DNA Replication
This enzyme unwinds the DNA double helix.
What is helicase?
- Helicase breaks the hydrogen bonds between base pairs, separating the two DNA strands to create the replication fork.
The process of making RNA from DNA.
What is transcription?
- Transcription is the process where RNA polymerase reads the DNA sequence and synthesizes mRNA as a complementary strand.
A mutation where one base is changed but does not affect the amino acid sequence.
What is a silent mutation?
- A silent mutation occurs when a nucleotide change does not alter the amino acid sequence due to the redundancy of the genetic code.
The three-letter sequence in mRNA that codes for an amino acid.
What is a codon?
- A codon is a triplet of nucleotides that specifies a particular amino acid in the genetic code. (ex: AUG - start codon)
The process of removing introns from pre-mRNA.
What is splicing?
- Splicing removes introns and connects exons in eukaryotic mRNA before translation.
The strand that is synthesized continuously.
What is the leading strand?
- The leading strand is synthesized in the same direction as the replication fork in a continuous manner, using DNA polymerase.
The enzyme that synthesizes RNA.
What is RNA polymerase?
- RNA polymerase binds to the promoter and synthesizes mRNA using DNA as a template.
The repair mechanism that removes and replaces a damaged section of DNA caused by UV light.
What is nucleotide-excision repair?
- Nucleotide-excision repair (NER) removes and replaces DNA segments that are damaged by UV radiation, such as thymine dimers.
The ribosomal site where new tRNA molecules enter.
What is the A-site?
- The A-site (aminoacyl site) in the ribosome is where new tRNA molecules bind to match their anticodon with the mRNA codon.
The part of a gene that remains in mature mRNA after splicing.
What is an exon?
- Exons are coding sequences that remain in mature mRNA and are translated into proteins.
Short DNA fragments on the lagging strand.
What are Okazaki fragments?
- The lagging strand is synthesized in small, discontinuous segments known as Okazaki fragments because DNA polymerase can only synthesize in the 5’ to 3’ direction.
The site of translation in the cell.
What is the ribosome?
- Translation occurs in ribosomes, which are responsible for assembling amino acids into proteins based on the mRNA sequence.
A mutation that inserts or deletes nucleotides, changing the reading frame.
What is a frameshift mutation?
- Frameshift mutations occur when nucleotides are added or removed, shifting the entire reading frame and disrupting the codon sequence.
The type of RNA that forms the structural and catalytic parts of the ribosome.
What is rRNA?
- Ribosomal RNA (rRNA) makes up the structure of the ribosome and helps catalyze peptide bond formation during translation.
The sequence that helps ribosomes recognize mRNA in eukaryotes.
What is the 5’ cap?
- The 5' cap protects mRNA and helps ribosomes recognize the transcript for translation.
The enzyme that removes RNA primers and replaces them with DNA.
What is DNA Polymerase I?
- DNA Polymerase I removes RNA primers from the lagging strand and replaces them with DNA nucleotides.
The molecule that carries amino acids to the ribosome.
What is tRNA?
- Transfer RNA (tRNA) carries specific amino acids to the ribosome and matches them with mRNA codons using its anticodon sequence.
The type of repair that corrects replication errors that escaped proofreading.
What is mismatch repair?
- Mismatch repair corrects base-pairing errors made during DNA replication that were not fixed by DNA polymerase proofreading.
The sequence in DNA that signals RNA polymerase to start transcription.
What is the promoter?
- The promoter is a DNA sequence where RNA polymerase binds to initiate transcription.
The repair mechanism that uses a homologous DNA template to fix double-strand breaks.
What is homologous recombination?
- Homologous recombination uses a sister chromatid as a template to accurately repair DNA.
The model of DNA replication where each new strand consists of one old strand and one new strand.
What is semiconservative replication?
- In semiconservative replication, each new DNA molecule retains one original strand and one newly synthesized strand, ensuring accurate copying of genetic material.
The process that converts mRNA into a protein.
What is translation?
- Translation occurs in the ribosome, where mRNA codons are read and tRNA molecules bring the correct amino acids to form a polypeptide chain.
The error-prone repair mechanism that joins broken DNA ends without a homologous template.
What is non-homologous end joining?
- Non-homologous end joining (NHEJ) repairs double-strand breaks in DNA but often results in small insertions or deletions that can cause mutations.
The first amino acid in most newly synthesized eukaryotic proteins.
What is methionine?
- The AUG start codon codes for methionine, which is the first amino acid added in translation.
The process that allows a single gene to produce multiple proteins.
What is alternative splicing?
- Alternative splicing allows different exon combinations to be used, increasing protein diversity.