#1
In the DNA double helix, adenine pairs with which other base?
Thymine
ExplanationAdenine pairs with thymine via two hydrogen bonds.
#2
Which enzyme is responsible for 'unzipping' the DNA double helix during replication?
DNA helicase
ExplanationDNA helicase unwinds the double helix during replication.
#3
In the context of DNA, what does the term 'complementary' mean?
Having opposite sequences
ExplanationComplementary DNA strands have base pairs that match A-T and C-G.
#4
Which technique allows the amplification of specific DNA sequences in vitro?
Polymerase chain reaction (PCR)
ExplanationPCR rapidly amplifies DNA sequences in vitro for analysis.
#5
What is the term for the process by which RNA is synthesized from a DNA template?
Transcription
ExplanationTranscription is the synthesis of RNA from a DNA template.
#6
Who is credited with the discovery of the double helix structure of DNA?
James Watson and Francis Crick
ExplanationWatson and Crick elucidated the structure based on X-ray diffraction data.
#7
Which X-ray diffraction photograph provided crucial evidence for the structure of DNA?
Photograph 51
ExplanationPhotograph 51 revealed the helical structure of DNA.
#8
What is the role of RNA primase in DNA replication?
Adds RNA primers to the template strand
ExplanationRNA primase initiates DNA replication by adding RNA primers.
#9
What is the term for the sequence of three nucleotides that codes for a specific amino acid in a protein?
Codon
ExplanationCodons are the basic units of the genetic code, encoding amino acids.
#10
Which nitrogenous base is not found in RNA?
Thymine
ExplanationThymine is replaced by uracil in RNA.
#11
What is the primary function of the enzyme DNA polymerase during replication?
Adds nucleotides to the growing DNA strand
ExplanationDNA polymerase synthesizes new DNA strands by adding nucleotides.
#12
What is the name of the DNA repair mechanism that corrects mismatched base pairs?
Mismatch repair
ExplanationMismatch repair fixes errors like base-pair mismatches during replication.
#13
In eukaryotes, where does transcription take place?
Nucleus
ExplanationTranscription occurs in the nucleus where DNA is located.
#14
Which type of RNA carries amino acids to the ribosome during protein synthesis?
Transfer RNA (tRNA)
ExplanationtRNA transports amino acids to the ribosome during translation.
#15
Which enzyme is responsible for RNA synthesis during transcription?
RNA polymerase
ExplanationRNA polymerase synthesizes RNA from a DNA template during transcription.
#16
What is the name of the scientist who discovered that DNA is the genetic material of the cell?
Oswald Avery
ExplanationAvery demonstrated that DNA, not protein, carries genetic information.
#17
What is the function of DNA polymerase in DNA replication?
Adds nucleotides to the growing DNA strand
ExplanationDNA polymerase synthesizes new DNA strands by adding nucleotides.
#18
Which scientist proposed the model of DNA replication known as the 'semi-conservative model'?
Meselson and Stahl
ExplanationMeselson and Stahl confirmed DNA replication follows a semi-conservative pattern.
#19
Who discovered the enzyme DNA helicase?
Kornberg and Lehman
ExplanationKornberg and Lehman identified and characterized DNA helicase.
#20
What is the function of DNA ligase in DNA replication?
Joins Okazaki fragments
ExplanationDNA ligase seals the nicks between Okazaki fragments.
#21
Who is known for proposing the structure of DNA as a triple helix?
Linus Pauling
ExplanationPauling initially suggested a triple helix model for DNA.
#22
Which scientist discovered the role of telomeres and telomerase in maintaining chromosome stability?
Elizabeth Blackburn
ExplanationBlackburn elucidated the role of telomeres in chromosome stability.
#23
Which scientist first proposed the concept of the central dogma of molecular biology?
Francis Crick
ExplanationCrick proposed the flow of genetic information from DNA to RNA to protein.
#24
What is the significance of the DNA sequence 5'-ATCG-3'?
It is the complementary strand of 3'-TAGC-5'
ExplanationIt forms a complementary strand with the sequence 3'-TAGC-5'.
#25
In the context of genetics, what does the term 'epigenetics' refer to?
Heritable changes in gene expression without altering the DNA sequence
ExplanationEpigenetics involves modifications that regulate gene expression without changing the DNA sequence.