Human Bio - Unit 2

• What is the full name of DNA?

  Deoxyribonucleic acid
• What is the primary function of DNA in cells?

  DNA carries genetic information that determines the structure and function of a cell
• Where is most DNA found in a cell?

  In the nucleus
• What is the shape of the DNA molecule?

  Double helix
• What are the components of a nucleotide?

  A nucleotide consists of a sugar, phosphate, and nitrogen base
• Which nitrogen bases are found in DNA?

  Adenine, Thymine, Cytosine, Guanine
• How do the nitrogen bases pair in DNA?

  A pairs with T and C pairs with G
• How many hydrogen bonds join A and T in DNA?

  2 hydrogen bonds
• How many hydrogen bonds join C and G in DNA?

  3 hydrogen bonds
• What forms the 'sides' of the DNA ladder?

  The sides are made of alternating sugar and phosphate molecules
• In which direction do the two strands of DNA run?

  One strand runs from 3’ to 5’ and the other from 5’ to 3’
• How long is the DNA in a cell?

  1. 3 metres
• How wide is DNA?

  Two-millionths of a millimetre
• How many molecules of DNA are in every human cell?

  46 molecules
• What is a nucleosome?

  A nucleosome is formed when DNA wraps around a group of 8 proteins called Histones
• What is chromatin?

  Chromatin is a tangled network formed by coiled DNA around Histones in non-dividing cells
• What happens to chromatin during mitosis?

  Chromatin super-coils to become chromosomes
• What are genes?

  Segments of DNA that code for proteins
• What is the genetic code?

  The base sequence of each gene which codes for one particular protein
• Where is mitochondrial DNA (mtDNA) primarily found?

  In the mitochondria
• How is mtDNA inherited?

  mtDNA is inherited only from the mother through the egg cell
• How many genes does mtDNA contain?

  37 genes
• What is the role of the 13 genes in mtDNA?

  They contain instructions for making enzymes needed in cellular respiration
• What is the process of DNA replication?

  DNA replication is the process where DNA makes exact copies of itself
• What are the three steps of DNA replication?

  Separating the strands, building new strands, and joining the strands back together
• What enzyme is responsible for unzipping the DNA molecule?

  Helicase
• What role do single-strand binding proteins (SSBs) play during DNA replication?

  SSBs temporarily bind to each side and keep them separated
• What is a primer in DNA replication?

  A primer is a short strand of DNA that starts the replication process
• In which direction does DNA polymerase work?

  DNA polymerase works from 5’ to 3’
• What is the leading strand in DNA replication?

  The leading strand runs from 5’ to 3’ and is continuously added onto
• What is the lagging strand in DNA replication?

  The lagging strand runs from 3’ to 5’ and is constructed in fragments
• What enzyme helps to join the strands back together during DNA replication?

  Ligase
• What is semi-conservative replication?

  Semi-conservative replication means each new molecule consists of one old and one new nucleotide strand
• What are proteins made of?

  Amino acids
• How does the sequence of bases in DNA affect protein production?

  The sequence of bases controls the order of amino acids in the protein
• What are the two main stages of protein synthesis?

  Transcription and translation
• Where does transcription occur?

  In the nucleus
• What is the role of RNA polymerase during transcription?

  RNA polymerase reads the template DNA strand and builds a complementary mRNA strand
• What replaces thymine in RNA?

  Uracil
• What is splicing in the context of mRNA processing?

  Splicing is the removal of introns from the mRNA strand