PART 1: mixed topics Flashcards
a single-based DNA gene coding changes that is LEAST LIKELY to significantly affect the function of resulting protein?
Silent mutations in the 3RD CODON BASE
a property of the enhancer element?
They could work when located long distances from the promoter
______ is considered as a transcriptional regulation control?
Chromatin remodelling
TRUE of biological membrane structure
Cholesterol is an amphipathic molecule
Defines the specificity of hormone activity in a cell
The presence of the hormone receptor
TRUE of hormones
lipophilic hormones need transport proteins
a vitamin that is essential for one-carbon metabolism
Folic Acid (vit B9)
Which statement is true about competitive inhibition?
Usually the inhibitor structurally resembles the normal substrate
The active form of Vitamin B12 coenzyme:
5-deoxyadenosylcobalamin
TRUE statement regarding carbohydrate digestion
It initially takes place in the mouth through the action of AMYLASE
In man, glucose from dietary cellulose could not be available for energy because:
man inherently lacks the enzyme to hydrolyze cellulose
A 3 month old infant develops diarrhea and abdominal discomfort following a milk formula. however, feeding history revealed that he was able to tolerate breast feedings and the same milk formula at birth. The most likely condition is
secondary lactose intolerance
Hexokinase differs from glucokinase by
hexokinase being inhibited by glucose 6 phosphate
What is the end product of glycolysis in exercising muscle and RBC?
lactic acid
The most important positive regulator of the committed step in glycolysis in the availability of
Fructose 2,6 bisphosphate
TRUE of the malate aspartate shuttle
it transports NADH from the cytosol into the mitochondria for oxidative phosphorylation
What is the initial step in the TCA cycle is catalyzed by:
citrate synthase
The hexose monophosphate shunt is metabolically significant to nuclei acid metabolism because it:
furnishes pentose phosphates
The rate limiting step in the pentose phosphate pathway catalyzed by:
glucose-6 phosphate dehydrogenase
The enzymatic reaction is common to both glycolysis and gluconeogenesis
phosphotriose isomerase
The inherent absence of this enzyme prevents muscle glycogenolysis to maintain glucose homeostasis:
glucose-6 phosphatase
Glycogen synthesis is activated while glycogenolysis is inhibited when:
glycogen synthase I predominates over glycogen synthase D
MANNOSE and FRUCTOSE enter the mainstream of carbohydrate metabolism via:
Embden Meyerhoff Pathway/Glycolysis
Fatty acids enter the mitochondrial matrix for oxidation in what form?
complexed w/ carnitine as acyl-carnitine
The number of reduced electron carriers generated when one mole of palmitate is subjected to oxidation:
7 FADH(2) and 7 NADH + H+
Majority of reducing equivalents necessary for fatty acid biosynthesis are generated during conversion of
pyruvate to malate
Ilang moles of NADPH+ H+ ang pwede iderive from the pathway utilized in transport of acetyl co-A out of the mitochondria?
8 MOLES
the site of action of the NSAIDS (nonsteroidal anti-inflammatory drugs) is
prostaglandin cyclooxygenase
hepatocytes contribute to the overall body content of ketone bodies primarily because of the absence of:
3-ketoacyl-coA transferase/acetoacetate succinyl coA transferase
The principal plasma carrier of dietary triacylglycerol is
chylomicron
activation of lipoprotein lipase requires which apoprotein?
apo C-II
VLDLs are synthesized in the liver for transport of _____ to the peripheral tissues
triacylglycerols
The committed step of cholesterol biosynthesis is catalyzed by _____ enzyme
HMG coA reductase
High dietary intake of cholesterol leads to:
decreased LDL receptor synthesis
Several of the enzymes of cholesterol biosynthesis require the _______ cofactor
NADPH
This molecule helps stabilize the action of pancreatic lipase on dietary lipids
co-lipase
aside from urea, the main circulatory system carrier of nitrogen atoms destined for excretion by the KIDNEY is
Glutamine (Qtie amine)
A deficiency in the ability to secrete enterokinase leads to
abnormally low levels of active intestinal proteases
(enteropeptidase is secreted by cells in the duodenum 🠮 converts trypsinogen (zymogen) into its active form Trypsin 🠮 activation of pancreatic digestive enzymes)
Transamidation (chemical reaction in which an amide reacts with an amine to generate a new amide) reaction includes the formation of _______
formation of liver asparagine from aspartate
Important cofactor for the transaminases:
pyridoxal phosphate (B6)
The production of alanine by peripheral tissue, especially by the muscle, is primarily dependent on:
Intracellular levels of pyruvate
Nitrogen of the muscle alanine can be derived from tissue ammonia through this enzyme action:
glutamate dehydrogenase
Sulfur for cysteine synthesis is derived from:
methionine
Severe PKU and shortened life span is a result of:
Deficiency of dihydrobiopterin reductase
Serine is synthesized by:
transamination of an alpha-ketoacid derived from TCA
Lysine is an essential amino acid because:
the epsilon-amino group of lysine cannot be formed by an aminotransferases
amino acids that are strictly KETOGENIC:
lysine and leucine
CORRECT precursor-product relationship from the
dopamine is a precursor to norepinephrine
The watson-crick model for the B-form of DNA is typified by:
bases located in the interior of the right-handed helix
Guanine-cytosine base pairs in a DNA molecule are more stable to denaturation than adenine-thymine pairs because:
G-C base pairs contain more hydrogen bonds than A-T pairs
DNA is distinguished from RNA by:
The presence of thymine instead of uracil
anti-cancer drugs like 5-fluouracil and 6-mercaptopurine act against malignant cells by:
Being incorporated into DNA before replication
_________ is a nucleotide
Adenylic acid
an essential vitamin in the synthesis of purine nucleotides
Folic acid (B9)
Which clinical condition does not involve a defect in purine metabolism?
