Transcript Water

Overview of BCOR 11
(These are just some of the
many themes we have talked
about this semester.)
Structure and Function
Increasingly Acidic
[H+] > [OH–]
Water
1. Cohesion/surface tension
2. Temperature moderation
3. Solvent Ability
•
4.
Increasingly Basic
[H+] < [OH–]
•
Neutral
[H+] = [OH–]
Hydrophilicity – dissolves polar
things & ions
Hydrophobicity – herds away
nonpolar things
Ionization ability (pH)
Figure 3.8
–
+
H
H
H
H
Figure on p. 53 of water
dissociating
H
H
H
Hydronium
ion (H3O+)
+
H
Hydroxide
ion (OH–)
Various forms of Carbon
molecules and functional
groups
H H H H O
C=O C C =C C C
N H
H H
H
H
H
H
C
C
C
C
C
C
Amino Acids and Proteins
Carbohydrates
monomers and polymers
Lipids
Membrane Functions
1. boundaries
2. Localize
specific
functions
3. transport
6. Cell-cell
adhesion
5. Cell-cell
communication
4. Signal detection
A. Transport – channels
and pumps
B. Links to structural
proteins
C. Receptors - doorbells
D. Enzymes – localized
biochemical rxns
E. Energy Generation –
utilize gradient
ATP
–
+
–
H+
+
H+ Proton pump
–
–
H+
H+
+
H+
+ H+ Diffusion
Sucrose-H+
of H+
cotransporter
H+
–
–
+
+ Sucrose
Voltage
Ligand
Mechanosensitive
Animal Cell
endoplasmic reticulum
ENDOPLASMIC RETICULUM (ER)
Rough ER
NUCLEUS
nucleus
Smooth ER
Plasma membrane
cytosol
Centrosome
CYTOSKELETON
Microfilaments
Intermediate filaments
Ribosomes
ribosomes
Microtubules
Golgi apparatus
Golgi apparatus
Peroxisome
Figure 6.9
mitochondrion
Mitochondrion
lysosome
Lysosome
In animal cells but not plant cells:
Lysosomes
Centrioles
Flagella (in some plant sperm)
Bacterial and Viruses
Storage and Transfer of
Energy
Enzymes bring substrates
together to lower the activation
energy of a reaction
DG = DH - TDS
e 8.14
A
C
B
D
HO
Free energy
Transition state
A
C
B
D
Reactants
OH
EA
OH
A B
∆G < O
C D
Products
Progress of the reaction
HO
-
+
OH
HO
Proton gradients power
reactions to create high
energy ATP
H2O
CO2
LIGHT
NADP+
ADP
LIGHT
REACTOR
CALVIN
CYCLE
ATP
NADPH
NADPH and ATP
can be used to
transfer energy
STROMA
(Low H+ concentration)
O2
[CH2O] (sugar)
Cytochrome
Photosystem II complex
Photosystem I
NADP+
reductase
Light
2 H+
Fd
3
NADP+ + 2H+
NADPH + H+
Pq
Pc
2
H2O
THYLAKOID SPACE 1
(High H+ concentration)
1⁄
2
O2
+2 H+
2 H+
To
Calvin
cycle
STROMA
(Low H+ concentration)
Thylakoid
membrane
ATP
synthase
ADP
ATP
P
Figure 10.17
H+
Fatty Acid Oxidation (b-oxidation)
Priming
Step
Saturated
hydrocarbon
Energy is captured
in many small steps
in this metabolic
pathway
-captures
Reducing potential
NADH + H+
FADH2
Ester
(acid)
Ketone
2e2 H+
removed
2e2 H+
removed
unsaturated
hydrocarbon
alcohol
Signaling, Information
transfer, and feedback
loops
Information stored in DNA is used
to build proteins
DNA
TRANSCRIPTION
1 RNA is transcribed
DNA
from a DNA template.
3
5
RNA
transcript
RNA PROCESSING
Exon
2 In eukaryotes, the
mRNA
DNA -> mRNA -> Protein
RNA
polymerase
RNA transcript (premRNA) is spliced and
modified to produce
mRNA, which moves
from the nucleus to the
cytoplasm.
