Key questions

• Describe Prokaryotic DNA​ Short

  Circular not associated with histone proteins​
• Describe Eukaryotic DNA​ Long

  Linear   associated with histone proteins​
• Name two organelles other than the nucleus that have DNA.​ Mitochondria and chloroplasts​
• Describe the DNA found in Mitochondria.​ Short

  Circular not associated with histone proteins​
• What is a gene?​ It is a base sequence of DNA that codes for a polypeptide or functional RNA​
• What is the position of a gene on a chromosome called?​ Locus​
• Most amino acids are coded for by more than one triplet code. What name is given to this?​ Degenerate code​
• The DNA code is described as non overlapping. What does this mean?​ The bases are read in triplets and then the next three triplets are read​
• The DNA code is described as universal. What does this mean?​ The triplet code codes for the same amino acid in all organisms​
• What is meant by the term Exon ?​ A sequence of DNA that codes for a polypeptide​
• What is meant by the term intron?​ A non-coding sequence that is found within a gene​
• What is a histone?​ Circular proteins that combined with DNA to make a chromosome​
• Cell division occurs in two main stages

  what are they?​ Nuclear division and cytokinesis​
• What is nuclear division?​ A process by which the nucleus divides​
• What is cytokinesis?​ A process by which the whole cell divides​
• What are the four types of nucleotide in DNA?​ Adenine

  guanine cytosine and thymine​
• What is the job of DNA helicase?​ To break the hydrogen bonds between opposing nucleotides​
• What is the job of DNA polymerase?​ Joins adjacent nucleotide together forming phosphodiester bonds​
• How many hydrogen bonds are found between A and T?​ 2​
• How many hydrogen bonds are found between C and G?​ 3​
• Draw and label nucleotide.​ ​
• What does DNA stand for?​ Deoxyribonucleic acid​
• What sugar is found in DNA?​ Deoxyribose​
• Which nucleotide binds to cytosine?​ Guanine​
• Which nucleotide binds to guanine?​ Cytosine​
• In DNA

  which nucleotide binds to adenine?​ Thymine ​
• Which nucleotide binds to thymine?​ Adenine​
• What is complementary base pairing?​ Occurs in DNA when Adenine always pairs with Thymine

  and Cytosine always pairs with Guanine​
• What bond joins adjacent nucleotides?​ Phosphodiester​
• Name the part of the DNA nucleotide that contains nitrogen.​ The base​
• What is an isotope?​ When an atom can have different atomic masses or when a molecule has the same molecular formula

  but a different structure. ​
• State the two types of cell division​ Mitosis and meiosis​
• What is mitosis?​ Cell division which produces two daughter cells which have the same number of chromosomes as the parent cell

  both are genetically identical.​
• What is meiosis?​ Cell division which produces four daughter cells each with half the number of chromosomes as the parent’s cell and are all genetically different.​
• What is meant by the term gene mutation? ​ A change in the order or number of nucleotides in a gene​
• What joins two chromatids together in a chromosome?​ Centromere​
• What occurs during interphase of mitosis?​ The cell carries out normal cellular activity including G1

  S G2 phase​
• What occurs during G1 phase​ The cell grows to its normal size after the previous division​
• What occurs during S phase​ The cell undergoes DNA replication​
• What occurs during G2 phase​ The cell produces new organelles specific for division​