100 QUESTIONS AND ANSWERS IN NUCLEIC ACID.
The following questions and answers will help students understand the concept of nucleic acids since they have been drawn comprehensively and randomly across the topic:
- What are nucleic acids?
Nucleic acids are biomolecules that store and transfer genetic information in living organisms.
- What are the two main types of nucleic acids?
The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
- What is the primary function of DNA?
The primary function of DNA is to store genetic information and transmit it from one generation to the next.
- Where is DNA found in eukaryotic cells?
In eukaryotic cells, DNA is primarily located in the cell nucleus.
- What is the structure of DNA?
DNA has a double helix structure composed of two strands of nucleotides.
- What are nucleotides?
Nucleotides are the building blocks of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.
- Name the four nitrogenous bases present in DNA.
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
- How do the nitrogenous bases pair in DNA?
Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G) via hydrogen bonds.
- What is the complementary DNA sequence for the following DNA strand: 5′-ATCGGTA-3′?
3′-TAGCCAT-5′
- What is the function of RNA?
RNA plays a crucial role in protein synthesis and gene expression.
- What are the three main types of RNA?
The three main types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
- Where is mRNA synthesized in eukaryotic cells?
mRNA is synthesized in the nucleus and then transported to the cytoplasm for translation.
- What is the function of tRNA?
tRNA carries amino acids to the ribosome during protein synthesis.
- Where is rRNA found?
rRNA is a structural component of ribosomes, found in both the cytoplasm and the rough endoplasmic reticulum.
- Which enzyme catalyzes the synthesis of RNA during transcription?
RNA polymerase.
- What is the role of a promoter in transcription?
A promoter is a DNA sequence that signals the starting point for RNA synthesis.
- What are exons and introns?
Exons are coding regions in a gene that are expressed, while introns are non-coding regions that are removed during RNA splicing.
- What is RNA splicing?
RNA splicing is the process of removing introns and joining exons to produce mature RNA molecules.
- What is alternative splicing?
Alternative splicing allows a single gene to code for multiple protein isoforms by combining exons in different ways.
- What is the genetic code?
The genetic code is the set of rules by which information encoded in mRNA is translated into proteins by the ribosome.
- How many nucleotides make up a codon?
A codon consists of three nucleotides.
- How many possible codons are there?
There are 64 possible codons (4 bases raised to the power of 3).
- How many codons code for amino acids, and how many are stop codons?
There are 61 codons that code for amino acids, and 3 codons (UAA, UAG, and UGA) function as stop codons.
- What is the start codon, and what amino acid does it encode?
The start codon is AUG, which codes for the amino acid methionine (Met) and serves as the initiation signal for translation.
- What is the role of the ribosome in translation?
The ribosome is the cellular machinery responsible for protein synthesis.
- Define the process of translation.
Translation is the process in which the ribosome uses mRNA as a template to synthesize a specific protein sequence.
- What are anticodons, and where are they found?
Anticodons are found on tRNA molecules and base-pair with codons on mRNA during translation.
- What is a mutation in the context of nucleic acids?
A mutation is a change in the DNA sequence that can lead to genetic variation.
- What are point mutations?
Point mutations are single nucleotide changes in the DNA sequence.
- Name three types of point mutations.
Three types of point mutations are: missense, nonsense, and silent mutations.
- What is a frameshift mutation?
A frameshift mutation is the insertion or deletion of nucleotides, causing a shift in the reading frame during translation.
- How can mutations be beneficial, harmful, or neutral?
Mutations can lead to beneficial traits, harmful diseases, or have no significant effect on an organism.
- What is DNA replication?
DNA replication is the process of copying DNA to produce two identical DNA molecules.
- What enzyme catalyzes DNA replication?
DNA polymerase.
- What is the role of helicase in DNA replication?
Helicase unwinds and separates the DNA double helix to provide single-stranded templates for replication.
- Explain the leading and lagging strands in DNA replication.
The leading strand is continuously synthesized, while the lagging strand is synthesized in short fragments called Okazaki fragments.
- What is DNA ligase’s role in DNA replication?
DNA ligase joins the Okazaki fragments on the lagging strand during replication.
- What are telomeres, and what is their function?
Telomeres are repetitive DNA sequences at the ends of chromosomes that protect them from deterioration and fusion with neighboring chromosomes.
- What is telomerase, and why is it essential in some cells?
Telomerase is an enzyme that helps replenish telomeres, preventing the loss of genetic information during successive cell divisions.
- How does DNA repair maintain the integrity of the genetic material?
