Recombinant DNA technology - Yr 2

Question 1

Reverse transcriptase

Answer 1

Enzyme which can manufacture DNA from RNA

Question 2

Retrovirus

Answer 2

Eg HIV, a virus containing RNA as genetic material which can replicate by manufacturing complementary DNA.

Question 3

Recombinant DNA Technology (genetic engineering)

Answer 3

Processes by which genes are manipulated, altered or transferred from organism to organism.

Question 4

Recombinant DNA

Answer 4

DNA of two different organisms combined as a result of gene transfer

Question 5

Promoter

Answer 5

Region of DNA required to allow transcription of the gene to take place.

Question 6

Terminator

Answer 6

Region of DNA required to stop transcription at the appropriate point

Question 7

DNA polymerase

Answer 7

An enzyme which manufactures DNA by joining nucleotides (using a complementary strand as a blueprint).
NB it does NOT cause complementary base pairing

Question 8

Restriction endonuclease

Answer 8

An enzyme which recognises and cuts DNA at a specific sequence of bases

Question 9

Gene machine

Answer 9

A method of producing a gene by feeding the desired nucleotide sequence into a computer.

Question 10

Oligonucleotide

Answer 10

Short sequence of DNA

Question 11

Genetically modified organism (GMO)

Answer 11

An organism resulting from gene transfer from one organism to another, which has recombinant DNA

Question 12

Vector

Answer 12

A carrier eg a plasmid or virus

Question 13

Gene transfer/cloning stages

Answer 13

Isolation of DNA; insertion into vector; transformation into host; identification by gene markers; growth/cloning of host cell population

Question 14

Complementary DNA

Answer 14

cDNA made with nucleotides lined up which are complementary to the mRNA template strand

Question 15

Palindromic sequence

Answer 15

nucleic acid sequence on double-stranded DNA or RNA where reading the 5’ to 3’ forward on one strand matches the sequence reading backward 5’ to 3’ on the complementary strand

Question 16

Sticky ends

Answer 16

The sequence of nucleotides exposed following an oblique ‘cut’ by a restriction endonuclease

Question 17

DNA ligase

Answer 17

An enzyme which can join the phosphate-sugar framework of two sections of DNA eg joining sticky ends

Question 18

Transformation

Answer 18

Reintroduction of plasmids back into host bacterial cells, by mixing them in a medium containing Calcium ions to increase their permeability

Question 19

Marker genes

Answer 19

Ways to identify whether a gene has been taken up by a bacterial cell eg using antibiotic resistance, fluorescence or specific enzyme presence.

Question 20

Replica plating

Answer 20

Method to identify bacterial cells with plasmids carrying antibiotic resistance genes by plating on antibiotic-rich medium

Question 21

Polymerase chain reaction

Answer 21

Automated method of in vitro cloning in which fragments of DNA are copied very quickly and many billions of times

Question 22

Primer

Answer 22

A short sequence of nucleotides with a set of bases complementary to those at one end of each of the two DNA fragments

Question 23

Annealing

Answer 23

Joining of the primers to their complementary bases at the end of the DNA fragment

Question 24

Thermocycler

Answer 24

A computer-controlled machine that varies temperatures precisely over a period of time

Question 25

GM crops

Answer 25

Genetically modified crops changed by insertion of gene eg for resistance, over-fast softening of fruit

Question 26

(Atryn) Anti-thrombin

Answer 26

Trade name for world’s first anticoagulant to be made from a genetically modified animal (a goat via its milk)

Question 27

Gene therapy

Answer 27

Using defective gene replacement using genes cloned from healthy individuals

Question 28

Germ-line gene therapy

Answer 28

Therapy involving replacing or supplementing the defective gene in the fertilized egg, so all of the cells in the new organism develop normally. Currently prohibited.

Question 29

Somatic-line gene therapy

Answer 29

Therapy involving targeting the damaged tissue itself, so needs to be repeated periodically as cells die and need replacement.

Question 30

CFTR

Answer 30

Cystic fibrosis trans-membrane-conductance regulator – chloride ion channel protein controls transport of Chloride ions across epithelial membranes.

Question 31

adenovirus

Answer 31

Viruses which infect the respiratory tract, by injecting their DNA into epithelial cells of the lungs, so are useful vectors for gene transfer

Question 32

Gene replacement

Answer 32

Defective gene is replaced with a healthy gene

Question 33

Gene supplementation

Answer 33

One or more copies of the healthy gene (which are dominant alleles) are added alongside the defective gene, so the effect of the defective gene is masked

Question 34

liposome

Answer 34

A lipid molecule wrapped around a gene, used to allow it across the cell-surface membrane

Question 35

SCID

Answer 35

Severe Combined Immunodeficiency- an example of a genetic disorder which can be helped using gene therapy

Question 36

Adenosine deaminase

Answer 36

The enzyme which destroys toxins which would otherwise kills leucocytes (white blood cells). The ADA gene is one which has been treated using gene therapy

Question 37

DNA probe

Answer 37

Short, single stranded length of DNA linked to an easily identifiable label eg radioactive or fluorescent probes

Question 38

DNA hybridisation

Answer 38

Combination of separated DNA strands with the probe, by binding it to the complementary bases on one of the strands.

Question 39

DNA sequencing

Answer 39

Methods to determine the exact sequence in which the nucleotides are lined up in a piece of DNA eg Sanger sequencing

Question 40

Cycle sequencing

Answer 40

A modified automated version of the Sanger method (12000 bases per min). The four deoxynucleotides are fluorescently labelled, polymerisation in a single tube, resulting mixture separated using capillary electrophoresis in a single narrow tube gel, then read by laser beam. Colour sequence is converted to DNA sequence by computer.

Question 41

Gel electrophoresis

Answer 41

Method to separate the radioactively-labelled fragments of DNA after PCR by applying a voltage across a gel matrix, followed by detection using photographic film

Question 42

Restriction mapping

Answer 42

Cutting DNA with a series of different restriction endonucleases (eg HindIII, BamHI, NotI), then separating the fragments. Distance between recognition sites can be discovered by the patterns of fragments produced.

Question 43

Genetic screening

Answer 43

Checking for individuals in a family for a mutant allele eg sickle-cell anaemia

Question 44

Genetic counselling

Answer 44

Advice for people at risk of genetic conditions i.e. when in family history, to discover risk to them and their family of its inheritance

Question 45

Genetic fingerprinting
(genetic profiling)

Answer 45

Technique to determine the genetic identity of an organism eg in forensics, paternity cases, diagnostics, breeding programmes in conservation. It depends on an organism’s genome containing repetitive, non-coding introns, which have core sequences unique to the individual.