Macromolecules (exam 2) Flashcards
functions of carbohydrates
- energy
- storage
- structure (matrix of connective tissue in our joints)
- cell recognition/communication: (AB blood type, this protein has a carbohydrate chain which is what distinguishes it from other types)
- modifies proteins affecting…. (glycosylating something can affect how it folds, how long it lasts…)
- structure/folding
- enzyme kinetics: Vmax and Km
- Turnover/degradation: turnover can be faster or slower depending on the carbohydrate chain
alpha 1-4 glycosidic bond
- more common
- easily broken down for energy and modified for storage
examples of alpha 1-3 glycosidic bonds
- sucrose
- starch
what kinds of bonds does glycogen have?
- both alpha 1-4 and alpha 1-6 glycosidic bonds
- this gives glycogen its characteristic branched structure
glycogen
the primary carbohydrate storage molecule
what kinds of bonds does lactose have?
Beta 1-4 glycosidic bond
how are common alpha glycosidic bonds processed?
they’re hydrolyzed by amylase
What does lactose require?
- the beta bond of lactose requires lactase
where is lactase only produced?
in the cells of mucosa of the small intestine
when does lactose intolerance occur?
when the body stops producing lactase
Lactose intolerance can be ______ or ______
temporary
genetic/developmental
_____ is a common filler in pharmaceuticals
lactose
where is amylase produced?
pancreas
saliva
how are sugar alcohols formed?
by the reduction of the carbonyl group
when do sugar alcohols occur?
polyol pathway
Sorbitol function
- sugar alcohol
- used for storage
- can be metabolized forward to fructose
- can be metabolized back to glucose
Sorbitol is an _____
effective osmole
Inositol function
- signaling
- myelin attachment
- nerve function
what are the forms of cyclic carbohydrates?
alpha or beta isomers
how is glucose transported into cells?
by either
- insulin dependent transporters
- insulin independent transporters
importance of insulin independent transporter proteins?
they maintain the basal level of glucose required for cell survival
what happens to excess glucose?
it enters the polyol pathway
where can you find a high percentage of insulin-independent transporters?
- kidney
- retinal
- nerve tissue (retina)
where can you find insulin dependent transporters?
- liver
what is the liver efficient in doing?
- handling high levels of blood sugar and bringing it back down
insulin independent transporters
- no inhibition
- doesn’t bind insulin
insulin dependent transporters?
- limited inhibition
- binds insulin (limited)
- shoots up and down according to blood sugar levels
how are acidic sugars formed?
by the oxidation of the 6’ OH group or the 1’ carbonyl group to a carboxyl group
where does formation of acidic sugars occur?
- in many tissues
- highest in the liver, kidney, and RBC
what does the liver use acidic sugar formatio for?
for conjugation (to change solubility)
example of an acidic sugar
Glucuronic acid
Functions of Glucuronic acid
- used as a detoxifying agent
- conjugates with molecules to increase solubility, transport, or excretion
- makes it easier to get rid of toxins and waste
dietetic candy
uses sorbitol as a sweetener. goes right through the digestive system
Bilirubin
byproduct of RBCs being broken down
how are amino sugars formed?
by the replacement of an OH group with an NH2
examples of amino sugars and their functions
glucosamine and galactosamine
- compose the matrix in connective tissue
what increases the structural nature of amino sugars?
beta bonds between alternating amino sugars
*other organisms do this in beta bonds but humans always use alpha bonds
hyaluronic acid
- weakest crosslinking, much more fluid
- proper
Chondroitin sulfate
- cartilage
- supplements for joint health because it’s the building block for the matrix of cartilage
matrix for connective tissue
- where the cells live in fluid, gel or a solid environment
- cells secrete/make the matrix
purposes of glycosylation
- modify/regulate protein function (change their Vmax and Km with their enzymes)
- stabilization of proteins in the serum (antibody Fc fragment)
- may aid in initial protein folding
- aids in cell recognition and binding to membrane proteins (type A, B, O blood type)
- increases hydration of molecules (mucus has a lot of carbohydrate moieties in it)
- involved in stabilizing structure like connective tissue
how do you do fatty acid nomeclature
of carbons: # of double bonds + the position of the double bond
eicosanoids
- diverse group of hormones and signaling molecules
how are eicosanoids produced
by the oxidation of fatty acids-particularly arachidonic and similar molecules
what are the primary enzymes involved in eicosanoid synthesis?
