Reading notes quiz#1, answer 4 of 5:

1. does irradiating food add radiation to food? Explain2. Describe the “octet rule”3. What are the two types of chemical bonds4. List at least 3 important properties of water5. Biological molecules are grouped into four categories; list at

least 3 of these four.

Reading Notes Quiz#2:Answer 3 of these 4 questions

1. Biological molecules are grouped into four categories. List 3 of these 4.

2. How do perms and relaxers work on hair?

3. Describe the difference between a monomer and a polymer; give an example of a monomer and a polymer (your example does not have to be a biomolecule).

4. Like all lipids, a triglyceride is insoluble in water because it lacks many fill in the blank functional groups. Triglycerides are used for fill in the blank and are made from two subunits, a single molecule of fill in the blank plus three molecules of fill in the blank.

HydrophobicHydrophilicFatty acidsGlycerolAmino acidGlycogenLong-term energy storageQuick and ready source of energyStoring genetic informationMaking a phospholipid membrane

What did this little piggy build his house with?

(why does he build it with that that stuff, and how does he build it?)

What do you get if you crack open a cell?

What: You are what you eat!the four classes of biomolecules

Nucleic acid (DNA, RNA)

Protein (amino acid)

Lipids (fat)

Carbohydrates (sugars)

Why build a cell with these materials?

What: Why (what is used for?):Lipids (fat) store energy (fats and oils)

build cell membranes (cholesterol & phospholipids)

cell to cell signaling (steroids)

Sugar (carbohydrates) build cell structures (cellulose), quick energy (glucose)

Protein build cell structures (microtubules)build cellular machines (enzymes)

Nucleic acid store genetic information (DNA)

How do you build a cell: Biomolecules are built using a

carbon scaffold + functional groups

Carbon scaffold (C and H)

Analogy: train cars

string of Christmas lights

Functional groups (O, N, P, S)

Analogy: Different cargo in each train car

Different colored light bulbs

monomer + monomer + monomer + monomer = polymer“Food” is a polymer, you tear it down into monomers a rebuild polymersAnalogy: tear down a house into 2x4’s, bricks, windows, and rebuild

Biomolecule #1Lipids - water insoluble hydrocarbons (C + H):

triglycerides (fats and oils)

phospholipids

cholesterol / steroids

What’s their structure? What are they made from?What’s their function?

One type of lipid: Triglycerides (fats and oils)

glycerol + fatty acid (sugar alcohol) + (hydrocarbon)

Why are hydrocarbons (like fatty acids) insoluble in water?

WHAT IS A TRIGLYCERIDE USED FOR?

Different types of fatty acids:Saturated: all bonds between carbon are single bonds

Unsaturated: some double bonds between carbons (therefore less Hydrogens)cis vs trans affects there physical property

Page 43, fig 3.13

Another type of lipid: Phospholipids

Phospholipids - p 44, fig 3.14

how are these different from triglycerides (fats and oils)?(what are they made from?)

What’s their function?

Another type of lipid: cholesterol & steroids

cholesterol & steroids - p 44, fig 3.15

how are these different from phospholipids and triglycerides?What are they made from?

how are they similar?

What’s their function?

Biomolecule #1Lipids - water insoluble hydrocarbons (C + H):

triglycerides (fats and oils) long term energy storage

phospholipids build cell membranes

cholesterol / steroids building cell membranes & signaling between cells

Lipids are insoluble in water because they are built from hydrocarbons, and hydrocarbons are hydrophobic because they do not have any functional groups that form hydrogen bonds with water.

Why is a water-insoluble molecule good for: storing energy, orbuilding cell membranes, orsignaling between cells?

Biomolecule #2Carbohydrates (sugars) - Carbon + H2O:

monomers: glucose, fructose, galactoseglycerolribose, deoxyribose

polymers:Disaccharides (lactose, maltose)starchglycogenCelluloseChitin

Carbohydrates monomers

carbohydrates polymers: various usesstarch, glycogen, cellulose

chitin (glucose + NH2, amino functional group

Biomolecule #2Carbohydrates (sugars) - Carbon + H2O:

monomers: function:glucose, fructose, galactose quick energy sourceglycerol build triglyceridesribose, deoxyribose build DNA, and RNA

polymers: function:Disaccharides (lactose, maltose) quick energy sourcestarch energy storage (plants)glycogen energy storage (muscle)Cellulose build structuresChitin build structures

