Chapter 2 Flashcards
Water is polar or nonpolar?
polar
Ion and polar molecules are insoluble or soluble in water?
soluble. (they are hydrophillic) and water is polar so remember, like dissolves like
Do nonpolar molecules interact with water?
no they do not. they are poorly soluble because water is polar and nonpolar molecules are not easily dissolve/interact with water. Also nonpolar molecules are hydrophobic
What are some inorganic ions
Na^+, K^+, Mg^+2, Ca^+2, HPO4^2-,Cl^-,HCO3^- (ions)
What are the four classes of molecules?
carbohydrates, lipids, proteins, nucleic acids
what is a glycosidic bond?
this bond allows monosaccharides to be joined together by dehydration reactions (loss of water) and linkage of sugars
name two common polysaccharides that are composed entirely of glucose and molecules in alpha configuration
glycogen=storage of glucose in animal cells
starch= storage in plant cells
glycogen and amylopectin also contain alpha(1-6) bonds and they serve as____________
branch points
cellulose is the main structural component of what?
plant cell walls
what is cellulose composed of and in what configuration?
glucose molecules, B configuration
why does cellulose have B(1-4)linkages?
This linkage allows the chains to pack more tightly. This allows the cellulose to form long extended chains that pack side by side to form fibers of great mechanical strength
What are the 3 main rules of lipids?
- energy storage
- major component of cell membranes
- important in cell signaling as steroid hormones and messenger molecules
define fatty acid
are long hydrocarbon chains (16-18 carbons) with a carboxyl group (COO-) at one end
define unsaturated fatty acids
have one or more double bonds. therefore it can not bond to as many hydrogens.
define saturated fatty acids
HAVE NO DOUBLE BONDS.
the hydrocarbon chain of a fatty acid is? hydrophobic or hydrophillic?
hydrophobic
name a saturated fatty acid
palmitate or stearate
name a unsaturated fatty acid
oleate
what are fatty acids stored as?
triacylglycerols
what is a triacylglycerol?
it is three fatty acids linked to a glycerol molecule
are triacylglycerol insoluble or soluble in water?
they are insoluble in water. this is why they can accumulate as fat droplets in the cytoplasm
why are fats more efficient energy storage than carbohydrates?
fats yield more than twice as much energy per weight of the material broken down
what is the principle component of the cell membranes?
phospholipids
what are phospholipids composed of?
2 fatty acids, joined to a polar head
When talking about the phospholipid.
The Hydrophobic tails are?
The Hydrophillic head is?
hydrophobic tails=hydrocarbon chains
hydrophillic head: phosphate group and polar attachment
What do you call a molecule that is part water-soluble and part water insoluble? give a example of such a molecule.
amphipathic molecules….
phospholipids are an example
glycerol phopholipids are composed of?
2 fatty acids bound to glycerol. bound to phophate group. which is bonded to another small polar molecule (choline, serine, inositol, ethanolamine)
how is sphingomyelin different then other phospholipids?
it is the only nonglycerol phospholipid. meaning the polar head group is formed from serine instead of glycerol
what is a glycolipid composed of?
two hydrocarbon chains and a carbohydrate polar head group
what is cholesterol composed of
four hydrophobic hydrocarbon rings and a polar hydroxyl (OH) group
the steriod hormones are derivatives of __________; that act as chemical messengers
cholesterol
what does DNA stand for?
deoxyribonucleic acid
what does RNA stand for?
ribonucleic acid
what does messenger RNA do?
carries information from DNA to the ribosomes
what does ribosomal RNA and transfer RNA do?
they are involve in protein synthesis.
still other _______ are involved in the regulation of gene expression and processing and transport of RNAs and protiens
other RNAS
DNA and RNA are polymers of ________ which consists of ___________- and _________ bases linked to a phosphorylated sugars
nucleotides
purine
pyrimidine
DNA has what two purines?
adenine and guanine
DNA has what two pyrimidines?
cytosine and thymine
RNA has what two purines?
adenine and guanine
RNA has what two pyrimidines?
cytosine and uracil
What do you call the sugar component in RNA?
ribose
what do you call the sugar component in DNA?
2’-deoxyribose
nucleoside + _____________= nucelotide
phosphate group
a nucleoside is composed of what?
it is composed of a base, and a sugar……
addition of phosphate group turns nucleoside to nucleotide
in nucleotides which carbon does the phosphate group link to
the 5th carbon of sugars
what is a phosphodiester bond?
joins nucleotides
it is between the 5’ phospate of one nucleotide and the 3’ hydroxyl of another
define oligonucleotides
are polymers of only a few nucleotides
RNA and DNA are _________ and may contain thousands or even millions of nucleotides
polynucleotides
what is connected to the 5’ carbon of the polynucleotide?
what is connected to the 3’ carbon of the polynucleotide?
phosphate group, hydroxyl group
polynucleotides are always synthesized in what direction?
