Biotechnology and Applications of Genetics

Question 1

What was the purpose of the Human Genome Project?

Answer 1

to sequence all the nucleotides in the human genome in the hopes we could improve our knowledge and understanding of genetic disorders and subsequently improve diagnosis and treatment

Question 2

What were the aims of the Human Genome Project?

Answer 2

Identify all the genes in the human genome and identify which chromosomes each was on
determine the sequence of the 3 billion base pairs in the DNA
Improve tools for data analysis
Transfer related technology to the private sector
address legal, ethical and social issues of the poject

Question 3

What time of sequencing was used in Human Genome Project? how did it work?

Answer 3

Sanger sequencing was used
it sequences relatively small sections of DNA at a time (usually <1000bps). Process took a long time

Question 4

How quickly can Next Generation Sequences (NGS) sequence an entire genome?

Answer 4

just a few hours

Question 5

What is Next Generation Sequencing (NGS) enable scientists to do?

Answer 5

study variation in the human genome amongst 100,000 people in the UK. CAlled the 100K Genome Project

Question 6

What were the main findings of the Human Genome Project?

Answer 6

20,500 genes in humans (fewer than expected)
more repeated DNA segments than anitcipated
Less than 7% of the families of proteins are specific to vertebrates (emphasises close relationship between all living organisms)

Question 7

How can gene therapy be used to treat genetic disorders?

Answer 7

by inserting functional DNA sequences into cells to counteract the effect of a defective gene

Question 8

How can genetic disease be treated?

Answer 8

by replacing genes or replicating the function of genes using drugs

Question 9

What are the 2 possible methods of replacing defective genes

Answer 9

somatic cell therapy and germ line therapy

Question 10

What is the aim of gene therapy?

Answer 10

treat a genetic disease by replacing defective alleles in a patient with copies of a new DNA sequence

Question 11

What is Duchenne Muscular Dystrophy caused by?

Answer 11

mutation in the dystrophin gene resulting in the failure to produce dystrophin

Question 12

What does the failure to produce dystrophin result in?

Answer 12

severe wasting of the muscles and sufferers are often wheelchair bound

Question 13

What drug has been developed to treat Duchenne Muscular Dystrophy?

Answer 13

disapersen, treats it by introducing a ‘molecular patch’ over the exon with the mutation making the gene readable again

Question 14

What is genomics?

Answer 14

the study of structure, function, evolution and mapping of genomes

Question 15

How should genomics enable healthcare to be improved by?

Answer 15

more accurate diagnosis
better prediction of the effect of the drug
improved design of drugs
new and improved treatments for disease

Question 16

How may Next Generation Sequencing technology change treatments of common diseases?

Answer 16

look at tailoring therapies to individual patients, a patient could have an individual treatment to a common disease

Question 17

What is tissue engineering?

Answer 17

restore, maintain, or improve damaged tissues or whole organs. Artificial skin and cartilage are examples of engineered tissues

Question 18

What is the role of stem cells?

Answer 18

accelerate tissue regeneration, can differentiate to any cell type according to the environment they are put into (e.g. tissue they are engineered in)

Question 19

What are some of the ethical issues with use of stem cells?

Answer 19

obtaining them from embryos and the cloning of human tissues and organs

Question 20

What is PCR?

Answer 20

Polymerase Chain Reaction - Amplifies DNA for analysis

Question 21

What is PCR useful for?

Answer 21

small or degenerate samples, to be able to do lots of tests on one sample

Question 22

What is Gel Electrophoresis?

Answer 22

method of separating DNA fragments according to size

Question 23

Why are DNA fragments attracted to the positive anode in gel electrophoresis?

Answer 23

DNA fragments have a -ve phosphate group so is attracted to +ve anode

Question 24

What is a DNA fingerprint?

Answer 24

unique characteristics of a nucleotide sequence of certain regions in DNA of an individual

Question 25

What regions of DNA show variation for a DNA fingerprint?

Answer 25

introns (non-coding regions), these are individual as exons code for amino acids and proteins that most of the species will need/require

Question 26

In A polymerase chain reaction STRs are amplified what are they? what does it mean?

Answer 26

STRs are Short Tandem Repeats
introns have sequences of nucleotides in which up to 13 bases repeat up to several hundred times

Question 27

How is the STRs Amplified?

Answer 27

by using a primer which is complementary (nucleotides matching/conforming) to the start of the sequence

Question 28

What is a primer?