RNA transcript
(pre-mRNA)
Intron
Aminoacyl-tRNA
synthetase
NUCLEUS
Amino
acid
tRNA
FORMATION OF
INITIATION COMPLEX
CYTOPLASM 3 After leaving the
nucleus, mRNA attaches
to the ribosome.
mRNA
AMINO ACID ACTIVATION
4
Each amino acid
attaches to its proper tRNA
with the help of a specific
enzyme and ATP.
Growing
polypeptide
Activated
amino acid
Ribosomal
subunits
polypeptide
5
TRANSLATION
A succession of tRNAs
add their amino acids to
the polypeptide chain
Anticodon
as the mRNA is moved
through the ribosome
one codon at a time.
(When completed, the
polypeptide is released
from the ribosome.)
5
E
A
AAA
UG GU U U A U G
Codon
Ribosome
DNA structure
Sugar-phosphate
backbone
5 end
5
O P O CH2
Nitrogenous
bases
CH3
O–
O–
4 H
H
3
O
H
O
1
N
N
H
H
O
Thymine (T)
H
2
H
O
O
P O
CH2
O–
H
H
N
O
H
H
H
G
CH2
O–
H
H
O
O
O
1
O– 4 H
H
Phosphate H
H
2
3
H
OH
Sugar (deoxyribose)
3 end
T
G
C
T
A
T
H
N
3.4 nm
G
A
N
O
5
P O CH2
C
G
C
O
Cytosine (C)
H
A
1 nm
H
H
T
T
N H
N
H
C
A
H
Adenine (A)
H
H
O
P O
H
N
N
H
O
N
N
H
A
A
O
T
T
A
N
N
N H
N H
H
Guanine (G)
G
DNA nucleotide
A
C
T
0.34 nm
Ribosomes translate the RNA
message into a polypeptide
CCU
U
CUU
CAU
CGU
His
CUC
CCC
CAC
CGC
C
C
Arg
Pro
Leu
CUA
CCA
CAA
CGA
A
Gln
CCG
CUG
CAG
CGG
G
tRNA
U
AUU
ACU
AAU
AGU
Asn
AUC lle ACC
AAC
AGC Ser C
A
Thr
3
A
AUA
ACA
AAA
AGA
Lys
Met or
AUG
ACG
AAG
AGG Arg G
mRNA
5
Second mRNA base
U
C
A
G
U
UAU
UUU
UCU
UGU
Tyr
Cys
Phe
UAC
UCC
UGC
C
U UUC
Ser
UCA
UUA
UAAStop UGAStop A
Leu
UAGStop UGG Trp G
UUG
UCG
Growing polypeptide
First mRNA base (5 end)
Amino end
Codons
start
GUU
GCU
G GUC Val GCC Ala
GUA
GCA
GUG
GCG
GAU
GGU
Asp
GAC
GGC
Gly
GAA
GGA
Glu
GAG
GGG
U
C
A
G
• Mitosis produces an exact copy of the
parent 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
Not paired
Homologs pair in
meiosis 1
diploid
haploid
Sister chromatids
separate in meiosis 2
Information
must be copied
exactly eqch
time a cell
divides
DNA replication machine
PCR is just
repeated cycles
of DNA synthesis
in a test tube
DNA is always
synthesized 5’ to 3’
DNA sequences are
determined by
“poisoning” a
synthesis reaction
with dideoxy
nuclotides
1º messenger
Effector
Enzymes
Target
Enzymes
2º messengers
Signal transduction pathways
AMPLIFY the signal
Cells
detect
signal &
respond
The trp operon: regulated synthesis
of repressible enzymes
trp operon
Regulatory
gene
Promoter
Genes of operon
trpD
trpC
trpE
trpR
DNA
trpB
trpA
Operator
3
mRNA
RNA
polymerase
mRNA
5
5
E
D
C
B
A
Protein
Polypeptides that make up
enzymes for tryptophan synthesis
Figure 18.21a
Tryptophan absent -> repressor inactive -> operon “on”
Cell type–specific transcription
Enhancer
Promoter
Albumin gene
All cells have the
same genes, but
only certain
genes are
expressed in
each tissue
Control
elements
Crystallin gene
Liver cell
nucleus
Lens cell
nucleus
Liver cell
Lens cell
Albumin gene
expressed
Fig 19.7
Different set of
activator proteins
in the two cell
types
Crystallin gene
not expressed
Albumin gene
not expressed
Crystallin gene
expressed
Cell Cycle Regulators and
Cancer
Thank you!