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Biology A level - Jaya > Module 8 - Gene technologies > Flashcards

Module 8 - Gene technologies Flashcards

1
Q

What is recombinant DNA?

A

transferring a fragment of DNA from one organism to another

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2
Q

How can transferring fragment DNA be passed to different organisms?

A

The genetic code is universal as well as the transcription and translation being similar allowing proteins to be made

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3
Q

What are the name of organisms that contain the transferred DNA?

A

Transgenic organisms

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4
Q

What are the 3 ways DNA fragments can be obtained?

A

using reverse transcriptase, using restriction endonuclease enzymes and gene machines

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5
Q

Explain the process of using reverse transcriptase to obtain DNA fragments

A
  1. Isolating DNA with free RNA nucleotides and reverse transcriptase to produce complementary RNA (cRNA)
  2. Then this is used to make a double stranded DNA strand
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6
Q

Why is mRNA used in reverse transcriptase to obtain a DNA fragment?

A

It doesn’t contain introns so it is easier to be used as a template

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7
Q

What are the features of a restriction enzymes target site?

A
  • Palindromic (the same forwards as it is backwards)
  • specific which means they have a complementary active site to a specific section of a gene
  • 4-6 DNA bases
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8
Q

Explain simply how restriction enzymes work?

A

A restriction enzyme is isolated with a DNA base sequence and it will bind to a specific area of a DNA base sequence causing it to cut a fragment. This then leaves a sticky end at on the fragment

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9
Q

Why are sticky ends useful?

A

They can be used to bind (anneal) the DNA fragments to another piece of DNA that has a sticky end with complementary base sequences

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10
Q

What is a gene machine?

A

a database containing necessary information has the ability to produce a DNA sequence from scratch

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11
Q

How do gene machines work?

A

The first is fixed to sme support and in a series of reactions, more DNA bases are added to one another using protecting groups. The protecting product is 20 DNA bases making an oligonucleotide. These can then be joined together to form a longer chain

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12
Q

What are protecting groups?

A

Protecting groups are added to chains to prevent the unwanted branching of the nucleotides

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13
Q

What is the difference between in vivo cloning and in vitro cloning?

A

In vivo takes place inside an organism and in vitro takes place outside an organism

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14
Q

Describe the steps involved in the first stage of in vivo amplification - the dna fragment is inserted into a vector

A

The same restriction endonuclease is used to cut open the vector DNA. This is done so that the sticky ends of the vector DNA and the DNA fragment, are complementary. DNA ligase is used to join the complementary sticky ends of the vector and fragment DNA to one another - ligation. This makes recombinant DNA

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15
Q

Describe the second stage of in vivo amplification - the vector transfers the DNA fragment into a host cell

A

If a plasmid vector is used, host cells have to be persuaded to take in the vector which can be done by chloride ions making the membrane more permeable and then a shock of heat forces the vector into the cell. If it is a bacteriophage, then it will inject its DNA into the host cell and the bacterial DNA will take it up. The host cell is now transformed

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16
Q

Describe the third step of in vivo amplification - identifying transformed host cells

A

When the gene is added to the vector, a marker gene can also be added. When the host cell clones, all cells will contain the cloned genes and marker genes. These marker genes allow only the transformed cells containing the marker gene to survive and grow.

17
Q

Examples of marker genes

A

Fluorescent and antibiotic resistance

18
Q

What is the PCR?

A

Polymerase chain reaction is used to make millions of copies of a fragment of DNA in just a few hours

19
Q

What are primers?

A

primers are a short piece of DNA that is complementary to the bases at the start of the fragment

20
Q

Describe briefly how PCR works

A
  1. Reaction mixture containing the DNA sample, free nucleotides, primers and TAQ polymerase is set up
  2. Heated to 95degrees to break H bonds between DNA
  3. cooled to 50degrees so primers bind to strands
  4. heated to 72degrees so that DNA polymerase can work
  5. Free DNA nucleotides bind via complementary base pairing
  6. Tow new copies of DNA is formed, one cycle of PCR done
  7. mixture starts again with strands now
21
Q

What does anneal mean?

A

to bind

22
Q

How is using recombinant DNA beneficial in agriculture?

A

They give higher crop yields, they can gain resistance to pests or weed killers which decreases costs

23
Q

How is recombinant DNA beneficial to industry?

A

Biological catalysts (enzymes) can be made from transformed organisms and are made in large quantities

24
Q

How is recombinant DNA beneficial in medicine?

A

Many drugs and vaccines are made from recombinant DNA. These can be made quickly and cheaply and in large quantities

25
Q

What are the negatives of recombinant DNA technology in agriculture?

A
  • Encourages monoculture
  • GM plants can interbreed with non GM plants
  • Encourages antibiotic resistance in plants
26
Q

What are the negatives of recombinant DNA technology in industry?

A
  • Anti-globalisation activists don’t like globalisation.
  • A few large firms own licenses and patents and therefore the may be more able to grow GM plants
27
Q

What are the negatives of recombinant DNA technology in medicine?

A

Companies who own technologies can limit how much they use it which could be considered unethical

28
Q

What is gene therapy?

A

the treatment of human diseases

29
Q

How does gene therapy work?

A

Defective genes inside a cell are altered. For example, if the genes are made up of wo recessive, then one will be altered to become dominant. If one is dominant then a DNA fragment is inserted in between an original DNA

30
Q

What are the two types of gene therapy?

A
  • Somatic therapy
  • Germ line therapy
31
Q

What is the difference between somatic and germ line therapy?

A

Somatic therapy involves altering normal body cells but these have no impact on egg cells. Germ line therapy involves altering egg cells and preventing the inheritance of that disorder

32
Q

What are the benefits of gene therapy?

A
  • No destruction of bone marrow
  • No donors are required
  • Less chance of rejection because it is own stem cells
33
Q

What are the negatives of gene therapy?

A
  • Faulty red blood cells may still be produced
  • Immune response against genetically modified cells

Biology A level - Jaya (48 decks)

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