Nucleotides and nucleus acids

• What do both DNA and RNA carry?

  Information
• What is the primary function of DNA?

  To hold genetic information
• What role does RNA play in relation to DNA?

  RNA transfers genetic information from DNA to ribosomes
• What are the two types of nucleic acids mentioned?

  DNA and RNA
• What are nucleotides composed of?

  A pentose sugar, a nitrogen-containing organic base, and a phosphate group
• What is the sugar component of DNA nucleotides?

  Deoxyribose
• What is the sugar component of RNA nucleotides?

  Ribose
• How do nucleotides join together?

  By phosphodiester bonds formed in condensation reactions
• What structure does a DNA molecule have?

  A double helix composed of two polynucleotides
• How does RNA differ from DNA in terms of structure?

  RNA is a relatively short single polynucleotide chain
• What is ATP?

  Adenosine triphosphate
• What are the components of ATP?

  Ribose, adenine, and three phosphate groups
• What happens when ATP is hydrolyzed?

  Energy is released to form ADP and a phosphate molecule
• What enzyme catalyzes the hydrolysis of ATP?

  ATP hydrolase
• What can the inorganic phosphate from ATP hydrolysis be used for?

  To phosphorylate other compounds, making them more reactive
• How is ATP produced during photosynthesis and respiration?

  By the condensation of ADP and inorganic phosphate catalyzed by ATP synthase
• What is the purpose of semi-conservative replication of DNA?

  To ensure genetic continuity between generations of cells
• What are the steps of semi-conservative replication of DNA?

  1. The double helix unwinds and hydrogen bonds break using DNA helicase.
  2. Both strands serve as templates for complementary base pairing.
  3. Adjacent nucleotides are joined by phosphodiester bonds using DNA polymerase.
• What is the genetic code composed of?

  Triplets of bases
• What does each triplet of bases code for?

  A particular amino acid
• What is a gene?

  A sequence of bases on a DNA molecule coding for a sequence of amino acids
• What are the non-coding sections of DNA called?

  Introns
• What are the coding regions of DNA called?

  Exons
• What are the features of the genetic code?

  • Non-overlapping: Each triplet is read once and does not share bases.
  • Degenerate: More than one triplet can code for the same amino acid.
• What is a mutation?

  A mistake in the base sequence of DNA
• What are some effects of mutations?

  They can alter the amino acid sequence and protein function
• What is the mutation that causes cystic fibrosis?

  A mutation that leads to the production of sticky mucus
• What is the mutation associated with sickle cell anemia?

  A mutated form of hemoglobin that distorts red blood cells
• What are the two stages of protein synthesis?

  Transcription and translation
• What occurs during transcription?

  • A molecule of mRNA is made in the nucleus.
  • DNA strands separate and one strand serves as a template.
  • RNA polymerase joins free nucleotides to form mRNA.
• What happens to mRNA after transcription?

  It moves out of the nucleus and attaches to a ribosome
• What occurs during translation?

  • mRNA attaches to a ribosome.
  • tRNA collects amino acids and carries them to the ribosome.
  • Amino acids join to form a polypeptide chain until a stop codon is reached.
• What is the role of tRNA in translation?

  To collect amino acids and carry them to the ribosome
• How does tRNA attach to mRNA?

  By complementary base pairing
• What happens to tRNA after it delivers amino acids?

  It detaches from the amino acids
• What signals the end of protein synthesis?

  A stop codon on mRNA