Lecture 2 MBB

Carbohydrate

A class of biomolecules

• composed of carbon, hydrogen, and oxygen

• used for energy storage (starch, glycogen)

• structure (cellulose)

• signaling

Lipid

Hydrophobic biomolecule

• including fats and membranes

• composed of fatty acids and glycerol

• functions in energy storage and membrane structure

Protein

Polymer of amino acids that folds into three‑dimensional structures to perform a wide range of cellular functions.

Nucleic Acid function

Polymers of nucleotides (DNA and RNA)

• store and express genetic information.

atomic number vs atomic weight vs isotope

• Atomic number = # of protons = # electrons

• Atomic weight/MW = # protons + # neutrons

• Isotope: Same number of protons, different number of

neutrons

Covalent Bond define and key characteristics

Bond formed by sharing electrons between atoms

• generally strong and directional

• includes single, double, and triple bonds.

polar covalent bond

electrons shared unequally

electronegativity

indication of an atom’s ability to attract an electron

Noncovalent Bond

Interactions that do not involve shared electrons; individually weak but collectively can be very strong; includes hydrogen bonds, ionic interactions, and van der Waals forces.

Ionic Bond

Electrostatic attraction between oppositely charged ions, often formed when electrons are transferred between atoms.

• held together by electrostatic interactions

Hydrogen Bond

Weak attraction between a covalently bonded hydrogen (donor group) and an electronegative atom on another molecule (acceptor group)

• donor group attaches to electroneg atom

• 
  

Nonpolar Covalent Bond

A covalent bond in which electrons are shared roughly equally, producing no permanent dipole.

4 major families of small organic compounds and what they make in the cell

sugars

• polysaccharides, glycogen, and startch in plants

fatty acids

• Fats and membrane lipids

amino acids

• Proteins

nucleotides

• nucleic acids

Monosaccharide

The simplest carbohydrate unit (e.g., glucose/sugar)

• building block of more complex sugars

• fastest burning energy source

Polysaccharide (definition and function)

A long chain of monosaccharides

• energy storage

• structural integrity (cartilage, cellulose).

Monomer

A single subunit that links to form a polymer.

Fatty Acid

Hydrocarbon chain that are the building blocks of fats and membrane lipids

Triacylglycerol (TAG)

made up of fatty acids

• slow burning energy source

Amino Acid definition and structure

Building block of proteins; contains an amino group, a carboxyl group, and a unique R group/ side chain.

R Group

The variable side chain of an amino acid that determines its properties.

at pH__, the carboxyl and amino groups are _______

7, ionized

Peptide Bond

Covalent bond linking the carboxyl group of one amino acid to the amino group of the next.

Polypeptide

A long linear chain of amino acids that can fold to form a protein.

Protein Folding (& how?)

Process by which a polypeptide adopts a unique, stable, three‑dimensional, biologically active structure.

• folds using both covalent and noncovalent interactions

Nucleotide structure

A nucleoside attached to one or more phosphate groups

nucleotide function

• short term carriers of ATP

• storage and retrieval of DNA and RNA

Nucleoside

A nitrogenous base bonded to a five‑carbon sugar, without any phosphate group.

nucleic acid

nucleotides connected by phosphodiester bonds

RNA function

Expresses genetic information.

Most macromolecules are made from a set of ______ that are

slightly ____ from one another

monomers, different

Proteins, nucleic acids and polysaccharides are synthesized by the stepwise __________ __ __________

polymerization of monomers

Condensation Reaction

A chemical reaction that links monomers by releasing water (dehydration synthesis).

Native State and position of r groups

The unique three‑dimensional conformation of a protein or RNA species due to noncovalent interactions

• hydrophobic r groups on inside, hydrophilic on outside

why is good specificity (shape alignment and chemistry) required between bonding macromolecules?

• cumulative effect of one noncovalent bond isn’t very strong

• contact at multiple points creates multiple noncovalent bonds able to withstand thermal jolting

Electrostatic Interaction

Attraction or repulsion between charged groups that is distance‑sensitive

• either molecule charge is weak on its own

Starch

Polysaccharide used for energy storage in plants.

Glycogen

Polysaccharide used for energy storage in animals.

Cellulose

Structural polysaccharide in plant cell walls.

where are hydrogen bonds commonly found?

crucial in water, DNA, and proteins.