Chapter 8 - Technology is used to treat diseases Flashcards
What is Biotechnology?
DEFINITION: The use of biological processes to produce useful products.
- Uses CELLULAR PROCESSES to make PRODUCTS that are of use to Humans.
- used to IMPROVE HUMAN WELFARE
What does modern Biotechnology encompass?
What does it improve for human welfare?
- expanded to include genetic testing, gene manipulation, cell replacement therapies including tissue engineering
used to improve human welfare
- Treatment and prevention of disease
- food production
- production of clean energy
- enhanced efficiency of manufacturing processes
What is DNA and where is it found?
WHAT IS DNA’S APPROXIMATE LENGTH?
- Deoxyribose nucleic acid
- usually in NUCLEUS but some found in the MITOCHONDRIA
- in SOME organisms in CYTOSOL
The average length of DNA molecule that makes up a HUMAN CHROMOSOME is 140 MILLION BASE PAIRS.
Explain the Structure of DNA
Made up of 1000s of NUCLEOTIDES
Each nucleotide consists of:
- DEOXYRIBOSE (a 5-carbon sugar)
- PHOSPHATE GROUP
- NITROGENOUS BASE (the base that contains nitrogen atoms)
NUCLEOTIDES are JOINED in such a way that the ALTERNATING SUGARS and PHOSPHATES form 2 CHAINS that are LINKED BY the NITROGENOUS BASES.
- THE BASES FROM 2 STRANDS ARE ATTRACTED TO ONE ANOTHER BY WEAK HYDROGEN BONDS, FORMING A CRISS-CROSS LINK BETWEEN THE 2 STRANDS.
The TWO CHAINS ARE TWISTED INTO A SPIRAL SHAPE KNOWN AS A DOUBLE HELIX.
- ALTERNATING SUGAR PHOSPHATE BACKBONE JOINED VIA COMPLEMENTARY NITROGENOUS BASES WHICH BRANCH OF AT EACH SUGAR MOLECULE
What are the 4 bases?
What is the Base pairing rule?
How are they Joined?
WHY IS THE BASE PAIRING IMPORTANT?
ADENINE (A) THYMINE (T) CYTOSINE (C) GUANINE (G) protein synthesis uracil is changed with T
THEY ARE COMPLEMENTARY
A -T
G-C
THE BASES FROM 2 STRANDS ARE ATTRACTED TO ONE ANOTHER BY WEAK HYDROGEN BONDS, FORMING A CRISS-CROSS LINK BETWEEN THE 2 STRANDS.
THE ORDER IN WHICH THE NITROGEN BASES OCCUR IN THE DNA MOLECULE IS THE GENETIC INFORMATION THAT DETERMINES THE **STRUCTURE OF THE CELL AND THE **WAY IT FUNCTIONS
What is artificial selection or selective breeding?
An ancient form of genetic engineering where humans select desired traits and choose parents bases on these traits.
- increasing the chance of the gene for those phenotypes desired to be passed on to offspring.
- INCREASE/DECREASE INCIDENCE of certain GENES.
Quite slow and INEFFICIENT PROCESS
- Genes are passed on BY CHANCE: probability is increased but not definitive
- necessary to WAIT for the NEXT GEN. to MATURE before KNOWING THE OUTCOME.
What is Genetic Engineering?
also known as RECOMBINANT DNA TECHNOLOGY
DEFINITION: the procedures used to produce recombinant DNA; involve introducing DNA into a cell from a different type of organism or DNA that has been modified in some way.
DNA IS EITHER ADDED OR REMOVED FROM A CELL.
THE DNA PRODUCED IS RECOMBINANT DNA
What is RECOMBINANT DNA?
definition: Synthetic DNA; made by inserting genes from one source into a DNA molecule from a different source.
What is a GENETICALLY MODIFIED ORGANISM (GMO)
An organism produced by genetic engineering
- All transgenic organisms are GMOs, but not all GMOs ARE TRANSGENIC
List some ways in which GMOs can be produced using recombinant DNA technology.
- introducing genes for desired traits into organisms
- using harmless bacteria to produce proteins and replacing faulty genes
What is a TRANSGENIC ORGANISM?
