Biochemistry - FFM1 Flashcards
Overview of Biochemistry for FFM1
Define:
Catabolism in term of metabolism
The metabolic pathway of breaking down large macromolecules into smaller units/monomers (Fats/Lipids —> Fatty Acids)
Define:
Anabolism in term of metabolism
The metabolic pathway of building up larger molecules from smaller monomer units (Nucleotides —> Nucleic Acids, DNA/RNA)
Examples of metabolites
Glucose
ATP
Hormones
Neurotransmitters
Electrolytes
Cations/Anions
Xenobiotics
What is:
Xenobiotic
Any chemical substance foreign to organism
Example of Xenobiotics?
Drugs
Environmental pollutants
Food additives
What are the monomers that, when put together, for lipids
Fatty Acids
What are the monomers that, when put together, form polysaccharides
Carbohydrates/Sugars
Types of Disease processes associated with biochemical processes?
Congenital/Inherited diseases
Metabolic Disorders
Vitamin Deficiencies
Cancer
Alzheimer’s
Cushing Syndrome
CV Diseases
Functionality of Biomolecules?
(5)
Enzymatic
Structural
Movement/Transportation
Information Carrying
Compartmentalization
Where are macromolecules assembled at within the cells?
Ribosomes
Membranes
Chromosomes
Starch/Glycogen
List of most common metabolic pathways?
Glycolysis
TCA/Citric Acid Cycle
Oxidative Phosphorylation
Other types of metabolic pathways with different products?
Glycogenesis
Glycogenolysis
Hexose Monophosphate Shunt
FA Synthesis
FA Degradation
AA catabolism
Urea Cycle
Purine/Pyrimidine Synthesis & catabolism
Properties of macromolecules (6)
Lipids, Carbs, NA, Proteins
Energy source
Building blocks of the body
Assembly into macromolecule complexes
Structural
Functionality
Types of nucleotides
RNA
DNA
Nucleotide(s) for information storage
DNA
Nucleotide(s) used to transfer information
mRNA
Nucleotide(s) used for translation
mRNA, rRNA, and tRNA
Nucleotide(s) used for catalytic functions
Enzymes
Nucleotide(s) used for energy transduction
ATP
Nucleotide(s) used as cofactors for enzymes
NADPH+, NADH
Overview of Central Dogma of Molecular Bio
DNA —> RNA —>Proteins
Does this genetic material flow one direction? Why or why not?
No - there are RNA viruses that will used reverse transcriptase to create DNA FROM RNA strand; also prions to not use DNA/RNA to cause disease
Describe the structure of nucleotides
1) Phosphate group on 5’ end
2) A pentose sugar with either a hydroxyl group on 2’ carbon end or hydrogen on 2’ carbon end
3) Nitrogenous base (purine/pyrimidine) attached to 1’ carbon
Describe structure of pyrimidine?
Single aromatic/benzene ring with Nitrogens located at 1’ and 3’ positions within ring
Describe structure of purine?
Double ring structure with pyrimidine structure attached to imidazole ring (pentose ring)
Which pyrimidine has an amine group attached at the 4’ C?
Cytosine
Which pyrimidine has a methyl group attached at the 5’ C?
Thymine
Which pyrimidine does not have any functional groups attached to it?
Uracil (for RNA)
Which nucleotide?
Guanine
Which nucleotide
Adenosine
Which nucleotide?
Thymine
Which nucleotide
Cytosine
Which nucleotide
Uracil
Type of bond forming backbone of DNA/RNA
Phosphodiester linkage
Formation of phosphodiester bonds
Condensation rxn between 5’ phosphate group and 3’ hydroxyl group; removes water molecule during rxn
Does DNA/RNA have polarity?
Why/why not?
