Chapter 6 - Biotechnology tools + techniques Flashcards

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1
Q

what are the four tools used in biotechnology

A
  • Restriction enzymes
  • DNA ligase
  • DNA polymerase
  • Primers
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2
Q

what are the 4 main techniques used in biotechnology

A
  • DNA sequencing
  • Polymerase Chain Reaction (PCR)
  • Gel electrophoresis
  • Recombinant DNA technology
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3
Q

what is traditional biotechnology

A

involves purposefully selecting organisms with desirable and useful traits for breeding and cultivation

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4
Q

what are restriction enzymes (restriction endonucleases)

A

Enzymes that cut DNA molecules at recognition sites. Two types of cuts: Sticky and blunt ends

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5
Q

what are sticky end cuts

A

One strand has overhanging complementary bases, is specific. Created when a restriction enzyme cuts DNA at different positions on each of the two strands

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6
Q

what are blunt end cuts

A

No overhang, not specific. Created when a restriction enzyme cuts DNA at the same position on both strands

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7
Q

what are recognition sites

A

A specific sequence of DNA at which a restriction enzyme will cut

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8
Q

what is DNA ligase

A

Enzyme used to catalyse the formation of a bond between two pieces of DNA

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9
Q

what is DNA polymerase

A

Enzyme that synthesises new strand of DNA based on a template strand and according to complementary base pair rules

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10
Q

What are primers

A

Short fragments of single stranded DNA or RNA. Assist in the synthesis of new strands of DNA by acting as a signal for the polymerase to begin synthesis

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11
Q

what is a restriction fragment

A

a short fragment of DNA generated when a restriction enzyme cuts a longer DNA sequence

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12
Q

what are the advantages of blunt end cuts

A

Fragments can join with any other blunt end fragment, non specific

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13
Q

what are the advantages of sticky end cuts

A

fragments can join efficiently with a desired fragment that is cut with the same restriction enzyme. Can produce specific products at faster rate, is specific,

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14
Q

how does DNA ligase work

A

by forming a phosphodiester bond between two fragments of DNA. Joins the 3’ hydroxyl end of one nucleotide to the 5’ phosphate end of another nucleotide

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15
Q

How is DNA ligase used on sticky end cuts

A

Two DNA fragments that have been cut with the same enzyme will have identical sticky ends, and thus complementary bases will be exposed. DNA ligase can then be used to recombine these two fragments even if they are from two unrelated organisms

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16
Q

How does DNA ligase work on blunt end cuts

A

Without the complimentary overhangs there is no formation of hydrogen bonds to stabilise the structure, process is less efficient

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17
Q

What biotechnological processes would the techniques of PCR and gel electrophoresis be used

A

DNA sequencing, mapping, profiling and recombinant DNA methods

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18
Q

Annealing

A

In PCR, The process of joining separate strands of DNA together, by joining sticky ends, as a result of hydrogen bond pairing, occurs when temperature is lowered

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19
Q

genome

A

All of the genetic material contained in an organism or cell, includes chromosomes in the nucleus and DNA in mitochondria and chloroplast

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20
Q

Plasmid

A

Extra chromosome or circular DNA molecule that can replicate independently of bacterial chromosome

21
Q

STR

A

Short tandem repeat, a short non-coding region of DNA that is repeated many times in the genome of an organism

22
Q

Vector

A

A vehicle the transports and introduces foreign DNA or genes into host cells where it is then reproduced by the host cell

23
Q

what is PCR used for

A

Method used to rapidly amplify small amounts of DNA​ (needed in crime scenes, only small amounts of DNA may be found​). Need larger amounts of DNA to perform tasks such as gel electrophoresis for DNA profiling​

24
Q

what are the components of PCR

A
  • Template DNA​ (DNA to be copied)
  • Taq polymerase​
  • Buffer solution to maintain pH​ for polymerase
  • Supply of free nucleotides​
  • DNA primers​
  • Thermocyclers (enables rapid temperature changes​)
25
Q

what is Taq polymerase

A
  • A DNA polymerase enzyme used to synthesise new strands of DNA in PCR​
  • Used because of it’s ability to withstand high temperatures without denaturing like most other enzymes​
  • Was first found in bacteria that live in hot springs of temps up to 95C
26
Q

what are the three steps of PCR

A
  • Denaturation​: DNA heated to 95ºC​. Separates the DNA molecule into its two stands by breaking the hydrogen bonds
  • Annealing​: Temp is reduced to 50-60ºC​. DNA primers then attach to the 3 prime end of each DNA strand​. Reduced temperature is necessary to allow base pairing and formation of hydrogen bonds
  • Extension​: Temp raised to 72ºC​. Taq polymerase synthesises in 5’ to 3’ directions on each strand​. Results in two copies of each strand of DNA
  • Repeat: steps continued until the DNA sample as been amplified into sufficient amounts for analysis
27
Q

Gel electrophoresis

A

Technique that separates large molecules (DNA and proteins) according to size and charge, for visualisation and identification purposes

28
Q

micro array

A

A collection of gene probes attached to a solid surface. A gene probe is a specific length of single strand of DNA. Can measure the level of gene expression in a sample of DNA

