lecture 1 - Cell chemistry & biosynthesis I & II

obtain energy: two paths - catabolic and anabolic metabolisms

Chemestry structure and molecules are important:

• have general sense of how catalysts work

Cell biology → multicellular organisms → species in community, etc

Macromolecules

Hability to understand cells

cells are simple (in terms of what they are made of)

Macromolecules that composes the cell:

• proteins

• nucleic acids

• carbohydrates

• lipids

Important chemical reactions: (keep in mind all the molecules we are tlaking about are polymers)

Condensation Reaction

• generating the polymer

  • elongating it

• generates H2O

• Remaining elements that pair together creates the covalent molecules

Hydrolysis Reaction

• taking away a polymer

• Add water and reinstate hydroxyl group

• remove polymer

• not favorable - do not take place unless you want it to

Thermodynamic Principles that Apply to all Systems

First law - energy is transformed. not lost or gained

Second law - as energy transforms, the amount energy is reduced over time. disorder increases over time.

Endorgonic & exorgonic reactions -

Endorgonic reaction - reactants have lower energy than the products. needs energy to procede

• the cell does this by providing ADP

exorgonic reaction - higher energy than products (favorable reaction)

no endorgonic reaction happens in a cell without being coupled with an exorgonic reaction.

• just because a reaction is favorable, doesnt mean the reaction happens all the time

  • all reactions have activation energy - reaction does not happens spontaneously. Even exorgonic reactions needs a bit of energy to start the reaction.

• Free energy - no disorder, can be use for work

  • negative → indicates favorable reaction

  • positive → indicates non-favorable reactions

Carbohydrates

+lipids + aminoacids

• have cyclic structure

• abundance of alcohol groups

• abundance of hydroxyl groups

  • allows for the linkage. polymerization

Aldehydes:

• incredibly reactant molecules

left off: 1:01:30

carbohydrates can serve as -

• energy storage

• structural components for tissue and cells

interesting fact: the difference bewteen non-digestable fiber and starch (which is digestable) is a small difference. the angle of bond in the structure.

Lipids

• hydrophobic molecules

• the ones (lipids) we see more in cells are faty acids

  • carboxylic acids (head)

  • hydrophobic tail

    • not polar

• perfect to generate barrier

• saturated tails vs saturated

• saturation - all the carbons have bonds with hydrogen or other carbon atoms

  • straight lipids - linear

  • solid at room temp

• unsaturation - double bonds between carbons

  • creates angle at double bond

  • liquid at room temp bc cant be packed together bc of the angles, so molecules cant be close together and are more dispersed

• you normally dont see free fatty acids in the cell. they are stored in storage molecules

  • triglycerides - storage fatty acids

• Fatty acids - holding large amoutns of potential chemical energy

  • metabolise fatty acid- obtain energy

• triglycerides -

  • 3 fatty acid molecules

  • undergo a condensation reaction with glycerol (a 3 carbon alcohol)

  • each alcohol group undergo condensation reaction w hydroxyl groups of the carboxyic acids in each fatty acid

  • produce water

  • get molecule that stores 3 fatty acids at the time

• lipids - have the ability to have dual solubility

  • head - polar (hydrophilic)

  • tail - non-polar (hydrophobic)

• phsopholipids -

  • start as triglyceral

Amino acids and Proteins

• have distincts R groups

  • behavior derives from R group

  • composed of amino group+carboxyl group+ R group

• Condensation -

  • happens between amino group of a molecule with a carboxyl of another

• Small polymer of amino acids - peptide

• large polymer of amino acids - protein