Q. What is the role of disulfide bonds in peptides?
A.
To form peptide bonds
B.
To stabilize tertiary structure
C.
To create secondary structure
D.
To facilitate enzyme activity
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Solution
Disulfide bonds form between cysteine residues and help stabilize the tertiary structure of peptides and proteins.
Correct Answer:
B
— To stabilize tertiary structure
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Q. What is the role of DNA ligase in DNA replication?
A.
Unwinds DNA
B.
Synthesizes RNA primers
C.
Joins Okazaki fragments
D.
Adds nucleotides
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Solution
DNA ligase joins Okazaki fragments on the lagging strand during DNA replication.
Correct Answer:
C
— Joins Okazaki fragments
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Q. What is the role of glutamine in nitrogen metabolism?
A.
Energy source
B.
Nitrogen donor
C.
Carbon source
D.
Hormone precursor
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Solution
Glutamine acts as a nitrogen donor in various biosynthetic reactions, including nucleotide synthesis.
Correct Answer:
B
— Nitrogen donor
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Q. What is the role of glutamine in the body?
A.
Energy source
B.
Nitrogen transport
C.
Hormone production
D.
Antioxidant
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Solution
Glutamine serves as a major nitrogen transporter in the body, playing a key role in nitrogen metabolism.
Correct Answer:
B
— Nitrogen transport
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Q. What is the role of HDL cholesterol in the body?
A.
Transporting cholesterol to cells
B.
Removing excess cholesterol from the bloodstream
C.
Storing triglycerides
D.
Increasing inflammation
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Solution
HDL cholesterol helps remove excess cholesterol from the bloodstream, reducing the risk of heart disease.
Correct Answer:
B
— Removing excess cholesterol from the bloodstream
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Q. What is the role of IgE antibodies?
A.
To fight bacterial infections
B.
To mediate allergic reactions
C.
To activate complement system
D.
To enhance phagocytosis
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Solution
IgE antibodies are primarily involved in allergic reactions and responses to parasitic infections.
Correct Answer:
B
— To mediate allergic reactions
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Q. What is the role of lactose permease in the lac operon?
A.
To synthesize lactose
B.
To transport lactose into the cell
C.
To degrade lactose
D.
To inhibit the repressor
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Solution
Lactose permease is a membrane protein that facilitates the transport of lactose into the E. coli cell.
Correct Answer:
B
— To transport lactose into the cell
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Q. What is the role of lysosomes in a cell?
A.
Energy production
B.
Digestion of macromolecules
C.
Protein synthesis
D.
Cell signaling
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Solution
Lysosomes contain enzymes that digest macromolecules, old cell parts, and microorganisms.
Correct Answer:
B
— Digestion of macromolecules
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Q. What is the role of memory cells in the immune system?
A.
To initiate the immune response
B.
To remember past infections
C.
To produce antibodies
D.
To destroy pathogens
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Solution
Memory cells are long-lived cells that remember past infections, allowing for a faster and stronger response upon re-exposure.
Correct Answer:
B
— To remember past infections
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Q. What is the role of monoclonal antibodies in medicine?
A.
To enhance immune response
B.
To target specific cells or proteins
C.
To replace missing antibodies
D.
To prevent infections
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Solution
Monoclonal antibodies are designed to target specific cells or proteins, making them useful in treatments for various diseases, including cancer.
Correct Answer:
B
— To target specific cells or proteins
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Q. What is the role of phosphofructokinase in glycolysis?
A.
Regulatory enzyme
B.
Energy production
C.
Substrate-level phosphorylation
D.
Dehydrogenation
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Solution
Phosphofructokinase is a key regulatory enzyme that controls the rate of glycolysis.
Correct Answer:
A
— Regulatory enzyme
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Q. What is the role of primers in PCR?
A.
To stabilize the DNA
B.
To initiate DNA synthesis
C.
To degrade unwanted DNA
D.
To amplify RNA
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Solution
Primers are short sequences of nucleotides that initiate DNA synthesis by providing a starting point for Taq polymerase.
Correct Answer:
B
— To initiate DNA synthesis
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Q. What is the role of regulatory sequences in genes?
A.
To code for proteins
B.
To initiate transcription
C.
To terminate transcription
D.
To enhance mutation rates
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Solution
Regulatory sequences are regions of DNA that control the timing and level of gene expression by facilitating or inhibiting transcription.
Correct Answer:
B
— To initiate transcription
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Q. What is the role of reverse transcriptase in recombinant DNA technology?
A.
To synthesize DNA from RNA
B.
To cut DNA at specific sites
C.
To ligate DNA fragments
D.
To amplify DNA sequences
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Solution
Reverse transcriptase is an enzyme that synthesizes DNA from RNA, which is important for creating complementary DNA (cDNA) in recombinant DNA technology.
Correct Answer:
A
— To synthesize DNA from RNA
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Q. What is the role of ribosomal RNA (rRNA)?
A.
Transcription of DNA
B.
Translation of mRNA
C.
Replication of DNA
D.
Repair of DNA
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Solution
Ribosomal RNA (rRNA) plays a crucial role in the translation of mRNA into proteins.
Correct Answer:
B
— Translation of mRNA
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Q. What is the role of RNA-binding proteins?
A.
To synthesize DNA
B.
To stabilize RNA structures
C.
To degrade proteins
D.