Orotic Aciduria
Salvage reactions that generate purine and pyrimidine nucleosides and nucleotides are characterized as:
requiring less energy than the de novo synthesis
The enzyme that catalyzes the committed step of purine nucleotide de novo pathway:
glutamine amidophosphoribosyl transferase
In the management of gout, allopurinol is given to inhibit xanthine oxidase, the enzyme that catalyzes the synthesis of:
uric acid
The correct flow of genetic information according to the central dogma of molecular biology is:
replication 🠮 transcription 🠮 translation
transfer RNA (tRNA) as an adaptor molecule serves to:
recognize the triplet codon in mRNA via its anti-codon arm
Degeneracy of the genetic code means
multiple codons may encode the same amino acid
The final product of gene expression is
protein
normal growth and development of cells are controlled by genes known as:
proto-oncogenes
The type of mutation that involves the substitution of a purine base with another purine base is:
transition
This mineral helps guard against DNA damage as a cofactor of glutathione:
selenium
A tool in molecular biology in which a DNA sequence of interest is exponentially amplified in vitro by repeated cycles of enzymatic DNA synthesis is:
polymerase chain reaction
In the construction of recombinant DNA, which enzyme is used to cut DNA at precise base sequences?
restriction endonucleases
In recombinant DNA technology, antibiotic resistance genes in plasmids are used to:
select and screen for recombinant DNA clones
The pain felt by a patient with an enlarging malignant tumor is partly contributed by
release of cytokines such as IL-1 and IL-6 by the tumor cells
Malignancy may be naturally prevented if the mutated cancer gene was repaired
before DNA replication
With persistence of a mutation in cells during organogenesis, the resulting event is
occurrence of physical malformations
to specifically identify the mutation in the affected DNA segment in a patient with cancer, which bioethics transfer method should be used?
southern
Taq polymerase is used in PCR (polymerase chain reaction) because it
is resistant to heat denaturation
A 60 year old woman has developed, red roughened skin in sun-exposed areas over the past 2 years. She also has a chronic, watery diarrhea. On physical examination she exhibits memory loss with confusion. These findings are most consistent with what vitamin deficiencies?
Niacin
A clinical study is performed involving dietary iron metabolism in adults. It is observed that intestinal absorption of iron can be enhanced in patients with iron deficiency anemia by supplementing their diet with another nutrient. Which vitamin has this effect?
Vitamin C
The metabolic function of the pentose phosphate pathway is to:
generate NADPH and pentoses for the biosynthesis of fatty acids and nucleic acids
The FNRI Philippine RENI committee 2002 recommends the following protein intake:
1.14 g/kg DBW/day
number of moles of ATP generated from the complete oxidation of pyruvate as it undergoes the pyruvate dehydrogenase reaction and the krebs cycle is:
15
Which of these is deficient in Coris disease?
debranching enzyme
Just before breakfast, what is the source of glucose in the body?
glycogen
For every mole of glucose that goes through the glycolytic pathway, what is the net number of pyruvate generated?
2
primary function of the pentose phosphate pathway
NADPH and ribose residues production
Which enzyme generates NADPH + H+ needed to reduce GSSG:
glucose 6 phosphate dehydrogenase
G6PD deficiency is characterized by
may manifest as hemorrhagic anemia
TCA cycle as the final common pathway in fuel metabolism provides greatest amount of energy by being directly linked to:
ETC
