Lecture 8: Cell & Molecular Biology of the Nervous System II Flashcards
What is the type of bond formed when amino acids condense?
covalent bond (also a peptide bond)
What are polymers of amino acids called?
polypeptides
Why are polypeptides always show in the N-terminal (amino) to C-terminal (carboxy) orientation?
they are always synthesized from N to C
What are the 4 main categories of R groups?
- negatively charged
- positively charged
- uncharged polar
- nonpolar
What isomer (L or D) of amino acids is found in proteins?
only L-isomers (acronym: LIP)
How do amino acids function in neurons?
- form proteins
- as neurotransmitters
- as neuromodulators (D-isomers)
molecular weight in daltons
number of amino acids x 100
How is a protein different from a peptide?
protein is larger
secondary structure of a protein
- result of H-bonding
- eg, alpha-helix, beta-pleated sheet
tertiary structure of a protein
formed by secondary structures interacting via non-covalent bonds (hydrogen, ionic, and Van der Waals)
What are 10 main functions that proteins have?
- enzymes
- transcription factors
- translation factors
- cytoskeleton
- motors
- ion channels
- ion transporters
- receptors
- cell adhesion
- signaling ligands
What are the 4 major types of proteins (categorized according to their chemical properties) expressed by cells?
- cytosolic-soluble proteins: water soluble, free in cytosol
- membrane-anchored soluble proteins: covalently attached to a lipid
- membrane-enclosed soluble proteins: get packed into vesicles; e.g., secreted proteins and peptides, proteins inside organelles
- integral membrane proteins: transmembrane proteins
ligand
any molecule that can interact with another molecule
What are 3 types of post-translational modifications?
- protein synthesis
- ligand binding
- covalent modification
- addition of second subunit
- unmasking
- stimulation of nuclear entry
- release from membrane
cytoplasm
- everything inside the plasma membrane except nucleus (cytosol + organelles)
- emerged from cell biology
