Mr Dewhurst- manipulating genomes

Question 1

what is a genome

Answer 1

all genetic information of an individual, population or species

Question 2

what is genomics

Answer 2

study of genomes

Question 3

what is gene technology

Answer 3

manipulation of DNA

Question 4

what are autosomes

Answer 4

chromosomes that aren’t sex related

Question 5

what is DNA profiling

Answer 5

producing an image of patterns in non-coding DNA in individuals

Question 6

what is the method of DNA profiling known as

Answer 6

Sanger method

Question 7

what is the uses of genome comparison in terms of pathogens

Answer 7

analyse pathogens genomes to identify the source of infection, antibiotic resistant bacteria, trace spread of pathogens and identify regions of the genome for new drugs to target

Question 8

what are the uses of comparing genomes of mammals

Answer 8

understand evolutionary relationships
accuracy of classification

Question 9

what is synthetic biology

Answer 9

creation of artificial pathways, organisms, devices or redesign natural systems

Question 10

what are 3 examples of synthetic biology

Answer 10

genetic engineering- insulin-producing bacteria
biological systems in industry - immobilised enzymes
new organisms - bacteria

Question 11

what is bioinformatics and examples

Answer 11

software analysis, store of biological data such as databases with all known alleles, amino acid sequences of proteins, structure of proteins

Question 12

what is computational biology and an example

Answer 12

use of computers to study biology - structure models to see effect of mutations on the structure and if this effects the function

Question 13

what is the first stage of DNA profiling- collection and extraction

Answer 13

take sample of blood, body cells hair follicles to extract DNA and then using a technique called PCR can produce enough DNA to profile- amplify

Question 14

what is the second stage of DNA profiling- digestion

Answer 14

strands of DNA are cut into smaller fragments using enzymes called restriction endonucleases - each enzyme makes one cut through each strand of DNA on helix
different enzymes cut a specific nucleotide sequence- lots of different restriction endonucleases

Question 15

what is in the test tube with DNA fragments

Answer 15

primers, terminator bases ( stop DNA synthesis),, DNA polymerase, excess nucleotides

Question 16

what is the third stage of DNA profiling- separation

Answer 16

separating DNA fragments - added into wells of agar plate and add a buffer solution and electrodes - using electrophoresis which uses an electric current to separate fragments as phosphate on fragment ( nucleotide) is negatively charged so attracted to cathode at bottom- shorter strands at bottom- move quicker

Question 17

what is the fourth stage of DNA profiling- hybridisation

Answer 17

hybridisation - fluorescent DNA probes or radioactive labels added to join to complementary sequence by forming hydrogen bonds so fragments are visible

Question 18

what is the last stage of DNA profiling- analysis

Answer 18

seeing evidence- if radioactive labels added first then x-ray images produced, if fluorescent dies added then it is viewed under UV rays
the shorter fragments will be at the bottom

Question 19

what is the purpose of Polymerase chain reaction

Answer 19

to amplify millions of copies of DNA - can be used for paternal testing, crime scenes, identifying new species

Question 20

what is the first stage of PCR

Answer 20

denature DNA by heating machine up to 95* which breaks hydrogen bonds between DNA strands so they separate

Question 21

what is the second stage of PCR

Answer 21

annealing of primers- machine cooled to 55* to allow primers to join which prevents strands joining back together and signals DNA polymerase where to begin replication

Question 22

what is the third stage of PCR

Answer 22

synthesis of DNA- temperature increased to 72* to allow taq polymerase to catalyse the formation of sugar phosphate backbone

Question 23

why is PCR good for crime scenes

Answer 23

often little traces of DNA found so not enough to provide evidence for analysis but can be copies and amplified for analysis

Question 24

what are the 2 principles of genetic engineering

Answer 24

genetically modifying DNA by combining DNA from different organisms to produce recombinant DNA
genes are isolated from one organism and inserted into another organism using a vector

Question 25

what is the summarised process of genetic engineering

Answer 25

1- gene isolated 2- copy of gene placed in vector 3- vector carries gene into recipient cell 4- recipient expresses novel gene ( new gene)

