Chapter 1 Content

Plasma Membrane

• The periphery of the cell, separating its contents from the surroundings

• composed of lipid and protein molecules that form a thin, tough, pliable hydrophobic bilayer.

• barrier to the free passage of inorganic ions and most other charged or polar compounds

Transport Proteins

allow the passage of certain ions and molecules

Receptor proteins

transmit signals into the cell

Membrane Proteins

participate in some reaction pathways

All cells have

a nucleoid/nucleus that replicates cells

Eukaryotes

• Double membrane

• bigger

• membrane-enclosed organelles: mitochondria, chloroplasts, lysosomes

• The compartmental segregation of energy-yielding and energy-consuming reactions helps cells to maintain homeostasis and stay away from equilibrium

Prokaryotes

no nuclear membrane

Aerobic Environment

• plentiful supply of oxygen

• some resident organisms derive energy from the trasnfer of electrons from fuel molecules to oxygen within the cell

Anaerobic Environment

• devoid of oxygen

• microorganisms adapted to these environments get energy by transferring electrons to nitrate (makes N2), sulfate (makes H2S), or CO2 (makes CH4)

• many die when exposed to oxygen: obligate _____

Facultative Anaerobe

can live with or without oxygen

Phototroph

trap and use sunlight as an energy source

Chemotroph

• get energy from the oxidation of chemical fuel

• some oxidize organic fuels: HS to S^0 (elemental sulfur), S^0 to SO4-, NO2-, NO3-, or Fe2+ Fe 3+

Autotrophs

can make all of their biomolecules from CO2

Heterotrophs

need organic nutrients from other organisms

Cyanobacteria

photoautotrophs

Chemoheterotrophs

Humans

Gram-Positive Bacteria

• colored by Gram’s stain

• thick layer of peptidoglycan outside plasma membrane

• lack other membrane

Gram-Negative Bacteria

• have an outer membrane made of a lipid bilayer - inserted lipopolysaccharides and proteins called porins that provide channels for diffusion of low molecular weight compounds and ions across this outer membrane

Nucleoid

• contains single smaller, circular molecule of DNA

Endoplasmic Reticulum and Golgi Complex

play central roles in the synthesis and processing of lipids and membrane proteins

Peroxisomes

where very-long chain fatty acids are oxidized

Lysosomes

filled with digestive enzymes to degrade unneeded cellular debris

Three Types of Cytoplasmic FIlaments

• actin filaments

• microtubules

• intermediate filaments

Endomembrane System

segregates specific metabolic processes and provides surfaces in which certain enzyme-catalyzed reactions occur

Four Most Abundant Elements in Living Organisms

Hydrogen, Oxygen, Nitrogen, and Carbon

Macromolecule

polymers with molecular weights above ~5000 made from relatively simple precursors

Proteome

The sum of all the proteins functioning in a given cell

Genome

the entire sequence of a cell’s DNA

Glycome

its entire complement of carbohydrate-containing molecules

stereoisomers

diff physical properties

Geometric Isomers (cis-trans isomers)

• differ in the arrangement of their substituent groups with respect to the nonrotating double bond

• different physical and chemical properties

Enantiomers

have identical physical properties (except with regard to polarized light) and react identically with achiral reagents

Diastereoisomers

different physical and chemical properties

Number of Stereoisomers

2^n

(n = chiral centers)

Optically Active

Molecule:

• one chiral center

• doesn’t have an internal plane of symmetry

Mixture:

• pure - need to be all R or S

• NOT RACEMIC; majority one configuration

Oxidation of Glucose

Change in Gibbs Free Energy

Hexokinase Reaction

First step of Glycolysis

Standard Free Energy Change Equation

Reaction 1 of Glycolysis

Reaction 2 of Glycolysis

Reaction 3 of Glycolysis

Increasing

The entropy of the world is constantly ____

Glucose Reaction