Answer 28

a strand of DNA about 10 nucleotides long that base pairs with the end of another longer strand, making a double stranded section, to which DNA polymers may attach prior to replication

Question 29

What are the 3 key stages of a Polymerase Chain Reaction?

Answer 29

Denaturing Stage
Annealing stage
Extension stage

Question 30

What happens during the Denaturing stage? (PCR)

Answer 30

Original ‘target’ DNA is heated to 95*C as it breaks hydrogen bonds between nucleotides separating DNA into 2 strands

Question 31

What happens during the annealing stage? (PCR)

Answer 31

Solution is cooled to 55*C, cool enough for primers to anneal to the complimentary base sequence on each of the single strands of DNA

Question 32

What happens during the extension stage? (PCR)

Answer 32

Solution heated to 70*C and taq polymerase catalyses the synthesis of a complimentary strand by adding complimentary nucleotides and catalysing the formation of phosphodiester bonds in the sugar-phosphate backbone. This is elongation for extension phase. For each initial fragment of double stranded DNA, two identical strands are produced

Question 33

Why is a buffer used in a PCR?

Answer 33

to keep the pH the same

Question 34

In Gel Electrophoresis what are the DNA fragments?

Answer 34

different sizes

Question 35

What is Agarose?

Answer 35

Agar with pores in the matrix

Question 36

What anode are DNA fragments attracted to in gel electrophoresis? why?

Answer 36

DNA fragments contain a negative phosphate group which is attracted to positive anode

Question 37

During gel electrophoresis how are DNA fragments organised?

Answer 37

the shorter fragments move further, and longer fragments not as far

Question 38

With the organisation of DNA fragments what pattern do they form?

Answer 38

banding occurs

Question 39

What is the product of gel electrophoresis?

Answer 39

Genetic fingerprint

Question 40

Why do individuals have a different genetic fingerprint?

Answer 40

different DNA profiles due to introns which are non-coding parts of DNA
introns contain repeats the number of repeats produces variation

Question 41

What are arguments pro screening of embryos?

Answer 41

preparation
prepare for possibly unhappy treatment
less stress
parents can educate themselves if child will suffer from disease
abortion??

Question 42

What are arguments against screening of embryos?

Answer 42

dangerous - taking sample from embryo in development
carrier of known issue may be discriminated against
abortion - sanctity of life
may interrupt to much with reproduction - may result in attempt to get the ‘perfect’ baby
can be an invasion of privacy

Question 43

What are arguments for genetically modifying crops?

Answer 43

higher yield (increasing food supply)
superior keeping qualities
substantial reduction in pesticide use on crops engineered for resistance to fungal pathogens and insect attack
improved nutritional quality of food
Pharming production of pharmalogical molecules in gm crops - plants have been modified to make antibodies, blood products, hormones, recombinant enzymes, and human + veterinary vaccines

Question 44

What are arguments against Genetically Modifying crops?

Answer 44

environmental risks like cross pollination and the development pf resistant super weeds
outcompeting wild species resulting in biodiversity loss
interrupting ‘natures arms race’
may pass on problem of antibiotic resistance

Question 45

What are current issues with malaria transmission?

Answer 45

evolution of insecticide resistance
malarial parasite developed multi-drug resistance

Question 46

How can development of chemicals that counter insecticide resistance or multi-drug resistance be done?

Answer 46

Sequencing of the genome of the organisms

Question 47

What is process of recombinant DNA formation + use?

Answer 47

removing gene from human cell and removing plasmid from bacteria
insert gene into plasmid
plasmid back into another bacteria to allow for reproduction of useful bacteria cells

Question 48

What is a plasmid?

Answer 48

circular DNA found in bacteria - carry a gene for a specific environment (adaptation)

Question 49

What is an oncogene?

Answer 49

mutated gene that could cause a cell to become cancerous

Question 50

What is restriction endonuclease?

Answer 50

enzyme, cut off ends of nucleotides (section of DNA)

Question 51

What is DNA ligase?

Answer 51

enzyme rejoins DNA (for chosen gene in recombinant DNA)

Question 52

How are sticky ends formed? (DNA)

Answer 52

removal of primers so they will be inserted in the correct place on plasmid

Question 53

What is Reverse transcriptase?

Answer 53

coding of DNA from mRNA

Question 54

What is the function of DNA polymerase?

Answer 54

extends the DNA strand forming backbone

Question 55

What is the issue with plasmids used in recombinant DNA?

Answer 55

can carry antibiotic resistant which if they transferred after cultured may result in antibiotic resistant harmful bacteria
could also mutate our own cells to become oncogenes through the cutting out process