Exam 2 Flashcards
Acids
when dissolved in h2o, releases H ions
Bases
acceptors of those H ions
Functional group of biological acids
carboxylic acid
pH scale is based on…
the concentration of hydrogen ions (H+) in a solution and how acidic/basic water is, and the negative log of the molar
concentration of H+ ions:
pH of acid
Lower pH number = higher [H+] =
greater acidity, #1-6
pH of base
Higher pH number, #8-16
pH of neutralization
pH = 7, neither too acidic nor basic
Buffers
a weak acid and its corresponding base; helps maintain constant pH
Importance of buffers
Important for preventing pH changes that could disrupt ability of blood to carry oxygen to tissues
Law of mass action
addition of a reactant on one side of a reversible system drives the system in the direction that uses up that compound
Isomers and different types
molecules with the same chemical formula but atoms are arranged in different ways. Types include structural, cis-trans, and optical
Structural isomers
differ in how atoms are joined together
Cis-trans isomers
different orientation around a double bond
Optical isomers
occur when C atom has four different groups attached to it (an asymmetric carbon)
4 functional groups discussed
Hydroxyl, carboxyl, amino, and phosphate
Hydroxyl
R-OH, forms hydrogen bonds with water to help dissolve molecules, enables linkage to other molecules by condensation
Carboxyl
R-O=C-OH, charged, acidic, ionizes in living tissues to form COOH- and H+, some are important in energy releasing reactions
Amino
R-N-H-H, charged, basic, accepts H ions in living tissues to form NH3+, enters into condensation reactions by giving up H+
Phosphate
R-O-P=O-O(-)-Cl(-), charged, acidic, enters into condensation reactions by giving up OH, when bonded to another phosphate, hydrolysis releases a lot of energy
Organic compounds and what they consist of
any of a large class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements, most commonly hydrogen, oxygen, or nitrogen
4 major types of organic compounds
proteins, carbs, lipids, and nucleic acids
Hydrolysis
break down polymers into monomers ‐ energy released, H2O consumed
Condensation reactions
form polymers ‐ energy required and H20 molecule removed, ex: dehydration synthesis
Spontaneous generation
creating life from inanimate objects/nature
Redi experiment
disproved of spontaneous generation by placing meat in open jars to demonstrate that dead maggots or flies would not generate new flies when placed on rotting meat in a sealed jar, whereas live maggots or flies would
Pasteur experiment
In 1858, Pasteur filtered air through a gun-cotton filter and, upon microscopic examination of the cotton, found it full of microorganisms, suggesting that the exposure of a broth to air was not introducing a “life force” to the broth but rather airborne microorganisms.
Life from outside Earth
Some meteorites contain molecules such as purines, pyrimidines, and amino acids, suggests that living organisms may have reached Earth via meteorite. meteorite was discovered in Australia in 1969, analyzed water: amino acids, nucleotide bases, and sugars found
Chemical evolution
1st theory on how life arose, conditions on primitive Earth led to formation of simple molecules, which led to formation of life
forms
Miller Urey experiment
a scientific experiment conducted in 1952 that simulated the conditions of early Earth’s atmosphere, demonstrating that organic molecules, like amino acids, could be formed from simple inorganic compounds through chemical reactions
Key to the origin of life
catalysts - proteins called enzymes that speed up reactions
Ribozyme
catalytic RNAs that speed up reactions involving their own nucleotides
what came first – DNA, RNA, or protein
possible that RNA was the first catalyst since its molecules are similar to enzymes, RNA could have acted as a catalyst for its own replication and synthesis of proteins, DNA could have then evolved from RNA
Protocell
steppingstones for origins of cells, are organized systems of parts w/ substances interacting, sometimes catalytically, have interior distinct from exterior environment, can self‐replicate
Cell theory
an important unifying theory of biology
Cell theory states that
- Cells are the fundamental units of life.
- All organisms are composed of cells.
- All cells come from preexisting cells.
- Modern cells evolved from a common ancestor
Cell theory implications
- Functions of all cells are similar
- Life is continuous
- Origin of life was origin of cells
Size of a prokaryotic cell
0.1 to 5.0 micrometers (μm) in diameter
Size of a eukaryotic cell
10 to 100 μm
Passive transport
no energy input required, with concentration gradient
Active transport
energy and transport protein required, against concentration gradient
What factors affect the rate of diffusion
- Size and mass of molecules or ions
- Temperature of the solution
- Density of the solution
- Concentration gradient
- Area and distance across which substance diffuses
Osmosis
diffusion of water, depends on relative concentrations of water molecule
Isotonic
equal solute concentrations
Hypotonic
low solute concentration, lot of water in cell
Hypertonic
high solute concentration, little water in cell
Turgor pressure
plant cells with rigid cell walls build up internal pressure that keeps more water from entering
3 proteins in active transport
- Uniporter: moves one substance in one direction
- Symporter: moves two substances in one direction
- Antiporter: moves two substances in opposite directions
Primary vs. Secondary active transport
Primary active transport requires direct hydrolysis of ATP, Secondary active transport energy comes from ion
concentration gradient established by primary active transport
Endocytosis vs. Exocytosis
Endocytosis - brings molecules and cells into a eukaryotic cell, bigger molecules need vesicles to get in
Exocytosis - materials in vesicles expelled from cell
Phagocytosis vs. pinocytosis vs. receptor-mediated endocytosis
Phagocytosis: molecules or entire cells are engulfed
Pinocytosis: vesicle forms to bring small, dissolved substances or
fluids into a cell
Receptor-mediated endocytosis - very specific; macromolecules bind to receptor proteins
