DNA to Eye Color?Just How does it Happen?

Problem?How do we go from DNA

to individual traits?

DNA acts as a blueprint

• DNA acts as a blueprint for making proteins

• It is these proteins that give you your hair and eye color!

Gee- what do ribosomes do?• Make Proteins• Where are they?• Cytoplasm & RER• DNA- the “recipe” for

making proteins is located in the nucleus

• HOW DO WE GET FROM NUCLEUS TO CYTOPLASM?

DNA to RNA?

• The instructions for assembling proteins are “transferred” from DNA to RNA, which is the second type of nucleic acid.

DNA vs. RNA

• Single Chain of nucleotides

• Sugar is Ribose

• Uracil instead of thymine

–Complimentary to adenine

Transcription• Transferring

information from DNA to RNA is called transcription

• Same as replication, except Adenine will pair with Uracil

–Fill in the strand

RNA Does the GRUNT WORK!• After Transcription-

RNA goes to the cytoplasm to find a Ribosome to make proteins

• 3 types of RNA to do this work!!

• mRNA• tRNA• rRNA

THE RNA’s • mRNA (messenger)

– Carries transcribed DNA code to ribosome

• tRNA (transfer)– Brings amino acids to

ribosome in correct order

• rRNA– w/ other proteins

makes up structure of ribosome

CHECKPOINT- Fill it in!!!!

• Double Helix

• Adenine

• Guanine

• Cytosine

• Thymine

• Deoxyribose

• Single Strand

• Adenine

• Guanine

• Cytosine

• Uracil

• Ribose

DNA RNA

CHECKPOINT 2

• mRNA

• tRNA

• rRNA

• Carries transcribed DNA code to ribosome

• Brings amino acids to the Ribosome

• Assists in ribosome structure

FINALLY! RNA to Proteins

First, ya gotta understand how the genetic code works!

Humans vs. Hard Drives

• DNA stores info in the form of long sequences of bases

• 30,000 genes in humans–3 billion base pairs

• Base pairs make up code for amino acid sequence, which make up the protein.

•A 3 base code in DNA or mRNA is called a codon.

Each codon translates to a particular amino acid.

•20 amino acids make up all proteins for life•Since codons are 3 bases, there are 64 different codon sequences

-Some amino acids have two or more codons.

These Codons are used by all living things; thus, showing the unity of life on

Earth

Protein Synthesis

• 1) Transcription- DNA is transcribed into mRNA in the nucleus

• 2) mRNA moves into the cytoplasm and attaches to a ribosome

Protein Synthesis (continued)• 3) Translation- the

ribosome reads the codon and matches it with its anticodon carried by the tRNA’s in the cytoplasm. Attached to these anticodons are the amino acids that will be built into a protein

Protein Synthesis (continued)• 4) Elongation-

Ribosome will continue to build proteins one amino acid at a time. During this time, tRNAs continue to bring the corresponding amino acids until ribosome enters a “STOP” codon.

– Ribosome falls off mRNA and protein ready for use

Now…Let’s practice