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Human Bio Year 12 > Biotechnology 2 > Flashcards

Biotechnology 2 Flashcards

1
Q

Outline what recombinant DNA technology is
What is it used for

A

Modified, synthetic DNA; made by inserting genes from one source into a DNA molecule from a different source (genetically modified/GMO)
-Replacing faulty genes
-Treat cystic fibrosis, diabetes, some cancers.
-Identify mutations
-determine inheritance of hereditary diseases

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2
Q

Define “transgenic organism”

A

Organism which has genetic material from another artificially inserted

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3
Q

Explain what restriction enzymes are and why they are important for the purpose of creating recombinant DNA

A

Restriction enzymes cut strands of DNA at a specific sequence of nucleotides (recognition site)
Found in bacteriophages and restricts duplication - stopping infection of bacterial cells by viruses

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4
Q

Describe what a recognition site is

A

specific sequence of nucleotides at which an enzyme cuts a strand of DNA

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5
Q

How does recombinant DNA technology work

A

1.Gene is isolated + cut using restriction enzyme in a staggered cut
2. isolated plasmid then cut with same restriction enzyme in a staggered cut
3. straight cut=clean break across strands of DNA=blunt end
4. staggered cut=fragment with sticky ends=unpaired nucleotides overhang at break
5. DNA ligase then splice (bind) gene (donor DNA) into the vector (plasmid)
6. virus (containing modified DNA) inserts its base sequence into bacterial cell, which then expresses the inserted human gene
7.bacteria is left to divide and produce clones
8.bacteria now able to produce protein using donor DNA

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6
Q

Outline how a virus can be used as a vector to create recombinant DNA

A

virus (containing modified RNA) inserts its base sequence into host cell, which then expresses the inserted human gene.

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7
Q

What are possible treatments for diabetes using gene therapy

A

Can reprogram alpha to beta cells using vectors
1.Virus containing proteins inserted into the pancreas
2. proteins change gene expression, cause alpha cells to produce insulin
3.new “beta cells” are resistant T-cells attack as are slightly different to regular ones
4. This would not be a lasting ‘cure’ and has been shown to work in mice for 4months

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8
Q

What is gene therapy
What are it’s two types
Limitations?

A

Use of genetic material to treat/prevent disease by identifying faulty genes and inserting healthy ones
limitations: treats single gene disorders as
-tissue hard to access
-requires continual replacement
Exvivo-removes persons own cells, delivers outside of body. Modified cells then return
Invivo-gene delivered directly into person

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9
Q

Describe what a recognition site is

A

A specific sequence of nucleotides at which an enzyme cuts a strand of DNA

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10
Q

Give the function of the enzyme DNA ligase

A

Capable of combining two small component of single strand DNA into one single structure

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11
Q

Define the term “synthetic hormone”
State two ways in which hormones can be artificially made

A

a hormone that has been artificially created
-chemically and using recombinant DNA

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12
Q

How is the functioning bacterial cell that can be used to make synthetic insulin produced

A

Cut out required gene using restriction enzyme
Bacterial plasmid/DNA removed from bacterial cell
Bacterial plasmid/DNA cut with the same restriction enzyme
Gene (for human insulin) inserted into bacterial plasmid/DNA
Recombinant plasmid is inserted into a bacterial cell

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13
Q

How is synthetic thyroxine produced

A

using chemical ingredients
hormone replacement therapy: daily doses of a synthetic form of the thyroid hormone, thyroxine e.g.

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14
Q

Describe the human genome project

A

Collaboration of scientists to determine the order of the bases for all human DNA. Huge impact on disease treatment.

