Transcript powerpoint 22 Aug

What can you tell me about this compound?
pyridoxine
CH2OH
HO
OH
N
H+
What can you tell me about this compound?
P
O
O
OH
OH
OH
IP3
O
P
P
What can you tell me about this compound?
H3C
NH
H2C
OH
CH
epinephrine
OH
OH
What can you tell me about this compound?
beta-carotene
Chapter 2
Apply Problem #5

If an aqueous (water) extract does not work but one
using benzene as the solvent does have an effect, what
might you conclude about the chemical nature of the
hormone? explain.
Hormone is lipophilic or nonpolar.
Explain:
Hormone dissolves in benzene, an organic solvent (nonpolar)
but doesn’t dissolve in polar solvent (water).
Proteins
The other main component of the cell membrane.
Functions of Protein
 Transport
 channels
 pumps
 carriers
 Communication
 receptors
 signaling molecules


hormones
“flags”
 Enzymes
 Structure
 Collagen, keratin, bone matrix, intracellular microtubules
 Antibodies
 Movement
 Muscle cells are 20% actin (protein)
Amino Acid Structure
O
O
+
H3N
H2N
CH
CH
OH
R
R group can be
• polar or nonpolar
• big or small
• charged – acidic or basic
R
O-
Amino acids – R groups
lysine
O
O
H2N
CH
CH2
CH2
CH2
CH2
NH2
C
OH
H2N
CH
C
OH
CH2
cysteine
SH
Amino acids – R groups
O
H2N
CH
CH2
C
aspartic acid
O
OH
tryptophan
H2N
CH
C
CH2
C
HN
OH
O
OH
Amino acids
O
H3C
H2N
CH
C
OH
CH2
NH
H2C
OH
CH
epinephrine
OH
tryosine
OH
OH
Peptides – dipetide formation
Formation from amino
acids: FOX fig 2.25
O
O
H2N
cysteine
CH
C
H2N
OH
CH
C
OH
H
CH2
glycine
SH
O
H2N
dipeptide
CH
CH2
SH
C
NH2
CH
H
COOH
+
H 2O
Tripeptide - glutathione
• glycine
• cysteine
• glutamic acid
Peptides
O
O
H2N
CH
C
OH
+
H2N
CH
CH2
CH2
CH2
SH
C
C
NH2
CH
COOH
H
dipeptide
O
OH
glutamic acid
OH
O
O
C
CH
H2
C
H2
C
C
NH2
O
H2N
CH
CH2
glutathione
SH
C
NH2
CH
H
COOH
Protein
Four levels of structural organization
 Primary structure
 Amino acid sequence
 gly-cys-ala-trp-glu-asp-gly-tyr-cys-ala Secondary structure
 Sections of peptide chain coil or fold into either:


Alpha helix
Beta sheet
 Tertiary structure
 Whole peptide chain (protein) folds/coils around itself
 H bonding, sulfide bridges, non-polar/non-polar interactions
 Quaternary structure
 More than one peptide chain associated with each other
Proteins
(FOX fig 2.26)
Tertiary Structure (FOX fig 2.27)
Protein Synthesis
within the context of homeostasis.
 Objectives
 Review
how proteins are synthesized
 Give an example of an effector action
 Review key organelles
 Preview regulation of ions
 Preview endocrine signaling
Protein Synthesis
within the context of homeostasis.
 Negative Feedback:
 Sensor
detects a change parameter’s level
 Control unit activates an effector
 Effect is to return parameter to normal level
 Typical effector action is to make a protein
 Another effect is to activate a protein
 protein
activation can lead to the release of
hormone or neurotransmitter
 protein activated is often an enzyme
Protein Synthesis Example:
Aldosterone
 What is aldosterone?
 Steroid
hormone produced by adrenal cortex
 It is a mineralocorticoid
 Promotes the retention of Na+ and loss of K+
 What induces the release of aldosterone?
 Low
Na+ and high K+
 Target organ?
 Kidney
– epithelial cells of distal tubule
carrier protein (albumin)
aldosterone
target cell
plasma membrane
Aldosterone on carrier approaches the
cell membrane
Aldosterone diffuses readily into the
lipophilic membrane.
Aldosterone receptor picks up
aldosterone and moves it into the cell.
aldosterone receptor
Aldosterone receptor complex heads
towards the nucleus.
know
cell
structures
Translation
(FOX fig 3.24)
Microtubules aid
movement of vesicles
to cell membrane
Pumps/channels
are degraded in
lysosomes when
no longer needed
Carbohydrates
 Contain CH2O
 6 carbon sugars – C6H12O6
 glucose (glu)
 fructose (fru)
 galactose (gal)
 5 carbon sugars – C5H10O5
 ribose
DNA
 RNA

Carbohydrates
 If glucose and galactose have the same formula
(C6H12O6) what is the difference?
 structural isomers (FOX fig 2.13)
CHO
CH2OH
H
O
HO
OH
OH
OH
OH
glucose
OH
H
H
OH
H
OH
CH2OH
glucose
reversed in
galactose
Ribose
 Found in DNA and RNA (FOX fig 2.29)
 Found in ATP (FOX fig 4.15)
 Found in NADH and FADH2 (FOX fig 4.17)
OH
HOH2C
O
HO
OH
ribose
removed in DNA
Disaccharides
(FOX fig 2.15)
Disaccharide short hand
 Sucrose = glu-fru
 Lactose = glu-gal
 Maltose = glu-glu
 What’s this?
 glu-glu-glu-glu-glu-glu-glu-glu-glu-
Polysaccharide
 glu-glu-glu-glu-glu-glu-glu-glu-glu Starch



Glycogen



linear chains of glucose
found in plants
densely branched chains of glucose
found in humans
Cellulose


chains of glucose (tend to stack into sheets)
found in plants
Why can’t we digest cellulose?
 First how do we digest starch?
 Amylase (enzyme) takes long chains of
glucose and breaks off disaccharide pieces.
 What are the characteristics of enzymes?
Enzymes
 Biological catalysts
 either make reactions happen
 or make reactions happen faster
 Names end in –ase
 starch (aka amylose) is digested with amylase
 Can be classified according to activity
 phosphatase – removes phosphate groups
 kinase – adds phosphate groups
 Proteins
Characteristics of Protein Interactions
Such as enzyme/substrate or receptor/hormone
 Binding site that is specific
 The substrate/hormone is called the ligand
(The ligand is the thing that binds to the protein)
 What is the ligand for the aldosterone receptor?
 What is the ligand for amylase?
 The rate of reaction or activity is dependent
on binding characteristics.
Binding characteristics
 Specificity – binding site designed for one
type of ligand
 Affinity – strength of bond between ligand
and binding site
 Competition – two or more ligands
competing for one binding site
 Saturation – occupation of binding sites
 thousands
of enzymes/receptors per cell
 graph (FOX fig 4.6)
Saturation
(FOX fig 4.6)
Why can’t we digest cellulose?
 starch has alpha linkages
 cellulose has beta linkages
Example of
ENZYME
SPECIFICITY!!
Functions of Carbohydrates
 Fuel
 Signaling Molecule
 Ribose is component of:
 DNA RNA
 ATP
 NAD/FADH
 Digestive Regulation
 Fiber normalize transit time
 Fiber decreases cholesterol, TAG and LDL