Genetic/Hereditary Material (DNA)

Standard: S7L3a – Explain the role of genes and chromosomes in the process of inheriting a specific trait.

Essential Question – What is genetic/hereditary material (DNA)?

Warm-up – Discuss with your partner what you already know about DNA.

DNADNA= = Deoxyribose Deoxyribose

Nucleic AcidNucleic Acid

The Blueprint For Life

What do we already know about DNA?

It is found in the nucleus DNA makes up chromosomes It is the hereditary material for all

cells Eukaryotes AND prokaryotes contain

DNA, although prokaryotes do not have a nucleus

Chromosomes and DNA GENES-sections of

DNA that contain instructions for characteristics

Our genes are on our chromosomes.

Chromosomes are made up of DNA.

CHROMOSOMES

DNA In humans, the DNA

molecule, if fully extended, would have a total length of 1.7 meters. If you unwrap all the DNA you have in all your cells, you could reach the moon ...6000 times!

DNA by the numbers

The average human has 75 trillion cells. DNA has a diameter of only 0.000000002

m. If you unravel all the DNA in the chromosomes of just ONE of your cells, it would stretch out 2 meters.

The earth is 150 billion m, or 93 million miles from the sun.

If you unravel all the DNA in the chromosomes of ALL of your cells, it would stretch from here to the sun more than 400 times!

The Double Helix - Discovery

Watson and Crick = scientists that discovered the shape of DNA IN 1953

Franklin = Contributed to discovery with X-ray photo of molecule in 1952

DNA Structure 3 PARTS OF DNA Nucleotide =

1. Sugar = Deoxyribose

2. Phosphate

3. Nitrogen Base

*Nucleotides link with sugar & phosphates alternating and bases sticking out in middle

DNA Structure-Nitrogen Bases

4 bases of DNA (GCAT):1.Guanine (G)2.Cytosine (C)3.Adenine (A)4.Thymine (T)

Complimentary Bases

Two Strands are held together by the bases in the middle.

G & C always bond.A & T always bond

Adenine and Thymine always join together

A T

Cytosine and Guanine always join

together

C G

Important:Important:

COMPONENTSDNA ISDNA is a series of nucleotides

connected together

The Double Helix = Shape of DNA: 2 sides of Nucleotides,` link in the middle at

the bases, then twist

DNA Models

Figure 10.3D

Ribbon model Partial chemical structure Computer model

Hydrogen bond

DNA Replication

1. Occurs during Interphase

2. DNA makes an exact copy of itself

3. Occurs in the nucleus of the cell Why is this necessary?

DNA Replication-STEPS

1. DNA separates or unzips

2. Nucleotides pair with bases on old chain

G-C A-T3. Two strands

created: ½ is the OLD strand; ½ is the NEW strand.

Unzipped DNA And Replication Of DNA

Exact copies of original DNA

Figure 10.4B

Complete The 2nd Strand Of DNA From Replication

A A T T T G C C G G A T A C G -OLD T T A A A C G G C C T A T G C -NEW T T T G G C A T T G A T C G C C -OLD A A A C C G T A A C T A G C G G -NEW A T A C G A C T T T A A A G G T -OLD -NEW T T A G C A T T A G C A T A T T -OLD -NEW G G G C C C A A A T T T C A T -OLD -NEW