To replicate DNA
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Solution
RNA-binding proteins play a crucial role in stabilizing RNA structures and regulating RNA metabolism, including splicing and transport.
Correct Answer:
B
— To stabilize RNA structures
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Q. What is the role of the buffer in gel electrophoresis?
A.
To provide nutrients to the gel
B.
To maintain pH and conduct electricity
C.
To stain the DNA
D.
To solidify the gel
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Solution
The buffer maintains pH and conducts electricity, allowing the DNA or proteins to migrate through the gel.
Correct Answer:
B
— To maintain pH and conduct electricity
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Q. What is the role of the electron transport chain in ATP synthesis?
A.
Substrate-level phosphorylation
B.
Oxidative phosphorylation
C.
Fermentation
D.
Glycolysis
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Solution
The electron transport chain is responsible for oxidative phosphorylation, which generates ATP using the energy from electrons.
Correct Answer:
B
— Oxidative phosphorylation
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Q. What is the role of the magnetic field in NMR spectroscopy?
A.
To ionize the sample
B.
To separate molecules
C.
To align nuclear spins
D.
To heat the sample
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Solution
The magnetic field aligns the nuclear spins of the sample, which is essential for obtaining NMR signals.
Correct Answer:
C
— To align nuclear spins
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Q. What is the role of the side chain (R group) in amino acids?
A.
Determines the amino acid's charge
B.
Determines the amino acid's polarity
C.
Determines the amino acid's reactivity
D.
All of the above
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Solution
The side chain (R group) of an amino acid determines its charge, polarity, and reactivity, influencing its role in proteins.
Correct Answer:
D
— All of the above
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Q. What is the role of the stationary phase in HPLC?
A.
To provide a mobile phase
B.
To separate analytes based on their interactions
C.
To inject the sample
D.
To detect the analytes
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Solution
The stationary phase in HPLC separates analytes based on their interactions with the stationary material.
Correct Answer:
B
— To separate analytes based on their interactions
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Q. What is the role of the TATA box in transcription?
A.
It is a coding region
B.
It is a binding site for RNA polymerase
C.
It is a site for RNA splicing
D.
It is a termination signal
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Solution
The TATA box is a DNA sequence that serves as a binding site for RNA polymerase and is crucial for the initiation of transcription.
Correct Answer:
B
— It is a binding site for RNA polymerase
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Q. What is the role of UV luminance spectroscopy in cancer research?
A.
Identifying genetic mutations
B.
Monitoring treatment efficacy
C.
Detecting early-stage tumors
D.
Analyzing tumor microenvironments
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Solution
UV luminance spectroscopy plays a role in detecting early-stage tumors by analyzing changes in tissue properties due to UV exposure.
Correct Answer:
D
— Analyzing tumor microenvironments
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Q. What is the role of Vitamin K in the body?
A.
Bone mineralization
B.
Antioxidant defense
C.
Blood clotting
D.
Energy production
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Solution
Vitamin K is essential for blood clotting as it is required for the synthesis of clotting factors in the liver.
Correct Answer:
C
— Blood clotting
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Q. What is the significance of the 'gene of interest' in recombinant DNA technology?
A.
It is the DNA sequence that is cloned
B.
It is the vector used for cloning
C.
It is the enzyme used for cutting DNA
D.
It is the host organism
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Solution
The 'gene of interest' is the specific DNA sequence that researchers aim to clone and manipulate in recombinant DNA technology.
Correct Answer:
A
— It is the DNA sequence that is cloned
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Q. What is the significance of the annealing temperature in PCR?
A.
It determines the speed of DNA synthesis
B.
It affects the specificity of primer binding
C.
It controls the amount of DNA produced
D.
It is irrelevant to the PCR process
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Solution
The annealing temperature is crucial as it affects the specificity of primer binding to the target DNA.
Correct Answer:
B
— It affects the specificity of primer binding
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Q. What is the significance of the equilibrium constant (K) in thermodynamics?
A.
It indicates the speed of a reaction
B.
It determines the direction of a reaction
C.
It reflects the ratio of products to reactants at equilibrium
D.
It measures the energy change of a reaction
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Solution
The equilibrium constant (K) reflects the ratio of products to reactants at equilibrium, indicating the extent of the reaction.
Correct Answer:
C
— It reflects the ratio of products to reactants at equilibrium
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Q. What is the significance of the protein p53 in relation to DNA?
A.
It promotes DNA replication
B.
It acts as a tumor suppressor by regulating the cell cycle
C.
It synthesizes RNA
D.
It repairs DNA damage
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Solution
p53 is a crucial tumor suppressor protein that regulates the cell cycle and helps prevent the proliferation of cells with damaged DNA.
Correct Answer:
B
— It acts as a tumor suppressor by regulating the cell cycle
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Q. What is the significance of the start codon?
A.
It signals the end of translation
B.
It codes for a stop signal
C.
It initiates protein synthesis
D.
It regulates gene expression
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Solution
The start codon (AUG) signals the beginning of translation and codes for the amino acid methionine.
Correct Answer:
C
— It initiates protein synthesis
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Q. What is the significance of using a buffer during protein purification?
A.
To increase protein solubility
B.
To maintain pH and ionic strength
C.
To enhance protein activity
D.
To precipitate unwanted proteins
Show solution
Solution
Buffers are used during protein purification to maintain pH and ionic strength, which are critical for protein stability and solubility.
Correct Answer:
B
— To maintain pH and ionic strength
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