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Explore the fascinating world of DNA traits and functions, from physical features passed down through generations to the structure and replication of DNA. Learn about the role of genes and chromosomes, base pairing rules, and the processes of transcription and translation. Discover how DNA determines the production of proteins and plays a fundamental role in the central dogma of biology.
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Traits • A physical feature, or characteristic, a living thing can pass on to its young. • Ex. Blood type, Eye color, Hair color, Facial features, and your body build…
Genes • Coded info that determines traits. • A region of DNA that controls a hereditary characteristic.
Chromosomes • carries the genes that control traits.
Structure of DNA Double Helix
What are the building blocks? • Nucleotides – joined by strong covalent bonds • Nucleotides composed of: • Phosphate group • Deoxyribose – 5 carbon sugar • One of four Nitrogenous bases • Adenine • Thymine • Guanine • Cytosine
Base Pairing Rules • Adenine = Thymine • Guanine = Cytosine
Functions of DNA • Replication – DNA makes DNA • Transcription – DNA makes RNA • Translation – RNA makes Proteins
DNA Replication • The helix unwinds • DNA unzips - nucleotides separate as hydrogen bonds break • Free nucleotides base pair with both nucleotide chains • 2 identical DNA molecules result
Leading Strand – continuous replication • Lagging strand – discontinuous replication
Semi Conservative Replication Each old DNA strand gets a new strand
Transcription • DNA unwinds and unzips. • RNA nucleotides base pair with the DNA master strand • Uracil bonds with Adenine • Cytosine with Guanine. • RNA strand separates and moves to the cytoplasm • DNA zips back up
Reverse Transcription • HIV – retrovirus • Makes DNA replica of its own RNA • Viral DNA joins normal DNA of host • Directs production of new virus particles
3 Types of RNA mRNA – messenger RNA tRNA – transfer RNA rRNA – ribosomal RNA
mRNA • Messenger RNA – single strand coded from the DNA master strand. • Contains a three base sequence – codon • Codon – codes for a specific amino acid
tRNA • Transfer RNA – contains sequence of three bases – anticodon • anticodon – which carry a specific amino acid to the mRNA
rRNA • Ribosomal RNA – located in the ribosomes
Translation • The mRNA attaches to a ribosome. • mRNA contains codons (3 nucleotides that code for 1 amino acid) • The tRNA contain three opposite letters called the anticodon. • tRNA carries an amino acid at the other end. • Anti codons base pair with codons • Amino Acids covalently bonded to each other • tRNA is released to get more Amino Acids
Central DogmaDNA --------------------RNA ------------------Proteintranscription translation