Yes - due to formation of phosphodiester bonds between nucleotides
Type of bonding between complementary strands of DNA
Hydrogen bonding
Explain Chargaff’s Rule
A’s = # T’s
#C’s = #G’s
All total - equal to 100%
Number of bonds between A—T
2 hydrogen/double bonds
(2 Attic Tents
Number of bonds between C—G
3 hydrogen/triple bonds
(3 Car Garage)
Types of RNA
mRNA
tRNA
siRNA
miRNA
rRNA
Functions of Protein
(9)
1) Energy (last source of)
2) Source of AA’s for new proteins
3) Enzyme catalysts
4) Structural
5) Receptor signaling
6) Carriers of small molecules
7) Movement (actin)
8) Communication
9) Transportation
What codes for proteins
DNA
Type of protein structures
1) Primary - AA chain
2) Secondary - alpha helices/beta sheets
3) Tertiary - formed protein of use
4) Quarternary - multiple proteins form together to create function unit (heme)
Explain structure of AA
Alpha carbon surrounded by carboxyl group, amino group, a hydrogen, and an R group conveying various functions TO that AA
L vs D chirality
Mirror images of one another; they are NOT superimposable though
Catagories of AA’s, based on R group
Polar/Nonpolar
Charged/Uncharged
Aromatic
(+) or (-) Charge
What’s my name, sign, 1 letter abbreviation and charge?
Aspartic Acid
Asp
D
Acidic (negative charge due to carboxyl group)
What’s my name, sign, 1 letter abbreviation and charge?
Glutamic acid
Glu
E
Acidic (negative charge due to carboxyl group)
What’s my name, sign, 1 letter abbreviation and charge?
Histidine
His
H
Basic (positive charge due to amine group)
What’s my name, sign, 1 letter abbreviation and charge?
Lysine
Lys
K
Basic (positive charge due to amine group)
What’s my name, sign, 1 letter abbreviation and charge?
Arginine
Arg
R
Basic (positive charge due to amine group)
What’s my name, sign, 1 letter abbreviation and charge?
Threonine
Thr
T
Uncharged/Polar
What’s my name, sign, 1 letter abbreviation and charge?
Cystine
Cys
C
Uncharged/Polar
What’s my name, sign, 1 letter abbreviation and charge?
Tyrosine
Tyr
Y
Nonpolar/Aromatic
What’s my name, sign, 1 letter abbreviation and charge?
Asparagine
Asn
N
Uncharged/Polar
What’s my name, sign, 1 letter abbreviation and charge?
Glycine
Gly
G
Nonpolar/Aliphatic
What’s my name, sign, 1 letter abbreviation and charge?
Alanine
Ala
A
Nonpolar/Aliphatic
What’s my name, sign, 1 letter abbreviation and charge?
Valine
Val
V
Nonpolar/Aliphatic
What’s my name, sign, 1 letter abbreviation and charge?
Leucine
Leu
L
Nonpolar/Aliphatic
What’s my name, sign, 1 letter abbreviation and charge?
Phenylalanine
Phe
F
Nonpolar/Aromatic
What’s my name, sign, 1 letter abbreviation and charge?
Isoleucine
Ile
I
Nonpolar/Aliphatic
What’s my name, sign, 1 letter abbreviation and charge?
Tryptophan
Trp
W
Nonpolar/Aromatic
What’s my name, sign, 1 letter abbreviation and charge?
Proline
Pro
P
Polar/uncharged
What’s my name, sign, 1 letter abbreviation and charge?
Methionine
Met
M
Polar/Aliphatic
What’s my name, sign, 1 letter abbreviation and charge?
Glutamine
Gln
Q
Polar/uncharged
What’s my name, sign, 1 letter abbreviation and charge?
Serine
Ser
S
Polar/uncharged
Nutritionally Essential AA’s?
