Untitled Quiz

DNA Structure and Replication

• DNA Helicase: Enzyme that unwinds and unzips the double helix by breaking hydrogen bonds between strands.
• Single Stranded Binding Proteins: Stabilize separated DNA strands during replication to prevent reannealing.
• RNA Primase: Synthesizes a short RNA primer for DNA replication initiation on both strands.
• DNA Polymerase: Enzyme that adds new nucleotides to the 3' end of a growing DNA strand.
• Leading Strand: Synthesized continuously toward the replication fork, with nucleotides added to the 3' end.
• Lagging Strand: Synthesized discontinuously away from the replication fork, forming Okazaki fragments.
• Okazaki Fragments: Short segments of DNA on the lagging strand that are joined later.
• DNA Ligase: Enzyme that connects Okazaki fragments, completing the lagging strand.

RNA Composition and Function

• RNA: Single-stranded nucleic acid with a structure similar to DNA but contains ribose and uracil instead of thymine.
• Ribose: Sugar component in RNA, differing from deoxyribose in DNA.
• Nitrogen Bases in RNA: Include adenine, guanine, cytosine, and uracil.

Types of RNA

• Messenger RNA (mRNA): Long strands of RNA that carry genetic information from DNA to the ribosome for protein synthesis.
• Ribosomal RNA (rRNA): Forms the core component of ribosomes, facilitating protein synthesis in the cytoplasm.
• Transfer RNA (tRNA): Smaller RNA molecules that transport amino acids to the ribosome, crucial for assembling proteins.

Transcription Process

• Transcription: DNA unzips, and one strand serves as a template to synthesize mRNA.
• RNA Polymerase: The enzyme responsible for synthesizing RNA from the DNA template during transcription.
• Complementary Nucleotide: Binds to the DNA strand during transcription to form mRNA.
• Introns and Exons: Introns are non-coding sequences removed during RNA processing; exons are the coding sequences that remain in the final mRNA.

mRNA Processing and Translation

• Processed mRNA: Carries the coding sequence for protein synthesis and exits the nucleus into the cytoplasm.
• Protein Synthesis: Instructions encoded in DNA dictate the formation of proteins.
• Amino Acids: There are twenty different amino acids that make up proteins, requiring twenty different codes.
• Codon: A sequence of three bases on mRNA that encodes a specific amino acid.
• Anticodon: A series of three bases on tRNA that base-pairs with the corresponding mRNA codon during translation.
• Ribosome Attachment: The 5' end of mRNA attaches to the ribosome to initiate protein synthesis.