M6 Ch12 Manipulating genomes

Question 1

What is genome sequencing?

Answer 1

Genome sequencing is info about gene location and provides evidence for evolutionary links between organisms

Question 2

What is genetic engineering?

Answer 2

Genetic engineering involves manipulation of naturally occurring processes and enzymes

Question 3

What are introns?

Answer 3

Introns are non-coding regions of DNA

Question 4

What is satellite DNA?

Answer 4

Satellite DNA (short-tandem repeats) = short sequences within introns repeated many times that appear at the same point in chromosomes

Question 5

What is the human genome project? (HGP)

Answer 5

The Human Genome project = international funded venture to sequence 3 billion bases in 20k+ genes of the human genome - corrections and analyses have been added to results over the years

Question 6

What is DNA profiling?

Answer 6

DNA profiling = producing an image of the patterns in the DNA of an individual - producing patterns assists in identification of individuals and determining family relationships

Question 7

What are the key processes that undergo DNA profiling?

Answer 7

Key DNA profiling processes:
-PCR (polymerase chain reaction) = amplifies the DNA by replication
-Electropheresis = seperates DNA fragments according to mass
-Hybridisation = probes added to identify fragments

Question 8

How to produce a DNA profile?

Answer 8

Producing a DNA profile:
1). Extract DNA
2). Undergo PCR and amplification
3). Digest sample (restriction endonucleases) - cut the strands into small fragments at specific sites
4). Electrophoresis
5). Hybridisation (add DNA probes, RNA complentary binds -> radioactive or fluorescent)

Question 9

What are the uses of DNA profiling?

Answer 9

Uses of DNA profiling:
-Crime scenes - samples
-Child paternity
-Immigration cases that prove/disprove family relationships
-Establish evolutionary relationships

Question 10

What is PCR? (polymerase chain reaction)

Answer 10

PCR = artificial way of DNA replication -> amplifies DNA, primers added, DNA is heated and cooled so it can seperate and bind together

Question 11

Describe the process of PCR. (polymerase-chain reaction)

Answer 11

PCR:
1). DNA sample mixed with DNA nucleotides and DNA polymerase
2).Mixture heated to 95 (denaturation) + bonds between strands break
3). Primers added
4). Temp reduced to 55 (annealing) - primers bind and now double stranded
5). DNA polymerase binding to strands
6). Temp at 72 (optimum for polymerase) adding free nucletotides

Question 12

Why does polymerase not denature in PCR?

Answer 12

Polymerase does not denature because it is extracted from extremophile bacteria -> can cope with high temperature

Question 13

What are the stages of electropheresis/DNA profiling?

Answer 13

Electropheresis stages:
1). cells broken down to release DNA (small amount -> amplifiy with PCR)
2). DNA cut into fragments using restriction endonucleases
3). Fragments seperates on bases of site using gel electropheresis
-Fragments injected into wella and electric current applied along gel

Question 14

Why is gel in electropheresis put into alakaline solution?

Answer 14

Gel is puit into alkali solution to seperate double strands into single ones

Question 15

Results of gel electropheresis/DNA profiling

Answer 15

Results of gel electropheresis/DNA profiling
-DNA negatively charged so it is attracted to positive end of gel
-Shorter DNA fragments move faster than longer fragments
-DNA seperated on basis of size

Question 16

Hybridisation of DNA profiling

Answer 16

Hybridisation = radioactive or fluorescent DNA probes added to DNA fragments on membrane
-Probes bind to complementary strands under pH and temp conditions

Question 17

What is DNA sequencing?

Answer 17

DNA sequencing = the process of determining the precise order of nucleotides within a DNA molecule

Question 18

Stages of DNA sequencing

Answer 18

Stages of DNA sequencing:
1). DNA mixed with primer, DNA polymerase, excess of nucleotides and terminator bases
2). Mixture placed in thermal cycler (96C=seperates strands, 50C=primers anneal to strand)
3). 60C=polymerase builds new strands by adding nucleotides with complementary base to single strand
4). When terminator base added, a strand terminates until all possible chains produced
5). DNA fragments serperated by length in capillary tubes - the fluorescence on terminater bases determine final base of each fragmentq

Question 19

Benefits of DNA profiling

Answer 19

Benefits of DNA profiling:
-Identification of individuals and family relationships
-use in crime scenes
-proving or disproving immigration cases

Question 20

Limitations of DNA profiling

Answer 20

Limitations of DNA profiling:
-Can be too dependent on in comparison to other evidence in crime scenes
-Mistakes can be made as it is done on multiple levels
-Potential contamination of DNA samples from other organisms

Question 21

What is genetic engineering?

