Chapter 2 Flashcards
Organic molecules (Name the 4)
Carbs
Lipids
Proteins
Nucleic Acids
The most abundant molecule in cells
Water
Slightly positive atom in water
Hydrogen
Slightly negative atom in water
Oxygen
Bonds that form between polar organic molecules
Hydrogen bonds
Solubility of nonpolar molecules
Poor
Dehydration reactions (H2O is removed) / sugars are linked by a
glycosidic bond
polymers of a few sugars.
Oligosaccharides
polymers of hundreds or thousands of sugars.
Polysaccharides
storage of glucose in animal cells.
glycogen
storage in plant cells
Starch
Both starch and glycogen are:
composed entirely of glucose molecules in the α configuration
main structural component of plant cell walls
cellulose
3 main roles of lipids
1.) Energy storage
2.) Cell membranes
3.) Cell signaling
long hydrocarbon chains (16 or 18 carbons) with a carboxyl group (COO–) at one end.
fatty acids
fatty acids with one or more double bond
unsaturated
fatty acids with no double bonds
saturated
Three fatty acids linked to a glycerol molecule.
Triacylglycerols
______ are more efficient energy storage than ____________, yielding more than twice as much energy per weight of material broken down.
Fats; carbohydrates
the principal components of cell membranes.
phospholipids
part water-soluble / part water-insoluble.
Amphipathic molecules
2 fatty acids bound to two carbons in glycerol.
Glycerol phospholipids
the only nonglycerol phospholipid in cell membranes
Sphingomyelin
two hydrocarbon chains and a carbohydrate polar head group (amphipathic).
glycolipids
four hydrophobic hydrocarbon rings and a polar hydroxyl (OH) group (amphipathic).
cholesterol
examples of steroid hormones
estrogen, testosterone
steroid hormones are derivatives of:
cholesterol
carries information from DNA to the ribosomes.
mRNA
types of RNA involved in protein synthesis
rRNA and tRNA
DNA and RNA are polymers of:
nucleotides
Nucleotides consist of purine and pyrimidine bases linked to:
phosphorylated sugars.
2 purines
adenine and guanine
2 pyrimidines
cytosine and thymine
RNA has _____ in place of thymine
uracil
Bases are linked to sugars to form:
nucleosides
bonds between the 5′ phosphate of one nucleotide and the 3′ hydroxyl of another.
phosphodiester
polymers of only a few nucleotides.
Oligonucleotides
may contain thousands or millions of nucleotides, like DNA or RNA
polynucleotides
Polynucleotides are always synthesized in the _______ direction.
5′ to 3′
the most diverse macromolecule
Protein
Proteins are polymers of 20 different ____________
amino acids.
Amino acids consists of: (5 things)
α carbon bonded
carboxyl group
an amino group
a hydrogen
a distinctive side chain.
Type of bond that joins amino acids
Peptide bond
chains of amino acids, hundreds or thousands of amino acids.
polypeptides
N terminus of polypeptide
α amino group
C terminus of polypeptide
α carboxyl group
types of bonds joining the side chains of insulin
disulfide bonds
___________ breaks non-covalent bonds (denaturation).
Heating
the sequence of amino acids in the polypeptide chain.
primary structure
regular arrangement of amino acids within localized regions.
secondary structure
Two common types of secondary structure:
α helix and β sheet.
the folding of the polypeptide chain due to interactions between side chains of amino acids in different regions of the chain.
Tertiary structure
the basic units of tertiary structure; are folded three-dimensional structures usually containing between 50-200 amino acids.
Domains
interactions between different polypeptide chains in proteins composed of more than one polypeptide.
Quaternary structure
catalysts that increase the rate of all chemical reactions in cells.
enzymes
If an enzyme is present, the conversion is accelerated, but equilibrium is:
unaltered
Enzymes are not ______ in chemical reactions
Consumed
Energy required to reach the transition state (enzymes reduce this)
activation energy
Enzymes must bind their substrates to form:
enzyme-substrate complex (ES).
A substrate binds to a specific region of the enzyme called:
active site
substrates bind by (3 things)
hydrogen bonds
ionic bonds
hydrophobic interactions
conformation of both enzyme and substrate is modified.
induced fit
digests bonds adjacent to hydrophobic amino acids
Chymotrypsin
digests bonds next to basic amino acids
trypsin
a nonprotein compound that is necessary for the functioning of an enzyme.
coenzyme
Many coenzymes are closely related to ________, which contribute part or all of the structure of the coenzyme.
vitamins
the product of a metabolic pathway inhibits an enzyme involved in its synthesis.
feedback inhibition
Feedback inhibition is a type of __________ regulation
allosteric
Phosphate groups are added to the side-chain OH groups of serine, threonine, or tyrosine residues.
phosphorylation