Question 26

what is one way of isolating genes

Answer 26

extract mRNA from cells to show what gene is expressed, reverse transcriptase then copies mRNA back to DNA called cDNA (complementary DNA) so it can be copied into double stranded DNA which codes for original protein

Question 27

what is another way of isolating genes

Answer 27

restriction endonuclease - cut gene staggered leaving some bases unpaired called sticky ends

Question 28

what is it called when sticky ends join together

Answer 28

ligation

Question 29

outline the process of inserting gene into a cell using a plasmid

Answer 29

1- chromosomal DNA of organism A is extracted 2- gene of interest is amplified using PCR A 3- multiple copies of DNA is made from organism A and is cut by restriction endonucleases - exposing complementary bases 4-plasmid is cut using same restriction endonucleases 4- gene is inserted into bacterial plasmid using ligase enzyme - forms phosphodiester bonds between nucleotides 5- plasmid now contains gene from organism A 6- the plasmid is then inserted into organism B

Question 30

what are 2 ways of getting the vector (plasmid) into recipient cell

Answer 30

heat shock- heats host cell from 0-42* in the presence of calcium ions to allow the membrane to become more permeable the CA2+ surrounds DNA to allow it to enter through phospholipid bilayer and foreign DNA enters cell electrical current - makes membrane more porous

Question 31

what are 3 problems that could occur using methods such as heat shock

Answer 31

- not all bacteria plasmids take gene so not all recipient cells have the required gene plasmid re-joined before DNA fragment entered DNA sticks to itself making its own plasmid

Question 32

what is a way of knowing if the recombient DNA is in the cell

Answer 32

add 2 antibiotic resistant genes - insert the plasmid into one gene to disrupt it so it is no longer coding for resistant protein to antibiotic add bacteria to antibiotic that wasn't disrupted, then bacteria onto plate that was disrupted- those ones not present in the bacteria that has been disrupted (antibiotic got rid of bacteria) - shows that the new gene is in bacteria

Question 33

what is transfection

Answer 33

electrofusion- electrical fields help to introduce DNA into cells T1 (recombinant) plasmids - inserted into bacterium called agrobacterium tumefaciens, which infects some plants and naturally inserts its genome into host cell

Question 34

what is somatic cell gene therapy

Answer 34

replacing mutated body cells with healthy body cells.

Question 35

what are the uses of both types of gene therapy

Answer 35

stop disease in embryos, cures conditions/diseases

Question 36

what are 3 methods of getting genes into cells

Answer 36

vector( viral vectors), plasmids , lysosomes

Question 37

why has gene therapy had limited success so far

Answer 37

hard to control where it is inserted so could disrupt other cells causing them to divide uncontrollably- cancer somatic- has to be regularly redone to millions of cells as body cells regenerate hard to get alleles into nucleus without the immune system fighting them as being foreign cells.

Question 38

what is germline cell therapy and some drawbacks

Answer 38

replacement of embryonic mutated cells with healthy ones- last whole lifespan illegal, could be used wrongly- design a baby, embryo cannot consent

Question 39

what are the two types of somatic gene therapy

Answer 39

In vivo – the new gene is inserted via a vector into cells inside the body Ex vivo – the new gene is inserted via a virus vector into the cell outside the body. These cells are then grown in the laboratory and returned to the person by an injection into a vein

Question 40

what are some reasons for genetic engineering of plants and animals

Answer 40

increases yield- more food supply for growing population pharmaceutical substances- treat diseases reduce use of pesticides- increases biodiversity grown in harsh conditions

Question 41

what are some reasons against genetic engineering

Answer 41

private companies will increase the prices that small business cannot afford due to large machinery needed- they get less business further health problems such as allergies- not known long term effects animal cruelty- goes against personal and religious beliefs

Question 42

what are some advantages to germline therapy compared to somatic cell therapy

Answer 42

permanent, doesn't affect only individual can't stop offspring having faulty allele, affects all cells not just body cells.