Comprehensive DNA, RNA, and Genetic Technology Review for Students

Who is considered the father of genetics?

Gregor Mendel

What did Gregor Mendel study to understand heredity?

Pea plant traits

What are the results of Mendel's F1 generation cross of tall and short pea plants?

All tall plants

What was the ratio of tall to short plants in Mendel's F2 generation?

6 tall to 2 short plants

What term did Wilhelm Johanssen coin?

Gene

Who coined the term 'genetics'?

William Bateson

What did Theodore Boveri demonstrate about chromosomes?

They are responsible for sexual identity.

What organism did Thomas Hunt Morgan use to provide evidence that genes are on chromosomes?

Fruit flies

What was the estimated death toll of the 1918 Influenza Pandemic?

50-100 million people worldwide

What secondary infection often developed after influenza, leading to fatalities?

Pneumonia caused by Streptococcus pneumoniae

What are the two strains of bacteria studied by Frederick Griffith?

R strain (non-virulent) and S strain (virulent)

What did Griffith's experiment demonstrate about the R strain?

It could be transformed into the S strain by a chemical substance from dead cells.

Who identified DNA as the transforming principle in Griffith's experiment?

Oswald Avery

What are the two categories of nitrogenous bases in DNA?

Purines (Adenine, Guanine) and Pyrimidines (Cytosine, Thymine)

What type of bond links nucleotides in DNA?

Phosphodiester bonds

What did the Hershey and Chase experiment demonstrate?

DNA, not protein, enters bacterial cells and is responsible for viral replication.

What structural motif in proteins did Linus Pauling discover?

The alpha helix

What did Chargaff's rules state about base composition in DNA?

Adenine equals Thymine (A=T) and Cytosine equals Guanine (C=G).

What model of DNA structure did Watson and Crick propose?

The double helix model

What does the Meselson and Stahl experiment demonstrate about DNA replication?

DNA replication in E. coli is semiconservative.

What is the difference between conservative and semiconservative DNA replication?

Conservative replication keeps the original DNA intact, while semiconservative replication uses one original strand as a template for a new strand.

What are restriction enzymes?

Proteins that recognize specific DNA sequences and cut the DNA to protect bacterial cells from foreign DNA.

Who studied the host-controlled restriction of bacteriophages?

Werner Arber

What is the significance of the transforming principle identified by Avery?

It demonstrated that DNA is the main component of heredity, contrary to the belief that proteins were the hereditary units.

What did Chargaff observe about DNA base composition across different species?

The base composition varies from one species to another but remains consistent within tissues of the same species.

What is the role of the S strain in Griffith's experiment?

It is virulent and causes the death of the mouse.

What is the purpose of gel electrophoresis?

To separate DNA fragments by size, with smaller fragments moving farther than larger ones.

What is a restriction enzyme?

An enzyme that cuts DNA at specific sequences, known as restriction sites.

What is the significance of Dan Nathans and Hamilton Smith in molecular biology?

They created gel electrophoresis, which is essential for analyzing DNA fragments.

What is the typical length of restriction sites recognized by restriction enzymes?

Most restriction sites are 4 to 8 bases in length.

What is an isoschizomer?

Different restriction enzymes that cut at the same sequence but may cut at different locations.

What are sticky ends in DNA cloning?

Single-stranded overhangs created by certain restriction enzymes that facilitate the joining of DNA fragments.

What is the role of DNA ligase in cloning?

It joins DNA fragments together, sealing the nicks in the sugar-phosphate backbone.

What is the function of a cloning vector?

To carry a DNA fragment of interest into a host cell for replication.

What are bacterial plasmids?

Circular, extrachromosomal DNA fragments that can replicate independently and often carry antibiotic resistance genes.

What is transformation in the context of bacterial cloning?

The process of introducing foreign DNA into a bacterial cell.

What is the significance of antibiotic resistance genes in plasmids?

They allow for the selection of bacteria that have successfully taken up the plasmid during cloning.

How does the length of a restriction site affect the frequency of DNA cleavage?

Shorter recognition sequences occur more frequently in random DNA sequences.

