Manipulating genomes.

• What is the process of determining the sequence of DNA bases called?

  DNA sequencing
• How have DNA sequencing techniques changed over time?

  They have become automated and faster
• What is a development that has increased the speed of DNA sequencing?

  High-throughput sequencing
• Why are new high-throughput sequencing techniques faster?

  They are automated compared to original methods
• What does high-throughput sequencing enable?

  Whole genomes to be sequenced much faster
• What substances are required in DNA sequencing?

  DNA template, nucleotides, polymerase, primers
• Why does the genome need to be fragmented before sequencing?

  Fewer errors occur with smaller fragments
• How does sequencing allow for genome-wide comparisons?

  It uses computational biology to compare genomes
• How has gene sequencing allowed for predicting amino acid sequences?

  The sequence of bases codes for amino acids
• What is the role of computational biology in gene sequencing?

  To compare genomes and predict phenotypes
• How can gene sequencing help detect disease mutations?

  By comparing genomes of affected and unaffected individuals
• How does gene sequencing identify evolutionary relationships?

  More closely-related species have similar DNA
• What does working out the base sequence of a gene allow?

  Identifying amino acid sequences and protein functions
• How has gene sequencing contributed to synthetic biology?

  It allows for the design of non-natural proteins
• What are DNA probes?

  Short, single-stranded sections of DNA
• Why are DNA probes approximately 20 bases in length?

  Shorter probes may not be specific enough
• How does gel electrophoresis separate DNA fragments?

  Shorter fragments move faster towards the positive electrode
• How can electrophoresis estimate the size of DNA fragments?

  By comparing distances moved to known sizes
• What is needed to visualize DNA bands after electrophoresis?

  Fluorescent or radioactive tag
• Why must proteins be heated before electrophoresis?

  To denature proteins and expose charges
• Why is SDS binding necessary for protein electrophoresis?

  SDS makes all proteins negatively charged
• What is a use of protein electrophoresis?

  Identifying proteins in a blood sample
• How can DNA fragments be amplified?

  Using the polymerase chain reaction (PCR)
• What does the PCR reaction mix need to contain?

  DNA fragment, nucleotides, primers, polymerase
• What are the stages of PCR?

  Denaturation, annealing, extension
• What happens during the denaturation stage of PCR?

  The mixture is heated to break hydrogen bonds
• What occurs during the annealing stage of PCR?

  The temperature allows primers to bind to DNA
• What is the optimum temperature for Taq polymerase in PCR?

  72°C
• What is meant by exponential amplification in PCR?

  DNA quantity doubles with each cycle
• Why is Taq polymerase used in PCR?

  It is thermostable and withstands high temperatures
• Why might the actual number of DNA fragments produced by PCR be lower than expected?

  Primers may fail to anneal or run out
• How many DNA strands are present after 10 cycles of PCR starting with one strand?

  $1024$
• What is an advantage of using PCR in DNA profiling?

  PCR amplifies small DNA samples for analysis
• Why is non-coding DNA used in DNA profiling?

  It contains variable repeating sequences
• What are the steps to produce a DNA profile?

  Collect DNA, amplify, cut, separate, visualize
• Why do individuals of the same species not have unique profiles from coding DNA?

  They have the same genes in coding DNA
• How can DNA profiles be compared?

  By comparing the number, position, and size of bands
• What is a transformed organism?

  An organism with altered DNA from genetic engineering
• What is a transgenic organism?

  An organism carrying DNA from another organism
• What is genetic engineering?

  Isolating and inserting genes into another organism