Intro to Genetics:DNA Structure & Function Genetics: the study of heredity

What determines an organism’s traits (characteristics)?

How are traits passed on from one cell to another, and from parents to offspring?

DNA: the molecule that carries genetic information

DNA has two important functions: Carry instructions for making proteins that

determine your traits Replicate – make exact copies of itself so it can

be passed on DNA is found in all cells (in the nucleus in

eukaryotic cells)

DNA

ChromosomesVery long, coiled/bunched up strands of DNA that contain many genes

Gene: Instructions for making a protein that determines a traitAnother Gene:

instructions for making a different protein that determines a different trait

Nucleotide Base PairsBuilding blocks of DNA

Genetic Info in Cells

DNA Structure

Objectives for Class:Describe the structure of DNA.

DNA Structure DNA is made out of

Nucleotides Nucleotides have 3 parts:

Deoxyribose Sugar Phosphate Nitrogenous Base (A, T, C, or

G) DNA molecule = double helix

of nucleotides Sides: alternating phosphates

& sugars Middle/ “Rungs” of ladder:

Pairs of Nitrogenous Basesconnected by Hydrogen bonds

Objectives for Class:Describe the structure of DNA.

Base PairingA ---- THydrogen bonds

connect themG ---- C

Objectives for Class:Describe the structure of DNA.

DNA Structure: Images

Objectives for Class:• Describe the structure of DNA.

DNA Replication: Overview DNA can make an

exact copy of itself!

Occurs every time a cell needs to reproduce

What is the first thing that would need to happen to replicate this DNA?

Objectives for Class:Describe the structure of DNA.

Steps of DNA Replication1. Double helix splits

(unwinds and unzips) Hydrogen Bonds break Separates into 2 single

strands2. New nucleotides match

up with each side DNA Polymerase is the

enzyme that does this Matches according to base-

pairing rules3. Two new strands twist upResult: Two Double Helices

Each half old, half new.

Objectives for Class:• List the steps of DNA replication

DNA Replication: Summary

Bio 9B: Friday, 2/17/12Title: DNA Review

Homework: Optional - Finish Parts 2 and/or 3 of the DNA Review PacketSilent Do Now: (in notebook w/ title & date)

1. Write the complementary base sequence to this single strand of DNA

2. Which of the pictures below best illustrates DNA replication? Why?

G A A C G T

A. B. C.

Bonus: Who is the perfect Valentine for a gentleman named CTCT?