DNA repair mechanisms correct errors and damage in the DNA sequence, preventing mutations from being passed on to daughter cells.
- What is DNA recombination?
DNA recombination is the process where two DNA molecules exchange genetic information.
- Name two types of DNA recombination.
Homologous recombination and site-specific recombination.
- What is homologous recombination?
Homologous recombination involves the exchange of genetic material between similar DNA sequences.
- Define genetic recombination.
Genetic recombination refers to the production of offspring with combinations of traits different from those found in either parent.
- What is RNA interference (RNAi)?
RNAi is a biological process in which small RNA molecules inhibit gene expression.
- What are microRNAs (miRNAs) and small interfering RNAs (siRNAs)?
miRNAs and siRNAs are small RNA molecules that are involved in RNA interference and gene regulation.
- How do miRNAs and siRNAs regulate gene expression?
They bind to target mRNA molecules and either promote degradation or inhibit translation, leading to reduced gene expression.
- What is a gene expression profile?
A gene expression profile represents the pattern of gene activity in a cell or tissue under specific conditions.
- What is epigenetics?
Epigenetics refers to heritable changes in gene expression that do not involve alterations in the DNA sequence.
50
. How do epigenetic modifications affect gene expression?
Epigenetic modifications, such as DNA methylation and histone acetylation, can either activate or repress gene expression.
- What is the central dogma of molecular biology?
The central dogma states that genetic information flows from DNA to RNA to proteins.
- What is reverse transcription?
Reverse transcription is the process of synthesizing DNA from an RNA template, which is carried out by reverse transcriptase.
- Name an important application of reverse transcription.
The reverse transcription polymerase chain reaction (RT-PCR) is used to amplify and detect RNA molecules.
- What is the significance of the Human Genome Project?
The Human Genome Project sequenced and identified all the genes in the human genome, providing valuable genetic information.
- How many base pairs are there in the human genome?
Approximately 3 billion base pairs.
- What is DNA sequencing?
DNA sequencing is the process of determining the precise order of nucleotides in a DNA molecule.
- Name two common DNA sequencing methods.
Sanger sequencing and Next-Generation Sequencing (NGS).
- How has Next-Generation Sequencing (NGS) advanced genetic research?
NGS allows researchers to sequence DNA rapidly and at a lower cost, enabling various applications such as whole-genome sequencing and transcriptomics.
- What is CRISPR-Cas9, and how is it used in genetic engineering?
CRISPR-Cas9 is a revolutionary gene-editing tool that can target specific DNA sequences to add, delete, or modify genes.
- How does CRISPR-Cas9 function in bacterial immunity?
In bacteria, CRISPR-Cas9 is part of an adaptive immune system that defends against viral infections.
- What is a vector in molecular biology?
A vector is a DNA molecule used to carry foreign genetic material into a host organism during genetic engineering.
- What are plasmids, and why are they often used as vectors?
Plasmids are small, circular DNA molecules found in bacteria. They are commonly used as vectors due to their ability to replicate independently in host cells.
- Define gene therapy.
Gene therapy is a medical approach that involves modifying a person’s genes to treat or prevent genetic diseases.
- What is the importance of the Genetic Information Nondiscrimination Act (GINA)?
GINA is a law that protects individuals from genetic discrimination by health insurance companies and employers based on genetic information.
- What is the function of nucleases?
Nucleases are enzymes that hydrolyze the phosphodiester bonds in nucleic acids, breaking them down into smaller fragments.
- Name a restriction endonuclease and its significance in molecular biology.
EcoRI is a commonly used restriction enzyme that recognizes and cuts specific DNA sequences, facilitating DNA manipulation.
- What are DNA probes, and how are they used in molecular biology?
DNA probes are short, single-stranded DNA molecules that can hybridize with specific complementary DNA sequences, allowing the detection of target genes.
- How do DNA microarrays work?
DNA microarrays are used to measure the expression levels of thousands of genes simultaneously and compare them under different conditions.
- What is the role of nucleic acid hybridization?
Nucleic acid hybridization is the process of binding two complementary single-stranded nucleic acids to form a double-stranded molecule.
- What is the polymerase chain reaction (PCR)?
PCR is a technique used to amplify specific DNA sequences, making it easier to study and manipulate DNA.
- What are the three steps in each PCR cycle?
Denaturation, Annealing, and Extension.
- How does real-time PCR differ from conventional PCR?
Real-time PCR allows monitoring of DNA amplification in real-time, providing quantitative data during the process.
- What is RNA sequencing (RNA-seq)?