What is the purpose of using a DNA ladder in gel electrophoresis?

To measure and compare the sizes of DNA fragments.

What is the original Berg cloning experiment known for?

It demonstrated the possibility of inserting foreign DNA into a plasmid and cloning it.

What is the function of ethidium bromide in gel electrophoresis?

It intercalates with DNA and fluoresces under UV light, allowing visualization of DNA fragments.

What happens if a plasmid is resealed without adding a new fragment?

The plasmid may not carry the desired DNA insert and could revert to its original form.

What is the significance of Sanger sequencing?

It is a method for determining the nucleotide sequence of DNA.

What is the role of alkaline lysis in plasmid DNA preparation?

It helps to break down cell components and isolate plasmid DNA from bacterial cells.

What is the purpose of using NEBcutter V2.0 or SnapGene viewer?

To analyze restriction sites and plan cloning experiments.

What are blunt ends in DNA cloning?

DNA fragments that have no overhangs after being cut by certain restriction enzymes.

What is the significance of the EcoRI restriction enzyme?

It recognizes the sequence GAATTC and cuts between G and A, producing sticky ends.

What is the purpose of using a glycerol buffer in gel electrophoresis?

To keep DNA samples in the wells and prevent them from floating away.

What is the relationship between DNA cleavage frequency and the base composition of DNA?

The frequency of cleavage is influenced by the abundance of the four bases in the DNA sequence.

What is the significance of the pBR322 plasmid?

It is a commonly used plasmid that carries genes for ampicillin and tetracycline resistance.

What does the term 'selectable marker' refer to in cloning?

A gene that allows for the identification of cells that have successfully taken up a plasmid.

What is the outcome of combining fragments from different sources in cloning?

It allows for the creation of recombinant DNA molecules with desired traits.

What is Sanger sequencing?

A method for determining the sequence of bases in a cloned DNA fragment using chain-terminating nucleotides.

What are ddNTPs?

Dideoxynucleotides that terminate DNA chain elongation, allowing for sequencing by stopping the addition of nucleotides.

What role does electrophoresis play in DNA sequencing?

It is used to separate DNA fragments based on size, allowing for the analysis of the sequence.

What is the maximum number of bases expected in a Sanger sequencing reaction?

800-1000 bases.

What is the purpose of a multiple cloning site in a plasmid?

It contains various restriction enzyme sites to facilitate the insertion of DNA fragments.

What is PCR and its significance?

Polymerase Chain Reaction is a technique to amplify DNA, allowing for exponential increases in DNA quantity from minimal starting material.

What are the three main steps of PCR?

Denaturation, annealing, and extension.

What occurs during the denaturation step of PCR?

Double-stranded DNA is melted into single strands at approximately 95 degrees Celsius.

What is the purpose of primers in PCR?

Primers bind to specific sequences on single-stranded DNA to initiate replication.

What is the role of Taq polymerase in PCR?

It is a heat-stable DNA polymerase that synthesizes new DNA strands during the extension phase.

What is the significance of the thermal cycler in PCR?

It rapidly heats and cools samples to facilitate the different stages of PCR cycles.

What is TA cloning?

A method of cloning PCR products that utilizes A overhangs on PCR strands and T overhangs on plasmids.

What are STRs?

Short tandem repeats, which are variable DNA sequences used in forensic analysis to identify individuals.

How does DNA differ from RNA?

DNA is double-stranded and contains deoxyribose, while RNA is single-stranded and contains ribose.

What are the main types of RNA and their functions?

mRNA (messenger RNA), rRNA (ribosomal RNA), tRNA (transfer RNA), snRNA (small nuclear RNA), snoRNA (small nucleolar RNA), miRNA (micro RNA), siRNA (short interfering RNA), and ribozymes (enzymatic RNA).

What is the central dogma of molecular biology?

It describes the flow of genetic information from DNA to RNA to protein.

What was the one gene, one enzyme hypothesis?

A hypothesis stating that each gene encodes a specific enzyme, linking genetics to biochemical function.

What is the significance of the discovery of repeated DNA sequences?

It revealed unique patterns in human genomic DNA that can be used for individual identification.

