Genetics

• DNA consits of: Deoxyribose base, nitrgonous base, phosphate group
• The four bases are Adenine (A), Thymine (T), Cytosine (C) and Guanine (G)
• Each DNA strand is made up of nucleotides which consist of deoxyribose sugar, phosphate group and one of the four bases.
• Nucleic acids have two main functions - storage of genetic information and catalysis of chemical reactions.
• Each DNA strand has an antiparallel structure - the two strands run in opposite directions to one another.
• In DNA, there is always an adenine paired with thymine and cytosine paired with guanine.
• Ribonucleic acid (RNA): RNA consists of ribose sugar, nitrogenous base and phosphate groups.
• Ribonucleic acid (RNA): RNA has a single chain structure with ribose instead of deoxyribose. It contains uracil instead of thymine as its complementary base to adenine.
• Ribonucleic acid (RNA): RNA has a single chain with ribose instead of deoxyribose and uracil instead of thymine.
• There are three types of RNA: messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA).
• Messenger RNA carries instructions from DNA to ribosomes where protein synthesis occurs.
• Rna is single stranded
• Transfer rna transfers amino acids to the ribosome during translation.
• Ribosomal rna makes up part of the ribosome which reads mRNA and translates it into proteins.
• DNA replication involves unwinding the double helix, separating the two strands, adding nucleotides to create new strands that match one of the original strands, and joining the nucleotides together using hydrogen bonds between complementary bases.
• During replication, one strand acts as a template for the new complementary strand.
• 1.DNA is used to store genetic information
• RNA is used to transfer genetic information
• •Nucleotides join by condensation to form polynucleotides with phosphodiester bonds
• The complementary base-pairing found in DNA molecules is important during the copying of DNA during mitosis.

  Suggest two reasons why

  it makes sure the DNA copied is identical / without errors / has the same sequence of nucleotides / nucleotides are in the same / correct order / sequence of bases (1) as any change could result in mutations / genetic disorders

  it allows for the forming of hydrogen bonds between the strands / makes sure the strands can bond together correctly (1) to ensure accuracy / stability of DNA replication during mitosis.