Inheritance + Genetic modification

• Variation


  The differences between individuals of the same species
• Genetic variation


  The differences between individuals caused by the DNA that they have inherited from their parents
• Environmental variation


  Differences between individuals caused by environmental factors (climate, habitat) on an organism's phenotype
• What is a gene?

  A gene is a section of DNA that are instructions for a specific protein
• What is a genome?

  It is all of the DNA of an organism
• How many chromosomes do humans have?

  46 (23 pairs)
• What is DNA?


  It is made of 2 strands colied together in a double helix shape. The 2 strands are linked in the middle by a series of base pairs
• What are the base pairs?


  - Adenine (A)

  - Thymine (T)

  - Cytosine (C)

  - Guanine (G)
• What does adenine always pair with?

  Thymine (T)
• What does thymine always pair with?

  Adenine (A)
• What does cytosine always pair with?


  Guanine (G)
• What does guanine always pair with?

  Cytosine (C)
• Summary of a gene


  A gene is a section of a double-stranded molecule known as a helix. This molecule is found within the nucleus of the cell, contained in thread-like structures called chromosomes. The 2 strands form a double helix linked by a series of paired bases. The base adenine is always linked to the thymine and the base of cytosine is always linked to guanine. Sometimes the genetic material of a cell changes. This is known as a genetic mutation. These changes occur very rarely but their incidence ca be increased by chemicals or ionising.
• What are the base pairs from?


  Triple codes or codons
• What is each codon for?


  A different amino acid
• What do a group of codons make?

  A gene
• What does the gene tell the cell to do?

  It tells it what order to put the amino acids in, the order of the amino acids is specific to each protein
• What is protein synthesis?

  The process of making proteins by using the information present in the DNA
• Why do we need protein synthesis?


  Because DNA can't leave the nucleus but protein synthesis occurs in the cytoplasm by ribosomes
• What is RNA?


  Ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.
• What does mRNA swap?


  The thymine for uracil (U) which is a single strand so you now have ribosomes instead of deoxyribose.
• Transcription


  mRNA is formed form DNA
• Translation


  How protein synthesis occurs from the mRNA
• What does translation need?


  - ERNA

  - Ribosomes

  - Anticodon

  - Amino acids
• ERNA summary


  ERNA contains an anticodon that is complimentary to the codon on the mRNA. This anticodon corresponds to a particular amino acid which is also attached to the tRNA. The mRNA attaches to the ribosome, where the tRNA with the complimentary anticodon matches up, lining up the amino acid. The ribosomes move along the mRNA, the amino acids join together and form a protein.
• Phenotype


  The characteristics that is shown as a result of the genetics you have (eye + hair colour)
• Genotype


  The genes you have for a particular characteristic (TAC CGC GTT AGA)
• Mutation


  A change in DNA that can affect the phenotype by altering the sequences of amino acids in a protein
• What are the 3 possible effects from a mutation?


  - No effect (most common)

  - Slight effect (pos or neg)

  - Large effect (pos or neg)
• What are the causes for a mutation?


  - Gamma rays

  - UV rays

  - X-Rays

  - Chemical (carcinogenic)
• What are the causes that are ionising radiation?


  - Gamma rays

  - UV rays

  - X-Rays
• What is a different version of a gene called?

  An allele
• What does an allele do?


  A gene is what decides you eye colour by the actual part of it that picks the colour is called the allele
• Dominant


  A characteristics that is displayed in your phenotype when 1 allele for it is present
• Recessive


  A characteristic that is displayed in your phenotype when you have both alleles for it
• Which gene is represented with a capital letter?

  The dominant one
• Which gene is represented with a lower case letter?

  The recessive one
• What is a punnet square?


  A chart that shows all the possible combinations of alleles that can result from a genetic cross
• Carrier


  Someone who has an allele for a characteristic but doesn't display it in their phenotype (Bb has the alleles for blue eyes)
• Homozygous


  The genotype is made of 2 of the same alleles (BB or bb)