Final Flashcards
prokaryotic cell
- cell wall
- nucleoid + single/looped chromosome
- no membrane bound organelles
eukaryotic cell
- no cell wall
- membrane bound organelles
- nucleus + multiple chromosomes
plasma membrane
- bilayer of lipid molecules (with hydrophobic heads + hydrophilic tails) that form the cellular membrane
- provides structure
- regulates entry and exit of molecules into and out of the cell
cytoskeleton
- provides cellular structure
- facilitates movement of cell + transport of molecules within the cell
- allows for localization of biochemical activities
- composed of microtubules, microfilaments, and intermediate filaments
microfilaments (actin filaments)
- solid rods made of actin found in the cytoplasm of the cell
- facilitate cell movement
microtubules
- hollow rods composed of tubulin
- facilitate cell division
intermediate filaments
- more stable than other cytoskeleton subunits
- confer stability + structural support for a cell
nucleus (structure)
- double membrane bound organelle
- nuclear envelope regulates nuclear entry
- contains nucleolus
DNA-containing organelle
nucleus
site of DNA replication
nucleus
organelle in which ribosome assembly begins
nucleolus
rough ER (structure)
- series of invaginated membranes (large surface area)
- ribosomes attached
site of protein synthesis
ribosomes (on rough ER)
modification of newly made proteins
rough ER (lumen)
origin site of transport vesicles (transport vesicles bud off ___)
rough ER
smooth ER (structure)
- series of invaginated membranes (large surface area)
- no attached
smooth ER (structure)
- series of invaginated membranes (large surface area)
- no attached ribosomes
- more tubular than rough ER
organelle which chemically modifies small molecules
smooth ER
organelle responsible for hydrolysis of glycogen
smooth ER
organelle which synthesizes lipids & steroids
smooth ER
golgi complex (structure)
- series of small, flattened sacs & membrane-bound vesicles
organelle resposible for concentration, packaging, and sorting proteins
golgi complex
organelle which modifies proteins received from rough ER
golgi complex
organelle which synthesizes polysaccharides for plant cell wall
golgi complex
mitochondrion (structure)
- double-membrane bound
- matrix formed by inner membrane; contains ribosomes, DNA, and enzymes used for energy conversion
organelle responsible for generating most cellular energy
mitochondria
location of energy generation in mitochondria
mitochondrial matrix
cellular locations of ribosomes
- free in cytoplasm
- attached to rough ER
- in mitochondria + chloroplasts
ribosome (structure)
- ribosomal RNA (rRNA) + protein molecules
primary lysosomes are generated by the ______
golgi complex
purpose of primary lysosomes
- contain digestive enzymes
- can fuse with phagosomes/endosomes to form secondary vesicles
secondary vesicles are formed via ______
fusion of primary vesicles + phagosomes/endosomes
purpose of secondary lysosomes
- break down molecules & release material from cells
secretory pathway
- proteins synthesized in ribosomes of rough ER
- transport vesicle carries proteins from rough ER to golgi complex for modification & packaging
- secretory vesicles bud off golgi complex
- secretory vesicle fuses with plasma membrane & contents are released to extracellular space (exocytosis)
endocytosis
- uptake of molecules into the cell via endosomes
- small molecules
phagocytosis
- uptake of molecules into the cell via phagosomes
- large molecules (food, bacteria, etc)
turnover
- continuous breakdown of proteins & other cellular components in a cell
- allows molecules to be reused to make new proteins, etc
autophagy
- lysosome digestion of a cell’s own components/materials
(organelles, etc) - allows materials to be reused
covalent bond
- sharing of electron pairs between molecules
- can be polar or nonpolar
type of bond: C–C
nonpolar covalent
type of bond: O–O
nonpolar covalent
type of bond: C–O
polar covalent
ionic bond
- attraction resulting from distinct, differing electrical charges on atoms
type of bond: Na–Cl
ionic
hydrogen bond
bond between hydrogen atom + electronegative atom
type of bond: H–O
hydrogen
type of bond: H–N
hydrogen
hydrophobic interactions
- tendency of nonpolar compounds to group together in an aqueous environment