29
Q

when would a mirco array be used

A

When trying to discern between genes that are desirable and those that are not, e.g. if some individuals are resistant to a disease, they may have a unique gene that scientists would like to locate and analyse

30
Q

DNA sequencing

A

Refers to the methods and technologies used to determine the order of the nucleotide bases (A, T, C, G) in the DNA molecule

31
Q

Why is DNA sequencing useful

A

Knowing the sequences can help determine the genetic code for particular phenotypes. There may be survival benefits in identifying. e.g. Genes that increase drought resistance in plants. has also assisted in determining genetic relatedness and evolutionary links

32
Q

what is the sanger method

A

Manual DNA sequencing done using electrophoresis

33
Q

what are dideoxynucleotides

A

used in the sanger method in addition to normal nucleotide triphosphates found in DNA. Same as nucleotides except the contain a hydrogen group on the 3’ carbon instead of a hydroxyl group. When integrated into a DNA sequence, they prevent the addition of further nucleotides, stopping the elongation of the DNA chain. Occurs because a phosphodiester bond cannot form between the dideoxynucleotide and the next nucleotide and thus the DNA chain is terminated

34
Q

What is NGS

A

Next generation sequencing, an automatic process that finds the order of nucleotides in a strand of DNA. The four nucleotides are labelled with four differently coloured dyes. As electrophoresis proceeds, a laser scans across the bottom of the gel, detecting the different dyes and thus the base sequence. A computer can then automatically analyse the info from the gel to read the base sequence

35
Q

DNA profiling

A

A technique used to identify an individual by comparing an unknown sample of DNA to known profiles. DNA profiling identifies people based on differences In the length of their DNA repeats by using STRs, PCRs and gel electrophoresis

36
Q

what are the five steps of DNA profiling

A
  • Isolating DNA from a somatic cell. A specific fragment is cut at the restriction site using restrictase. ​
  • PCR (Polymerase chain reaction) copies small amounts of DNA.​
  • Fragments are separated based on the length of fragments & number of repeats. Uses gel electrophoresis (smaller fragments have less STR’s and migrate further.)
  • The DNA is visualised under the UV light ​
  • Profiling formed using the DNA unique set of patterns of bands.​
37
Q

Recombinant DNA technology

A

Tools and techniques used to transfer a gene from a cell of a member of one species to the genome of a different species

38
Q

Recombinant DNA

A

DNA that is composed of one or more genes from two different organisms, usually two different species.

39
Q

Transgenic organism (GMO genetically modified organism)

A

An organism that has been modified by incorporating into its genome a piece of foreign DNA

40
Q

example of a GMO

A

A sheep may be transformed with the gene for a blood clotting factor so that this protein is secreted in its milk. This factor can then be harvested from the milk and used to treat people with certain forms of haemophilia

41
Q

summarise the technique used to make a GMO

A
  • PCR is usually used to clone the gene of interest.
  • Plasmid is removed from bacterium.
  • Restriction enzymes are used to cut the plasmid and the DNA fragment containing the gene of interest.
  • The foreign DNA is inserted into the plasmid using enzyme ligase.
  • This creates the recombinant plasmid.
  • The plasmid is reinserted into the bacterium.
  • The bacterium is used to insert the recombinant plasmid into the plant cell in a tissue culture.
  • Plants are generated from the cell clone.
42
Q

disadvantages of GMO crops

A
  • GMO crops could potentially reduce biodiversity in a region by outcompeting with indigenous plant life.
  • Toxins potentially produced by GMO crops could negatively affect certain organisms within the ecosystem.
  • Cross-pollination by GMO crops could also result in herbicide resistant weeds and grasses.
  • GMO’s could cross pollinate with organic non-GMO crops.
  • Pest resistant GMO crops could accelerate the evolution of resistant pest species.
43
Q

what are some desirable traits that inspire scientists to create transgenic organisms

A

Disease resistance, faster growth rate, greater product quality and yield, tolerance to adverse environmental conditions

44
Q

Transgenic Atlantic Salmon

A

AquAdvantage Salmon is capable of growing at double the rate of traditional salmon. A more effective hormone-regulating gene found in Pacific Chinook salmon replaced the hormone regulating gene in Atlantic Salmon which sped the growth of the fish.

45
Q

Golden Rice

A

A bioengineered transgenic rice crop, containing B-carotene. Which is an attempt to solve the issue of vitamin-A deficiency in many poverty stricken countries. Uses the Agrobacterium method. ​

46
Q

what are the three considerations conservation planning to maintain viable gene pools should consider

A
  • Biogeography ​
  • Reproductive behaviour ​
  • Population dynamics
47
Q

Biogeography

A

The study of the distributions of animal and plant species and how distributions relate to the environment and changes over time. If the distribution of a species changes over time, this can help scientist decide whether or not an area needs active protection, restoration or management

48
Q

Reproductive behaviour

A

Behaviour related to the production and care of offspring, including the establishment of mating systems, courtship, sexual behaviour, fertilization, and raising of young​. An understanding of reproductive behaviour works to prevent inbreeding and loss of advantage alleles, gene pool diversity, and reproductive fitness

49
Q

Population dynamics

A

Is the study of the number, gender, age and relatedness of individuals in a population. Population size is directly affected by the number of births, deaths, immigrations and emigrations