Lecture 2 Flashcards
Acids
Contributes H+ to solution
Bases
Decrease H+ in solution
Buffers
Minimize changes in pH of a solution
pH
-log[H+], scale ranges from 0 (most acidic) to 14 (most basic)
Law of mass action
For reversible reactions –> high concentration of products drives reaction towards more reactants, high concentration reactants drives reaction towards more products
How are functional groups important to physiology?
Functional groups change mol. shape/formula, shape influences function, can help form new bonds
Types of biomolecules
Carbohydrates, lipids, proteins, nucleotides/nucleic acids
Carbohydrates
Most abundant, can be simple (mono-) or complex (poly-)
Formula for carbohydrates
Carbon, hydrogen, oxygen- CnH2nOn –> carbon and oxygen will always be the same, hydrogens doubled
Carbohydrates provide
Quick energy
Difference between carbohydrate and hydrocarbon
Molecular formula - carbs follow the CnH2nOn formula
Lipids
Carbon and hydrogen, very structurally diverse
Diversity of Lipids
Eicosanoids, steriods, phospholipids, triglycerides (glyerol, fatty acid chains)
Saturated vs. unsaturated lipids
Saturated= saturated with hydrogens (single bonds only); ex. butter
Unsaturated= contains a double or triple bond; ex. junk foods
Result of inability to breakdown triglycerides
Digestion and absorption issues, vitamin deficiencies
Phospholipids
Addition of a phosphate group to a glyceride, makes molecule polar; generates phospholipid bilayer membranes –> phosphate side is polar end (hydrophilic)
How many amino acids are there?
20
Proteins
Enzymes, comprised of amino acids, four levels of structure, most versatile
Protein bonding
Disulfide bonds, hydrogen bonds, van der waals forces, ionic bonds/repulsions (all create unique protein shape
What are the layers of protein structure
Primary, secondary, tertiary, quaternary
Function of R group in amino acid backbone
Impacts different abilities/function/complexity to what amino acids/proteins can do
Sequence of amino acids
Generates different functions of proteins
What changes the 3D structure of proteins and influences shape and function?
R groups in amino acids, amino acid chain order, folding (bond interactions) –> adds to properties
Denatured proteins/enzymes
Heat, pH, changed location/solvent –> broken down quaternary, tertiary, secondary structure of proteins (primary structure remains in most occasions, unless strong acid)
Polymer formation
Dehydration synthesis (removal of water to connect peptide chains)
Primary protein structure
Sequence of amino acids; influences interactions in secondary sequence
Secondary protein structure
Alpha-helix, beta-pleated sheets
Quaternary protein structure
Fibrous proteins, globular proteins; contains subunits
Protein bonding
Hydrogen bonds, van der waals forces, ionic bonds, ionic repulsions, disulfide bonds –> all generate unique protein structure
In order for an enzyme to work, it must be
Soluble
How are protein interactions modulated?
Specificity, affinity (proteins are selective about bonding/binding)
Isoforms
Functionally similar proteins, encoded by similar genetics but not identical
Protein interactions
Binding, selectivity, molecular complementarity (specificity, affinity), isoforms
Selective protein binding
Induced-fit model (lock and key mechanism); use of binding sites –> cofactors and inhibitors can alter binding sites/bindings
Allosteric activation/inhibition
Changes conformation of protein to allow or inhibit interaction with ligand
Influence of pH and temperature on protein
Alter 3D shape of protein by disrupting hydrogen or S-S bonds, may be irreversible if protein denatures
Physical factors that affect protein function
Temp, pH, concentration of protein (up and down regulation), concentration of ligands, maximum reaction rate (saturation) –> availability of necessary components
Rate of protein activity
Maximal activity at certain temp, pH (optimal range) –> range of rates with varied temps, pH, etc.
