http://members.aol.com/wayneheim/dna-w.jpg

PS

PS

PS

PS

PS

PS

PS

PS

PSP

SP

SP

SP

SP

SP

SP

S

T A

G C

C G

A T

T A

C G

G C

T A

Key Points:

1) Double Helix2) Sugar-phosphate backbone3) Nucleotide Rungs4) Hydrogen bonds

Guanine

Adenine

Thymine

Cytosine

DNA Nucleotides:

ComplementaryBase Pairing: DNA

G CA T

RNA: Ribonucleic Acid

1) Single stranded (usually)

2) Nucleotide Uracil replaces Thymine

3) Four species (for this course):

3.1) messenger RNA (mRNA)3.2) ribosomal RNA (rRNA)3.3) transfer RNA (tRNA)3.4) “interfering” RNA (iRNA)

ComplementaryBase Pairing: RNA

G CA U

Histoneproteincomplex

DNA

(a) the nucleosome: DNA wraps aroundhistone proteins.

(b) solenoids: loop of nucleosomes.

(c): solenoids form aloop.

(d): idealized crosssection of a chromosome:several solenoid loops.

(e): portion of a chromosomewithout the protein scaffold.

DNA Packaging:

http://users.ntua.gr/sofial/DNA.jpg

TGC

ACG

A TA TG

TC

GG

AT

CC

TA

A

A TG CG CT A

CAGCCTAGGATT

(a) DNA replication: strands separate

TGC

ACG

A TA TG

TC

GG

ATT

ACGC

GTAA

TAT

A TG CG CT A

CAGCC

AT

TA

CG

CG

TA

AT

AT

(b) Synthesis of new, complementarystrands.

Replication“Stuff”

TermsAmino acid = basic building block of polypeptide chains.

Polypeptide chain = series of linked amino acids. AKA peptide chain.

Protein = one or more polypeptide chains, folded and taking on a 3 dimensional configuration.

Enzyme = a type of protein that speeds up chemical reactions.

TryTyrPhe Ser

PheSerArg Ala Phe Tyr

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPROTSYn.html

Genetic Code (mRNA)

1) Triplet2) Redundant3) Universal

Five Steps in ProteinSynthesis (PETAP):

1) Photocopying

2) Editing

3) Transportation

4) Assembly

5) Packaging

Five Steps in ProteinSynthesis (PETAP):

1) Photocopying

2) Editing

3) Transportation

4) Assembly

5) Packaging

= Transcription

= Post-transcriptional modification

= Transportation

= Translation

= Post-translational modification

Common Sense Terms Scientificese

I. Photocopying (Transcription)

Definition:An RNA strand is synthesized from the DNA

using complementary base pairing.

Process:

1) “Transcription stuff” binds to a promoter region of the DNA.

2) An enzyme “slices” the DNA, making it single stranded.

3) Another enzyme (polymerase) synthesizes a strand of RNA using one of the DNA strands as a template.

DNA

RNAtranscript

TGC

ACG

A UTTG

GG

AACAC

TA

AACUUG

GU

G

A

GA

A

CU

U

C

Transcription“Stuff”

II. Editing(Post-transcriptional modification)

Definition:Nonmessage segments in the newly synthesized RNA

strand are edited out.

Process:1) Enzymes excise the introns (nonmessage segments) from the RNA strand.

2) Other enzymes splice together the exons (message segments) giving messenger RNA (mRNA).

exon 1 intron 1 exon 2 intron 2 exon 3

Punctuationmarks

PunctuationmarksRNA transcript:

exon 1 intron 1 exon 2 intron 2 exon 3

Editing:

exon 1

Punctuationmarks

exon 2 exon 3

Punctuationmarks

mRNAmessemger RNA

III. Transportation (Transportation)

Definition:mRNA is transported from the nucleus to the cytoplasm

and attaches to a ribosome.

Process:

(same as the definition)

IV. Assembly (Translation)

Definition:The mRNA codons are “read” and the corresponding amino

acid is added to the polypeptide chain.

Process:

1) A codon enters the “reading frame” of a ribosome.

3) The amino acid carried by the tRNA molecule is added to the polypeptide chain.

3) Steps 1 to 3 are repeated until all codons are “read.”

2) A transfer RNA (tRNA) molecule with the complementary anticodon binds to the codon of mRNA.

Trp

C CAanticodon

other RNA

amino acid

Transfer RNA(schematic)

“bar code”

Ser

A G A

U A C GU G

Phe

A A AU C G

U G C

Thr

U UC U A C GU G

PheA A A

U C GU G C

Thr

U UC

Arg

G C C

Arg

G C C

Ser

A G A

Trp

C CA

mRNA

tRNA

ribosome

peptidechain

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPROTSYn.html

http://tidepool.st.usm.edu/pix/protsynth.gif

Posttranslational Modification:ALWAYS HAPPENS

Polypeptide Folding

Posttranslational Modification:Sometimes happens

• Folded polypeptide chains join (e.g., ALDH-2, hemoglobin)

• add a sugar

• add a fat

Posttranslational Modification:Protein Activation/Deactivation

• Phosphorylation (add a phoshate group)

• Acetylation (add an acetyl group)

• Alkylation (add a ethyl, methyl group)

• Ubiquitination (add the protein ubiquitin to an existing protein usually instructs the cellular machinery to degrade/destroy the protein)

2 1G A -like gene cluster on chromosome 11:

10 20 30 40 50 600

length in kilobases (kb):

Blow up of Exon 1 of the hemoglobin gene:

GTGCACCTGACTCCTGAGGAGAAGTTGGCC..AGGNucleotides:Val His Leu Thr Pro Glu Glu Lys Ser Ala.. ArgAmino Acids:

ACATTG:Start trans-

scriptionhere

Exon 1 Exon 2 Exon 3Intron 1 Intron 2

Promoters: TATA CAAT

ATG:Start

TranslationHere

TAA:Stop

TranslationHere

CATTGC:Stop trans-scription

here

Attach atail of

multipleadenines

here

Blow up of the hemoglobin gene:

1 30 31 104 105 146CodonNumber:

5 10 15 20 250length in kilobases (kb):

-like gene cluster on chromosome 16:1 2 1 2 1

Open window (A) and fly kite (B).  String (C) lifts small door (D) allowing moths (E) to escape and eat red flannel shirt (F).As weight of shirt becomes less, shoe (G) steps on switch (H) which heats electric iron (I) and burns hole in pants (J).Smoke (K) enters hole in tree (L), smoking out opossum (M) which jumps into basket (N), pulling rope (O) and lifting cage (P),allowing woodpecker (Q) to chew wood from pencil (R), exposing lead.Emergency knife (S) is always handy in case opossum or the woodpecker gets sick and can't work.

The Self-Operating Napkin: As you raise spoon of soup (A) to your mouth it pulls string (B), thereby jerking ladle (C) which throws cracker (D) past parrot (E). Parrot jumps after cracker and perch (F) tilts, upsetting seeds (G) into pail (H). Extra weight in pail pulls cord (I), which opens and lights automatic cigar lighter (J), setting off sky-rocket (K) which causes sickle (L) to cut string (M) and allow pendulum with attached napkin to swing back and forth thereby wiping off your chin.