Exam 1 Flashcards
What is cell theory?
- all living organisms are made up of cells
- cells are the most basic organizational units
- all cells come from preexisting cells
what are some advantages of phase contrast over bright field?
- increased contrast
- higher magnifications
how do you improve the resolution of a light microscope?
adjust the course and fine focus
characteristics of carbon
- valence of 4
- most likely to bond with oxygen, hydrogen, nitrogen, and sulfur
how are covalent bonds formed?
by the sharing of a pair of electrons between two atoms
what is electronegativity
an atom’s tendency to attract electron to itself in a chemical bond
what makes water a versatile solvent?
its charges are really efficient at breaking other molecules up
non-polar bonds
share electrons equally
polar bonds
share electrons unequally
phosphodiester bonds
covalent bonds that link the 5’ phosphate group of one nucleotide to the 3’ hydroxyl group of another
glycosidic bond
covalent bonds that connect a carbohydrate molecule to another molecule
Dehydration reaction
a chemical reaction that involves the removal of a water molecule, allowing two molecules to bond together
Hydrolysis reaction
a chemical reaction that involves the addition of water to break a bond in a polymer, splitting it into smaller units
peptide bonds
covalent bonds formed between the carboxyl group of one amino acid and the amino group of another
Virus
a microscopic infectious agent that can replicate only inside the living cells of an organism
Viroid
a small, circular piece of RNA that is infectious and can cause disease in plants. Lacks a protein coat
Allosteric inhibition
a mechanism where a molecule binds to a site other than the active site on an enzyme. causes a change in shape and reduces the enzyme’s activity
feedback inhibition
a process in which the end product of a metabolic pathway inhibits an earlier step in the pathway
Michaelis Constant (Km)
a measure of the substrate concentration at which an enzyme-catalyzed reaction proceeds at half its maximum velocity
Vmax
the maximum rate of an enzyme-catalyzed reaction when the enzyme is saturated with substrate
Endosymbiont theory
the origin of mitochondria and chloroplasts evolved from free-living prokaryotic cells that were engulfed by ancestral eukaryotic cells
how does an ionic bond form?
when one atoms donates an electron to another atom
features of hydrocarbons
organic compounds
composed of only C and H
can be linear or branched
describe amino acid structure
central carbon atom bonded to an amino group, a carboxyl group, a H atom, and an R-group (side chain)
Types of R-groups
- can be nonpolar (hydrophobic),
- polar (hydrophilic),
- acidic (negatively charged, or
- basic (positively charged)
directionality in cell biology
refers to the orientation of biological molecules
Primary protein structure
linear sequence
secondary protein structure
local folding patterns
tertiary structure
overall 3D shape of a protein