cell metabolism exam 1

what could be considered a primary role for enzymes

enzymes accelerate the attainment of equilibrium, provides energy to subtrates so that the substrates readily reach the transition state, allow formation of transition state enabling reaction, enzymes only affect the energy of initiation or transition state energy

select the atoms that are (needed in trace amounts) by humans and probably gerbils

mg, v, cr,mn, fe, co, ni, cu, zn, se, mo,i

select the atoms that are (needed in abundance) by humans and probably gerbils

H,c,n,o (na,k,ca,p,s,cl)

from the list below select the biomolecule that is not used, metabolically as an energy source

nucleic acids (nucleotide)

what biomolecules are used as an energy source

proteins, lipids, carbohydrates, nucleic acids

a patient at (6 years old) presents with severe accumulation of lipids in many tissues and especially the liver. if the choices are wolmans disease and cholesterol ester storage disease what is the diagnosis

CESD (wolmans is lethal by age 1), exon splice error

what is expected from a wolmans disease patient

massive accumulation of exogenous cholesterol esters, results from premature stop codon, no functional protein detectable, lethal by age 1

what is expected of a cholesterol ester storage disease (CESD) patient

massive accumulation of exogenous cholesterol esters, caused by a single G to A mutation, disrupts splicing point for an exon, allows for low but functional levels of an enzyme

what is expected of a hers disease patient

phosphorylase deciciency (liver isozyme deficiency). symptoms is hepatomegaly (large liver), liver damage, hypoglycemia

what is expected of a diabetes melitus patient

overproduction of glucose by the liver, underutilization of glucose by other tissues

what is expected of a I Von Gierke disease patient

blood glucose deficiency caused by lack of enzyme glucose-6-phosphatase in the liver. symptoms is hypoglycemia, hepatomegaly (liver cancer), threat of lactic acidosis

which cellular compartment houses the enzymes related to wolmans disease and CESD

lysosomes

an enzyme that changes chirality would be classified as a

isomerase

what classification of enzyme is hexokinase

transferase

examination a lineweaver Burker plot for an enzyme system after an inhibitor is added reveals a sudden increase in the Y intercept. which of the following statements best describes what is happening at the enzyme level

the inhibitor is binding at a site that is not the active site and disrupting catalysis

competitive inhibition

inhibitor binds at the catalytic site inhibiting substrate binding but not catalysis

allosteric inhibition

inhibitor binds at a distal non catalytic site and blocks catalysis but not substrate binding

uncompetitive inhibition

inhibitor aids in susbtrate binding but also blocks catalysis

transition state inhibition

when bound, the enzyme achieves its lowest energy state and is no longer functional

suicide inhibition

binds to the enzyme and is catalyzed resulting in a covalent bond with the enzyme

which type of inhibitor would provide the best starting point for developing a therapy for ethanol sensitivity

uncompetitive inhibition

in hers disease what is the enzymatic failure

absence of liver phosphorylase

considering a muscle cells stimulated by epinephrine but is overloaded with atp. what is likely form and state of phosphorylase

A form, R state

why can liver cells generate glucose, but muscle cells cannot

muscle cells lack glucose-6-phosphatase

are the statements correct

(a) glucose is removed from glycogen by the enzyme phosphorylase creating glucose-6-phosphate

(b) this is how we know phosphorylase uses atp for the cutting

both are incorrect

both hers disease and type 1 von gierke disease possess the symptom of hypoglycemia. why does Von gierke also have the threat of lactic acidosis

Von Gierke clears glucose-6-phosphate by glycolysis rather than export

is the statements correct

(A) an isozyme is a variant of a given enzyme found in a different cellular location

(B) therefore, isozymes come from the same gene

B is incorrect

at which point is an enzyme in its lowest energy conformation

transition state

apoenzyme

inactive enzyme

holoenzyme

active enzyme

dG=0

equilibrium

dG>0

unfavorable

dG<0

favorable

what is the velocity formula

Vmax*[S}/kM + [S]

are the statements correct

(A) Km is a value of ½ of vmax

(B) is vmax is 200 units per second then km is 100 units per second

both are incorrect

nucleus

genomic storage/expression

mitochondria

ATP production

Rough ER

secreted/membrane-bound protein protection

cytoplasm

cellular protein synthesis

lysosome

cellular digestion

how was metabolism to be determined to be a highly conserved system across species

glycolysis was found in yeast and animals

what genetic error causes CESD

exon splice error

what genetic error causes Wolman’s disease

premature stop codon

proteins

structure/catalysis

nucleic acids

information storage/coenzymes

lipids

cell signaling/membranes

carbohydrates

storage/source of electrons

which of the diseases manifests due to dramatically reduced but still present activity of a particular enzyme?

CESD (cholesterol ester storage disease)

which biomolecule class plays the largest role in metabolism

proteins

which biomolecule class plays the largest role in energy storage

lipids

which biomolecule class plays the largest role in signaling

proteins

which biomolecule class plays the largest role in energy production

carbohydrates

which biomolecule class plays the largest role in catalysis

proteins

which cell compartment is the primary site of protein production

cytosol

which cell compartment is the primary site of atp production

mitochondria

which cell compartment is the primary site of cell digestion production

lysosome

which cell compartment is the site of protein generation for membrane bound proteins

rough ER

Which enzymes are likely to be significantly regulated?

unidirectional arrows

what does bold/underlined enzymes mean

they are considered to have higher binding affinity in the forward direction than other enzymes that consume the same substrate

steady state system

conditions remain constant, so no net charge

equilibrium system

rate of forward and reverse reactions are equal, so no net charge

dg<0

spontaneous

dg>0

non spontaneous

what is the formula for km

vmax(s)/v -s

what does km represent?

the concentration of S at which ½ of the active sites of the enzymes are filled and the velocity is ½ of vmax

if km is small

it takes low levels of s to fill the active site and the ES complex is strong

if km is large

it takes high levels of s to fill the active site and the ES complex is weak

graph for competitive inhibitors

km increases, vmax stays the same

graph for uncompetitive inhibitors

km drops and vmax drops

graph for noncompetitive inhibitor

km stays the same, vmax drops

kinase enzyme

catalyzes addition of PO4 to Serine, threonine, tyrosine

phosphatase

removes PO4 moiety

why do le chateliers principle technically does not apply to living systems (although we can use them to an extent)

cell pathways are never at equilibrium, temperature is likely to remain unchanged, living systems are not closes systems.

the enzyme catalyzes the conversion of organic compounds to alternative forms

isomerase

role of glycogen in liver

maintains blood glucose levels, highest concentration of glycogen by weight. glucose released during fasting periods.

which enzyme of glycolgenolysis is most likely to run in reverse

phosphoglucomutase

phosphorylase A

usually active, and usually R form. primarily in liver

phosphorylase B

usually inactive, and usually T form. resting muscles are almost all in B form

which metabolite is going to connect glycogenolysis to other pathways

glucose-6-phosphate

what is the role of glycogen in the muscle

serves as energy storage, used as last resort.

a technician is testing phosphorylase in muscle cells and notes that u