- cyclooxygenase (COX)
- lipoxygenases (LOX)
what does COX produce
prostaglandins and thromboxanes (prostanoids)
what does LOX produce
leukotrienes and lipoxins
what does the COX pathway result in
molecules with a cyclical structure
Prostanoids
- locally active hormones/signals which are rapidly degraded
- type of eicosanoids
what do prostanoids often exhibit
- opposing functions which are kept in balance during homeostasis and can change/be induced during pathological conditions
functions of prostanoids
- inflammation mediation
- cardiovascular homeostasis
- reproductive function
what does the LOX pathway produce
- complex molecules without a cyclic component
Acylglycerol/glycerides
- ester of glycerol and fatty acids that occurs naturally as fats and fatty oils
how do phospholipids start out?
- as diacylglycerol with a phosphate group covalently bonded to the third site of the glycerol molecule
how are phospholipids formed
- presence of phosphate group changes the diacylglycerol to phosphatidic acid (same thing as phospholipid)
functions of phospholipids
- membrane structure (phospholipid bilayer)
- signaling
- fatty reservoir for hormone production (COX pathway)
fatty acid chains
diacylglycerol
Phosphatidylcholine
- component of HDLs
- increases fluidity
- yields fatty acids for signaling
- (example of phospholipid modification)
Phosphatidylinositol
- high concentration in nerve cells
- cell attachment/organization
- signaling, PIP2
where is cholesterol
embeds in the hydrophobic region
function of cholesterol
- stabilizes the transition state (fluidity)
Steroidogenic pathway
- cholesterol entering the mitochondria and undergoing conversion to pregnenolone
- then can turn into other things
once cholesterol turns into pregnenolone, what happens?
can be converted into
- mineralocorticoids
- glucocorticoids
- estrogens/androgens
can steroids enter any cell?
yes
what happens if a receptor is present when the steroid enters the cell
the complex becomes a transcription factor
what happens if when the steroid enters the cell, there’s no receptor?
- steroid broken down
what happens if there’s an excess of steroid
stored in the membrane
what happens when there’s increased sterols in the membrane
- increased membrane rigidity
- makes membrane less fluid (can’t transport things)
- decreases cell reactivity
bile salts
- function
- where is it produced
liver produces bile salts to aid in the emulsification of fat in the small intestine
how are bile salts formed
bile acids interact with Na+
what are fat soluble vitamins based on?
cholesterol
list the fat soluble vitamins
A, D, E, and K
Fat soluble vitamins
- essential nutrients with either the vitamin or the precursor needing to come from a dietary source
functions of proteins
- structure
- hormones/signaling
- NTs
- blood clotting
- viscosity
- antibodies
- transport
- enzymes
hi
hi
what is the point of variation between AAs
R group
how is the rate of reaction impacted:
unlimited substrate
increases
how is the rate of reaction impacted:
pH
affects charge and reactivity of active site, best rate at optimal pH
how is the rate of reaction impacted: temperature
rate increases until denaturation occurs
the reaction continues until _______
all the enzyme is in the enzyme-substrate complex
Vmax is the
point of saturation
holoenzyme (functional)
apoenzyme + prosthetic group
cofactors
- inorganic
- usually metal ions
- Mg2+, Fe2+. Zn2+
- required by certain enzymes
example of a cofactor
- ATPases require a Mg2+ cofactor to put stress on the high energy bonds
Coenzymes
- organic molecules
- such as vitamins and carrier molecules
example of a coenzyme
- the complex, pyruvate dehydrogenase requires thiamine (B1) to act as an electron sink for the carboxylation of pyruvate
prosthetic group
A tightly bound, specific non-polypeptide unit required for the biological function of some proteins.
apoenzyme
the protein part of an enzyme
holoenzyme
- an active enzyme and can perform the catalytic activity.
why are apoenzymes important
they are responsible for the specificity of enzymes to their substrates
are apoenzymes active? why or why not?
