DNA Deoxyribonucleic Acid-Code-blueprint-hereditary material

2 2

I Can: Identify parts of a DNA Molecule

Do Now: 1. How are DNA, genes and

chromosomes related?

DNA contains many genes that are wrapped with special proteins to make a chromosome

Key VocabularyDNA – hereditary material that is

passed from parent to offspringGene – piece of DNA containing

information for making a specific protein

Chromosomes – DNA wrapped around special proteins that keep it together.

Genome: complete set of genes in an organism

DNA StructureDouble Helix – Two strands that look like a twisted ladder

Made up of millions smaller parts called Nucleotides.

Each nucleotide has:1. Phosphate group2. sugar3. base

Nucleotides

Phosphate

Sugar

Base

Nucleotides

Phosphate and sugar form the sides

Bases form the “steps”.

There are four types of bases:A, T, C, & G

Nucleotides

A

Adenine

T

Thymine

G

Guanine

C

Cytosine

Complementary Base Pairing

Adenine (A)Thymine (T)

Cytosine (C)Guanine (G)

Form a base pair.

Form a base pair.

The order of the bases in one strand determines the order of the bases in the other strand.

Complementary Base Pairing

G

G

A

T

T

A

A

C

T

G

C

A

T

C

I can: Explain how DNA copies itself

Do Now: 1. The sides of a DNA molecule are made up of _________.2. The steps of the DNA molecule are made up of ________.3. The four bases in DNA are ________.4. Write the sequence of bases for the second strand:

A G G - C T C - A A G - T C C - T A G

Adenine, Thymine, Cytosine, Guanine

bases

Sugar and phosphate group

T C C - G A G – T T C - A G G – A T C

What is DNA Replication?DNA Replication

Copying DNA in a cell before it divides

How much DNA do we need to copy?bacteria: 3 million base pairshumans: 3 billion base pairs

Where does it happen?

Why does it happen?So daughter cells

have a complete copy of the parent DNA

?

?

?

?

When does it happen?Remember

Interphase in mitosis?

S-phase or synthesis

How does DNA replicate?

Semi-conservative: New DNA molecule has one old strand and one new strand

I can: Explain how DNA copies itself

Do Now: 1. In what phase of the cell cycle does

DNA replicate?2. Where in the cell does DNA replicate?

3. DNA replicates semi-conservatively. What does semi-conservative mean?

HW: page 57 # 1-6

INTERPHASE

NUCLEUS

New DNA molecule has one old strand and one new strand.

Key VocabularyReplication fork – site where DNA is separated and copied

Enzymes – made by living things; proteins with a specific function (saliva)Helicase separates two strands of DNA

DNA Polymerase adds new bases

Sequence: order of bases – ATCGCAT

How does DNA replicate?1. Replication Fork

Site where DNA is separated and copied

The EnzymesHelicase: separates or “unzips” the two

strands of the double helix

The EnzymesDNA polymerase: adds new bases and proofreads the bases

Video Cliphttp://highered.mcgraw-hill.com/olcweb/cgi/plu

ginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120076/micro04.swf::DNA%20Replication%20Fork

Step 1: Helicase separates the two strands

Step 2: DNA Polymerase adds bases to copy each strand of DNA

Step 3: Two new DNA molecules are created

Write the complementary DNA strand for each of these DNA strands:

DNA• GAATTACA• CCAATTAG• ATAGACAG

DNA• CTTAATGT• GGTTAATC• TATCTGTC

1) After replication, the new DNA molecule has one _______ strand and one ______ strand

2) Sites where DNA separation & replication occur are called: __________ _______

3) DNA separates into two strands by the enzyme called __________.

4) The enzyme ________________ adds bases along the original DNA strand.

DNA Replication Review

old new

Replication fork

Helicase

Polymerase

I can: compare and contrast DNA and RNADO NOW: What are the functions of Helicase and

DNA polymerase?

Helicase unwinds DNADNA Polymerase adds new bases

Think Pair ShareYour custom bike

What are genes?Where are they located?What are ribosomes?Where are they located?

Instructions for a protein

Nucleus

Make proteinscytoplasm

(Gene)

DNA

Ribosome

RNA Protein

Ribonucleic Acid (RNA )StructureUracil (U) replaces Thymine (T)T pairs with A, but A pairs with UC pairs with GSingle strandMessenger RNA (mRNA) carries the

sequence for making a protein from the nucleus to the ribosome

DNA: A G G - C T C - A A G - T C C - T A G

mRNA: U C C - G A G - UU C - A G G - A U C

Quickdraw: How does DNA lead to a trait?

DNA RNA Protein

Trait• Stays in the

nucleus• Holds

instructions for making proteins

• Made in the nucleus and goes to the cytoplasm

• Used as body structures (muscle, bone, skin, hair), enzymes, hormones, etc.

• Observable characteristic• “Who you are”