Download DNA and Its Proccesses

KEYSTONE REVIEW:
TOPIC 6
DNA AND ITS PROCESSES
NUCLEIC ACID
• Monomer: nucleotide
• 5 carbon sugar
• Phosphate group
• Nitrogenous base
TYPES OF NUCLEIC ACID
DNA
•
•
•
•
Deoxyribonucleic acid
2 strands
Deoxyribose-sugar
Nitrogenous base
•
•
•
•
Adenine
Thymine
Cytosine
Guanine
RNA
•
•
•
•
Ribonucleic acid
1 strand
Ribose-sugar
Nitrogenous base
•
•
•
•
Adenine
Uracil
Cytosine
Guanine
TYPES OF RNA
Messenger RNA
• Transcribed
off of DNA in
the nucleus
• Carries the
“genetic
code” from
the nucleus to
the ribosomes
Transfer RNA
• Transcribed off
of DNA in the
nucleus
• Transport/carr
y the amino
acids from the
cytoplasm to
the ribosome
as needed by
the mRNA
Ribosomal RNA
• Transcribed off
of the DNA in
the nucleus
• Makes up part
of a ribosome;
actual
function in
Protein
Synthesis not
clearly
understood
THREE MAIN PROCESSES
INVOLVING NUCLEIC ACID
• Replication
• Make a copy of DNA from
DNA
• Transcription
• Convert the info in DNA to
RNA format
• Translation
• Use RNA format to create a
polypeptide/protein
REPLICATION
• DNA to DNA
• Unzip DNA double strand
• Add in new base pairs to each half
• Base-pairing rules:
A with T
G with C
• Result: 2 identical strands of DNA each has one of the
original strands and a newly synthesized strand
• link
TRANSCRIPTION
• Create ONE strand of mRNA from a piece of DNA
• Unzip strands
• Add mRNA base pairs to one side
• Base-pairing rules:
A with U
G with C
• Result: 1 strand of mRNA that is complementary to the DNA
TRANSLATION
• Create an amino acid sequence/chain from an
mRNA template
• Feed mRNA through ribosome
• Add one amino acid (via tRNA) for each 3-letter mRNA
segment (codon)
• Stop when a STOP codon is reached
TRANSCRIPTION AND
TRANSLATION
• Link – to the Amoeba Sisters
CODONS
• A “code” in each 3-letter mRNA pieces
• Codes for amino acids
MUTATIONS AND ERRORS
• Mutation—change in DNA
• Can occur in ANY of these processes
• Types:
• Duplication
• Deletion
• Substitution
TYPES OF MUTATIONS
Duplication
Deletion
Substitution
SUMMARY
• Nucleic acid is key to storing information for the
assembly of proteins
• Nucleic acid comes in two types—DNA and RNA
• Each has structural differences
• Nucleic acid can be replicated, transcribed, and
translated
• Mutations can occur
• Beneficial or harmful or neutral
• Lead to genetic variation