DNA Structurepg: 109

DNA• Deoxyribonucleic Acid (DNA) –

holds ALL the instructions for making proteins

• Nucleic Acid (DNA) is made up of nucleotides.

Nucleotides are made up of:1. Deoxyribose sugar

2. Phosphate

3. Nitrogenous base

Draw and label a nucleotide:

There are 4 different nitrogenous bases:

• Adenine (A)• Thymine (T)• Guanine (G)• Cytosine (C)

ThymineAdenine

CytosineGuanine

• Chargaff’s Rule – amount of adenine is equal to the amount of thymine & the amount of guanine is equal to the amount of cytosine

• The order of the nitrogenous bases determines the kind of protein made.

• ATE and EAT – same letters, different meaning

Adenine GuaninePurines(2 rings)

Thymine CytosinePyrimidines

(1 ring)

Who’s Who• In the 1950s,

James Watson and Francis Crick were the first to describe the shape of DNA

• Rosalind Franklin should also receive credit – without her work, they would not have been able to finish

Shape• DNA has 2 strands

• DNA is long so to save space it twists itself into a shape called a double helix

• If you flatten DNA it looks like a ladder. The sides of the ladder are made up of alternating phosphates and sugars.

Review

•A bonds with•G bonds with•T bonds with•C bonds with

T

C

AG

Prymidines

Purines

• Adenine (A)• Thymine (T)• Guanine (G)• Cytosine (C)

Nitrogen bases

Structure

Deoxyribose (sugar)

Nitrogen Bases

Phosphate

Base

Sugar

Phosphate

Replication of DNA• DNA Replication – copying DNA to

make identical copies– one will be passed along to the new cells

during mitosis/meiosis

BONDSAdenine = ThymineGuanine = Cytosine

SIDESPhosphate+

Sugar

1) What is the full name for DNA?

2) What do we call the shape of DNA?

3) Who first discovered the shape of DNA?

4) What type of sugar is found in DNA?

5) What 2 substances make up the sides of DNA?

6) A phosphate, nitrogenous base, and a sugar make a:

7) Where in the cell is DNA found?

8) DNA makes ________ for the body.

9) What are the nitrogenous bases in DNA?

10)What does adenine pair with?

DNA Replication

Pg: 44

Steps of Replication1. An enzyme breaks the bonds holding the

two strands together– That enzyme continues down the DNA

strand “unzipping” it

Steps of Replication

2. New nucleotides fly in and connect with the open nucleotides

- Now there are 2

duplicate DNA

strands!

Reading DNA Replication

1.TGGCAATG• ACCGTTAC

2.GTATGCCA• CATACGGT

3.AATGCCGT• TTACGGCA

4.CCCATGAC• GGGTACTG

RNA Structures

pg: 53

DNA Replication Review

1.ATGGCT• TACCGA

2.GCAGTT• CGTCAA

3.TCGAGA• AGCTCT

4.TTCCGA• AAGGCT

RNA

• Ribonucleic acid (RNA) – translates DNA genetic code into the actual proteins for the cell

RNA

• Has single strand• Ribose sugar• NO Thymine, Uracil

instead

ComparisonDNA• Double Strand• Deoxyribose sugar• Has thymine

RNA• Single Strand• Ribose sugar• Has NO thymine,

uses Uracil instead

RNA Transcription

ex ATGGCT• UACCGA

1. GCAGTT• CGUCAA

TranscriptionDNA

TranscriptionDNA

2. AATGCC• UUACGG Transcription

DNA

3. TTGCAG• AACGUC Transcription

DNA

Protein is what the cell makes!

• Amino acid – building blocks of protein

3 types of RNA:

1. Messenger RNA (mRNA) – brings instructions from the DNA

2. Transfer RNA (tRNA) – takes amino acids to rRNA

3. Ribosomal RNA (rRNA) – puts amino acids in the right order to make protein

Step 1

Step 1: Make RNA• Transcription – enzymes use 1 strand

of DNA to make an RNA strand (instead of Thymine, uses Uracil)

Step 2

Step 2: Translation – making protein• Codon – 3 letters on the mRNA that code

for a protein• Anticodon – a tRNA that matches the

codon, carries an amino acid

tRNA

tRNA

Amino Acid

CodonsUUG –

AGU –

ACA –

GGG -

LeucineSerine

ThreonineGlycine

UAU –

GUU –

CUU –

GCA -

TyrosineValine

LeucineAlanine

Quiz1. What are the 4 bases of RNA?

2. What sugar does DNA have?

3. What sugar does RNA have?

4. Replicate this DNA: ATGG

5. What is the process of making RNA called?

6. Transcribe this DNA into RNA: AATG

7. What amino acid does CAA code for?

8. What does RNA help make for your body?

9. Define Codon:

10.Which RNA brings instructions from DNA?

Protein Synthesis

Pg. 65

Messenger RNA (mRNA) carries instruction message from the DNA

Amino Acid basic building block of a protein

Transfer RNA (tRNA) transfers amino acids to the ribosomes

Translation translates the information in the mRNA into proteins

Codon 3 nitrogenous bases that form amino acids

Ribosomal RNA (rRNA)in the ribosomes, uses the directions to put amino acids in the right order

Anticodona tRNA that binds the 3 codons, the opposite molecule from a codon