- spontaneous (increases entropy)
van der Waal’s forces
- temporary attractions between molecules
- results from movement of electrons in cloud around atom
- allows for interactions between nonpolar/uncharged molecules (ex. carbon atoms with fully occupied orbitals
dissociation constant (Ka)
- quantifies the ability of an acid to dissociate in water, as weak acids are more likely to exist as contiguous molecules in water, while strong acids are more likely to dissociate
high Ka indicates a ____ acid
strong (more dissociation)
low Ka indicates a _____ acid
weak (less dissociation)
pKa
pH at which an acid is half-dissociated
Zwitterionic form
- amino acid form in which the carboxyl group is deprotonated and the amino group is protonated
- state in which amino acids are typically found at neutral pH
alanine side chain properties
nonpolar/hydrophobic
alanine functional group
“simple” aliphatic (CH3)
glycine side chain properties
nonpolar/hydrophobic
glycine functional group
“simple” aliphatic (H)
phenylalanine side chain properties
nonpolar/hydrophobic
phenylalanine functional group
aromatic
leucine side chain properties
nonpolar/hydrophobic
leucine functional group
aliphatic
isoleucine side chain properties
nonpolar/hydrophobic
isoleucine functional group
aliphatic
histidine side chain properties
- positive/hydrophilic
- can be positive or neutral at physiological pH
histidine functional group
imidazole ring
cysteine side chain properties
- polar
- terminal sulfur + able to form disulfide bridges with other cysteines
cysteine functional group
sulfhydryl
proline side chain properties
- nonpolar/hydrophobic
- capable of self-bonding (bond forms between side chain and amino group)
proline functional group
weird aliphatic (self-bonding creates a ring)
methionine side chain properties
nonpolar/hydrophobic
methionine functional group
aliphatic
first amino acid in all polypeptides
methionine
glutamate side chain properties
negative
glutamate functional group
carboxylic acid
aspartate side chain properties
negative
aspartate functional group
carboxylic acid
glutamine side chain properties
polar
glutamine functional group
carboxyamide
asparagine side chain properties
polar
asparagine functional group
carboxyamide
valine side chain properties
nonpolar/hydrophobic
valine functional group
aliphatic
tryptophan side chain properties
nonpolar/hydrophobic
tryptophan functional group
aromatic
serine side chain properties
polar
serine functional group
hydroxyl
threonine side chain properties
polar
threonine functional group
hydroxyl
tyrosine side chain properties
polar
tyrosine functional group
hydroxyl
lysine side chain properties
positive/hydrophilic
lysine functional group
amino
arginine side chain properties
positive/hydrophilic
arginine functional group
guanidinium
bonds in a polypeptide around which rotation can occur
phi & psi bonds
bond in a polypeptide around which rotation cannot occur
peptide bond
primary structure
a protein’s amino acid sequence
secondary structure
alpha helices & beta pleated sheets
pattern of hydrogen bonding in alpha helices
hydrogen bond occurs between carbonyl of amino acid i and i+4
pattern of hydrogen bonding in beta pleated sheets
- sheets stabilized by hydrogen bonding between 2-antiparallel beta strands
- each amino acid forms 2 hydrogen bonds
tertiary structure
- protein folding into 3D conformation
- driver by weak interactions
quaternary structure
interactions between multiple polypeptides to form complex proteins
orientation of bonds in parallel beta sheets
- amino acid 1 bonds 2x to 2 other amino acids
- forms 2x hydrogen bonds (one each)
orientation of bonds in anti-parallel beta sheets
- amino acid 1 bonds 2x to 1 other amino acid
- it’s the like more even one but it’s antiparallel
tertiary structure of myoglobins
- myoglobins primarily in aqueous environment
- hydrophobic amino acids oriented towards interior; hydrophilic on outside
tertiary structure of porins
- porins often embedded in membranes (hydrophobic environment)
- hydrophobic amino acids oriented towards outside (interacting with environment); hydrophilic amino acids on interior
- “inside-out” orientation
hemoglobin quaternary structure
- 2 alpha globins + 2 beta globins = 4 linked polypeptides