What is the role of oligonucleotides in PCR?

They serve as primers that bind to the target DNA sequence to initiate amplification.

What is the function of the ThermoPol buffer in PCR?

It provides the necessary salts and magnesium ions for optimal DNA polymerase activity.

What is the expected outcome of PCR after multiple cycles?

An exponential increase in the quantity of the target DNA fragment.

What is the purpose of using fluorescently labeled ddNTPs?

They allow for automated detection of DNA sequences during Sanger sequencing.

What is the significance of the polymerase chain reaction in forensics?

It enables the amplification of DNA from small samples, aiding in criminal investigations.

What is the role of RNA in protein synthesis?

RNA serves as the template for translating genetic information into proteins.

What is the relationship between DNA, genes, and proteins?

Genes are segments of DNA that encode instructions for synthesizing proteins.

What were Francois Jacob and Jacques Monod studying independently?

Jacob studied phage effects on bacteria, while Monod studied enzyme activity regulation.

What are the two cycles of Lambda phage infection?

The lytic cycle, where the phage replicates and lyses the host, and the lysogenic cycle, where the phage genome integrates into the bacterial genome as a prophage.

What is the result of transferring prophage from male lysogenic bacteria to female non-lysogenic bacteria?

It results in phage activation, also known as induction.

What is the significance of erotic induction in bacterial gene regulation?

It suggests that a cytoplasmic factor keeps the prophage silent in lysogenic bacteria.

What does Monod's double growth curve illustrate?

It shows that bacteria exhibit exponential growth when adapting to the presence of lactose due to enzyme adaptation.

What is the role of B-galactosidase?

It cleaves lactose into glucose and galactose, facilitating lactose metabolism.

What is the lac operon?

It is a set of genes responsible for lactose metabolism, with regulation mechanisms involving the lacI repressor.

What does the lacI- mutation do?

It prevents the repressor from inhibiting the lac operon, leading to constitutive expression of the lac genes.

What is the function of IPTG in the context of the lac operon?

IPTG inhibits the lac repressor, resulting in activation of transcription.

What did Jacob speculate about the relationship between DNA and protein synthesis?

He speculated the existence of an unstable RNA intermediate that carries information between DNA and protein.

What is the transcription process?

It involves initiation, elongation, and termination, where RNA polymerase synthesizes RNA from a DNA template.

What are the three types of RNA polymerase in eukaryotes?

RNA Polymerase I transcribes rRNA, RNA Polymerase II transcribes mRNA, and RNA Polymerase III transcribes tRNA and small RNAs.

What is the TATA box?

It is a DNA sequence that is crucial for the binding of transcription factors and RNA polymerase II at the promoter.

What is the role of transcription factors?

They are proteins that help RNA polymerase bind to DNA and initiate transcription.

What is the C-terminal domain (CTD) of RNA polymerase II?

It consists of heptapeptide repeats and is phosphorylated during transcription initiation and elongation.

What is the significance of serine phosphorylation in RNA polymerase II function?

Ser5 phosphorylation is required for initiation, while Ser2 phosphorylation is necessary for promoter clearance and elongation.

What is the 5' cap on mRNA?

It is a methylated guanosine cap that protects mRNA from degradation and is important for translation initiation.

What is the effect of alpha-amanitin on RNA polymerase II?

It is a specific inhibitor that completely inhibits RNA polymerase II without affecting Pol I or Pol III.

What is the purpose of enhancers in gene regulation?

Enhancers increase the likelihood of transcription by interacting with transcription factors and RNA polymerase, even if they are located far from the promoter.

What is the function of SL1 in transcription?

SL1 is a selectivity factor that helps RNA polymerase I bind to the promoter for rRNA transcription.

What happens during the termination phase of transcription?

RNA polymerase dephosphorylates the CTD, leading to the end of transcription.

What is the significance of the PaJaMa experiment?

It provided evidence for the existence of an unstable RNA intermediate in the process of gene expression.

How does chromosomal transfer occur in bacteria?

Bacteria can mate and transfer genetic traits, which can be disrupted experimentally to study gene regulation.