Apoenzymes alone are not active enzymes; they must bind to an organic or inorganic cofactor in order to be activated
how are holoenzymes made
- After binding to a cofactor, apoenzyme forms a holoenzyme
competitive inhibitors
- resemble the substrate and bind to the active site
noncompetitive inhibitors
- bind to an allosteric site
- alter the shape of or access to the active site
is inhibition reversible?
yes inhibition can be reversible or irreversible
reversible inhibition
the enzyme remains functional after removal of the inhibitor
irreversible inhibition
the inhibitor permanently alters the enzyme leaving it nonfunctional
explain substrate level inhibition
- can occur when an enzyme has 2 binding sites, active and allosteric, for the substrate
- these 2 sites would have different Km values, with the allosteric binding occurring as [S] increases
what does binding at the allosteric site do?
decreases the binding/conversion at the active site
what does a different kM mean??
different affinities
Vmax
maximum turnover rate for enzyme
what catalyzes the first step in the detoxification of alcohol
alcohol dehydrogenase
what’s an example of toxin mitigation
detoxification of alcohol
explain the steps of detoxification of alcohol
- alcohol
- acetaldehyde by alcohol dehydrogenase
- acetate
acetaldehyde
- highly toxic molecule exerting negative effects on the liver and CNS, and complex effects on the cardiovascular system
how does toxin mitigation of alcohol work?
- by slowing the conversion to the intermediate, the most negative effects can be somewhat mitigated
product level inhibition
- product binds a allosteric site on the enzyme to slow reaction
what is product level inhibition involved in? explain how
metabolic regulation
- the product inhibition ensures that glucose will not be dedicated to ATP production unless the cell is utilizing it
metabolic regulation
physiological mechanism by which the body takes in nutrients and delivers energy as required
list 2 examples of product level inhibition
- hexokinase
2. many Krebs cycle enzyme
what do the Km and Vmax tell us?
basic information about the enzyme’s function
what does Km refer to?
- affinity of enzyme for substrate
- the [S] at 1/2 Vmax
what does lower Km mean?
higher affinity
what does higher km mean?
lower affinity
what does Vmax give you insight on?
the capacity of the [E] to handle fluctuations in [Substrate[
what is this: when all the enzyme is in the ES complex
Vmax
isoenzymes
- catalyze the same reaction but due to minor structural changes, have different activity levels
where are hexokinases found?
- in most tissues
- considered the maintenance enzyme
where is glucokinase primarily found
in the liver
glucokinase is technically a…
very specific form of hexokinase
medical application of isoenzymes
- because they’re tissue specific, their presece in the blood is indicative of damage to a specific tissue type
- CREATINE PHOSPHOKINASE (CPK, CK)
CPK1
brain and lugns
CPK2
heart
CPK3
skeletal muscle
functions of nucleic acids
- genetic information
- direct protein synthesis
- energy
- NTs
what are nucleic acids made up of?
nucleotide monomers
2 examples of nucleic acids
DNA and RNA
what is the monomer of DNA
AMP
what are the basic components of a nucleotide
nitrogenous base
ribose sugar
phosphate group
list the pyridimines
cytosine
uracil (RNA)
thymine (DNA)
list the purines
Guanine
Adenosine
which is larger: purines or pyrimidines
purines
in nucleotides: where is the phosphate group bonded to?
the 5’ carbon of a sugar
in nucleotides: where is the nitrogenous base bonded to?
1’ carbon of sugar
list the nitrogenous bases
cytosine uracil thymine guaine adenine
composition of nucleotide
phosphate group, 5 carbon sugar, nitrogenous base
Ribose
- sugar for RNA
- 5-carbon simple sugar
Deoxyribose
- sugar for DNA
- has the same 5-carbon formula as that of ribose sugar but loses an oxygen atom
_______ reaction forms DNA
Condensation
how is DNA made?
nucleotides bind so that the 3’ OH group of one attaches to the 5’ phosphate of the other
In a DNA chain, the polymer will only attach new monomers….
to the 3’ end
list the DNA forms
B DNA
A DNA
Z DNA
B DNA
- most common
- right handed helix
A DNA
- shorter
- more dense
- right handed helix
- RNA DNA complexes
- double stranded RNA regions
Z DNA
- longer
- stretched out
- left handed helix
- increased methylation
- shut down
list the ribonucleic acid forms
mRNA rRNA tRNA hnRNA sRNA
mRNA
coded message that directs peptide synthesis
rRNA
stabilizes mRNA in the ribosome
tRNA
transfers AA to ribosome for peptide construction
hnRNA
- heterogenous nuclear RNA
- unedited RNA
- contains introns that have to be removed
snRNA
- small nuclear RNA
- forms complexes with proteins forming snRNPs
snRNPs
perform splicing of hnRNAs to produce mRNAs
energy molecules
contain high energy bonds
- nucleic acid modification
NT
- adenosine is simply the nucleoside w/o the phosphate group
- nucleic acid modification