Unable to form ourselves in the body; MUST take in from diet
Nutritionally Nonessential AA’s
The human body can produce these; we don’t need them from diet
List of Essential AA’s
PVT TIM HALL
Arginine
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
List of Nonessential AA’s
Alanine
Asparagine
Aspartate
Cysteine
Glutamate
Glutamine
Glycine
Proline
Serine
Tyrosine
Best source of energy
Carbohydrates
Functions of Glycolipids
- Immune recognition on outside of cell membrane
- Physical barriers
Functions of glycoproteins
1) Regulation of folding inside cell membrane
2) Structural proteins
Hexose Sugars
Glucose
Galactose
Mannose
Fructose
Pentose Sugars
Ribose
Deoxyribose
Disaccharides
Sucrose
Lactose
Maltose
Sucrose formed from…
Glucose and Fructose
Lactose formed from…
Glucose and Galactose
Maltose formed from…
2 glucose molecules (D-glucose)
Which disaccharide am I?
Maltose
Which disaccharide am I?
Lactose (1,4 Link)
Which disaccharide am I?
Sucrose (1,2 link)
Types of Starch
Amylose
Amylopectin
Describe amylose
Liner, non-branched
Connected by 1,4 glycosidic bonds (forms spiral)
Describe amylopectin
Glucose storage in plants
Animals can digest
alpha (1,4) glycosidic bonds with branch at alpha (1,6) (forms branches)
Glycoproteins
NAC - n-acetyl-glucosamine
GAG - glycosaminoglycan
Glucuronic acid
Iduronic acid
Function of Lipids
Energy storage
Compartmentalization
Signaling
Vitamins
Define micelle
spherical amphiphilic structures with hydrophobic core and hydrophilic shell; formed from lipids
Polar head group larger than aliphatic HC chains
What are functions of lipids?
Signaling molecules
Inflammatory molecules
Issues in metabolic disorders
What is an oil?
- Hydrophobic liquid of mostly plant based origin
- Hydrocarbons, trigycerides, pr FA’s of varying lengths.
Define lipid
- Non-polar, amphipathic molecule (predominately hydrophobic)
- Broad category for fats, waxes and detergents
- Can form micelles, bilayer sheets
What is a fat?
- For medicine, triglyceride
- Hydrophobic solid/semisolid substance
What is a micelle?
- Single layer of amphipathic molecules that form cyclic structure
- Composed of hydrophobic tails towards the interior; hydrophilic head towards the exterior
What is a detergent?
- amphipathic compound acting as surfactants
- form micelles
What is a saturated fatty acid (FA)?
One which has long hydrocarbon tail composed of only single bonds - completely saturated with hydrocarbons
What is an unsaturated fatty acid (FA)?
- One which has long hydrocarbon tail composed of hydrocarbons with 1 or more cis-double bonds seen
- cis-Double bond allows for bend in the hydrocarbon tail
- mono or poly depending on number of double bonds
Why are unsaturated FA and trans-fatty acids similar?
Both have long hydrocarbon tails; trans fatty acid has a double bond but not breaks in the hydrocarbon chain. Structurally similar to one another.
