DNA and inheritance (2.3)

• What does DNA stand for?

  Deoxyribose Nucleic Acid
• What is DNA coiled into?

  A double helix
• What is a chromosome?

  A linear arrangement of genes
• What is a gene?

  A short section of DNA
• How many pairs of chromosomes are in the body?

  23
• What are identical pairs of chromosomes called?

  Homologous pairs
• What is an allele?

  Different forms of the same gene
• What is the backbone of DNA made out of?

  Sugar and phosphate
• What does the structure of DNA include?

  Hydrogen bonds, bases, sugar and phosphate
• What are the names of the bases in DNA?

  Adenine, Thymine, Cytosine and Guanine
• What does Adenine pair with?

  Thymine
• What does Cytosine pair with?

  Guanine
• What is a genotype?

  Collection of alleles that determine certain characteristics
• What is a phenotype?

  Visible characteristics of an organisms as a result of its genes
• What is a dominant allele?

  Represented by a capital letter and is always expressed
• What is a recessive allele?

  Represented by a lower case letter and is only expressed if it has 2 copies
• What does homozygous mean?

  Alleles that are identical, e.g FF or ff
• What does heterozygous mean?

  Different alleles from the same gene e.g Ff
• What is the triplet code?

  A code of 3 bases
• What can be determined by the triplet code?

  The sequence of an amino acid in a protein
• What are the male chromosomes?

  XY
• What are the female chromosomes?

  XX
• What do genetic profiles show?

  A pattern of DNA bands that are specific to an individual
• What can genetic profiling determine?

  Paternity, solve crimes
• How do you produce a DNA fingerprint?

  Isolation, fragmentation, separation and comparison
• What does isolation do in genetic profiling?

  Separate the DNA from other tissues
• What does fragmentation do in genetic profiling?

  Uses an enzyme to break DNA into smaller pieces
• What does separation do in genetic profiling?

  Pass an electric current over a layer of gel which has DNA fragments at one end. The fragments will move different distances across the gel, called gel electrophoresis
• What does comparison do in genetic profiling?

  Match the pattern of fragments on the gel with other samples of DNA
• Benefits of DNA profiling

  Can solve crimes, identify disease, reliable, paternity cases
• Limitations of genetic profiling

  Invasion of privacy, expensive
• What is genetic engineering/ modification?

  Changing the genetic material of an organism by giving it a gene from another organism
• Example of how genetic engineering is used

  Crops being created to be herbicide resistant
• How are genes cut in genetic engineering?

  With an enzyme
• Why are organisms grown when their genes are replaced in genetic engineering?

  So that all cells in the organism will contain the gene
• What is a disadvantage of genetic engineering?

  Long term effects are unknown
• Advantages of genetic engineering

  Ability to maximise crop yield, can become resistant to something