Biochem

Amino acid exists in its zwitterion if dissolved in water. Adding a strong acid HCl to the solution makes HCl donate a proton to the -COO- of the amino. What is lost in the chemical structure of the amino acid?

- charge

During the formation of the peptide bond, which of the following takes place?

-OH group is lost from the -COOH group of one amino acid, and H atom is lost from the amino group of another amino acid.

The average molecular weight of an amino acid residue in protein is closer to 128. The creation of peptide bond that links 2 amino acids releases water molecule through dehydration synthesis reaction. Hence, the average molecular weight of an amino acid residue in protein is about ________________

110

How many codons are required to synthesize the gene-coding mRNA bases for 43 amino acids?

129

The DNA extracted from the bacterial cells of Staphylococcus sp reveals that 33% of the base are Thymine. With this information, what % of the bases are Cytosine?

17%

A tripeptide has

3 amino acids and 2 peptide bonds

Adult hemoglobin has 2 alpha chains of 141 amino acids each, and 2 beta chains of 146 amino acids each. How many amino acids are there in an adult hemoglobin molecule?

574

Even though there are only 20 amino acids that exist, there are actually ____ possible tRNA molecules

64

If there are 7 Ozaki fragments on a lagging strand with each fragment made of 183 bases, how many primers will be required to replicate the entire length of a lagging strand?

7

Which of the following pH levels will least likely affect enzyme activity?

7

Which of the following is a purine?

ADP

The process that initiates or increases the action of an enzyme.

Activation

The antiviral drug Tipranavir has no obvious structural similarity to a protein substrate. It is used to treat HIV, by binding to viral proteases thus blocking the activity of a viral enzyme that helps the virus make more copies of itself. This is an example of ___

Allosteric effect

A tRNA with a complementary codon in its anticodon site will bind with the codon at site P, bringing a/an____

Amino Acid

Which of the following information is responsible in specifying the three-dimensional shape of a protein?

Amino Acid Sequence

What ribosomal site does the first tRNA to bind with the mRNA codon?

Aminoacyl (A) site

The base sequence of noncoding strand of DNA is similar to that of _____ except for Uracil nitrogenous base.

Anticodon

The addition of the next nucleotide to the growing chain of nucleotides

Bonds the nucleoside triphosphate to the 3'OH

Given the anticodon, GGACUGAUU, which of the following bases comprise the DNA template?

CCTGACTAA

The human body uses cysteine amino acid to produce the antioxidant glutathione, as well as the amino acid taurine. Which functional group gives cysteine its distinct property?

CH2-SH

Succeeding nucleotides are linked by DNA polymerase III to the OH- bearing _____________.

Carbon 3 of deoxyribose

Enzyme that specifically catalyzes the hydrolysis only of the last amino acid on a protein chain

Carboxylpeptidase

The _______ states which codon stands for a specific amino acid that in turn can synthesize a particular protein

Codon Code

Sequence of 3 nucleotides on m-RNA that codes for one amino acid.

Codons

Atorvastatin drug (Lipitor) is used to treat high cholesterol. Atorvastatin has a shape complementary to the active site of HMG-CoA reductase enzyme. Binding to this enzyme blocks its action in the synthesis of mevalonate, a metabolite needed in cholesterol synthesis. What inhibitory action is described?

Competitive inhibition

When separated, the two strands of a double helix DNA molecule are identical.

Correct

Human enzyme present in serum which is used in clinical assay to detect the likelihood of heart attack.

Creatine phosphokinase (CPK)

Once transcription is completed, which of the following is NOT necessary for protein synthesis to occur?

DNA

The 2 anti-parallel strands coil together to form a double helix in

DNA

After the synthesis of Okazaki fragments, the RNA primers are enzymatically removed and replaced with appropriate DNA nucleotides by ______________.

DNA polymerase III

Which process requires the free dATP, dGTP, dCTP, and dTTP molecules?

DNA synthesis

What type of bond connects the two polypeptide chains of human insulin?

Disulfide Bond

Modulation of pain and reduced peristalsis is the function of this neurotransmitter

Enkephalins

Alcohol dehydrogenase is found primarily in the liver and stomach. It converts ethanol to acetaldehyde, a toxin in which is then further broken down by acetaldehyde dehydrogenase to acetic acid, then to CO2 and H20. What is the substrate of alcohol

Ethanol

Which among these compounds cannot denature proteins?

Fatty acids

Which neurotransmitters can act as the major fast inhibitory transmitters in the brain & spinal cord?

GABA and Glycine

If the anticodon contains the base sequence CUGAGUC, what is the base sequence of the transcribed DNA strand?

GACUCAG

Which of the following is NOT a pyrimidine?

Guanine

If DNA polymerase III added bases in the 3 -🡪 5' direction to synthesize a DNA strand, which would not repeatedly by required by the lagging strand?

Gyrase

The bond that stabilizes tertiary structures between polar groups on side chains of -C=O groups and -N-H groups.

Hydrogen bond

Which of the following is/are true of enzymes? I. They increase the rate of reaction by markedly lowering the activation energy. II. They raise activation energy by shifting the equilibrium to favor the products. III. They lower activation energy by altering the synthesized products of a reaction.

I only

Which of the options does NOT describe a denatured protein?

Increased solubility

The graph shows that the rate of reaction increases rapidly at low substrate concentrations, and levels off to a plateau at high substrate concentrations. Which will increase again the rate of reaction?

Increasing the enzyme concentration

Sulfonamides antibiotics are structural analogs of para-aminobenzoic acid (PABA). When antibiotic binds to the dihydropteroate synthase enzyme, the enzyme is inhibited from synthesizing folic acid which is necessary in protein and nucleic acid synthesis of bacteria. What inhibitory action is demonstrated? Which is the natural substrate of the E-S complex?