2 examples of essential FA’s
Linoleic acid
Linolenic
Composition of fat
- Glycerol backbone linked with FA chains via ester bond
- Bond is easy to break; allows molecules to be transferred
Glycerols with one FA attached
MonoAcylGlycerol
Act as detergent during digestion
Glycerol with 2 FA chains attached
DiAcylGlycerol
Glycerol with 3 FA’s attached
TriAcylGlycerol
Types of membrane lipids
1) Glycerolphospholipids
2) Sphyingolipids
3) Cholesterol
4) Others
Types of Sphingolipids (2)
Phosphosphingolipid/sphingomyelin
Glycosphingolipids
Types of glycerophopholipids (4)
Phosphatidylcholine (PC)
Phosphatidylserine (PS)
Phosphatidylethanolamine (PE)
Phosphatidylinositol (PI)
Explain picture
Structure of Glycerophospholipids
(Backbone with attachements (sat or unsaturated)
- Glycerol backbone
- 2 FA’s - 2’ FA is unsaturated, 1’ end FA is typicall saturated
- Phosphate attached to glycerol
- Head group attached to phosphate
Phosphatidylcholine functions/properties
- Most common
- Required as part of diet
- Part of lung surfactant
- Can contribute to cellular signaling
Phosphotidylethanolamine functions/properties
- primary constituent of bacterial membranes
- Constituent of mammalian membranes
- Can contribute to cellular signaling
Phosphatidylserine functions/properties
- Found inner leaflet of membrane
- Signal in apoptosis
- Less common
Phopshotidylinositol funtions/properties
- Minor constituent in mammals
- Involved in intracellular signaling
- IP3 releases Ca2+
- PIP3 is a signaling molecule
Plasmologen function/properties
- Comprise good amount of lipids in membranes/myelin
- Have ether linkage w/ double bond instead of ester linkage
- Synthesized in perioxisomes
Cardiolipin functions/properties
- Specialized lipid
- Found in mitochondrial membrane
- Makes mitochondrial membrane more impermeable to ions/regulates ion entry into mitochondria
Plasmologens vs DiAcylglycerophospholipids (DAG’s)
Too similar - how different?
DAG’s have phosphodiester/ester linkage/bond
Plasmologens have a vinyl-ether
Enzymes to degrade lipids:
1) Phospholipase A1
2) Phospholipase A2
3) Phospholipase B
4) Phospholipase C
5) Phospholipase D
1) Remove FA from glycerol backbone
2) Remove FA from glycerol backbone
3) Remove FA at either 1/2 positions, use lysophosphatidylcholine as substrate
4) Removes head group between glycerol and phosphate
5) Removes head group after phosphate
Importance of phospholipase A2
- Activated through hormone signaling
- Releases arachidonic acid from PI or PC
- Arachidonic acid converted to prostaglandins (inflammation)
Importance of Phospholipase C
- Releases IP3
- Generates DAG
- Part of 2nd messenger system of cells
Sphingomyelin functions/properties
- Seen in many membranes, predominantly in neuronal/myelin
- Phosphocholine headgroup
- Structure based on serine NOT glycerol
- Bonded by aliphatic/amide bonds
- Role in intracellular communication (outer layer)
Functions of glycolipids
Carbohydrate layer on outer membrane of membrane
Provide mechanical integrity to bilayer
Protect bilayer from breaking
Cholesterol functions/properties
- Major component of bilayer
- Get from diet or from synthesis of AceCoA
- HIGHLY REGULATED!
- Carried thru body in lipoprotein particles
(chylomicrons, LDL, HDL) - Allows bilayer to have both rigidity and fluidity at the same time (bilayer too fluid, gives support)
Detergent properties
- larger head group than normal ampipathic molecules
List of common detergents
Lysophosphatidylcholine
MonoAcylGlycerol
Sodium Dodecyl Sulfate
FA’s
Lipids found on inner membrane
- PS
- PI
Lipids found on outer membrane
Glycolipids
Lipids found on outer AND inner membrane
Cholesterol
Types of lipid motion within the bilayer
(fastest to slowest)
1) Bond vibrations
2) Gauche-trans isomerization
3) Protrusion
4) Lateral diffusion
5) Undulations
6) Flip-flop (enzymes required to do quickly)
Properties of proteins
- most abundant molecule
- most functionally diverse molecule
- AA’s joined together by peptide bond
Functions of proteins
1) Energy
2) Enzymes
3) Movement
4) Cell signaling
5) Transport
6) Structural integrity
Most AA’s are in what conformation
L-amino
What confers functionality to final protein product