Answer 21

Genetic engineering is the manipulation of the genome to achieve a desired outcome
Basic principles= isolating a gene fur a desired characteristic in one organism into another using a suitable vector)

Question 22

What is meant by transgenic?

Answer 22

Transgenic is an organism carries a gene from one organism - often called a genetically modified organism (GMO)

Question 23

Process of genetic engineering

Answer 23

Process of genetic engineering:
1 isolating the desired gene 2. Formation of a recombinant DNA 3. Transforming the vector

Question 24

Isolating the desired menu as the first step of genetic engineering

Answer 24

By restriction endonuclease (DNA profiling) at specific base sequences
Sticky ends = unevenly it DNA where desire gene is easier to insert

Question 25

Formation y recombinant DNA as the second stage of genetic engineering

Answer 25

Formation o recombinant DNA → plasmid combines with dna to form recombinant DNA → used as vectors as they contain marker genes, allowing scientists to see if bacteria has taken Up the plasmid → restriction endonuclease cuts open plasmid so there are complimentary shiny ends no the DNA fragment → DNA lipase forms phosphodester bands between phosphates + sugar

Question 26

Process of transformation y vector in genetic engineering

Answer 26

Transformation = plasmid with recombinant dna transformed into host cell → electroporation =electrical current applied no bacteria → membranes became porous + plasmids moves into the cell

Question 27

What is electroporation?

Answer 27

Electroporation is when an electrical current
Is applied lo bacteria → membranes becomes porous → plasmids into cell → used for genetic engineering

Question 28

How is electroporation used with eukaryotic cells?

Answer 28

Electroporation can also be used toget DNA fragments directly into eukaryotic cells → passes through porous membrane → fuses with nuclear DNA → however, the current potentially damage membrane

Question 29

How is genetic engineering used in prokaryotes?

Answer 29

Prokaryotes = gm prokaryotes produces substances eg hormones such as insulin, and antibiotics

Question 30

How does genetic engineering work with animals?

Answer 30

Gm in animals → membranes are harder to manipulate → but
Animals produce medically important proteins and helps to cure genetic diseases

Question 31

Describe the process of genetic engineering in plants?

Answer 31

Genetic engineering in plants =
1. Cut leaf
2. Expose leaf to bacteria containing weed and antibiotic resistant gene
3. Allow bacteria to deliver genes to leaf cells
4. Wait for gene altered cells to multiply and form clump (callus)
5. Allow callus to sprout shoots and roots
6. Plants transferred to soil where they develop into fully differentiated plants that are resistant

Question 32

DNA sequencing projects

Answer 32

DNA sequencing projects - eg HGP = enables scientists to build a collection of sequenced DNA fragments from organism that is then stored and propagated in microorganisms

Question 33

Benefits of genetically modified microorganisms

Answer 33

Benefits of genetically modified microorganisms:
-developing new medical treatments
-development of gene technology
-medical research

Question 34

Genetic engineering ethical concerns

Answer 34

Genetic engineering ethical concerns:
-Potentiality of disease outebreak is scientist affected/disease outbreak

Question 35

Genetic engineering uses

Answer 35

Genetic engineering uses:
-Produce insulin
-Genetic modification of pathogens -> makes them more resistant -> used in military -> biological warfare

Question 36

GM plants ethics

Answer 36

GM plants ethics:
+ = food security
- = soya - insertion of BT protein poisonous to insects
+/- = herbicide resistence - more used = greater monoculture = susceptibility to disease
+ = medical use
+ = improve nutritional value

Question 37

What is patenting?

Answer 37

Patenting = can’t use GM crops without patent (paying) - people may not afford it, unable to grow seeds for next yields as crops bought can only be used that year they bought it

Question 38

GM animals + ethics

Answer 38

GM animals + ethics:
- = more difficult
+ = disease resistance
+ = dna insertion - faster growth - faster bigger yield
- = animal rights - risk of harm
+ = create human proteins

Question 39

What is somatic cell therapy?

Answer 39

Somatic Cell Therapy:
-Not passed onto future generations
-Needs to be topped up
-Mitosis - original cells with problem replace the new cell - issue passed onto children
-SCT involves altering alleles in target body cells

Question 40

What is germline cell therapy?

Answer 40

Germline cell therapy:
-Healthy alleles inserted into eggs
-Passed onto future genreations
-Illegals in many countries due to human rights - ethical issues - desirable characteristics