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15
Q

Explain what cell replacement therapy is
using Parkinson’s and Alzheimer’s disease as examples

A

Replacing damaged cells w/stem cells (can differentiate into specialised cells)
potential treatment for neurogenerative disorders like
Park.-replace dying neurons with healthy neuronal tissue from embryos (controversial as unethical)

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16
Q

Distinguish between cystic fibrosis and huntington’s

A

cystic-recessive genetic disorder=short life expectancy

huntingtons-single gene disorder caused by gene mutation

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17
Q

Distinguish between parkinsons and alzheimers

A

parkinsons- slow damage to nerve cells that produce dopamine vital for smooth control of muscles/movement.
symptoms:tremors, shaking, stiffness

alzheimers-changes in brain leading to deposits of protein and loss of connection bwn neurons
symptoms:memory loss, imparied reasoning/judgement

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18
Q

Define tissue engineering

A

to restore healthy tissues/organs for patients and eliminate need for tissue or organ transplants/artificial implants
-reduce risk of rejection as patients own cells used

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19
Q

In what ways can gene therapy be achieved

A

-Replacing mutant gene with healthy
-fixing/inactivating gene
-inserting new gene that will fight disease
-make immune system recognise diseased cells

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20
Q

Describe DNA profiling. How does it occur

A

DNA profile can be created from a small sample of DNA (e.g. from the saliva or a fingerprint on a glass, or very old/damaged DNA)
-From single sample many copies can be produced using a technique called the PCR
-DNA profiles are created using a process called gel electrophoresis

21
Q

What can DNA profiling be used for

A

-individual’s identity/parentage.
-anthropological research
-detecting genetic variations and/or mutations

22
Q

Describe the process of gel electrophoresis

A

Technique table to separate DNA strands based on their lengths.

1.Restriction enzymes cut DNA into smaller lengths separated by gel electrophoresis
2.DNA pieces placed in wells in gel that is immersed in solution of an electrolyte.
3.Electrodes at either end of the gel -negative electrode is closest to the DNA and positive electrode is at the opposite side.
4.when electric current passed through gel, negatively charged DNA moves towards the positive electrode.
5.smaller DNA pieces move faster than larger, so are located further from negative electrode when current is stopped.
6.results in pattern of bands similar the barcodes
-banding pattern is an individual’s DNA profile

23
Q

What is PCR

A

Polymerase chain reaction. Technique focusing specific bit of DNA code to make billions of DNA copies

24
Q

What are the three steps of thermocycling

A

Denaturing: two strands of DNA separate
annealing: short section of DNA=primers are bound to the separated strands
extension/synthesising: short section of DNA extended to make longer strands

25
Q

What occurs during denaturation? Temperature?

A

95 degrees. Breaks hydrogen bonds holding complementary base pairing and the two DNA strands separate

26
Q

What occurs during annealing?
Temperature?

A

Temperature decreased to about 50 degrees. Allows short strands of DNA called primers to bind to complementary end sequences of single DNA strands.

27
Q

What occurs during extension/synthesising?
Temperature?

A

Mimics DNA replication. Activates DNA polymerase which is used to attached complementary nucleotides at the end of paired primers. This extends nucleotide chain and creates new strand of DNA.

28
Q

What are phylogenetic trees. What are there use?

A

Dendrograms. Represent evolutionary relationships derived from a common ancestor.
-base of tree=common ancestor
-branches of tree are organisms arisen from common ancestor
-point of separation=speciation event

29
Q

What are some uses for PCR

A

Detect harmful bacteria
Paternity testing
Identify species
Identify viruses/viral infections
Test for inherited diseases
Amplify small samples of DNA left at crime scenes

30
Q

How did TAQ polymerase improve PCR technique

A

-Allow for heat tolerance in DNA polymerase
-preventing inactivation of polymerase
-Now heat at higher temperature can separate DNA strands therefore increasing efficiency while decreasing waste and cost.

