Cell and Molecular Biology ch. 1 pt 1 Flashcards
Atoms
Made up of neutrons (in nucleus), protons + (in nucleus), and electrons -
Molecules
Groups of 2 or more atoms held together by chemical bonds due to electron interactions
Electronegativity
Ability of an atom to attract electrons
Ionic Bonds
Involve the transfer of electrons from one atom to another where both atoms have different electronegativities
Example: Na + Cl –> Na+ (loses e-) Cl- (gains e-)
Covalent Bonds
Electrons are shared between atoms of similar electronegativities
Which bonds can be single, double, or triple bonds?
Covalent bonds
Which bonds can be polar or nonpolar?
Covalent bonds
What is the difference between polar and nonpolar bonds?
- Nonpolar: equal sharing of electrons between two atoms of similar electronegativity
- Polar: unequal sharing of electrons between two atoms of different electronegativities; results in a dipole
Ex. O-H in water is polar covalent
What are hydrogen bonds and what type of bonds are they?
iii. A weak bond between a hydrogen attached to a highly EN atom, and a negatively charged atom on another molecule (F,O,N)
Ex. O-H in water where H reacts with O on a different water molecule
Properties of Water (5)
- Excellent solvent
- High heat capacity
- Ice floats
- Cohesion/ surface tension
- Adhesion
Addition: What is heat of vaporization?
Amt of heat needed to turn 1g of a liquid into a vapor, without a rise in the temp. of the liquid.
Excellent solvent details
The dipoles break up charged ionic molecules - easy to dissolve substances
High heat capacity details
The degree to which a substance changes temp. in response to gain or loss of heat.
Ex. Temp. of large body of water = very stable in response to air temp. changes. Must add lots of energy to warm up this water - also explains water’s high heat of vaporization
Ice floats details
Water expands as it freezes and becomes less dense - explained by H-bonds becoming rigid and forming a crystal that keeps the molecules separated
Cohesion/ surface tension details
Water is attracted to like substances due to H-bonds. Strong cohesion b/w H2O molecules produce a high surface tension that allows for phenomena like water bugs walking on water.
Adhesion details
Water is also attracted to unlike substances
Ex. Wet finger to flip pages - capillary action describes the ability of a liquid to flow without external forces (e.g. against gravity)
What are organic molecules made up of?
Carbon atoms
Monomers (1 unit) form what which are what? Two answers.
Monomers form macromolecules which are polymers (series of repeating monomers).
Functional Groups
Clusters of atoms that give organic molecules their key properties
Ex. OH, COOH, NH2, Phosphate, Carbonyl, Aldehyde, Ketone, CH3
FG OH facts
name - you know this. Polar and hydrophilic
FG COOH facts
Carboxyl. Polar, hydrophilic, weak acid
FG NH2 facts
Amino. Polar, hydrophilic, weak base
FG PO4^3-facts
Phosphate, polar, hydrophilic, acid
FG C double O facts
Carbonyl, polar and hydrophilic
FG CH3 facts
name - you know this. Nonpolar and hydrophobic
What are carbohydrates?
Sugars, starches, and fibers
As well as starch, glycogen, cellulose, and chitin
Carbo.: Monosaccharides
A single sugar molecule (e.g. glucose and fructose)
- Alpha or beta based on the position of the OH on the anomeric carbon (OH down - alpha; OH up - beta)
Anomeric Carbon
C derived from carbonyl carbon (ketone or aldehyde FG) of the open-chain form of the carbo. molecule and is a stereocenter (an atom with 3+ diff. attachments, interchanging of these attachments leads to another stereoisomer).
Carbo.: Disaccharide
Two sugar molecules joined by a glycosidic linkage (O bonds the two sugars) (e.g. sucrose - glucose + fructose, lactose - glucose + galactose, maltose - glucose + glucose)
Carbo.: Polysaccharide
Series of connected monosaccharides; polymer. Bonds form via dehydration synthesis and breakdown vis hydrolysis.
Starch
A polymer of alpha-glucose molecules; store energy in plant cells
Glycogen
A polymer of alpha-glucose molecules; store energy in animal cells (differ in polymer branching from starch)
Cellulose
A polymer of beta-glucose; structural molecules for walls of plant cells and wood
Chitin
A polymer similar to cellulose, except each beta-glucose group has a nitrogen-containing group (n-acetylglucosamine) attached to the ring.
- A structural molecule in fungal cells as well as insect exoskeletons.
Lipids
Hydrophobic molecules that function in insulation and energy storage
- Triglycerides
- Phospholipids
- Steroids
- Lipid Derivatives/Structures
- Cell Membrane Fluidity
What do lipids make up?
Structural components of cholesterol and phospholipids in membranes
What do lipids participate in?
Endocrine signaling