Biomolecule #3Proteins - modified carbon skeleton backbone:

backbone is amino + carbon + carboxylic acid,plus many diverse functional groups

monomers:amino acids

polymers: peptides/proteins enzymesMicrotubulesHemoglobinMembrane proteins

Protein monomer is amino acid.amino acids have modified carbon skeleton backbone:

amino + carbon + carboxylic acid,plus many diverse functional groups

Amino Acid Functional Groups:

Proteins are the most versatile biomolecules because they are made from chemically diverse monomers (amino acids with many different functional groups)

A protein (or peptide) is a polymer made from amino acids

Biomolecule #3Proteins -

…but what does a protein do?

Just about everything!

polymers: peptides/proteins function:enzymes “machine” / metabolismMicrotubules used to build structures Hemoglobin used to transport other moleculesMembrane proteins selective doorway into cell

What’s an enzyme? What do I mean by “cellular machine”?

Enzymes are “machines” that enable certain bonds to form or break faster than they would without the enzyme

How do machines work?Shape determines function

Cup

Spoon

Hammer

knife

How does a Protein do its function? It folds into a particular shape.

Primary structure: String of amino acids

Secondary structure: Backbone H-bonds with self, making helix or sheet

Tertiary structure: Functional groups determines shape

shape determines function/activity

ADH (Alcohol DeHydrogenase) protein structure

QuickTime™ and a decompressor

are needed to see this picture.

Proteins can unfold (denature)

Too hot

Too acidic or too basic

Biomolecule #4:Nucleic acids nitrogen-containing “base”

+ sugar (ribose or deoxyribose)+ phosphate

Monomer (nucleotide bases): function:A (Adenine) energy “currency”T (Thymine) and U (Uracil)G (Guanine)C (Cytosine)

Polymer: function:DNA store genetic informationRNA “translate” from DNA to protein

Nucleic acid monomers (nitrogen-containing “base”+ sugar + phosphate) and polymers (polynucleotide, example: DNA, RNA)

How does DNA store information?

RNA “translates” information stored in DNA into a protein that

can actually do something

(enzyme, structural scaffold, etc)

Chemical Nature of DNA: good for storing genetic information

DNA stores information well: polyanionic - prevent folding,

therefore structure not changed by encoded information (imagine if the property of the message you wrote on paper changed the physical properties of the paper/info)

easy to copy because of double helix with base pairing

(like shaking hands) stable

O

O

O

O

PO

O

H

PO

PO

OO

N

N

N

N

N

O

N

N

N

O

O

O

N

ON

O

O

P

O N

O

N

O

O N

O

P

O

N

X

X

X

N

N

O

O

O

N

O

N

O

O

O

N

O

O

O

P

N

O

O

O

N

N

N

O

N

N

H

H

H

H

H

H

PO

H

H

H

H

H

HH

O

N

NN

N

O N

O

OX

O

O

PO

O

H

H

O O

R

R

-

-

-

-

sugar

-

-

T/U

A

CG

A

T/U

-

-

nucleobase pairs

R

R

R

C

chargedphosphodiesterlinkages

Repeating charge does not fold

G

Chemical Nature of Protein: good for building structures and catalyzing chemical reactions

Proteins are made of 20 amino acids, offering many different chemical functionalities (positive and negative charges, hydrophobic, base, thiol)

Therefore proteins can fold into many shapes, and their physical propeties (function) can change dramatically

R

H

R

HR

H

R

H O

N

H

O

N

H

O

N

H

O

N

H

NN

NN

HO

HO

HO

HO R

H

R

HR

H

R

H

R2 R3R1

..

.. ..

R 5 R 6R 4

δ+

..

direction of polypeptide chain

direction of polypeptide chain

Hydrogen bonds holding strands togetherR = aminoacids

δ- δ+δ- δ+

δ- δ+δ-

δ+δ- δ+

δ- δ+δ- δ+

δ-

Repeating dipole can fold = conformation

Amino acids contain chemical functionalitythat are primarily responsible for catalysis

Step back and wonder

Why are there 4 nucleotides in DNAWhy those particular 4 nucleotides?

Why 20 amino acids?Why those particular 20 amino acids?

Why is there RNA?Why does RNA use AGCU and DNA use AGCT?

Does life have to use DNA, RNA and protein?