DNA Transcription Translation and Mutations DNA n Two

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DNA - Transcription, Translation, and Mutations

DNA - Transcription, Translation, and Mutations

DNA n Two strands coiled called a double helix n Sides made of a

DNA n Two strands coiled called a double helix n Sides made of a pentose sugar Deoxyribose bonded to phosphate (PO 4) groups by phosphodiester bonds n Center made of nitrogen bases bonded together by weak hydrogen bonds

DNA Double Helix “Rungs of ladder” Nitrogenous Base (A, T, G or C) “Legs

DNA Double Helix “Rungs of ladder” Nitrogenous Base (A, T, G or C) “Legs of ladder” Phosphate & Sugar Backbone 3

Antiparallel Strands n n One strand of DNA goes from 5’ to 3’ (sugars)

Antiparallel Strands n n One strand of DNA goes from 5’ to 3’ (sugars) The other strand is opposite in direction going 3’ to 5’ (sugars)

DNA 5 O 3 3 P 5 O O C G 1 P 5

DNA 5 O 3 3 P 5 O O C G 1 P 5 3 2 4 4 P 5 P 2 3 1 O T A 3 O 3 5 O 5 P P 5

Synthesis Phase (S phase) n n S phase during interphase of the cell cycle

Synthesis Phase (S phase) n n S phase during interphase of the cell cycle Nucleus of eukaryotes DNA replication takes place in the S phase G 1 interphase Mitosis -prophase -metaphase -anaphase -telophase G 2

DNA Replication n Begins at Origins of Replication Two strands open forming Replication Forks

DNA Replication n Begins at Origins of Replication Two strands open forming Replication Forks (Y-shaped region) 3’ New strands grow at the forks 5’ Parental DNA Molecule 3’ Replication Fork 7 5’

Proofreading New DNA polymerase initially makes about 1 in 10, 000 base pairing errors

Proofreading New DNA polymerase initially makes about 1 in 10, 000 base pairing errors n Enzymes proofread and correct these mistakes n The new error rate for DNA that has been proofread is 1 in 1 billion base pairing errors n

DNA Damage & Repair n n Chemicals & ultraviolet radiation damage the DNA in

DNA Damage & Repair n n Chemicals & ultraviolet radiation damage the DNA in our body cells Cells must continuously repair DAMAGED DNA Excision repair occurs when any of over 50 repair enzymes remove damaged parts of DNA polymerase and DNA ligase replace and bond the new nucleotides together

DNA, RNA, and Protein The Code § Experiments during the 1960 s demonstrated that

DNA, RNA, and Protein The Code § Experiments during the 1960 s demonstrated that the DNA code was a three-base code. § The three-base code in DNA or m. RNA is called a codon.

Central Dogma n DNA is copied as RNA – Transcription ¨ RNA uses U

Central Dogma n DNA is copied as RNA – Transcription ¨ RNA uses U instead of T n RNA is read to make proteins – Translation ¨ Read by using the reverse of RNA, similar to DNA’s 2 nd strand

DNA, RNA, and Protein Translation § In translation, t. RNA molecules act as the

DNA, RNA, and Protein Translation § In translation, t. RNA molecules act as the interpreters of the m. RNA codon sequence. § At the middle of the folded strand, there is a three-base coding sequence called the anticodon. § Each anticodon is complementary to a codon on the m. RNA.

Activity n The first number tells you where the mutation starts, followed by the

Activity n The first number tells you where the mutation starts, followed by the number or what is deleted ¨ Ex: 487 del 7 means starting at base 487 7 bases are deleted.

What Are Mutations? n Changes in the nucleotide sequence of DNA n May occur

What Are Mutations? n Changes in the nucleotide sequence of DNA n May occur in somatic cells (aren’t passed to offspring) n May occur in gametes (eggs & sperm) and be passed to offspring

Chromosome Mutations n. Five types exist: ¨Deletion ¨Inversion ¨Translocation (don’t worry) ¨Nondisjunction (don’t worry)

Chromosome Mutations n. Five types exist: ¨Deletion ¨Inversion ¨Translocation (don’t worry) ¨Nondisjunction (don’t worry) ¨Duplication

Deletion n. Due to breakage n. A piece of a chromosome is lost

Deletion n. Due to breakage n. A piece of a chromosome is lost

Inversion n. Chromosome segment breaks off n. Segment flips around backwards n. Segment reattaches

Inversion n. Chromosome segment breaks off n. Segment flips around backwards n. Segment reattaches

Duplication n. Occurs when a gene sequence is repeated

Duplication n. Occurs when a gene sequence is repeated

MUTATION SPONTANEOUS MUTATIONS INDUCED MUTATIONS MUTATIONS Mutations areMUTATION SPONTANEOUS MUTATIONS INDUCED MUTATIONS MUTATIONS Mutations are
Mutations Mutations overview Smallscale mutations Missense mutations NonsenseMutations Mutations overview Smallscale mutations Missense mutations Nonsense
Mutations Mutations Types of Mutations Point Mutations occursMutations Mutations Types of Mutations Point Mutations occurs
DNA Transcription Protein Translation DNA Transcription l lDNA Transcription Protein Translation DNA Transcription l l
DNA Transcription Protein Translation DNA Transcription l lDNA Transcription Protein Translation DNA Transcription l l
Mutations in DNA Mutations Mutations changes in theMutations in DNA Mutations Mutations changes in the
MUTATIONS Mutations Changes to DNA are called mutationsMUTATIONS Mutations Changes to DNA are called mutations
GENE Mutations CHROMOSOMAL Mutations DNA Mutations A thirdGENE Mutations CHROMOSOMAL Mutations DNA Mutations A third
DNA MUTATIONS Advanced Biology MUTATIONS Genetic mutations occurDNA MUTATIONS Advanced Biology MUTATIONS Genetic mutations occur
Protein Synthesis Transcription and Translation DNA Transcription RNAProtein Synthesis Transcription and Translation DNA Transcription RNA
DNA Transcription and Translation Biology for Majors TranscriptionDNA Transcription and Translation Biology for Majors Transcription
Protein Synthesis Transcription and Translation DNA Transcription RNAProtein Synthesis Transcription and Translation DNA Transcription RNA
DNA REPLICATION TRANSCRIPTION AND TRANSLATION DNA REPLICATION DNADNA REPLICATION TRANSCRIPTION AND TRANSLATION DNA REPLICATION DNA
TRANSLATION DNA Transcription RNA Nucleus Cytoplasm Translation ProteinTRANSLATION DNA Transcription RNA Nucleus Cytoplasm Translation Protein
GENETIC MUTATIONS Exploring point mutations and chromosomal mutationsGENETIC MUTATIONS Exploring point mutations and chromosomal mutations
Mutations and Genetic Engineering Mutations Types of mutationsMutations and Genetic Engineering Mutations Types of mutations
Prokaryotic Transcription Both Eukaryotic Transcription Prokaryotic Transcription 1Prokaryotic Transcription Both Eukaryotic Transcription Prokaryotic Transcription 1