Side chains - allow for bending, folding of protein
What is the only AA without chirality
Glycine - no alpha chiral carbon
Characteristics of peptide bond
- Does not allow rotation around the bond - double bond quality
- trans configuration - allows steric hindrance to be dispersed among the R groups
- polar, uncharged (no ionization, will contribute to H-bonding - can form 2 H-bonds between peptides)
Who’s the one exception to formation of other H-bonds with other AA’s
Proline - due to cyclic nature and there is no amine group to bond with
Levels of protein structure
Primary, Secondary, Tertiary, Quarternary
Primary structure properties
Single AA’s linked to one another via peptide bonds
The order in which the AA’s joined to one another
Stabilized by covalent bonds
Secondary structures
Alpha helices
Beta pleated sheets
Beta turns
Alpha helices properties
- Form spontaneously
- Rigid rod-like coil
- Side chains pointed outward
- Most stable conformation
- H-bond +/- parallel to axis of helix (4th residue)
- Formation of maximum number of possible H-bonds
Beta pleated sheet properties
- 2+ peptide chains arranges anti/parallel to one another
Beta turns properties
- most common turn
- Change in direction of chain
- H-bond from main carbonyl O to main chain NH3 residues along chain
Common AA’s seen in Beta turns
Glycine - smallest R group
Proline - causes kink in peptide chaino
Function of Superoxide Dismutase
Catalyzes superoxide free radical (O2-) into O2 or H2O2
- example of Beta barrel structure
Mutation in superoxide dismutase causes
Familial Amyotrophic lateral Sclerosis (AML, motor neuron disease)
Tertiary Structure Interactions
- H-bonding
- Hydrophobic interations
- van der Waals interactions
- Ionic bonds (albeit rare! - stabilizaton of interior)
- Disulfide bridges
Define disulfide bridge
Covalent bond between 2 cysteine residues
Forms cystine residue
If one AA in peptide chain is read incorrectly -
Can cause protein to have different shape, functionality, or new unexpected properties
Different domains for proteins
1) Ligand-binding site
2) EGF precursor homology domain (epidermal growth factor)
3) O-linked sugar domain
4) Membrane spanning domain
5) Cytoplasmic domain
Examples of quarternary structure:
Hemoglobin - 2 alpha and 2 beta chains form
FA Synthase Comples - homodimer
Heptahelical receptor - G protein, heterotrimer
Fibrous protein properties
- Cylindrical rods that are long
- Low water solubility
- Structural role
- Large amounts of secondary structures
- N true tertiary structure - secondary/quarternary structures are strong
Examples of Fibrous proteins
Collagen
Elastin
Keratin (IF for epithelial cells)
Collagen properties
- Most abundant protein in body
- Present in all tissue
- Framework for tissue formation/stucture
- 3 L-handed helices (Gly-X-Y) form large R-handed super helix
- H-bonds stabilize
- X = proline; Y = hydroxyproline, hydroxylysine
Why glycine in collagen?
Only R group small enough to allow close proximity of chains to one another
Why proline in collagen?
Rigidity to helix due to ring structure (conformationally inflexible)
Why hydroxyproline or hydroxylysine in collagen?
Hydroxyproline = involvement with H-bond formation
Hydroxylysine = allows attachment of carbohydrate moieties (glucose and galactose)
Types of post translational modifications for proteins
Phosphorylation, Hydroxylation, Carboxylation, Ubiquitininization
What roles do these post-translational modifications have
Regulatory - either activate or deactivate activity of protein
Henderson-Hasselbalch Equations
Describes relationship between pH to acid and conjugate base
Why use Henderson-Hasselbalch?
Estimation of pH of buffer solution
Equilibrium pH in acid-base rxns
Calculate isoelectric point of proteins
Buffer point for Acid/Base
- pKa is best buffering point
- +/- 1 from pH: within this range = good buffer.
- Solution doesn’t want to change - less pH change is better
What is isoelectric point
- pH value where molecule is NET NEUTRAL (net charge = 0)
- pH where proteins net neutral = less soluble, precipitate out of solution
How to find net charge of proteins?
- Find acidic/basic AA’s.
Acidic = -1
Basic = +1
-