What are the functions of DNA? Protein Synthesis What are the functions of DNA?

Central Dogma of Biology DNA  RNA  Protein Proteins then have the ability to directly/indirectly influence every aspect of a cell Transcription: The process by which the information in a segment of DNA (a gene) is transferred to RNA Translation: The process by which RNA’s message is converted into protein

RNA Stands for ribonucleic acid Another type of nucleic acid Usually single-stranded Contains the bases: Adenine (A), Guanine (G), Cytosine (C), and Uracil (U) U is complementary with A

NUCLEIC ACIDS are built from subunits called ____________________ NUCLEOTIDES SUGAR in RNA is ________________ ribose

3 KINDS OF RNA HELP WITH INFO TRANSFER FOR PROTEIN SYNTHESIS RIBOSOMAL _________________RNA (rRNA) Combines with proteins to form ribosomes _________________RNA (tRNA) Matches m-RNA codon to add correct amino acids during protein synthesis _________________RNA (mRNA) carries code from DNA to ribosomes TRANSFER MESSENGER

Enzyme called _____________________ Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNA polymerase DNA RNA Enzyme called _____________________ separates strands, then uses one strand as a template to assemble an RNA copy. RNA POLYMERASE

Transcription Three Steps: Initiation Elongation Termination

Initiation RNA Polymerase binds to places with specific DNA sequences called _______________. PROMOTERS tell the enzyme where to start. PROMOTERS

Elongation RNA polymerase then moves along the gene sequence and adds the complementary _________ nucleotides. RNA

Termination RNA polymerase eventually reaches a _____ signal at the end of the gene, and transcription is then complete. The DNA molecule then comes back together. stop

RNA’s require EDITING before use The DNA of eukaryotic genes contain sequences of nucleotides, called __________, that are not involved in coding for proteins. The DNA sequences that code for proteins are called __________. introns exons

RNA’s require EDITING before use A _____________________ is added to the 5' end of the pre-mRNA while elongation is still in progress A _______________ is added to the 3' end of the pre-mRNA once elongation is complete. Both protect the mRNA from degradation. 7-methylguanosine cap poly (A) tail

RNA Editing The __________ are cut out of the RNA The __________ are spliced together to form the mRNA. introns exons

RNA Editing

The Big Picture “Blueprints” of master plan TRANSCRIPTION (DNA→ RNA) & PROCESSING takes place in nucleus TRANSLATION (RNA→ proteins) takes place on ribosomes in cytoplasm “Blueprints” of master plan are carried to building site

Translation

Why are Proteins Important? Proteins directly and indirectly affect every function of a cell Some common, important types of proteins: Enzymes (facilitate chemical reactions) Membrane proteins (help regulate what passes in/out of the cell membrane) Regulatory proteins (regulate key processes in the cell)

The Genetic Code In transcription, the ‘message’ within a gene was transcribed from the ‘language’ of DNA to the ‘language’ of RNA In translation, the message will be translated from the ‘language’ of RNA (nucleotides) to the ‘language’ of proteins (amino acids) The instructions for making a protein are stored in three-nucleotide sequences on the mRNA called codons

The Genetic Code Each codon in an mRNA strand corresponds to an amino acid, a start, or a stop signal The following charts are used to decipher the mRNA codons into their corresponding amino acids

AUG 64 possible codons 20 amino acids Section 12-3 64 possible codons 20 amino acids Some amino acids have more than one codon. START= _______ 3 codons for _____ AUG STOP

Codon Charts

Interpreting Codon Charts Which amino acid corresponds to the codon “UCA”? Which amino acid corresponds to the codon “GUA”?

Interpreting Codon Charts Which amino acid corresponds to the codon “CCA”? Which amino acid corresponds to the codon “AUC”?

EACH tRNA carries only one kind of _____________ amino acid ANTICODON ___________ on tRNA matches up with ________ on mRNA CODON

Translation Three Steps: Initiation Elongation Termination

Initiation start The ribosome assembles around the target mRNA. The first tRNA is attached at the ______ codon. start

Elongation The tRNA transfers an amino acid to the tRNA corresponding to the next codon The ribosome then moves (translocates) to the next mRNA codon to continue the process, creating an amino acid chain.

