DNA & RNA

• James Watson and Francis Crick discovered the double helix structure of DNA.
• the molecule that carries genetic information for the development and functioning of an organism

  DNA
• DNA is made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix.
• Adenine is paired with Thymine
• Guanine is paired with Cytosine
• This is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules.

  Replication
• DNA replication is one of the most basic processes that occurs within a cell.
• the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment


  step 1
• While helicase and the initiator protein separate the two polynucleotide chains, primase (red) assembles a primer. This primer permits the next step in the replication process


  step 2
• What separates the two polynucleotide chains?

  helicase and initiator protein
• DNA polymerase wraps itself around that strand, and it attaches new nucleotides to the exposed nitrogenous bases. In this way, the polymerase assembles a new DNA strand on top of the existing one.

  step 3
• The nucleotides that make up the new strand are paired with partner nucleotides in the template strand; because of their molecular structures, A and T nucleotides always pair with one another, and C and G nucleotides always pair with one another. This phenomenon is known as complementary base pairing and it results in the production of two complementary strands of DNA.


  step 4
• A new DNA strand is synthesized. This strand contains nucleotides that are complementary to those in the template sequence.

  step 5
• a molecule that is present in the majority of living organisms and viruses. It is made up of nucleotides, which are ribose sugars attached to nitrogenous bases and phosphate groups.

  RNA
• This helps in the synthesis of proteins in our body. This nucleic acid is responsible for the production of new cells in the human body. It is usually obtained from the DNA molecule.

  RNA
• A nucleic acid present in all living cells that has structural similarities to DNA.

  RNA
• The process by which the information in a strand of DNA is

  copied into a new molecule of messenger RNA (mRNA).

  transcription
• The process of protein synthesis by ribosomes in the cytoplasm or endoplasmic reticulum.

  DNA translation
• Protein synthesis is the process in which cells make proteins. It occurs in

  two stages: transcription and translation.
• DNA


  deoxyribonucleic acid
• RNA


  ribonucleic acid
• Each strand of DNA is made up of sugar deoxyribose and phosphate groups.
• Each sugar surrounding a DNA strand is one of the four bases: adenine (A), cytosine (C), guanine (G), or thymine (T).
• What connects the two strands of DNA?

  chemical bonds
• The sequence of the bases along DNA’s backbone encodes biological information, such as the instructions for making a protein or RNA molecule.
• An RNA molecule has a backbone made of alternating phosphate groups and the sugar ribose, rather than the deoxyribose found in DNA.
• Attached to each sugar of RNA is one of four bases: adenine (A), uracil (U), cytosine (C) or guanine (G).
• What are the different types of RNA that exist in cells?


  messenger RNA (mRNA), ribosomal RNA (rRNA), transfer (tRNA)
• Some RNAs are involved in regulating gene expression.
• Certain viruses use RNA as their genomic material.