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DNA

WHY DO WE STUDY DNA?

Central DogmaDNA RNA PROTEIN

BUILDING BLOCK/MONOMER DNA is made of nucleotides of

Deoxyribose (sugar) PO4 (phosphate group) Nitrogen bases

1. adenine—A 2. guanine—G 3. thymine—T 4. cytosine—C

phosphate group

deoxyribose (sugar)

nitrogen-containingbase

NITROGENOUS BASES

Double ring PURINESAdenine (A)Guanine (G)

Single ring PYRIMIDINESThymine (T)Cytosine (C) T or C

A or G

hydrogen bond

covalent bond

BASE PAIRING RULES A bonds to T with 2 hydrogen bonds

G bonds to C with 3 hydrogen bonds

Double helix

REPLICATION DNA makes a copy of DNA Where? In the nucleus DNA makes DNA

CGATATATTCCCGAG

ATTCAGTTCAGACCC

ACGTTATACGCTAAC

RNA DIFFERS FROM DNA1. RNA has a sugar ribose

DNA has a sugar deoxyribose2. RNA contains the base uracil (U)

DNA has thymine (T)3. RNA molecule is single-stranded

DNA is double-stranded

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TRANSCRIPTION DNA RNA Where? In the nucleus

animation

FOR YOU TO TRY…TRANSCRIPTION (MAKE MRNA)

CGATATATTCCCGAG

ATTCAGTTCAGACCC

ACGTTATACGCTAAC

THREE TYPES OF RNA Messenger RNA (mRNA) -

carries genetic information to the ribosome

Ribosomal RNA (rRNA) - makes the ribosomes

Transfer RNA (tRNA) - transfers amino acids to the ribosomes where proteins are made

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.

MESSENGER RNA (MRNA)

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A U G G G C U C C A U C G G C G C A U A AmRNA

startcodon

codon 2 codon 3 codon 4 codon 5 codon 6 codon 7codon 1

mRNA has a code (codon) for tRNA

TRANSFER RNA (TRNA)

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amino acidattachment site

A A G

anticodon

Phenylalanine

amino acid

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RIBOSOMAL RNA (RRNA)

PART OF RIBOSOME

TRANSLATION RNA protein Where? In cytoplasm. The chain of amino acids linked

together is a specific protein.

animation

FOR YOU TO TRY… MAKE ANTICODONS (TRNA)

GCUAUAUAAGGGCUC

UAAGUCAAGUCUGGG

UGCAAUAUGCGAUUG

FOR YOU TO TRY… TRANSLATIONMAKE AMINO ACIDS FROM MRNA

GCUAUAUAAGGGCUC

UAAGUCAAGUCUGGG

UGCAAUAUGCGAUUG

PUT IT ALL TOGETHER Given the following DNA sequence

CGATATATTCCCGAG 1. What is the complimentary DNA?

2. What is the mRNA strand (codon)?

3. What is the tRNA (anticodon)?

4. What amino acids are created?

WHAT IF THERE IS A MISTAKE? MUTATION-error

Substitutions Insertions Deletions Frameshift Translocation Inversion

Not all are harmful

SUBSTITUTION

INSERTION

CCA TAT CAT GGC CCA TAT GCA TGG C

DELETION

FRAMESHIFT MUTATIONS HAPPEN BECAUSE OF INSERTIONS OR DELETIONS

Original: The fat cat ate the wee rat.

Frame Shift (“a” added): The fat caa tet hew eer at.

TRANSLOCATION

CCC GCG ATT TAT CCC TAT ATT GCG

INVERSION