Induced-fit mechanism

Erythromycin antibiotic binds to the 23S rRNA component of the 50S ribosome and interferes with the assembly of 50S subunits. What process is immediately affected?

Initiation of Translation

The elongation of replicating DNA strand is made possible through the nucleophilic substitution reaction catalyzed by DNA polymerase. It allows the 3-hydroxyl group a nucleophilic attack on the incoming dNTP. Which is the leaving group and species formed from -OH, respectively? A. inorganic phosphate (Pi) and H+.

Inorganic phosphate (Pi) and H+

A hormone that promotes cellular uptake of glucose and formation of glycogen and fats

Insulin

An enzyme having multiple forms, each form catalyzes the same chemical reaction

Isoenzyme

Which is the most accurate about the limitation of DNA polymerase III?

It can only synthesize the leading and lagging strands in 3' to 5' direction

If the template strand moves opposite to the direction of replication, what is true about replicating strand?

It is a leading strand with nucleotides added in 5' to 3' direction

Identify the structure labelled with letters C and E.

Lagging strand

The first tRNA carrying the _______ amino acid binds to the start codon at _____ of ribosome.

Methionine, P site

Given the TATA box and bases sequence of antisense strand, which amino acids are synthesized? TATAAA TAC CCA GCA GGA TGA CAT AAA AUG GGU CGU CCU ACU GUA UUU Meth Gly Arg Pro Thr Val Phe

Methionine-Glycine-Arginine-Proline-Threoni ne-Valine-Phenylalanine

The amino acid at the end of the chain having the free -NH3 group.

N-terminal amino acid

A chemical released from a nerve ending that transmits impulses from one neuron (nerve cell) to another neuron, or to a muscle cell.

Neurotransmitters

Aspirin inhibits a cyclooxygenase so that prostaglandins may not be synthesized, thereby reducing pain, fever, inflammation, and blood clot. Aspirin does not bind to the active site of cyclooxygenase but to another separate site, and induces a change to the enzyme's active form. What inhibitory action occurs?

Noncompetitive inhibition

After the first tRNA, the succeeding ones bind to mRNA codons at ____ ribosome. When tRNA is on the ____ site, it adds its amino acid to the polypeptide chain.

P;A

The hydrochloric acid (HCL) produced by parietal cells in the stomach creates an acidic environment that enables pepsinogen to unfold and cleave off 44 amino acids from itself in an autocatalytic fashion, thereby activating pepsin enzyme. Which is the zymogen and the active enzyme, respectively?

Pepsinogen and Pepsin

Proteins are least soluble in water at their isoelectric point. Hence, proteins can be separated from the solution at this pH because protein molecule, at this state, forms ___

Precipitate

Which of the following are NOT involved in transcription and translation processes?

Primers

A Biochemistry class completed a series of experiments and observed that a protein-digesting enzyme (intestinal protease) worked best at pH 8.0 in 37* C. During an experiment, the students conducted some of these procedures that follow. Procedure 1- Increasing the amount of protease. 2- Increasing the amount of protein. 3- Decreasing the pH of solution to 5. 4- Increasing the temperature to 45*C. 5- Decreasing the intensity of light. Which procedure would have the least effect on the rate of protein digestion?

Procedure 5

Which component of the amino acid makes it unique or distinct from the rest of amino acids?

R-side chain

Which of the following nucleic acids is located mostly in the cytoplasm and a single stranded structure?

RNA

A mode of transfer of genetic information that is not only a violation of the Central Dogma of Molecular Biology, but also not feasible

RNA ---- DNA

Enzymes can alter the ______ of a chemical reaction

Rate

Enzymes can accelerate the rate of chemical reactions by ____ the activation energy of the chemical reaction.

Reducing

The site of protein synthesis

Ribosomes

Not all enzymes are proteins. Which among these enzymes are made of ribonucleic acids?

Ribozymes

Which of the following codons can code for punctuation?

STOP

DNA stably stores the genetic information that lasts for hundreds of years. Which one refers to the genetic information?

Sequence of nitrogenous bases

Which of the following is considered an Excitatory Neurotransmitter?

Serotonin

The clinical sample used in enzyme assay detect aspartate aminotransferase, a biomarker for heart attack or hepatitis.

Serum

Cholecystokinin is produced by the ___

Small Intestine

The factor which does not affect pKa value of an amino acid is the

Standard ambient temperature

The specificity of enzymes also extends to

Stereospecificity

Which of the following is not involved in transcription?

Stop codon

The limitation of an enzyme to catalyze specific reactions with specific substrates.

Substrate specificity

The coding strand of DNA is complementary to the _____

Template strand

A protein that allows the termination of translation by recognizing the termination codon or stop codon in mRNA sequence

Termination factor

A nucleotide sequence in DNA that causes the RNA polymerase to cease transcription

Terminator

In DNA synthesis which reaction occurs?

The nucleophilic attack of 3' OH deoxyribose on a-phospate of incoming dNTP

What nitrogenous base is not found in the table of genetic codes?

Thymine

Protein that recognize stop codons and react to such codons to terminate translation.

Translation proteins

A unique amino acid structure dues to its side chain that is bonded to a central carbon atom and to an amino group as well.

Tryptophan

The codes for amino acids in the Table of Genetic Codes are identical to the sequence of bases carried by ___________________.

mRNA

Isoelectric point of the protein, is the ___ at which the net charge of the protein is zero.

pH

The unfolding of a protein molecule termes as denaturation destroys protein's conformation. Which level of protein structure remains intact after the denaturation reaction?

primary