- heterotetramer (four non-identical amino acids)
3 major differences between DNA & RNA
- DNA = double helix; RNA = single-stranded
- DNA ribose = no hydroxyl on 2’ carbon; RNA = additional hydroxyl group
- DNA = thymine; RNA = uracil
nucleoside
- 5 carbon sugar + nitrogenous base
- nucleotide without phosphate group(s)
location of phosphodiester bond in nucleotides
5’C
location of betaglycosidic linkage in nucleotides
1’C
locations of bonds joining chains of nucleotides
3’OH - oxygen - phosphate - oxygen - 5’C
chemical basis for stem-loop structures in RNA
possible because RNA is single-stranded; does not form double helix/complementary base pairs (no complementary strand -> stem loop & non-Watson-Crick base pairing possible)
in DNA, antiparallel conformation facilitates _____
hydrogen bonding
A-T base pairs form ___ hydrogen bonds
2
C-G base pairs form ___ hydrogen bonds
3
two types of chemical interactions which strengthen DNA molecules
- hydrogen bonding (between base pairs)
- van der Waal’s interactions (between “stacked” pairs)
“lock and key” model of enzyme-substrate interaction
theory that enzymes naturally fit into active sites & enzyme conformation does not change
induced-fit model of enzyme-substrate interaction
theory that bond with enzyme induces conformational change in enzyme which facilitates substrate binding
4 types of interactions that can be occur between an enzyme & substrate in enzyme active site
- hydrogen bonding
- van der Waal’s
- ionic interactions
- hydrophobic interactions
competitive inhibition ____ Vmax
does not affect
competitive inhibition ____ Km
increases
uncompetitive inhibition ____ Vmax
decreases
uncompetitive inhibition ____ Km
decreases
noncompetitive inhibition ____ Vmax
decreases
noncompetitive inhibition ____ Km
does not affect
3 fractions produced in cell fractionation by differential centrifugation
- nuclear
- mitochondrial
- microsomal
gel filtration chromatography
separates proteins according to size
ion-exchange chromatography
separates proteins according to ionic charge
affinity chromatography
isolates proteins via binding of a protein to a ligand capable of specific binding
immunoprecipitation
used to isolate proteins
co-immunoprecipitation
used to identify molecules which interact with protein of interest in the cell
monoclonal antibody
- identical copies of antibody
- can bind antigen on one epitope (one antibody per antigen)
polyclonal antibodies
- antibodies capable of binding same antigen on different epitopes
- can bind multiple antibodies per antigen
sucrose bonds via a _____ glycosidic linkage
1,2
lactose bonds via a _____ glycosidic linkage
1,4
maltose bonds via a _____ glycosidic linkage
1,4
bonds in cellulose indigestible by humans
beta-1,4
____ is the major phospholipid from which most membrane phospholipids are derived
phosphatidate
pepsin inactive form
pepsinogen
pepsinogen activated by ____
- HCl (partially activated)
- pepsinogen
- pepsin
cholecystokinin (CCK)
- digestive hormone
- signals pancreas to release digestive enzymes
- signals gallbladder to release bile salts
secretin
- digestive hormone
- induces pancreas to release sodium bicarbonate
trypsin zymogen
trypsinogen
trypsin activated by ____
- trypsin
- enteropeptidase
chymotrypsin zymogen
chymotrypsinogen
chymotrypsin activated by ____
trypsin
carboxypeptidase zymogen
procarboxypeptidase
carboxypeptidase activated by ____
trypsin
lipase zymogen
prolipase
lipase activated by
trypsin
alpha-amylase cleaves
alpha-1,4 bonds
alpha-glucosidase cleaves
alpha-1,4 bonds
maltase cleaves
alpha-1,4 bonds
dextrinase cleaves
alpha-1,6 bonds
maltase cleaves ____ to _____
- maltose
- 2 molecules glucose
sucrase cleaves ____ to _____
- sucrose
- glucose + fructose
lactase cleaves ____ to _____
- lactose
- glucose and galactose
glucose and galactose are taken up into intestinal cells via _____, a form of active transport
the SGLT - sodium-linked glucose transporter
fructose is taken up into intestinal cells via the ____
GLUT5 transporter
glucose, fructose, and galactose are transported out of the cell via the ____
GLUT2 transporter
CCK behavioral effects
- increased satiety
- decreased food intake
- decreased body weight
NAD+ is _____; NADH is _____
oxidized; reduced