1
Overview of BCOR 11
(These are just some of themany themes we have talkedabout this semester)
Structure and Function
Water1.1. Cohesion/surface tensionCohesion/surface tension2.2. Temperature moderationTemperature moderation3.3. Solvent AbilitySolvent Ability
•• HydrophilicityHydrophilicity –– dissolves polar dissolves polarthings & ionsthings & ions
•• HydrophobicityHydrophobicity –– herds away herds awaynonpolar nonpolar thingsthings
4.4. Ionization abilityIonization ability (pH) (pH)
H
Hydroniumion (H3O+)
H
Hydroxideion (OH–)
H
H
H
H
H
H
+ –
+Figure on p. 53 of water dissociating
Incr
easi
ngly
Aci
dic
[H+ ]
> [O
H– ]
Incr
easi
ngly
Bas
ic[H
+ ] <
[OH
– ]
Neutral[H+] = [OH–]
Oven cleaner
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
pH Scale
Battery acid
Digestive (stomach) juice, lemon juiceVinegar, beer, wine,colaTomato juice
Black coffee RainwaterUrine
Pure waterHuman blood
Seawater
Milk of magnesia
Household ammonia
Household bleach
Figure 3.8
Various forms of Carbonmolecules and functional
groups
CC
C
C
CC
HCCCCC=OO
N H
HH
HHHHH
HH
=C
2
Amino Acids and Proteins LipidsCarbohydrates
monomers and polymers
Membrane Functions
3. transport
4. Signal detection
5. Cell-cellcommunication
2. Localize specific functions
1. boundaries6. Cell-celladhesion
A. Transport – channelsand pumps
B. Links to structuralproteins
C. Receptors - doorbellsD. Enzymes – localized
biochemical rxnsE. Energy Generation –
utilize gradient
Voltage Ligand Mechanosensitive
Proton pump
Sucrose-H+
cotransporter
Diffusionof H+
Sucrose
ATP H+H+
H+
H+
H+
H+
H+
++
+
+
++–
–
––
–
–
3
Rough ER Smooth ER
Centrosome
CYTOSKELETON
Microfilaments
Microtubules
Peroxisome
Lysosome
Golgi apparatus
Ribosomes
In animal cells but not plant cells:LysosomesCentriolesFlagella (in some plant sperm)
NUCLEUS
Intermediate filaments
ENDOPLASMIC RETICULUM (ER)
Mitochondrion
Plasma membrane
Figure 6.9
endoplasmic reticulumnucleus
mitochondrion lysosome
Golgi apparatus
cytosol
ribosomes
Animal CellAnimal Cell
Bacterial and Viruses
Storage and Transfer ofEnergy
ΔΔGG = = ΔΔHH - - TTΔΔSS
-
HOOH
HO
OH
+HO
OH
Enzymes bring substratestogether to lower the activationenergy of a reaction
Free
ene
rgy
Progress of the reaction
∆G < O
EA
Figure 8.14
A BC D
Reactants
AC D
B
Transition state
A BC D
Products
4
LIGHTREACTOR
NADP+
ADP
ATP
NADPH
CALVINCYCLE
[CH2O] (sugar)STROMA(Low H+ concentration) Photosystem II
LIGHTH2O CO2
Cytochromecomplex
O2
H2OO21
1⁄2
2
Photosystem ILight
THYLAKOID SPACE(High H+ concentration)
STROMA(Low H+ concentration)
Thylakoidmembrane
ATPsynthase
PqPc
Fd
NADP+
reductase
NADPH + H+
NADP+ + 2H+
ToCalvincycle
ADP
PATP
3
H+
2 H++2 H+
2 H+
Figure 10.17
Proton gradients powerreactions to create high
energy ATP
NADPHNADPH and ATPATPcan be used tocan be used totransfer energytransfer energy
Fatty Acid Oxidation (Fatty Acid Oxidation (ββ-oxidation) -oxidation)
Energy is capturedin many small stepsin this metabolicpathway
-captures Reducing potential NADH + H+
FADH2
Saturatedhydrocarbon
unsaturatedhydrocarbon
2e-2 H+removed
alcoholKetone2e-
2 H+removed
Ester(acid)
PrimingStep
Signaling, Informationtransfer, and feedback
loopsTRANSCRIPTION
RNA is transcribedfrom a DNA template.
DNA
RNApolymerase
RNAtranscript
RNA PROCESSING In eukaryotes, theRNA transcript (pre-mRNA) is spliced andmodified to producemRNA, which movesfrom the nucleus to thecytoplasm.
Exon
Poly-A
RNA transcript(pre-mRNA)
Intron
NUCLEUSCap
FORMATION OFINITIATION COMPLEX
After leaving thenucleus, mRNA attachesto the ribosome.
