A 1.2 - NUCLEIC ACIDS

• what is genetic material

  store of information that, when copied, can be passed from cell to cell and from parent to offspring
• why is genetic information also able to be called hereditary information

  as genetic material is inherited
• how do all living organisms store genetic material

  as DNA
• DNA full name

  deoxyribonucleic acid
• RNA full name

  ribonucleic acid
• where were nucleic acids first discovered

  in the cell nucleus
• What are nucleic acids?

  large molecules (macromolecules) made from subunits called nucleotides which link to form polymers
• how do viruses store genetic material and how is it controversial

  use RNA which does not fit the theory that genes are made of DNA in all living organisms, however, viruses may not be considered a living thing as they do not reproduce
• what are the 3 components of nucleotides

  sugar, phosphate group, nitrogenous base
• sugar

  has 5 carbon atoms so is a pentose sugar
• phosphate group


  acidic and negatively charged part of nucleic acids
• nitrogenous base


  contains nitrogen and has either one or 2 rings of atoms in its structure
• how are nucleotides linked together into a chain or polymer

  covalent bonds are formed between the phosphate group of one nucleotide and the pentose sugar of the next nucleotide
• how are nucleotides added when produced

  always added to the growing polypeptide in the same way; phosphate of nucleotide being added it linked by a covalent bond to the pentose sugar of the previous nucleotide
• what shape does it make when we link nucleotides together in this way

  series of alternating sugar and phosphate groups, with a chain of carbon, oxygen and phosphorus atoms covalently bonded together
• what does this alternating chain form

  strong sugar phosphate backbone in DNA and RNA which helps conserve the sequence of bases

  
• how many different bases are there in DNA and RNA

  4 different bases
• what do all of the bases contain

  Nitrogen
• What are the 4 bases of DNA?

  adenine, cytosine, guanine, thymine
• what are the 4 bases of RNA

  adenine, cytosine, guanine, uracil
• How is information stored in DNA?

  the sequence of bases determines how information is stored - coded form that is the universal genetic code that is shared by all organism
• What is RNA?

  a single, unbranched polymer of nucleotides which are subunits of a polymer (monomer)
• how many nucleotides are in a molecule of RNA

  unlimited amount but they are always linked in the same way, by a condensation reaction
• what happens during a condensation reaction

  2 molecules are combined to form a single molecule and water is eliminated
• what is DNA composed of

  strands or polymers of nucleotides where the pentose sugar is deoxyribose and the bases are A, C, G, T

  
• each base has it base pairs which are

  adenine pairs with thymine; cytosine pairs with guanine
• what forms between these base pairings in DNA

  hydrogen bonds form between them; 2 bonds form between A and T; 3 bonds form between C and G
• how many strands of nucleotides are there in DNA

  2
• how are these 2 strands arranged

  they are said to be parallel to each other; however, they run in opposite directions so they are said to be antiparallel
• how does the antiparallel structure effect the end of the nucleotide

  one strand will end with phosphate group the other will end with a deoxyribose
• what would happen if both strands started in the same direction

  bases would not be able to form hydrogen bonds
• what shape do DNA molecules generally have

  adopt a helical shape
• what is a helix


  coiled structure that has a constant diameter of 2nm; as DNA has 2 strands it has a double helix
• what is the first difference between DNA and RNA - strands

  there are usually 2 polymers of nucleotides in DNA whereas there is only one in RNA; DNA is double stranded and RNA is single stranded
• what is the second difference between DNA and RNA - bases

  DNA has bases A, C, G, T but RNA has bases A, C, G, U; uracil replaces thymine
• what is the third difference between DNA and RNA - sugar

  sugar in DNA is deoxyribose whereas in RNA it is ribose; deoxyribose has one fewer oxygen atom than ribose

  
• what does complementary base pairings allow


  an exact copy of a DNA molecule to be made in the process called replication
• What happens in DNA replication?

  the two strands of the double helix sperate providing a template for the creation of a new strand
• how are these new strands formed

  formed by adding nucleotides one buy one and linking them together
• what characteristic must each new nucleotide strand have

  must be carrying the base that is complementary to the next base in the template strand thus allowing for identical copies of the parent DNA