Biolchem 415: Lec. 2
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Biolchem 415: Lec. 2
Flashcards that correspond to University of Michigan Biolchem 415 Lecture 2.
What are some functions of lipids?
Form membranes (barriers), serve as fuel (hydrocarbon chains rich in energy), serve as signal (lipid derivatives used to transmit signals)
What are some properties of lipids?
Dual chemical properties, hydrophobic and hydrophilic
Lipids have hydro (phobic/philic) heads and hydro (phobic/philic) tails
What purpose do bilayers serve?
Membranes compartmentalize cells and separate the outside from the inside of the cell
What is a membrane?
A lipid bilayer
What types of membrane proteins are there?
Transmembrane and membrane associated proteins
Why can membranes be selectively permeable?
Influenced by the presence of proteins associated with the membrane
What are some examples of selective permeability in membranes?
Channels, pores, transporters, receptors
What do prokaryotic cell membranes lack?
Intracellular membranes. Only possess inner (plasma) membrane, cell wall, and outer membrane
What are organelles?
Found in eukaryotic cells and they are membrane-enclosed compartments
What purpose do organelles serve?
Biochemical functions are sequestered in organelles
Where is cytoplasm?
Surrounded by plasma membrane, but not enclosed by any intracellular membranes
How is the cytoplasm organized?
Cytoskeleton (series of structural filaments)
What does the rough ER do?
Has ribosomes attached and involved in processing new proteins
What does the smooth ER do?
lacks ribosomes and plays variety of roles like detox in the liver
What is Tay-Sachs Disease
Results from defect in lysosome function and leads to muscle weakness, dementia, and early childhood death
What is exocytosis? Give examples.
Proteins deposited outside of the cell.
Hormones such as insulin, antibodies, digestive enzymes, neurotransmitters
What is exocytosis?
Bringing biomolecules into cells
What is an endosome?
Structure that forms when the plasma membrane invaginates and buds off
What is familial hypercholesterolemia?
Defective endocytosis of cholesterol from the blood leads to high blood cholesterol levels and heart attacks
What is phagocytosis?
Large amounts of material can be taken into the cell
What is Brownian Movement?
Movement of a molecule or ion along a random path
What permits dynamic interactions between molecules?
What does Brownian Movement of water do?
Diffusion of biomolecules throughout cells, within organisms, and within the environment
List stabilizing forces in molecules in order from strongest to weakest?
Covalent bonds, electrostatic interactions, hydrogen bonds, Van der Waal interactions, hydrophobic interactions
What does the polarity of water account for?
Water's ability to dissolve biochemical molecules
What is Coulomb's Law?
The energy of an electrostatic interaction between two charges
D=1 in vacuum and 80 in H2O
How does water affect electrostatic interactions?
What do Hydrogen bonds form between?
Electronegative atom and hydrogen atom
**Lengths of H bonds are longer than covalent bonds
What accounts for the cohesiveness of water?
Water is very polar and H-bonds between water molecules cause cohesiveness
How does water affect H-bonded molecules?
Water disrupts hydrogen bonds between two molecules by competing for the H-bonding capability
What molecules can interact in Van der Waals interactions?
Nonpolar, uncharged biomolecules
What causes Van der Waals interactions?
Fluctuation and asymmetry of electrons in atoms causing fleeting dipoles
What interactions are DNA strands held together by?
H-bonds and Van der Waals interactions
Why is it important that the bonds between DNA strands aren't strong?
DNA needs to be able to be broken apart by enzymes so the genetic information can be accessed in replication and transcription
How many H-bonds are between A-T and C-G?
What is the hydrophobic effect?
Spontaneous clustering of hydrophobic molecules in water
What is the advantage of having nonpolar molecules stick together when immersed in water?
More disorder of water (because less used to make a solvent cage) has increased entropy and is energetically favorable
What does it mean to be amphipathic and what are the results in aqueous environments?
Having both hydrophilic and hydrophobic properties. In water, phospholipids form membranes
What is pH a measure of? What is it defined as?
The H+ concentration in a solution. pH=-log
Acid/base: Which is the proton donor and which is the proton acceptor?
: proton donor
: proton acceptor
What is gastric esophageal reflux disease (GERD)?
Pathological condition that results when the esophagus is exposed to the acid of the stomach
What is K
and how does it deal with acid ionization?
Equilibrium constant/acid dissociation constant. The larger the K
, the stronger the acid
What is the Henderson-Hasselbalch equation?
Relates the pH and the ratio of base to acid. Used to determine the dissociation of an acid at a particular pH value.
. . .
. . .
. . .
What is the buffer?
An acid-base conjugate pair that resists changes in pH of a solution
What pH is a buffer most effective?
Near its pK
What does it mean to be mono/di/triprotic?
The conjugate acid-base pairs can release 1/2/3 protons
What are functional groups?
Array of atoms that have distinctive chemical properties