CYTOPLASM
mRNA
Poly-A
Growingpolypeptide
Ribosomalsubunits
Cap
Aminoacyl-tRNAsynthetase
AminoacidtRNA
AMINO ACID ACTIVATION
Each amino acidattaches to its proper tRNAwith the help of a specificenzyme and ATP.
Activatedamino acid
TRANSLATION A succession of tRNAsadd their amino acids tothe polypeptide chainas the mRNA is movedthrough the ribosomeone codon at a time.(When completed, thepolypeptide is releasedfrom the ribosome.)
Anticodon
A CC
A A AUGGUU UA UG
UACE A
Ribosome
1
Poly-A
5′
5′
3′
Codon
2
3 4
5
Information stored in DNA isused to build proteins
DNA
mRNA
polypeptide
DNA -> mRNA -> Protein
5
DNA structureSugar-phosphate
backboneNitrogenous
bases
5′ endO–
O P O CH2
5′
4′O–
HH
OH
H
H3′
1′H O
CH3
N
O
NH
Thymine (T)
O
O P O
O–
CH2
HH
OH
HH
HN
N
N
H
NH
H
Adenine (A)
O
O P O
O–
CH2
HH
OH
HH
HH H
HN
NN
OCytosine (C)
O
O P O CH2
5′
4′O–
H
O
H
H3′
1′
OH2′
H
N
NN H
ON
N HH
H H
Sugar (deoxyribose)3′ end
Phosphate
Guanine (G)
DNA nucleotide
2′
NC
T
A
A
T
CG
GC
A
C G
AT
AT
A T
TA
C
TA0.34 nm
3.4 nm
G
1 nm
G
T
Amino end Growing polypeptide
tRNA
mRNA
Codons
3′
5′
Ribosomes translate the RNAmessage into a polypeptide
Second mRNA baseU C A G
U
C
A
G
UUUUUCUUAUUG
CUUCUCCUACUG
AUUAUCAUAAUG
GUUGUCGUAGUG
Met orstart
Phe
Leu
Leu
lle
Val
UCUUCCUCAUCG
CCUCCCCCACCG
ACUACCACAACG
GCUGCCGCAGCG
Ser
Pro
Thr
Ala
UAUUAC
UGUUGC
Tyr Cys
CAUCACCAACAG
CGUCGCCGACGG
AAUAACAAAAAG
AGUAGCAGAAGG
GAUGACGAAGAG
GGUGGCGGAGGG
UGGUAAUAGStop
Stop UGAStopTrp
His
Gln
Asn
Lys
Asp
Arg
Ser
Arg
Gly
UCAGUCAGUCAGUCAG
Firs
t mR
NA
bas
e (5′ e
nd)
Third
mR
NA
bas
e (3′ e
nd)
Glu
• Mitosis produces an exact copy of theparent cell.– Used for growth and asexual reproduction.
• Meiosis produces reduced (haploid)gametes, which are genetically unique.– Necessary for sexual reproduction.
Meiosis generates variation through:- independent assortment of chromosomes- crossing over
Mitosis vs Meiosis
Homologs pair inmeiosis 1
Sister chromatidsseparate in meiosis 2
haploid
Not paired diploid
6
Informationmust be copiedexactly eqchtime a celldivides
DNA replication machine
DNA sequences aredetermined by“poisoning” asynthesis reactionwith dideoxynuclotides
PCR is justrepeated cyclesof DNAsynthesis in atest tube
DNA is alwayssynthesized 5’ to 3’
Cellsdetectsignal &respond
Signal transduction pathwaysAMPLIFY the signal
1º messenger
2º messengers
EffectorEnzymes Target
Enzymes
7
Genes of operon
Protein
Operator
Polypeptides that make upenzymes for tryptophan synthesis
Regulatorygene
RNA polymerase
Promoter
trp operon
5′
3′mRNA
trpDtrpE trpC trpB trpAtrpRDNA
mRNA
E D C B A
The trp operon: regulated synthesisof repressible enzymes
Figure 18.21a
5′
Tryptophan absent -> repressor inactive -> operon “on”
Cell type–specific transcriptionEnhancer Promoter
Controlelements
Albumin gene
Crystallin gene
Liver cellnucleus
Lens cellnucleus
Albumin geneexpressed
Albumin genenot expressed
Crystallin genenot expressed
Crystallin geneexpressed
Liver cell Lens cell
Fig 19.7
All cells have thesame genes, butonly certaingenes areexpressed ineach tissue
Different set ofactivator proteinsin the two celltypes
Cell Cycle Regulators andCancer
Thank you!