RNA-seq is a method used to analyze and quantify gene expression levels by sequencing the total RNA present in a sample.
- What is the significance of non-coding RNAs (ncRNAs)?
ncRNAs play various roles in gene regulation and cellular processes, despite not encoding proteins.
- What is the function of ribozymes?
Ribozymes are catalytic RNA molecules that can perform enzymatic reactions.
- What is a molecular beacon?
A molecular beacon is a single-stranded DNA or RNA probe that forms a stem-loop structure and emits a fluorescent signal upon binding to its target sequence.
- How are nucleic acids extracted from cells or tissues?
Nucleic acid extraction involves breaking open cells and isolating DNA or RNA using various chemical and physical methods.
- Name a genetic disorder caused by a mutation in the hemoglobin gene.
Sickle cell anemia.
- What is the significance of the Polymerase Chain Reaction (PCR) in forensic DNA analysis?
PCR is used to amplify small DNA samples in forensic DNA analysis, allowing identification and comparison of genetic profiles.
- How do nucleic acids contribute to the development of personalized medicine?
Nucleic acid analysis can help identify genetic variations that affect drug response and guide personalized treatment plans.
- Explain the role of small nuclear RNAs (snRNAs) in gene splicing.
snRNAs are involved in the splicing process, forming a complex known as the spliceosome that removes introns during RNA processing.
- How do retroviruses use reverse transcription in their life cycle?
Retroviruses, like HIV, use reverse transcription to convert their RNA genome into DNA, which is then integrated into the host cell’s genome.
- What is the role of topoisomerases in DNA replication?
Topoisomerases relieve tension in the DNA molecule by cutting and rejoining the DNA strands, preventing tangling during replication.
- What is the difference between DNA methylation and histone acetylation?
DNA methylation involves the addition of a methyl group to DNA bases, while histone acetylation involves the addition of acetyl groups to histone proteins.
- What is the significance of the CRISPR-Cas system in genome editing?
The CRISPR-Cas system provides a precise and efficient way to edit genomes, revolutionizing genetic research and potential medical applications.
- How do researchers use RNA interference (RNAi) as a tool in molecular biology?
RNAi can be used to silence specific genes, allowing researchers to study gene function and identify potential therapeutic targets.
- What is the connection between telomeres and aging?
Telomeres shorten with each cell division, and their length is associated with cellular aging and senescence.
- How does genetic diversity contribute to the survival of a species?
Genetic diversity increases a species’ chances of adapting to changing environments and surviving potential threats.
- Explain the concept of DNA fingerprinting.
DNA fingerprinting is a technique that uses genetic markers to identify individuals uniquely, often used in forensic investigations and paternity testing.
- What are the potential ethical concerns related to gene editing technologies like CRISPR-Cas9?
Ethical concerns include the potential for germline editing, unintended consequences, and the equitable distribution of genetic therapies.
- How are short tandem repeats (STRs) used in DNA profiling?
STRs are regions of DNA with short, repeated sequences, and they are used as genetic markers in DNA profiling and forensics.
- What is a gene knockout, and how is it achieved?
A gene knockout involves disrupting a specific gene’s function in an organism, often achieved using genetic engineering techniques.
- How do miRN
As regulate gene expression?
miRNAs bind to specific mRNA sequences, leading to mRNA degradation or translational inhibition.
- What is the role of reverse transcriptase in retroviruses?
Reverse transcriptase converts the viral RNA genome into DNA, allowing it to integrate into the host cell’s genome.
- How do long non-coding RNAs (lncRNAs) function in gene regulation?
lncRNAs play diverse roles in regulating gene expression, including chromatin modification and transcriptional control.
- How does RNA interference (RNAi) offer potential therapeutic applications?
RNAi can be used to target and silence disease-causing genes, presenting a potential treatment approach for various genetic disorders.
- What is the connection between telomerase and cancer?
Increased telomerase activity in cancer cells allows them to maintain telomere length and evade cellular aging and senescence.
- What are molecular chaperones, and how do they assist in nucleic acid processing?
Molecular chaperones help proteins and nucleic acids fold correctly and assist in various cellular processes, such as DNA replication and RNA splicing.
- What is the role of nucleic acids in the immune system?
Nucleic acids act as immune triggers, activating the body’s immune response against viruses and other pathogens.
- How has our understanding of nucleic acids revolutionized biology and medicine?
The discovery and understanding of nucleic acids have led to significant advances in genetics, genomics, molecular biology, biotechnology, and medicine, impacting various aspects of human life and health.