2.3 Carbon-Based Molecules

LEQ: What is the relationship between proteins and nucleic acids?

• Reading: 32.1, 2.3; Quiz tuesday; test next monday

• Activator: ruminations– “DNA neither cares nor knows. DNA just is.” Richard

Dawkins.

– In your group, discuss what this quote might mean

• Key terms – protein, nucleic acid

2.3 Carbon-Based Molecules

Proteins are responsible for nearly every task that a cell performs.

• Monomer: amino acid– Common structure, unique R groups– left: general amino acid structure– right: serine is polar, hydrophilic

2.3 Carbon-Based Molecules

– Polypeptides consist amino acids linked by peptide bonds

– Information-rich.

2.3 Carbon-Based Molecules

2.3 Carbon-Based Molecules

2.3 Carbon-Based Molecules

• Polypeptides differ in number and order of amino acids.– characteristic sequence; changes alter function– Amino acids interact to give a protein its shape.

hydrogen bond

Hemoglobin

2.3 Carbon-Based Molecules

The information & function of proteins is encoded in the sequence of nucleic acids.

• RNA– Protein synthesis– Chemical reactions– Gene regulation….

• DNA– Encodes biological

information

2.3 Carbon-Based Molecules

2.3 Carbon-Based Molecules

A phosphate group nitrogen-containing molecule,called a base

deoxyribose (sugar)

• Monomer (multi-part): nucleotide

2.3 Carbon-Based Molecules

• The nitrogen containing bases are the only difference in the four nucleotides.

2.3 Carbon-Based Molecules

• Polynucleotides (left) have a unique sequences of bases:– Hydrogen bonding– DNA is double stranded (right)

2.3 Carbon-Based Molecules

Genes store the information necessary to assemble proteins.

• A gene is a segment of DNA that stores genetic information on a chromosome.– mutation

2.3 Carbon-Based Molecules

Summary:

• Explain how both nucleic acids and proteins are polymers. Be sure to describe the monomers that make up the polymers.