Criado por Lewis Johnson
mais de 7 anos atrás
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Questão | Responda |
Techniques In Biotechnology DNA Sequencing | Description: • This technique determines the order of nucleotides on a DNA strand. • A typical DNA sequence has the correct base pairs matched (A-T AND C-G). • If these bases don’t match then a mutation can occur. • Scientists will use a sequenced genetic disorder (sickle cell anaemia) and match it with someone who “potentially” has this disorder or compares a genetic disease with a “normal” sample. • DNA sequencing is to make a person’s profile (fingerprint) (mapping our genome) Example • Maternity or Paternity tests. They use this test to determine whether the parent’s nucleotides (DNA sequence of bases) match those of the child. |
Techniques In Biotechnology Polymerase Chain Reaction (PCR) | Description: • A DNA profile can be created from a very tiny sample of DNA. • From a single sample many copies can be produced using a technique called the polymerase chain reaction (PCR). • To amplify the sample, you will need to use a PCR machine. Examples: • Amplifying small amounts of DNA into a larger sample. • Used for forensics etc • Used to detect infectious disease at an early stage • DNA profiling. |
Polymerase Chain Reaction (PCR) Process | → Denaturing • Separating complimentary strands of DNA by using heat. • The temperature used is 96 degrees. → Annealing • Adding a primer (small strand of DNA) which binds to the complimentary base sequences. This is replicating the DNA. • DNA strand is heated and cooled (54 degrees) • TAQ polymerase is the enzyme used in PCR. It binds to the primer on the DNA strand which synthesises a new DNA strand / creates a new complementary strand of DNA. • It is used because it is capable of withstanding high temperatures so it will not denature during the process of PCR. → Extension / Elongation • DNA Polymerase makes a copy of DNA by binding to the DNA strand. |
Techniques In Biotechnology DNA Profiling | Description: • To determine someone’s DNA profile, a sample of their DNA is cut at a particular base sequence. • Every person has various lengths of DNA and will produce a different profile (just about everyone has a different fingerprint). • To find out our own DNA profile they will use a technique called electrophoresis which is where they will place a DNA profile onto a bed of gel. • This DNA sample can be in the forms of blood, saliva, skin cells and semen. Examples: • DNA profiling can be used for establishing an individual’s identity (e.g. that of a corpse or in crime investigations), or determining their parentage. • This process is carried out when human biological fluid (blood, semen etc) is found at a crime scene and will then be used as evidence. • It is also used to identify if people carry a mutated gene (early identification) for hereditary disease so there can be early treatment. • Examples of diseases are: cystic fibrosis, Huntington’s disease and sickle cell anaemia. |
DNA Profiling Process of Electrophoresis | 1. A piece of DNA (which is NEGATIVE) is placed at the negative end of a gel bed. 2. An electric current is passed through the gel. 3. The loading wells are Negative and the DNA is negative so they repel each other. 4. The negatively charged DNA strand will move towards the positive end of the gel bed. 5. Negative and Positive charges attract and draw the DNA lengths through the gel. 6. DNA pieces at different lengths travel at different speeds. 7. Small fragments move faster and move further away from the loading wells (closer to the positive end) 8. Large fragments will move at a slower speed and closer to the loading wells. 9. This dragging of DNA lengths through the gel will cause the DNA to form a band. Each band codes for different DNA. |
Techniques In Biotechnology Genetic Probes | Description: • Is a fragment (small piece) of single stranded DNA or RNA. • Labelled with radioactive isotopes or fluorescent markers. • These markers are used to pinpoint the region on a chromosome where a defective gene is located. • It is used to detect alleles for Huntington disease, cystic fibrosis and Duchene muscular dystrophy. Examples: • Used in forensics. • Investigation into suspected outbreaks and the detection of unsuspected transmission. |
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