31
Q

How does PCR provide evidence for evolutionary relationships

A

Teeth, bones, hold DNA after organism dies. PCR can help learn about extinct lineages like mastodens

Forensic scientists can use PCR to learn about past relationships i.e. diet and infections

32
Q

What is DNA sequencing? Describe the method

A

Determination of precise order of nucleotides in a sample of DNA
1. Synthetic nucleotide lacking OH group added to growing strand (dideoxy ribonucleotides (ddNTP’s)
2. Synthetic nucleotide stops elongation of sequence because there is no OH group for next nucleotide to attach
3.Happens at each nucleotide sequence creating different lengths of DNA sequence (can be separated using gel electrophoresis)
4.Order of nucleotides can be determined by knowing which base added to length

33
Q

What happens when DNA is formed

A

-sugar molecule loses H atom form hydroxy group
-each nucleotide loses 2x phosphate groups

34
Q

Uses for sanger method of DNA sequencing

A

-identify mutations or to compare DNA from different organisms
(identify inherited disorders like sickle-cell anaemia, cystic fibrosis, some forms of cancer)
-maternity/paternity tests (father/mother dispute)
-compare species in order to track evolutionary changes

35
Q

Describe ethical considerations of genetic information

A

-Autonomy: self determining to be tested/not tested, to know/share information, decide own future independent of genetic information
-Confidentiality: sensitive treatment of genetic information accessed only by authorised access
-Equity: right to fair/equal treatment regardless of genetic information
-Privacy: right to be left alone and make decisions regarding genetic testing and resulting information, independent of others

36
Q

Describe DNA code of organisms and how it differs overtime.

A

All living organisms use same DNA code. New are gained by mutation and lost by natural selection/genetic drift.
DNA code different for different species.
As species change overtime, more difference in DNA

37
Q

How is DNA or protein sequences used as evidence

A

-more similarities in DNA sequence bwn two species=more closely related they are
-more difference in DNA sequence=more distantly related

38
Q

Define comparative genomics

A

comparison of genome sequences of different species, areas of similarities and differences are identified.
Preserved genes and genes supplying different characteristics can then be discovered.

39
Q

Define junk DNA

A

Non-coding regions of DNA (no function or purpose)

40
Q

Define endogenous retroviruses and it’s function

A

Long stretch of non-functional DNA.
-store genetic info as RNA. RNA genome copied into DNA (reverse transcription)
-DNA inserted into on of host cell’s chromosomes

41
Q

How does a retrovirus become endogenous. How will this effect offspring

A

if copied it’s DNA into cell whose chromosome is inherited by next generation
-offspring of infected will have copy of ERV in same location (8% of genome) in specific locations

42
Q

How is ERV evidence for evolution

A

Close relatives, human and chimpanzee, have same ERV inserted into genome of common ancestor, as they both have located in similar chromosomes

43
Q

Define mitochondrial DNA. vs nuclear

A

Minimal DNA found in mitochondria
-small circular molecule
-inherited only from mother
-5-10 in each mitochondria
-code for 37 genes (24 for tRNA) (13 for enzymes in cell resp.)
-has increased rate of mutation than nuclear DNA, proportional to time passed
-closeness in relations depends on similarities in mtDNA

nuclear is linear, code for thousands, from mother and father (chromosomes)

44
Q

How are protein sequences utilised in evidence for evolutionary relationships?

A

linked amino acids in precise sequence
can be compared between two species by viewing amino acids
difference in sequences enables estimate of ranfe of evolution bwn species form common ancestor. increase time=increase number of amino acids different
-animals of same species have identical amino acid sequence

45
Q

Define ubiquitous proteins

A

present proteins in all species that carry out same function

46
Q

What is cytochrome C and it’s function

A

performs step in production of cellular energy
-104 amino acids in humans, 37 found at same position in every sequenced cytochrome C molecules

47
Q

Describe bioinformatics

A

using computer technology to compare genetic sequences (DNA or protein)
-detect mutations

48
Q

What us meant by annotation in bioinformatics

A

identifies location of genes and coding regions of genome
-trace evolution of large number of organisms by measuring change in DNA

Human Bio Year 12 (17 decks)

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