DNA & Protein Synthesis

History Before the 1940’s scientists didn’t know what material caused inheritance. They suspected it was either DNA or proteins.

History A series of experiments proved that DNA was the genetic material responsible for inheritance.

DNA O O=P-O N CH2 C1 C4 C3 C2 Phosphate Group Nitrogenous base (A, T, G, C) CH2 C1 C4 C3 C2 5 Sugar (deoxyribose)

DNA - double helix T A P O 1 2 3 4 5 P O 1 2 3 4 5 G C T A

DNA The genetic code is a sequence of DNA nucleotides in the nucleus of cells.

DNA DNA is complementary Complementary: bases on one strand match up with the bases on the other strand (A-T and G-C) Example: Strand 1- ATG GGC CTA Strand 2- TAC CCG GAT

DNA Replication Replication Process by which DNA copies itself Happens when chromosomes copy themselves before mitosis and meiosis Semi-conservative replication: Each new piece of DNA is made up of 1 old strand and 1 new strand

Original DNA DNA unzips Each original strand grows a new strand

DNA never ever leaves the nucleus DNA is the master copy of the directions a cell needs to live so it needs to be protected DNA in the nucleus is safe But DNA in the cytoplasm can be destroyed

DNA Gene - a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color, etc.) A gene is a stretch of DNA.

RNA is a copy of DNA that goes out into the cytoplasm to tell the cell what to do in order to stay alive RNA: ribonucleic acid You can always make more RNA so it’s ok if it gets destroyed (You can’t make more DNA!!!)

RNA O O=P-O N CH2 C1 C4 C3 C2 Phosphate Group Nitrogenous base (A, U , G, C ) CH2 C1 C4 C3 C2 5 Sugar (ribose)

T – A G – C U – A G – C DNA RNA How many strands? 2 1 Nucleotide subunit Deoxyribose sugar Ribose sugar Bases ______ (T) Adenine (A) Guanine (G) Cytosine (C) ______ (U) Phos-phate Group Deoxyribose Sugar Nitro-gen Base Phos-phate Group Ribose Sugar Nitro-gen Base T – A G – C U – A G – C

RNA Function: obtain information from DNA & synthesizes proteins

3 differences from DNA Single strand instead of double strand Ribose instead of deoxyribose Uracil instead of thymine

3 types of RNA Messenger RNA (mRNA)- copies information from DNA for protein synthesis Codon- 3 base pairs that code for a single amino acid. codon

3 types of RNA 2. Transfer RNA (tRNA)- collects amino acids for protein synthesis Anticodon-a sequence of 3 bases that are complementary base pairs to a codon in the mRNA

3 types of RNA 3. Ribosomal RNA (rRNA)- combines with proteins to form ribosomes

Amino Acids Amino acids- the building blocks of protein At least one kind of tRNA is present for each of the 20 amino acids used in protein synthesis.