Nucleic Acids, Proteins, & Gene Expression Honors Biology

Macromolecules are large organic carbon compounds Carbohydrates Lipids Proteins Nucleic Acids

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

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

Monomer: Nucleotide 5-Carbon Sugar Phosphate Group Nitrogen Base Polymer: DNA (double stranded)/ RNA (single…)

Biological Functions: Storage of heritable information in every cell Helps make protein

You started as one cell with one set of DNA Now you are trillions of cells! Each cell has the same DNA

Process for copying DNA into every cell Occurs in all living organisms Many enzymes are used!

Basic olgenetics/dna-rna2.swf olgenetics/dna-rna2.swf Complex replication-advanced.html replication-advanced.html

For 3.5 billion years, DNA has been replicating For the production of new cells: Single celled organisms reproduce Multicellular organisms grow Occasionally errors occur

Any change in genetic material Small scale mutations refer to nitrogen base errors

Changes in zygote DNA are replicated into every cell ~50 of your 3,200,000,000 bp are mutations

Environment can change your DNA in somatic cells

Mutations are necessary for the survival of populations Mutations are responsible for genetic diseases Some mutations enable you to shoot lasers out of your eyes

Substitution: exchanges nucleotides Deletion: removal of a nucleotide Insertion: addition of a nucleotide

Point mutation in the gene that codes for Hgb. DNA: Thymine replaced with Adenine Results in valine instead of glutamine Hgb folds incorrectly RBCs become sickle shaped RBCs cannot carry O2

Deletion of a gene that codes for protein CCR5 CCR5 is a surface receptor protein on a white blood cell Individuals with this mutation show resistance to HIV

Monomer: Amino Acid Carboxylic Acid (C & O) Amine Groups (N & H) Polymer: Polypeptide Chain 3D Structure of Protein Complex proteins fold

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

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

How are these molecules constructed in the biosphere

DNA  RNA  Protein

Organisms are a collection of traits!

Every cell of every organism has genetic information Entire set of DNA for an individual organism

Molecular process of converting DNA genes into a trait

Stage 1: Transcription Gene (section of DNA) is converted into mRNA code Stage 2: Translation mRNA, tRNA, rRNA link amino acids based on code Stage 3: Folding Polypeptide chain is folded into a specific protein shape

molgenetics/translation.swf molgenetics/translation.swf hill.com/olc/dl/120077/micro06.swf hill.com/olc/dl/120077/micro06.swf

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

Not all rxns. occur spontaneously Activation energy: the energy required to start a reaction

Inside a cell Chemical reactions occur all the time These reactions are normally slow

Enzymes Speed up reactions by lower the activation energy

Complex 3D polypeptide chain (proteins)

Enzymes interact with substrates Make molecules Break molecules

Water breaks down eggs PEPSIN is an enzyme What is the substrate in the experiment? Which test tube will break down the egg fastest?

Lock and Key Model Enzymes must fit perfectly with substrate Therefore, one enzyme per substrate

Induced Fit Model: The active site of an enzyme binds to a substrate Enzyme changes shape to perform a biological rxn.

Amylase: in your mouth breaks down starch Peptidase in your stomach break down proteins Lipase: in your small intestine break down lipids There are over 2000 known enzymes in your body

1. Temperature: Increase in temp.  increase in enzyme speed Too much heat, the enzyme is denatured or destroyed 2. pH: Also denature the enzyme