Exam I Flashcards
Electronegativity Trend
F>O>N>C>H
An amine can ____ a proton to become ____ charged.
gain, positively
A carboxylic acid can ____ a proton to become ____ charged.
lose, negatively
The larger the Ka is, the ____ it is to dissociate. (____ acid)
easier, stronger
The smaller the Ka is, the ____ it is to dissociate. (____ acid)
harder, weaker
What is pKa? The value at which there is ____
an equal concentration of ionized and unionized species
If pH = pKa, there is ____
an equal amount of charged and uncharged species
pKa of Amines
pKa ~ 9-10
pKa of Carboxylic Acids
pKa ~ 4-5
Phospholipid Structure: ____ Head ____ Tail
Hydrophobic Head
Hydrophilic Tail
(Amphipathic Molecules)
____ molecules are more soluble in body fluids.
Hydrophobic (Polar)
____ molecules can pass through lipid membranes.
Hydrophilic (Non-Polar)
Strengths of Intermolecular Forces
Covalent > Electrostatic > Hydrophobic > Hydrogen Bonding > Van der Waals
Partition Coefficient: describes the extent to which an ____ compound dissolves in ____
uncharged, an aqueous solvent versus organic solvent
Drugs that are ____ tend to stay in the blood circulation and surrounding interstitial fluid.
hydrophilic
Drugs that are ____ tend to get trapped inside the tissue and are slowly eliminated.
hydrophobic
Electron-poor atoms
Electrophiles
Electron-rich atoms
Nucleophiles
Henderson-Hasselbach Equation
pH = pKa + log [A]/[HA]
L- vs. D- Amino Acid Configurations
- Read the word “CORN”.
- Clockwise - L Configuration
Counter-Clockwise - D Configuration
Proteins in humans are synthesized from a set of 20 ____-____- amino acids.
L-alpha
Hydrophobic (Non-Polar) Amino Acids (8 total)
Alanine, Isoleucine, Leucine, Methionine, Phenylalanine, Proline, Tryptophan, Valine
Hydrophilic (Polar) Amino Acids (7 total)
Asparagine, Cysteine, Glutamine, Glycine, Serine, Threonine, Tyrosine
Basic Amino Acids (Positively-Charged) (3 total)
Arginine, Histidine, Lysine
Acidic Amino Acids (Negatively-Charged) (2 total)
Aspartic Acid, Glutamic Acid
Isoelectric Point: pH value at which a molecule carries no ____
electrical charge
Isoelectric Point Equation
When it is an acidic amino acid, use ____.
When it is a basic amino acid, use ____.
pI = (pKaC + pKaN) /2
acidic: pI = (pKaC + pKaR) /2
basic: pI = (pKaR + pKaN) /2
Essential Amino Acids (PVT TIM HALL)
Phenylalanine, Valine, Threonine
Tryptophan, Isoleucine, Methionine
Histidine, Arginine, Leucine, Lysine
What is the Kreb’s Cycle?
The biosynthesis of non-nutritionally essential amino acids used to generate energy through oxidation of Acetyl-CoA
Peptide: a chain of ____ linked via ____
amino acid residues, amide bonds
Free amino acids can move from ____ to the brain, gut, kidney (produces ____), or the liver (produces ____ and ____).
muscle, NH3, urea, glucose
What is the Urea Cycle?
A process which converts toxic ammonia into urea by use of amino acids and a series of enzymes
Protein Synthesis:
DNA –1–> mRNA –2–> Proteins –> Post-Translational Modifications
- Transcription (occurs in Nucleus)
2. Translation (occurs in Cytosol)
Steps of Translation (3 total)
- Initiation
- Elongation
- Termination
Primary Structure
amino acid sequence
Secondary Structure
folding of segments of polypeptides into geometrically ordered units (alpha-helix or beta-sheets); governed by hydrogen bonds
Tertiary Structure
the assembly of secondary structural units into larger functional units such as the mature protein and its components domains; governed by non-covalent bonds and disulfide bridges
Quaternary Structure
the number and types of polypeptide units of oligomeric proteins and their spatial arrangements
Post-Translational Modifications of Proteins
1. Proteolysis
PRODUCT: protein cleavage
INVOLVED ENZYME: proteases
PURPOSE: protein maturation
Post-Translational Modifications of Proteins
2. Acetylation Deacetylation
PRODUCT: acetyl N-terminal, acetyl side chain of Lys residues
INVOLVED ENZYME: acetylase
PURPOSE: change charge binding; histone and gene regulation
Post-Translational Modifications of Proteins
3. Phosphorylation
Dephosphorylation
PRODUCT: Ser-OH --> Ser-OP3 Thr-OH --> Thr-OP3 Tyr-OH --> Tyr-OP3 INVOLVED ENZYME: kinase phosphatase PURPOSE: change charge; cell signaling
Post-Translational Modifications of Proteins
4. Lipid Attachment
PRODUCT: farnesylation
INVOLVED ENZYME: lipid transferase
PURPOSE: anchor proteins to membrane for regulation
Post-Translational Modifications of Proteins
5. Glycosylation
PRODUCT: addition of carbohydrates to Asn, Ser, Thr
INVOLVED ENZYME: glycosyl transferase
PURPOSE: glycoproteins; protection of cell surface
In what ways does glycosylation affect a protein? (6 total)
Affects solubility, stability, cellular localization, trafficking and clearance, immunogenicity, and self-recognition
- What classification of proteins contain keratins, cytoskeletal proteins, and extracellular matrix proteins?
- What are two examples of cytoskeletal proteins?
- What are four examples of extracellular matrix proteins?
- Structural Proteins (Fibrous)
- Actin and Myosins
- Collagens, Fibronectin, Laminin, Proteoglycans
What classification of proteins contains enzymes, receptors for signal transduction, antibodies, transcription factors, chaperons, carrier proteins, and growth factors?
Functional Proteins (Globular)
What is the function of myoglobin?
Stores oxygen in muscle
What is the function of hemoglobin?
Stores and transports oxygen in blood
Cytochrom C: heme-containing ____ localized in the ____ inner membrane and is involved in production of ____ via the ____ (oxidative phosphorylation)
protein, mitochondria, ATP, electron transport chain
Metabolic Disorders
1. Type I Diabetes
CAUSE / DEFICIENCY IN: insulin because immune system attacks insulin producing cell
TREATMENT: insulin
Metabolic Disorders
2. Type II Diabetes Mellitus
CAUSE / DEFICIENCY IN: either low insulin or insulin resistance
TREATMENT: insulin, diet, glucose-lowering medicine
Metabolic Disorders
3. Urea Cycle Disorder
CAUSE / DEFICIENCY IN: N-acetyl glutamate synthase; carbamoyl phosphate synthase, ornithine transcarbamylase; argininsuccinate synthase
TREATMENT: give the down stream metabolite