrophobic: a characteristic of avoiding water molecules

-this is important for the fuctioning of lipids

-=Fats=-

definition: organic compound consisting of glycerol attached to three fatty acids

-some fats can be solid at room temperature

-other can be liquids at room temperature (oils)

-store energy for later use

-fatty tissues cushion the body's organs 

-provides insulation

-if consumed in huge amounts, then its unhealthy (can have heart disease)

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

examples: lard, butter

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

-this is because some of its carbon atoms are double-bonded to each other 

examples: fats in fruits, fish, and vegetables, corn oil, olive oil, vegetable oil..etc

-=Steroids=-

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

-all have a core set of four rings

-differ in the kinds and locations of fuctional groups attached to rings

-are classifies as lipids 

-hydrophobic

-some steroids circulate in body as chemical signals

Cholesterol: an essential molecule found in membranes that surround your cells

-starting point from which body produces other other steroids

-high levels of certain cholesterol in the blood can increase cardivascular diseease. (heart and vessel)

Concept Check:

1.What property do lipids share?

Lipids are all hydrophobic.

2.What are the parts of a fat molecule?

Glycerol(three carbon backbone) attached to three fatty acids which contain hydrocarbon chains.

 

3.Describe two ways that steroids differ from fats.

a)the structure of fats is different from steroids as fats have a three-carbon backbone and steroids have four fused carbon rings 

b)steroids circulate in your body as chemical signals while fats are store energy for later use and cushion your organs.

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

It means that it contains the less than the maximum number of hydrogen atoms in one or more fatty acid chains.