AIM
EXAMPLE
DEFINITION An organism that has had DNA from ANOTHER SPECIES INTRODUCED into it ARTIFICIALLY.
AIM:
- introduce a trait that is not normally present
EXAMPLE
- GOLDEN RICE; developed to address vitamin A deficiency in developing countries
- the deficiency kills 670 000 children under the age of 5 every year
- PRODUCED BY INTRODUCING A GENE FROM MAIZE AND A BACTERIUM FOUND IN SOIL INTO RICE.
- ALLOWS the rice to PRODUCE BETA-CAROTENE, which the HUMAN BODY CAN USE TO SYNTHESISE VITAMIN
Explain the development of recombinant DNA technique
BY STANLEY NORMAN COHEN & HERBERT BOYER IN 1973
technique:
- ISOLATE and AMPLIFY GENES OR DNA SEGMENTS
- INSERT them into a BACTERIAL CELL = TRANSGENIC BACTERIUM
- INTRODUCED GENES become PART of the TRANSGENIC ORGANISM’S DNA
- CAN BE PASSED FROM ONE GEN. TO NEXT.
What is the process for RECOMBINANT DNA TECHNOLOGY TO BE MADE POSSIBLE?
- GENE of the DESIRED TRAIT MUST BE IDENTIFIED
- THEN ISOLATED
- DNA RECEIVING the gene must be ‘OPENED’
- GENE is then ADDED to the RECIPIENT and JOINS ITS DNA.
What are bacteriophages?
OR PHAGES
A VIRUS that INFECTS BACTERIA
What is the key breakthrough in genetic engineering via the use of phages?
- Discovered that certain enzymes in bacteria are able to restrict the duplication of bacteriophages by cutting up viral DNA.
- these enzymes cut the DNA at a point where there is a certain sequence of bases (RECOGNITION SITE/SEQUENCE)
- enzyme that cuts the DNA is a restriction enzyme because it restricts the duplication of bacteriophages.
What is the recognition site?
vs
What is a recognition sequence?
A specific sequence of nucleotides at which an enzyme cuts a strand of DNA
the sequence of bases in the recognition site.
What is ENDONUCLEASE?
An enzyme that breaks a nucleic acid within the strand by separating 2 nucleotides
EXAMPLE OF A RESTRICTION ENZYME
What is a restriction enzyme?
An enzyme that cuts strands of DNA at a specific sequence of nucleotides
- will cut straight or staggered cut
explain straight cut and blunt end
STRAIGHT CUT:
- A cut produced when a restriction enzyme makes a clean break across the 2 strands of DNA so that the ends terminate in a base pair: called blunt ends
BLUNT ENDS:
- the end produced by a straight cut of a sequence of nucleotide bases
- BOTH STRANDS TERMINATE IN A BASE PAIR
explain staggered cut and sticky end
STAGGERED CUT
- A cut produced by when a restriction enzyme creates fragments of DNA with the unpaired nucleotides that overhang at the break in the strands called sticky ends
STICKY ENDS
- the overhanging end produced by a staggering cut of a sequence of nucleotide bases
- sometimes called COHESIVE END
- IS A STRETCH OF UNPAIRED NUCLEOTIDES IN THE DNA MOLECULE THAT OVERHANG AT THE BREAK IN THE STRANDS
what is Palindromic?
A sequence that reads the same backwards and forwards
What are the properties of a Recognition SITE?
And what does this mean?
- are 4-8 BASE PAIRS IN LENGTH
- PALINDROMIC
This along, with the complementary nature of the bases, means that the same sequence occurs on both strands within the recognition site.
HENCE both strands will be cut resulting in the DNA molecule forming 2 segments
Each restriction enzyme will:
- Recognise a certain base sequence
2. cut at a certain point
What contributes to the type of cut?
EXAMPLES
- CERTAIN BASE SEQUENCE
- ENZYME AND ITS CUTTING STYLE
Xmal enzyme and Smal
- same recognition site
5’ - CCCGGG-3’
Xmal cuts between the first and second nucleotides and PRODUCES STICKY ENDS
Smal Cuts between the third and fourth nucleotides and produces BLUNT ENDS