1. Nucleic Acid and Protein Synthesis
DNA
Proteins are found in all ________ ________
Are species specific/ individual specific (transplant rejections)
Importance of DNA
Chromosome: DNA + ____
__________: 5 carbon sugar , nitrogen base and phosphate
Draw a nucleotide here
1953 Watson and Crick – model of DNA molecule
as a spiral helix
living things
RNA
nucleotide

2. Structure of DNA Double helix (like a ladder twisted on its long axis)
Side of ladder – sugar and phosphate
Rungs = _________ ______ pairs (draw here)
Only _____ nitrogen bases in DNA:
Purines: adenine and guanine
Pyrimidines: thymine and cytosine
Arranged in complementary base pairs:
A------T All Teachers
G------C Go Crazy
nitrogen base
four

3. The Roles of DNA and RNA Replication of DNA
________________________________________________
DNA ladder unzips at base pairs
Free nitrogen bases assemble on the open strands,
forming two new complete strands.
Occurs with a great degree of accuracy
Requires enzymes called DNA polymerases
the process of making an identical copy of a section of double stranded DNA

4. RNA Transcription: copies the information of DNA
Transcription = making complementary copy of _________ segment
Is it an exact copy? Explain why or why not?
Made inside the nucleus
Leaves nucleus and goes to ribosome in cytoplasm to direct synthesis of protein
RNA differs from DNA. RNA has:
One strand
Ribose sugar
Uracil replaces __________ as fourth nitrogen base
RNA is smaller than DNA
Three types of RNA
1: mRNA – carries “recipe” from protein to ____________
2: tRNA – carries amino acids to ribosomes
3: rRNA – in ribosome
mRNA transcribes in nucleus:
mRNA leaves nucleus and moves to ribosome to direct protein synthesis
DNA
thymine
ribosome

5. CODONS Codons determine amino acid sequence PROTEIN SYNTHESIS
Codon = group of three nitrogen bases on ________ that codes for an amino acid. Also called triplets.
2-3 codons for each amino acid (20 -22).
1 codon (_______) is start codon.
Several stop codons.
PROTEIN SYNTHESIS
Translation: proteins are synthesized
mRNA moves to _____________.
Acts as a template for protein synthesis.
tRNA has anticodon that will match mRNA codons.
As ribosomes move across mRNA, tRNA brings appropriate amino acids to it.
__________ acids bond together forming a peptide chain, which forms a polypeptide, which, when reaching macromolecular size, is a ______________.
mRNA
AUG
ribosome
Amino
protein