Genetics

• What is a species?

  A species is a group of organisms which are so similar that they can interbreed to produce fertile offsprings
• All humans belong to the same species, but we are all not identical. What are differences between organisms known as?

  Variations
• Many characteristics showing variation may be passed on from generation to generation. What is this known as?

  Interbreeding characteristics
• What is an Allele?

  A form of gene
• What is continuous variation?

  Variations shown in characteristics which shows a continuous range between minimum and maximum
• What is discrete variation?

  Characteristics that can easily be separated into distinct categories/groups
• Continuous variation occurs because several different genes influence the same characteristics. Such characteristics are said to be polygenic (inheritance determined by the interaction of genes acting together).
• Examples of continuous variation:

  • Height
  • Hand span
  • Tail length in mice
  • Diameter of a shell
  • Length of a leaf
• Examples of discrete variation:

  • Eye colour
  • Fingerprints
  • Blood groups
  • Ability/inability to tongue roll
  • Attached/detached ear-lobes
• The phenotype refers to the physical expression or appearance of a trait, while genotype refers to the genetic makeup responsible for producing that trait, usually written in symbols e.g. BB, BB, bb.
• Phenotypes are observable traits such as eye color, hair texture, height, etc., while genotypes refer to the specific combination of alleles inherited from parents that determine an individual's phenotype.
• Where can genetic information be found?

  Genetic information can be found in genes, found on chromosomes, found in the nucleus of the cell
• Sex chromosomes:

  • Males = XY
  • Female = XX
• What name is given to sex cells such as eggs and sperm?

  Gametes
• "A female llama and a male camel successfully interbred to produce a baby called Rama. He looks more like a camel but has a long soft fleece. Scientists believe that he will be infertile."

  Select a phrase from the news report which suggests that a llama and a camel might be members of the same species?

  Successfully interbred
• "A female llama and a male camel successfully interbred to produce a baby called Rama. He looks more like a camel but has a long soft fleece. Scientists believe that he will be infertile." What evidence from the news report suggests that a camel and a llama are different species?

  Infertile
• Brown eyes in dominant to blue eyes. The brown eyed gene masks the effect of the blue eyed gene when both forms are present. The blue eyed gene is said to be recessive since it is masked by the brown eyed gene.
• The genotype of an individual determines their phenotype (their physical characteristics).
• Phenotypes are determined by the combination of alleles inherited from parents.
• If both alleles are the same (e.g. BB or bb) we say that the person is homozygous for that gene.

  If both alleles are different (e.g. Bb) we say that the person is heterozygous for that gene.
• Monohybrid Cross

  
• What is the definition of a Monohybrid Cross?

  A genetic cross that shows the inheritance of one characteristic
• True or False:

  Fertilisation is considered a random process

  True
• Give the definition of the term Genetic Engineering

  The process of artificially transfering DNA from one type of organism to another
• Human Growth Hormone

  Medicinal: Used to treat dwarfism and other growth disorders
• Factor VIII

  Medicinal: Used to treat blood clotting disorders
• Golden Rice

  Food: Added vitamins to give the rice higher nutritional value
• Tomatoes

  Food: Longer shelf life (less spoil)
• Advantages and disadvantages of medical genetic engineering:

  Table:

  
• Advantages and disadvantages of food genetic engineering:

  Table:

  
• Stage 1 of Genetic Engineering:

  Identify section on DNA containing required gene.
• Stage 2 of Genetic Engineering:

  Extract required gene from the source chromosome using a special enzyme.
• Stage 3 of Genetic Engineering:

  Plasmid is extracted from the bacterial cell.
• Stage 4 of Genetic Engineering:

  Plasmid is cut open using the same special enzyme from stage 2.
• Stage 5 of Genetic Engineering:

  Required gene is inserted into the plasmid and sealed using a different enzyme.
• Stage 6 of Genetic Engineering:

  Plasmid is inserted into a host (new) bacterial cell.
• Stage 7 of Genetic Engineering:

  Genetically modified bacteria grows and multiplies.
• Stage 8 of Genetic Engineering:

  Extract the protein and purify it.