Lecture #2 Date ______

• Chapter 4~Carbon & The Molecular Diversity of Life

• Chapter 5~ The Structure & Function of

Macromolecules

• Objectives:– Chemistry Quiz– Compare and contrast the 4

groups of organic compounds

You should know

• Atomic mass, atomic #, valence shells• Bonds

– Ionic– Covalent

• Polar (hydrophilic) vs Non-polar (hydrophobic)

– Hydrogen

• Isomer vs Isotope• Properties of H2O

Practice

1) 7p, 7n, 7e

2) 7p, 8n, 7e

3) 8p, 7n, 7e

4) 9p, 9n, 9e

• How many different elements are here?

• Which are the same?• Which has/have a charge

of -1?• Which has/have an atomic

weight of 15 amu?• Which has/have 1 valence

e-?

Organic chemistry

• Carbon-tetravalence-tetrahedron-shape

determines function

Organic Compounds

Hydrocarbons

• Only carbon & hydrogen (petroleum; lipid ‘tails’)

• Covalent bonding; nonpolar• High energy storage

• Isomers (same molecular formula, but different structure & properties)

– structural~differing covalent

bonding arrangement

– geometric~differing spatial arrangement

– enantiomers~mirror images pharmacological industry (thalidomide – morning sickness drug)

Testosterone vs Estrogen (fig. 4.8)

Organic compounds

• To build organic compounds you take hydrocarbon chains and add functional groups.

• Molecules with the same functional groups will have similar physical and chemical properties.

Functional Groups – besides H

Monomer vs Polymer

Carbohydrates

Monosaccharides – smallest unit

Glucose Isomers

Glycosidic Linkages

Polysaccharides

• Polysaccharides – Storage:

• Starch~ primary storage molecule for plants• Glycogen – storage molecule for animals (in liver

and muscles), alpha links, can be broken down by human enzymes

– Structural: • Cellulose~ most abundant organic compound; • Chitin~ exoskeletons; cell walls of fungi;

surgical thread

Uses of carbohydrates

Simple vs Complex Carbs?

Why are complex carbs better?

1. Weight management – take longer to eat

2. Fiber makes you feel fuller

3. Contain vitamins, minerals, etc.

What happens when you eat too many carbs?

• Excess carbs stored as fat

• Simple carbs will cause a drastic increase in glucose – causes a release of insulin

• Insulin then tells your body to store fat

• Complex carbs do not cause a drastic increase in glucose levels (are broken down slowly)

Low Carb Diets?• Carbs are needed to synthesize glycogen which

are needed for effective workouts

• Without glycogen, you cannot burn as much fat

• Body uses fuel in this order (Glycogen, Fat, Muscle)

• Low calorie diets can make your body burn muscle which causes a loss in total calorie burning potential – muscle cells have more mitochondria)

• Weight comes off because of lost muscle but comes back as fat (NOT GOOD)

• Ideal amount: 2000 cal diet = 250 g carbs

Lipids – fats, waxes

Triglycerides – contain C,

H, O(H:O > 2:1)

Saturated vs Unsaturated

Phospholipids - Amphipathic

Steroids

• Lipids with 4 fused carbon rings

• Ex: cholesterol:cell membranes;precursor for other steroids (sex

hormones); atherosclerosis

Are ALL Fats Bad?

–Hydrogenating (adding hydrogen) unsaturated fats to make them solid (peanut butter and margarine) are just as unhealthy as saturated fats

Unhydrogenated Peanut Butter

• Men need 4-7% body fat

• Women need 9-16% body fat

• Going below these percentages is harmful since your body can’t perform all its normal functions

Good Things About Fat• More energy than carbs or

proteins• Helps absorb Vitamins A, C,

etc.• Healthy skin• Gives us fatty acids for growth

The Good – Omega-3 Fats

• Lower blood pressure

• Decrease risk of heart attack

• Protect against irregular heartbeats

How much should you eat?

YUM!

• You should consume 20 to 30% of your total calories from fat

• No more than 10% should be saturated fats

Too much or too little can be a health risk!

