membrane systems

hydrophobic effect

the natural tendency of nonpolar substances to aggregate and exclude themselves from aqueous solutions

what comprise the endomembrane system

1. ER

2. golgi

3. endosomes

4. lysosomes

what does the ER do

handles protein synthesis, lipid production, and molecular transport

what is the ER lumen more chemically similar to

outside of the cell (distinct from cytosol)

what gives the rough ER it’s appearance

ribosomes embedded in the ER

what is the rough ER the production site of

proteins and lipids

what is the process for which DNA is turned into RNA

transcription wh

what is the process for which nucleic acids are made into proteins

translation

what is the most versatile macromolecule

proteins

what carries out most of the catalytic activities of cells

proteins

what is the name of a protein catalyst (protein that speeds up reactions)

enzyme

what are proteins made up of

amino acids

true or false: the carbon of amino acids is a stereocenter

true

L vs D isomers of amino acids

L - if amino group is on the left

R - if amino group is on the right

what amino acid isomer is the ONLY form found in proteins produced by ribosomes

L isomer (amino acid on left)

what are the four groups of amino acids

1. nonpolar

2. polar

3. acidic

4. basic

what part of the amino acid is responsible for the different functions

the r group

what are characteristics of the non-polar amino acids

• hydrophobic R groups

• only interactions are Van der Waal

what is the smallest amino acid

Glycine

what amino acid does not have L or D isomers

Glycine

what are the aromatic non-polar amino acids

• phenylalanine

• Tryptophan

what is unique about proline

the R group is covalently bonded back to the backbone

a very rigid structure

what is unique to Leucine and isoleucine

structural isomers (have the same molecular formula and mass)

what are characteristics of the uncharged polar amino acids

• hydrophilic R groups

• hydrogen bonding

• No net charge (can’t do ionic cause uncharged)

what is unique about Cysteine

• under reduction conditions form sulfhydryl group (-SH)

• Under oxidized conditions form disulfide (-SS)

what is characteristic of basic amino acids? acidic amino acids?

basic

• carry a positive charge at neutral pH

• nitrogen R groups

acidic

• carry a negative charge at neutral pH

• -COOH R group

how do amino acids link together

via a covalent bonds (peptide bonds)

are peptide bonds stable or unstable?

stable

what bond holds proteins together to form polypeptides

peptide bonds

what is the reaction name to form peptide bonds

condensation reaction

what is loss in a condensation reaction

water

what groups are linked to form a peptide bond

• COOH group from one amino acid

• NH₂ group from another amino acid

what terminal of the peptide bond is positive? negative?

positive - N terminus

negative - C terminus

what is the largest expense of energy

building proteins

_____ holds the instructions for protein building

DNA

describe the 3D geometry of peptide bonds

planar (restricted in rotation)

what is the half life of peptide bonds

7 years

what is the weight of one amino acid

110 Da (aka 110 g/mol)