View
44
Download
0
Category
Tags:
Preview:
DESCRIPTION
DNA, RNA & PROTEINS Part 1. The molecules of life. DNA provides the instructions for an organisms structure and characteristics DNA can be copied to make new cells that are identical to the original cell (Replication) RNA (Nucleic Acid used for making protein) Transcription Translation - PowerPoint PPT Presentation
Citation preview
DNA, RNA & PROTEINSDNA, RNA & PROTEINSPart 1Part 1
The molecules of life
• DNA provides the instructions for an organisms structure and characteristics
• DNA can be copied to make new cells that are identical to the original cell (Replication)
• Roles of DNA: Store, Copy and Transmit Information
• RNA (Nucleic Acid used for making protein)– Transcription– Translation
• Protein synthesis– Amino acids
DNADNA• Deoxyribonucleic Acid (DNA) is the
blueprint for life: contains ALL the necessary information to make a new organism
DNA structure• DNA is a polymer of
nucleotides– Each nucleotide composed of
• a phosphatephosphate, • a sugar (deoxyribose), • and organic nitrogenous base.
Four DNA bases• Four kinds of nitrogenous bases:
Purine basesA = AdenineG = Guanine
Pyrimidine basesT = ThymineC = Cytosine
DNA: Complimentary base pairing• Adenine pairs with Thymine
A T
• Cytosine pairs with Guanine
C G
Each DNA strand is a compliment of the other
Original strand Matching copy A TC GG CT AA TG CG CT AT A
DNA STRUCTURE
• DNA is a double helix • Discovered by
Watson and Crick, 1953
DNA structure
Antiparallel Strands
DNA REPLICATION (in the nucleus)
• Each DNA strand becomes a template, parent strand becomes apart
• Proper base-pairs areassembled on that template(with proper enzymes:polymerase and ligase).
• There’s always a pool of nucleotides (A,C,T,G) in the nucleus
Semi-Conservative Replication½ of the original is “conserved” and the other half is “new”
RNA structure and synthesis• RNA: Ribonucleic Acid• Is very similar to DNA
(repeating subunits, nucleotides).
• Difference between RNA and DNA:– Each nucleotide contains a different sugar
(ribose instead of deoxyribose)– Bases are A, G, C, and U (uracil, not thymine)
A pairs with U; G pairs with C
RNA
• RNA is single stranded and shorter
• RNA is less stable than DNA: RNA doesn’t persist in the cell for long (sometimes it exists for a few seconds), whereas DNA can persist for the life of the cell.
Protein Synthesis
DNARNA
Proteins
• 3 different RNA molecules involved in protein synthesis:– Messenger RNA (mRNA)– Ribosomal RNA (rRNA)– Transfer RNA (tRNA)
transcription
translation
Recommended