DNA, RNA, Mutations

Objective 2: 6a,b,c Biology: DNA, RNA, Mutation

The student knows the structures and functions of nucleic acids in the mechanisms of genetics. The student is expected to:

• (A) describe components of deoxyribonucleic acid (DNA), and illustrate how information for specifying the traits of an organism is carried in the DNA;

• (B) explain replication, transcription, and translation using models of DNA and ribonucleic acid (RNA);

• (C) identify and illustrate how changes in DNA cause mutations and evaluate the significance of these changes

Remember THIS?

Making a DNA copy of DNA is replication. Cells need to copy their DNA for mitosis (growth, repair, and maintenance). Daughter cells are genetically identical. DNA is also copied for meiosis (reproduction). Daughter cells are genetically different and have ½ the # of chromosomes.

C

P

D

C

P

D

C

P

D

P

D

G

P

D

GP

D T

P

DA

P

DT

P

D A

P

D

G

NitrogenBase

Phosphate group

Deoxy-ribose

DNA is made of building blocks called nucleotides. They consist of a deoxyribose sugar, a phosphate group and a nitrogen base. The bases are adenine, thymine, guanine, and cytosine.

RNA is made of building blocks called nucleotides.

They consist of a ribose sugar (instead of a

deoxyribose sugar), a phosphate group and a

nitrogen base. The bases are adenine, uracil,

guanine, and cytosine.

NitrogenBase

Phosphate group

ribose

DNA RNA

Both have adenine, guanine, and cytosine as bases

Has the base thymine

Has the base uracil

Both have a sugar phosphate backbone.

Sugar: Deoxyribose Sugar: ribose

There are three types of RNA:

mRNA-messenger (transcribes DNA)

tRNA-transfer (translates mRNA)

rRNA-ribosomal (used as a machine for translation)

REPLICATION : DNA copies DNA A T G C

http://www.johnkyrk.com/DNAreplication.html http://nobelprize.org/chemistry/educational/dna/b/replication/dna_compounds.html

TRANSCRIPTION: mRNA copies DNAA U G C T A

http://www.johnkyrk.com/DNAtranscription.html

TRANSLATION: mRNA is decoded and a protein is made from amino acids. A UG C

http://www.johnkyrk.com/DNAtranslation.html

MUTATION: Any change in the DNA sequence. If it is a point mutation (one letter is changed), it can change the amino acid sequence by changing the code.

Deletion

ATC ATG

Point mutation

Transcription

Translation 

DNA mRNA ProteinIn nucleus On ribosome

Let’s try it:

1. Write this DNA base pair sequence on you paper.

2. Write the complementary strand of DNA that would bond to them.

3. Translate the strand into mRNA.

4. List the amino acids that these codons stand for. Use the amino acid chart on the next slide.

ATGTGGCAG

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

Complementary strand that would form in Replication.

TACA

C

C

C

GT

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

AUGUGGCAG

DNA mRNA Amino Acids

Methionine

Tryptophan

Glutamine

Transcription Translation

Peptide Bonds

ATGCCATTCAATTAACCCTCC

1. Write this DNA base pair sequence on you paper.

2. Write the complementary strand of DNA that would bond to them.

3. Translate the strand into mRNA.

4. List the amino acids that these codons stand for.

DNA Original Strand

ATG CCA TTC AAT TAA CCC TCC

DNA Replicated Strand

TAC GGT AAG TTA ATT GGG AGG

mRNA AUG CCA UUC AAU UAA CCC TCC

Amino Acids

Met Pro Phen Asp Stop

DNA Simulation

http://www.johnkyrk.com/DNAanatomy.html

Interactive DNA Workshop

http://www.pbs.org/wgbh/aso/tryit/dna/index.html