NucleicAcid

Proteins

Amino Acids/Side Chains

–Nonpolar – contain –CH2 or –CH3 (Hydrophobic)

–Polar uncharged – Contain O or only –H (Hydrophilic)

• Ionizable – acid (R groups are negative) or base groups (R groups = +)

Peptide Bonds/Polypeptide

Primary Structure – amino acid sequence

determines the protein

-If you switch 2 amino acids, you get a whole new

protein

Amino acid substitution – 1 out of 600 amino acids

Secondary Structure –

alpha helix & beta pleated

sheet

Tertiary Structure

Quaternary Structure – 2 or more polypeptides bond together

Protein Folding Animation

• http://intro.bio.umb.edu/111-112/111F98Lect/folding.html

• http://intro.bio.umb.edu/111-112/111F98Lect/folding.html

AP LAB 2

– Pre-Lab

Warm-up- Have out your organic compounds WS – we will go over it

1.What bonding is associated with the following:– Primary structure of protein?– Secondary?– Tertiary?

2.What 2 main functions do proteins provide your body?

3.What four things does a amino acid have (structure)?

4.What is the smallest unit of a nucleic acid?

What we’ve covered the last few days

• Organic compounds – carb, lipid, protein, nucleic acid– Monomer, function, elements, examples– Able to recognize structural/molecular formulas

• Enzymes– Protein folding– Characteristics– Environmental factors affecting rate (lab)– Regulation (end of class today)

Homework

• Study for test

• Internet review – not for a grade

• No Quiz tomorrow – canceled– Quizzes – drop 1 per 9 weeks

Protein Folding

Inactive Active

Chemical Reactions/EA

• Metabolism – all chemical reactions in a biological system

• Catabolism – breakdown of substances

• Anabolism – formation of new products

Induced Fit

Induced Fit

Anabolic Enzyme

Catabolic Enzyme

Enzymes

• Bind to substrate (molecule it acts on)

• Are specific (binds to certain substrate)

• Has active site (where substrate binds)

• Are reusable

• Are affected by temperature and pH

Enzyme Animations• http://highered.mcgraw-hill.com/sites/

0072495855/student_view0/chapter2/animation__how_enzymes_work.html

• http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__enzyme_action_and_the_hydrolysis_of_sucrose.html

• http://www.phschool.com/science/biology_place/labbench/lab2/binding.html

Go over Quiz

Finish Enzyme Lab

• Safety Goggles – pH lab group, temperature group when heating

• Whiteboard – data while you are finishing, be ready to explain data after lab

Enzyme Lab Conclusion

• Rate of reaction is determined by measuring the disappearance of substrate or the accumulation of product

• Rate of reaction is the slope of the linear portion of the graph

• Reaction rate is affected by pH, substrate conc., enzyme conc., temperature, and ionic con.

Conclusions• Enzymes have optimum pH,

temperature, and salt concentrations that they work in

• General rules– Temp

• Lower the temp, the slower the molecules collide – slower the reaction rate

• Higher the temp, the faster the molecules move around – faster the reaction rate

• Too high a temperature (60-70 C) – protein denatures – reaction doesn’t occur

• pH – too high or too low the H+ or OH – ions react with the amino acid side chains (R groups) – improper folding occurs – reaction slows

• Salt conc. – too much or too little causes improper folding of protein

• Substrate concentration – lower the substrate conc., the slower the reaction

• 6. After an enzyme is mixed with its substrate, the amount of product formed is determined at 10-second intervals for 1 minute. Data from this experiment are shown below:

Time (sec) 0 10 20 30 40 50 60

Product formed (mg) 0.00 0.25 0.50 0.70 0.80 0.85 0.85

• What is the initial rate of this enzymatic reaction? Show your calculation.

.025 mg/sec

• What is the rate after 50 seconds? Show your calculation. Why is it different from the initial rate?

.02125/sec (substrate is running out)

Factors Affecting Enzyme Activity

Cofactors/Coenzymes – other molecules that aid in enzymatic function (can bind along with the

enzyme)

ATP/Energy Coupling

Enzyme Regulation – Inhibition/Activation

Allosteric Regulation

Enzymes –Active and Allosteric

Sites

Enzyme Animations

• http://www.northland.cc.mn.us/biology/biology1111/animations/enzyme.swf

• http://bcs.whfreeman.com/thelifewire/content/chp06/0602001.html

Feedback Inhibition