What can you tell me about this compound?

NH+

CH2OH

OHHO

pyridoxine

What can you tell me about this compound?

OH O

O

OH

O

OH

P

P

PIP3

What can you tell me about this compound?

OH

OH

CHH2C

OHNH

H3C

epinephrine

What can you tell me about this compound?

beta-carotene

Chapter 2Apply 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

+H3N

CH O-

O

R

H2N

OH

O

R

CH

R group can be• polar or nonpolar• big or small• charged – acidic or basic

H2N CH C

CH2

OH

O

CH2

CH2

CH2

NH2

lysine

Amino acids – R groups

H2N CH C

CH2

OH

O

SH

cysteine

H2N CH C

CH2

OH

O

HN

tryptophan

Amino acids – R groups

H2N CH C

CH2

OH

O

C

OH

O

aspartic acid

Amino acids

H2N CH C

CH2

OH

O

OH

tryosine OH

OH

CHH2C

OHNH

H3C

epinephrine

Peptides – dipetide formation

H2N CH C

H

OH

O

H2N CH C

CH2

OH

O

SH

Formation from amino acids: FOX fig 2.25

CH COOH

H

H2N CH C

CH2

NH2

O

SH

+ H2Odipeptide

cysteineglycine

Peptides

CH COOH

H

H2N CH C

CH2

NH2

O

SH

NH2

CH

C

H2C

OH

O

H2C C

O

glutathione

H2N CH C

CH2

OH

O

CH2

C

OH

O

Tripeptide - glutathione • glycine• cysteine• glutamic acid

CH COOH

H

H2N CH C

CH2

NH2

O

SH

glutamic acid

+

dipeptide

ProteinFour 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

plasma membrane

aldosterone

carrier protein (albumin)

target cell

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.

knowcell

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)

OH OH

OH

OH

CH2OH

O

CHO

OHH

HHO

OHH

OHH

CH2OH

glucose 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)

ribose

removed in DNA

OHHOH2C

HO OH

O

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

linear chains of glucose found in plants

Glycogen 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 InteractionsSuch 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 ofENZYME

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