5’ to 3’ direction
DNA is made up of two polynucleotide chains. how are the bases on the inside joined
hydrogen bonds
what bases pair with the following:
Guanine
adenine
cytosine
thymine
what are the most diverse of all molecules
protiens
name five functions of protiens
structural components
transport and storage of small molecules
transmit information between cells (protein hormones)
defense against infection (antibodies)
enzymes
proteins are polymers of how many amino acids
20
when talking about an amino acid. what is connected to the alpha carbon?
side chain, amino group, carboxyl group, and hydrogen
what are some basic amino acids
lysine, arginine, histidine
what are some acidic amino acids
aspartic acid, glutamic acid
amino acids are grouped based on characteristics of the side chains including properties such as (4)?
nonpolar side chains
polar side chains
side chains with charged basic groups
acidic side chains terminating in carboxyl groups
amino acids are joined by what bonds?
peptide bonds
define peptide bond
its how amino acids are joined
define polypeptide
chains of amino acids, hundreds or thousands of amino acids in length
one end of a polypeptide terminates in a ____ (N terminus) and the other in an ____________ (C terminus)
alpha amino group
alpha carboxyl group
insulin consist of two
polypeptide chains
the side chains of three pairs of cysteine residue are joined by ?
disulfide bonds
the sequence of amino acids in a protein is determined by
order of nucleotides bases in a gene
proteins also have distinct _____________________________ that are critical to their function
3- dimensional (3-d) conformations
the shape and function of proteins is determined by their____________
amino acid sequences
who demonstrated the importance of proteins 3- structure?
Christian Anfinsen
Christian Anfinsen disrupted proteins by treatments such as heating, which breaks ______________
non-covalent bonds (denaturation)
protein structure has what four levels
primary
secondary= alpha helix and beta sheet
tertiary
quaternary
when talking about the secondary structure of a protein, both the alpha helix and beta sheet are held together by _________ between the ____________ groups of _________
hydrogen bonds
CO and NH
peptide bonds
hemoglobin is composed of
four polypeptide chains
what is the basic unit of a teritary structure (protien wise)
domains
what is the fundamental properties of an enzyme?
increase rate of chemical reactions WITHOUT THEMSELVES BEING CONSUMED or permanently altered
increase reaction rates without altering the CHEMICAL EQUILIBRIUM between reactants and products
When a _________ is converted to a __________ the chemical equilibrium between S and P is determined by the laws of thermodynamics
a substrate
a product
equilibrium is determined by the
final energy states of S and P
The substrate must be first converted to a higher energy state called?
transition state
the energy required to reach transition state=
activation energy
a fundamental rule of proteins is to __________
act as enzymes
what are enzymes
they are catalysts that increase the rate of all chemical reactions in cells
enxymes must bind to their substrate to form an?
enzyme-substrate complex (ES)
define active site
this is where a substrate binds to a specific region of an enzyme
specific side chains in the ____________ and form bonds with reaction intermediates
active site may react with the substrate
chymotrypsin digest protiens by?
catalyzing the hydrolysis of peptide bonds
chymotrypsin is a _______: these enzymes cleave peptide bonds adjacent to specific types of amine acids
a serine protease
chymotrypsin
digests bonds adjacent to hydrophobic amino acids
trypsin
digest bonds next to basic amino acids
what are active sites
these are clefts or grooves on the surface of an enzyme formed by the tertiary structures
substrates originally bond by
hydrogen bonds, ionic bonds, and hydrophobic interactions
trypsin
digests bonds next to basic amino acids
the active sites of serine proteases contain _____, _______, ______
serine,
histidine
aspartate
substrates bind by insertion of the _________ adjacent to the cleavage site into a pocket at the active site
amino acid
define lock and key model
the substrate fits precisely into the active site
define induce fit (for enzyme related )
conformation of both enzyme and substrate is modified
define coenzymes
small organic molecules that work together with enzymes to enhance reaction rates
THESE ARE NOT ALTERED BY REACTION
what is nicotinamide adenine dinucleotide (NAD)
it is a coenzyme that carries electrons in oxidation-reduction reactions
NAD can accept ______ and __ electrons from one substrate, forming NADH
H+ and two electrons
NADH can then donate the _________ to a second substrate, re-forming NAD
electrons
define prosthetic groups
small molecules bound to protiens that have critical functional roles
feedback inhibition is a type of ?
allosteric regulation
define allosteric regulation
enzyme activity is controlled by the binding of small molecules regulatory sites on an enzyme
many coenzymes are closely realted to vitamins, which?
contribute part or all of the structure of the coenzyme
phosphate groups are added to the side chain OH groups of ??????
serine, threonine, or tyrosine residues
in feedback inhibition what happens?
the product of a metabolic pathway inhibits an enzyme involved in it synthesis
if delta G <0, this reaction will proceed?
in the forward direction
if delta G >0, this reaction will proceed?
in the reverse direction; B will be converted to A
