Nucleic Acids, Proteins, & Gene Expression

Honors Biology ch 4 & 8

Macromoleculesin the

Biosphere

Macromolecules are large organic carbon compoundsCarbohydrates (Cell Energy)LipidsProteins Nucleic Acids

Life is built out of carbon molecules

Part 4: Proteins & Nucleic Acids

Prior to 1900’s human civilization understood:Cells preformed various functions for lifeProteins and nucleic acids existed

History of Nucleic Acids & Proteins

1941 Beadle and Tatum determined:Nucleic acids and proteins were linkedAnd responsible for many cell functions

History of Nucleic Acids & Proteins

Monomer: Nucleotide5-Carbon SugarPhosphate GroupNitrogen Base

Polymer: DNA/ RNA strands

Nucleic Acid Structure

Biological Functions:Storage of heritable informationHelps make protein

Nucleic Acid Function

Monomer: Amino AcidCarboxylic Acid (C & O)Amine Groups (N & H)

Polymer: Polypeptide Chain

3D Structure of ProteinComplex proteins fold

Protein Structure

Biological Functions:Catalyze chemical reactions (enzyme)Build & repair tissuesTransport & signal molecules

Protein Function

Human Tissues: Skin, Hair, Nails, Organs…Enzymes: make or break molecules

Biological Examples of Proteins

How are these molecules constructed in the biosphere

Building Proteins

DNA RNA Protein

Gene Expression

Part 5: Gene Expression

Organisms are a collection of traits!

Genes of life

Every cell of every organism has genetic information

Entire set of DNA for an individual organism

Genes of life

Molecular process of converting DNA genes into a trait

Gene Expression

Gene Expression Detailed Process

Stage 1: TranscriptionGene (section of DNA) is converted into mRNA

codeStage 2: Translation

mRNA, tRNA, rRNA link amino acids based on code

Stage 3: FoldingPolypeptide chain is folded into a specific

protein shape

Gene Expression Basic Process

http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swf

http://highered.mcgraw-hill.com/olc/dl/120077/micro06.swf

http://www.youtube.com/watch?v=41_Ne5mS2ls

Translation Animations

Enzymes

One chemical changes into another:Reactant: chemical that enters rxn.Product: chemical produced by the rxn.

Review: Chemical Reaction

Not all rxns. occur spontaneouslyActivation energy:

the energy required to start a reaction

Review: Chemical Reaction

Inside a cellChemical reactions occur all the timeThese reactions are normally slow

Biological Organisms

Biological CatalystsEnzymes

Speed up reactions by lower the activation energy

Complex 3D polypeptide chain (proteins)

Enzyme Structure

Enzymes interact with substratesMake molecules

Break molecules

Enzyme Function

Water breaks down eggsPEPSIN is an enzyme

What is the substrate in the experiment?Which test tube will break down the egg fastest?

Experiment

Lock and Key ModelEnzymes must fit perfectly with substrateTherefore, one enzyme per substrate

Enzyme Specificity

Induced Fit Model:The active site of an enzyme binds to a

substrateEnzyme changes shape to perform a biological

rxn.

Enzyme Specificity

Amylase:in your mouth breaks down starch

Peptidasein your stomach break down proteins

Lipase:in your small intestine break down lipids

There are over 2000 known enzymes in your body

Common Enzymes in your Body

1. Temperature: Increase in temp. increase in enzyme speedToo much heat, the enzyme is denatured or

destroyed

2. pH: Also denature the enzyme

What affects an enzymes?

Experimental Results

Experimental Results