Nucleic acids

• What is the structure of nucleic acids?

  • They are made up of monomers called nucleotides
  • Each nucleotide consists of three components:
  • A pentose sugar (ribose or deoxyribose)
  • A phosphate group
  • A nitrogenous base
• What are the two main types of nucleic acids?

  Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)
• What are the three components of a nucleotide?

  1. A pentose or deoxyribose sugar
  2. A phosphate group
  3. A nitrogenous or organic base
• What remains constant in all DNA molecules?

  • The pentose sugar
  • The phosphate group
  • These form the sugar-phosphate backbone
• How many different nucleotides are there within DNA?

  Four
• What are the four different nitrogenous bases in DNA?

  • Adenine (A)
  • Guanine (G)
  • Cytosine (C)
  • Thymine (T)
• Which bases are purines in DNA?

  Adenine and Guanine
• Which bases are pyrimidines in DNA?

  Cytosine and Thymine
• What monomers make up DNA?

  • DNA is made up of nucleotides
  • Each nucleotide is a monomer consisting of a pentose sugar, a phosphate group, and a nitrogenous base
• How are nucleotides linked together in DNA?

  • Nucleotides are linked by condensation reactions
  • These reactions form phosphodiester bonds between the sugar and phosphate groups
  • The order of nucleotides determines genetic variation within a population
• Where is genetic information contained in a cell?

  • In the nucleus
  • Specifically within chromosomes
• What are chromosomes made up of?

  • Deoxyribonucleic acid (DNA)
  • Found in the nucleus
• How do genes contribute to genetic variation?

  Genes determine the characteristics that cause individuals to be different from each other, resulting in genetic variation.
• What are nucleic acids?

  Organic molecules containing carbon, hydrogen, oxygen, nitrogen, and phosphate groups.
• How are nucleotides linked together to form DNA?

  • Nucleotides are linked by condensation reactions
  • This forms a polynucleotide chain
  • DNA is therefore a polymer
• What is the structure of DNA?

  • Consists of two polynucleotide strands linked by hydrogen bonds
  • Complementary base pairing rule:
  • Adenine always pairs with Thymine (A-T)
  • Guanine always pairs with Cytosine (G-C)
  • Strands twist to form a double helix
• According to the complementary base pairing rule, which base always pairs with Adenine in DNA?

  Thymine
• According to the complementary base pairing rule, which base always pairs with Guanine in DNA?

  Cytosine
• What determines the sugar-phosphate backbone in DNA?

  The pentose sugar and the phosphate group form the sugar-phosphate backbone of DNA.
• How does base pairing in DNA maintain genetic stability?

  • A must always pair with T
  • G must always pair with C
  • This ensures each base is present in identical amounts
• How does the sequence of bases in DNA contribute to genetic variation?

  The exact order or sequence of different bases along the polynucleotide chain forms the genetic information stored by the DNA, causing variation between species.
• What is one primary function of DNA?

  Contains coded information in the form of genes.
• How do genes determine the characteristics of an organism?

  Genes determine the code for proteins, which in turn determine the characteristics of the organism.
• What does it mean that the two polynucleotide chains in DNA are anti-parallel?

  The strands run in opposite directions, with one strand running from the 5' end to the 3' end and the other from the 3' end to the 5' end.
• What is the primary structural difference between DNA and RNA?

  RNA is single stranded whereas DNA is double stranded.
• What is the pentose sugar in RNA?

  Ribose
• Name the pyrimidine bases found in RNA.

  Cytosine (C) and Uracil (U)
• What are the three types of RNA?

  1. Messenger RNA (mRNA)
  2. Transfer RNA (tRNA)
  3. Ribosomal RNA (rRNA)
• What is the role of mRNA?

  Messenger RNA (mRNA) is involved in protein synthesis. It is made in the nucleus and moves into the cytoplasm, carrying genetic information from DNA to ribosomes.
• Describe the structure and function of tRNA.

  Transfer RNA (tRNA) is single stranded and clover leaf shaped. It has an anticodon, which is a three-base sequence that codes for a specific amino acid attached to one end. tRNA is involved in protein synthesis by delivering amino acids to ribosomes based on mRNA codons.
• What is the function of rRNA?

  Ribosomal RNA (rRNA) is part of the ribosome, where it helps in protein synthesis by facilitating codon-anticodon recognition and peptide bond formation.
• What are the three components of a nucleotide?

  A pentose sugar, a phosphate group, and a nitrogenous base.
• Name the bases that are classed as pyrimidines in DNA.

  Cytosine (C) and Thymine (T).
• What is the name given to the coiled/twisted structure of DNA?

  Double helix.
• What type of bonds are formed between bases in DNA?

  Hydrogen bonds.
• How many different types of RNA are present in a cell?

  Three.
• Name the monomer of DNA.

  Nucleotide.
• If a sample of DNA has 15% base T, how much G is there?

  35%.
• What is the function of tRNA?

  Transfer RNA (tRNA) delivers amino acids to ribosomes during protein synthesis.
• What are the nitrogenous bases in DNA?

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