Protein Synthesis:

DNA CONTAINS THE GENETIC INFORMATION TO PRODUCE PROTEINS BUT MUST FIRST BE CONVERTED TO RND TO

DO SO.

Why do cells need DNA?

DNA contains the information cells need to function and live.

Why do cells need to replicate (copy) their DNA?

To make new cells

How do cells replicate their DNA?

unwound by an enzyme.

1. The DNA double helix is

adds complementary nucleotides.

2. Another enzyme moves down the 2 original DNA strands and

3. Two separate DNA molecules are formed, each withone new strand and one old strand.

Replication Mistakes6 billion base pairs per cell.All are replicated in a few hours.

Mistake happens one per billion

nucleotides.

Mistakes = MutationsMutations are changes in the base

sequence of the DNA molecules.This can have serious affects on

genes and the functions of cells.Cancer is caused by mutations in

DNA.

MutagensPhysical of chemical factor

that increases the frequency of mutations.

Examples: UV rays, X-rays, smoking

3 Types of Mutations

Insertion: Adding nucleotide

Deletion Deleting nucleotide

Substitution Switch nucleotide

Protein Synthesis

Transcription

DNA vs. RNASingle

strandedRibose

sugarUracilAnywhere

Double stranded

Deoxyribose sugar

Thymine Nucleus

3 Types of RNAMessenger RNA (mRNA): Carries

information from DNA to ribosome for________________.

Transfer RNA (tRNA): Transport _________________.

Ribosomal RNA (rRNA): makes up the _____________.

protein synthesis

amino acids

ribosomes

TRANSCRIPTION

PROCESS OF MAKING RNA FROM DNA

Steps of Transcription1. An _________ attaches to a

section of DNA, separating the two strands.

2. The enzyme moves down the DNA, building a strand of RNA that is ______________ to the DNA.

3. The enzyme reads a _____ code and the new strand of RNA is completed and moves into the _______________.

enzyme

complementarySTOP

cytoplasm

Protein Synthesis

Translation process of making proteins from RNA

The genetic codeThe base sequence is read in groups

of _____ ___________ __________. Each 3-nucleotide sequence is called

a ______. Each codon encodes for a specific

______ _____or a ______or ______signal.

three adjacentnucleotides

codon

amino acidstart stop

Amino Acid

Anti-codon

Steps of Translation

1. mRNA attaches to a _________. Amino acids floating in the cytoplasm are transported to the ribosome by _______.

2. The first tRNA binds to the ______ codon: AUG.

ribosome

tRNA

start

3. Another tRNA binds to the next codon and carries the appropriate amino acid. A _______ ______ forms between the two amino acids.

4. The first tRNA leaves and the ribsome moves across the next _______.

peptide bond

codon

5. Another tRNA binds to the codon and attaches the corresponding amino acid. The ____________ chain continues to grow.

6. Finally, the ribosome reads the ______ ______, and the polypeptide falls off the ribosome.

http://www.wellesley.edu/Chemistry/chem227/nucleicfunction/translation/prtsynth.mov

polypeptide

STOP codon

Amino acid

tRNA

ribosome

mRNA

polypeptide

The final step of protein synthesis:

The polypeptide made at the end of translation, folds into the proper ________, becoming a functional ________. shape

protein

The central dogma of biology

DNA RNA protein