Download 4 Steps of DNA Replication

4 Steps of DNA Replication
•Step 1: Enzymes break the
hydrogen bonds between the
base pairs, causing the 2 chains
to separate like a zipper
•Step 2: Each chain serves as a
pattern. Free nucleotides in the
nucleus pair with bases on the
chains; A-T, G-C.
• Step 3: As the pairs bond, an enzyme
links the phosphate of each nucleotide
to the sugar of the previous one.
• Step 4: The pairing and bonding
continue until the original two DNA
chains are made into new paired
chains.
Protein Synthesis
• Transcription: “transcribing” the
sequence of DNA bases that “codes”
for a single protein (a gene) into a
molecule of mRNA.
Steps
• Step 1: “unzip” that part of DNA that codes
for a specific protein.
• Step 2: “transcribe” the sequence of bases in
the DNA “antisense” strand into a
complimentary mRNA strand.
• Step 3: mRNA moves off of the DNA and
enzymes “re-zip” the DNA.
• ALL 3 forms of RNA are formed by the
process of Transcription: mRNA, tRNA, and
rRNA.
Translation
• Changing (translating) the genetic code
of mRNA (each codon specifies one of
the 20 amino acids) into a functional
protein.
• Occurs at a ribosome.