Unit 1 Flashcards
Hydrogen bonding
- Non covalent bond
- electrical attraction btw EN atom + partial positive of hydrogen
- hydrogen participating in polar bond
- other atom is partially EN + participating in a polar bond
Types of bonds from weakest to strongest
- H bond
- Ionic
- Covalent
Equation for ionization of water
2H2O –> H3O+ + OH-
Polarity of amino acid R groups
- Nonpolar: mostly C and H (no charged or EN atoms)
- Polar uncharged: partial charges –> H bonding (all have O except one) e.g. hydroxyl, carbonyl, sulfhydryl
- Polar charged: charge specific to R group, charged side chains –> H bonding, ionic bonding –> highly soluble (e.g. carboxylic acid, amine)
Characteristics of peptide bonds
- Joins a carbonyl carbon + an amino nitrogen atom
- Is covalent
- Involves a condensation reaction
What is an alpha carbon?
- In amino acid
- Carbon in between amino and cabroxyl group
- R groups attach to alpha carbon
What are the four levels of protein structure?
- Primary: linear amino acid sequence (N-terminus to C-terminus)
- Secondary: folding into local segments of structure (regular H bonds on backbone, amino to carboxyl)), alpha helix/beta pleated sheet (parallel/anti-parallel)
- Tertiary: interaction of elements of secondary structure –> global 3D structure (ionic bonds/electrostatic, H bonds, hydrophobic interactions)
- Quaternary: 2+ polypeptides interact to form final functional protein (not all proteins) (covalent + non-covalent interactions)
Disulfide bonding in proteins
- Covalent stabilization of protein structure
- Found in secreted proteins (destined for a more hostile extracellular environment)
- Formed in ER (oxidizing environment)
Nucleotide vs nucleoside
- Nucleotide: base + sugar (pentose) + phosphate
- Nucleoside: base + sugar (pentose)
Nuclei acid chain grows by linking which functional groups of two nucleotides?
5’ phosphate and 3’ hydroxyl group
Which monomers are used to grow a nucleic acid?
doexyribo Nucleoside Tri-Phosphate (dNTP) (making phosphodiester bonds between nucleotides requires energy input so energy level of nucleotides raised by addition of 2 phosphate groups), condensation rxns
What force holds together two anti-parallel strands of the DNA double helix?
H bonds between A-T and C-G
DNA vs RNA
DNA:
- double stranded
- deoxyribose (H on C2)
- A-T, G-C
RNA:
- single stranded
- ribose (OH on C2, makes RNA less stable)
- A-U, G-C
Alpha vs beta glucose
Alpha:
- OH below plane
Beta:
- OH above plane
Why can’t animals degrade cellulose?
Animals do not have the enzymes to break down beta 1-4 bonds
What do phospholipids + triglycerides have in common?
They both have a glycerol backbone
Purines
2 rings: adenine, guanine
Pyrimidine
1 ring: cytosine, thymine, uracil
Secondary structure of DNA
Two strands of DNA run antiparallel with bases facing inward (hydrophobic) and phosphate sugar backbone on the outside
Anomeric carbon
Carbon in carbohydrate linear structure w/ carbonyl group, when ring forms, it has the OH attached to it (two anomers –> alpha/beta glucose)
Glycosidic bonds
- Carbohydrate monomers link (C1 to C4) in a condensation rxn
- 2nd sugar flips in beta glycosidic linkage so that the bond can form at the top
Complex carbohydrates
- Amylose (starch): alpha glucose, plant energy storage
- Amylopectin (starch): alpha glucose, plant energy storage, moderately branched
- Glycogen: alpha glucose, animal energy storage, highly branched
- Cellulose: beta glucose, structural plant, unbranched (straight chain)
- Chitin: beta glucose: structural animals + fungi
Triglycerides
- 3 glycerols, 3 fatty acids linked by condensation
Fatty acids can be:
- Saturated: no db, solid
- Cis unsaturated: db on same side of C chain, liquid
- Trans unsaturated: db on opposite side of C chain (artificial), liquid
Phospholipid
- Polar group, phosphate, glycerol, 2 fatty acid tails
- Ampipathic (one end hydrophobic, other end hydrophilic)
