PART 1: mixed topics Flashcards by Bea Macatangay

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

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a property of the enhancer element?

They could work when located long distances from the promoter

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______ is considered as a transcriptional regulation control?

Chromatin remodelling

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TRUE of biological membrane structure

Cholesterol is an amphipathic molecule

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Defines the specificity of hormone activity in a cell

The presence of the hormone receptor

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TRUE of hormones

lipophilic hormones need transport proteins

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a vitamin that is essential for one-carbon metabolism

Folic Acid (vit B9)

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Which statement is true about competitive inhibition?

Usually the inhibitor structurally resembles the normal substrate

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The active form of Vitamin B12 coenzyme:

5-deoxyadenosylcobalamin

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TRUE statement regarding carbohydrate digestion

It initially takes place in the mouth through the action of AMYLASE

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In man, glucose from dietary cellulose could not be available for energy because:

man inherently lacks the enzyme to hydrolyze cellulose

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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

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Hexokinase differs from glucokinase by

hexokinase being inhibited by glucose 6 phosphate

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What is the end product of glycolysis in exercising muscle and RBC?

lactic acid

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The most important positive regulator of the committed step in glycolysis in the availability of

Fructose 2,6 bisphosphate

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TRUE of the malate aspartate shuttle

it transports NADH from the cytosol into the mitochondria for oxidative phosphorylation

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What is the initial step in the TCA cycle is catalyzed by:

citrate synthase

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The hexose monophosphate shunt is metabolically significant to nuclei acid metabolism because it:

furnishes pentose phosphates

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The rate limiting step in the pentose phosphate pathway catalyzed by:

glucose-6 phosphate dehydrogenase

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The enzymatic reaction is common to both glycolysis and gluconeogenesis

phosphotriose isomerase

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The inherent absence of this enzyme prevents muscle glycogenolysis to maintain glucose homeostasis:

glucose-6 phosphatase

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Glycogen synthesis is activated while glycogenolysis is inhibited when:

glycogen synthase I predominates over glycogen synthase D

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MANNOSE and FRUCTOSE enter the mainstream of carbohydrate metabolism via:

Embden Meyerhoff Pathway/Glycolysis

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Fatty acids enter the mitochondrial matrix for oxidation in what form?

complexed w/ carnitine as acyl-carnitine

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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:

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?

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