Nucleotides and Nucleic acids
Comprised of base, sugar, phosphate; transmit and store information (DNA, RNA), transmit and store energy (ATP, cAMP, NAD, FAD)
Types of extracellular fluids (2)
Plasma, interstitial fluids
Functional compartments of the body
Extracellular (plasma, interstitial fluid) and intracellular fluid
Interstitial fluid
Fluid between the circulatory system and cells
Difference between extracellular and intracellular fluid
Intracellular - cytoplasm, extracellular - fluid outside cells, fluid in blood
Homeostatic difference between extracellular and intracellular fluid
Difference in charge, chemicals, between fluids but differences ARE homeostatic
Fluid mosaic model of a membrane
Phospholipid bilayer, membrane contains variety of other proteins, carbohydrates (glycoproteins), cholesterol
Cell membrane functions
- physical barrier
- gateway for exchange (between intracellular and extracellular compartments)
- communication (cell membrane proteins)
- cell structure - intracellular and extracellular matrix
Cell membrane protein types
Integral, peripheral, lipid-anchored
Cell membrane proteins
Ion channels, carriers, receptors, enzymes, linkers, cell identity-markers
Cell membrane lipid types
Phospholipids, sphingolipids, cholesterol
Cell membrane function is dependent on
Arrangement/presence of protein and lipids within the bilayer
Non-membranous cell inclusions
Ribosomes, proteasomes, vaults, protein fibers
Rough ER vs. Smooth ER
Rough ER: produces proteins
Smooth ER: produce fatty acids, steroids, inactivation/detoxification of drugs
Different tissue types have different compositions of organelles/organelle types to accommodate
Different functionalities of tissues
Mitochondria
Site of aerobic synthesis
Peroxisomes
Contain hydrogen peroxide, serve to detoxify cells, degrade fatty acids
Cytoskeleton
Cell shape, internal organization, intracellular transport, assembly of cells into tissues, movement
Cytoplasmic protein fibers
intermediate (keratin, myosin), microtubules (tubulin, flagella, cilia), actin (microfilaments)
Smallest –> largest cytoplasmic protein fibers
actin, intermediate, microtubules
Motor proteins
Myosins (muscle contractions), kinesins (movement along microtubules), dyneins (cilia, flagella)
Nucleolus function
Control RNA synthesis for ribosomes
Primary tissue types
Epithelial, connective, muscle, nerve
CAMs
Cell adhesion molecules (include cadherins, integrins, selectins)
What proteins facilitate gap junctions?
Connexin proteins
Gap junctions
Create bridges between adjacent cells to allow for VERY fast communication between cells (all cells in a tissue acting together, ex. heart contraction)
What proteins facilitate tight junctions?
Claudin and occludin proteins
Tight junctions
Prevent movement between cells
Desmosomes
Anchor cells to each other
What proteins facilitate anchoring junctions?
Cadherin proteins
Types of cell junctions
Anchoring, tight, gap
Anchoring junctions
Adherens junction, desmosomes, told cells in close contact to either other
Composition of epithelial tissues
Epithelial cells, basal lamina, underlying tissue
Basal lamina
Acellular matrix layer secreted by epithelial cells
Glandular epithelium
Secrete endocrines and exocrines
Covering and lining epithelium
Forms outer covering of skin (epidermis) and some internal organs, lines lumen of hollow organs (vessels, ducts, digestive, respiratory, urinary, reproductive tracts)
Types of connective tissue
Loose, dense, adipose, blood, cartilage, bone
Connective tissues
Most abundant tissues, many types
What kind of tissue is blood?
Connective tissue
What kind of tissue is muscle?
Connective tissue
Muscle tissue is highly specialized to
Contract
Three types of muscle
Skeletal (striated), cardiac (striated), smooth
Nervous tissue
Detects and responds to changes in body’s external or internal environment
Organs
Groups of tissue with related functions (four tissue types in various combinations)
Chemical work
Transport work
Mechanical work
Movement, kinetic and potential energy; utilizing ATP to move muscles to do work
Second law of thermodynamics
Processes move from state of order to disorder; over time, things break down (entropy) –> you have to overcome entropy to do work
Activation energy
Energy must be put into the reaction before a reaction can proceed; the push needed to start a reaction
Exergonic vs. endergonic energy change
Exergonic –> energy released
Endergonic –> energy generated
Example exergonic reaction
Glucose breakdown (energy released by broken molecule)
Endergonic reaction example
Synthesizing glucose (energy needed to build molecule)
Enzyme function
Make activation energy smaller –> more reactions can occur; speeds up reactions without being consumed (help molecules react)
Consequence of large activation energy
Make reactions irreversible
Isozymes
Catalyze same reactions but under different conditions –> we all have enzymes that do the same thing but with slight differences individually (polymorphisms, conditional requirements, etc.)
Example isozyme
Tyrosinase (melanin-producing enzyme), siamese cats have heat sensitive version (will not work in hot spots–> enzyme only active in cool regions of body –> face and tail)
Factors that influence rate of enzyme-catalyzed reaction
Temp, pH, substrate concentration, non-substrate binding chemicals (inhibitors, modulators), metabolic pathways (feedback inhibition)
Protein bonding
Disulfide bonds, hydrogen bonds, van der waals forces, ionic bonds/repulsions (all create unique protein shape