Termination The ribosome disassembles. When a stop codon is reached, the ribosome releases the polypeptide. The ribosome disassembles.

https://www.youtube.com/watch?v=itsb2SqR-R0

What kind mutations do you think are most detrimental?

What are Mutations? ____________ are changes in the genetic material. Mutations can happen when cells make _________ in copying their own DNA or be caused by _______________ or ___________ in the environment. ________________ is more prone to making mistakes than _________________. Mutations mistakes radiation chemicals RNA polymerase DNA polymerase

KINDS OF MUTATIONS Mutations that produce changes in a single gene = ____________________. Mutations that produce changes in whole chromosomes = _______________________. GENE MUTATIONS CHROMOSOMAL MUTATIONS

GENE MUTATIONS Mutations involving ________________ ____________ = __________________ because they occur at a single point in the DNA sequence. TYPES OF POINT MUTATIONS: Substitutions Deletions Insertions one or a few nucleotides Point mutation

SUBSTITUTION A T T C G A G C T A T T C T A G C T Changes one base for another A T T C G A G C T A T T C T A G C T How many amino acids are changed?

SUBSTITUTION Three Types: Silent: change in the genetic sequence that does not change the protein sequence Missense: change in DNA sequence that changes the codon to a different amino acid Nonsense: change in the genetic code that results in the coding for a stop codon rather than an amino acid

SICKLE CELL ANEMIA CAUSE: (autosomal recessive) A changed to T (glu to val) gene on chromosome #11 that codes for part of hemoglobin protein (carries oxygen in blood)

DELETION A T T C G A G C T A T T C A G C T Piece of DNA code is lost A T T C G A G C T A T T C A G C T How many amino acids are changed?

INSERTION A T T C G A G C T A T T C G C A G C T Extra piece of DNA is added A T T C G A G C T A T T C G C A G C T How many amino acids are changed?

GENE MUTATIONS Substitutions usually affect no more than a single ____________, but deletions and insertions can have a more dramatic effect. Amino acid

FRAME SHIFT MUTATIONS Change multiple bases in code thefatcatatetherat INSERTION thefatcataatetherat DELETION the fat cat ate the rat the fat cat aat eth era t the fat ata tet her at

FRAME SHIFTS Frame shift mutations change every ___________ in the ___________ that follows the shift. Frame shifts can alter a protein so much it is unable to _____________. amino acid protein function

Location of the shift is important! AT BEGINNING the fat cat ate the rat AT END the fac ata tet her at the fat cat ate thr at MUTATIONS AT _____________OF GENE DAMAGE __________ OF THE CODE! BEGINNING MORE

CHROMOSOMAL MUTATIONS Mutations involving changes in the _____________ or ______________ of whole chromosomes TYPES OF CHROMOSOMAL MUTATIONS: Deletions Duplications Inversions Translocations number structure

DELETION Piece of chromosome is lost ________________________________________

Duchenne Muscular Dystrophy CAUSE: (X linked recessive) DELETION in gene that codes for a muscle protein

DUPLICATION Piece of DNA is copied too many times _________________________________________________

HUNTINGTON’S Degenerative brain disorder Symptoms appear age 30-40 Lose ability to walk, think, talk, reason Cause = ADDITION of extra CAG repeats

INVERSION Segment flips and reads backwards

TRANSLOCATION Segment breaks off and joins a different non-homologous chromosome

MUTATIONS Most mutations are ____________ meaning they have little or no effect on gene ____________. Mutations that cause ________________ are usually ____________ Harmful mutations are associated with many ________________ and can cause _________. neutral function defective proteins HARMFUL genetic disorders cancer

MUTATIONS Mutations are also a source of _________________ and can be _____________. genetic variability beneficial Can help an organism _____________________. Provide _________ in population for ________________ to act upon. survive and reproduce variation natural selection

POLYPLOIDY Condition in which an organism has extra sets of chromosomes = _______________ __________ in humans, but beneficial in some ___________. Triploid (___) or tetraploid (___) plants are often ________________ than diploid plants. POLYPLOIDY LETHAL plants 3N 4N larger and stronger