DNA, Processes and Biotechnology Flashcards

8984554058	DNA	a double-stranded helix information molecule containing genetic material that code for production of proteins by the cell	0
8984554061	what the helix strands are held together by	hydrogen bonds between opposing pairs of nitrogen bases	1
8984554066	Nucleotides	basic building blocks of nucleic acids (DNA/RNA) linked together by phosphodiester bonds. consist of 5 carbon sugar, negatively charged phosphate and nitrogenous base	2
8984554074	Semi-conservative replication	1 of 2 strands is conserved from one generation while another strand is new	3
8984554076	DNA helicase	unzips the long molecule of DNA, at the origin, by breaking hydrogen bonds between nucleotides.	4
8984554077	Replication fork	junction between unwound single strands of DNA and the intact double helix and moves along parental DNA strand for continuous unwinding	5
8984554079	DNA primase	shows polymerase where to start by setting primers on the origin. DNA polymerase attaches loose nucleotides from the nucleus with matching base pairs on both separate strands of DNA.	6
8984554081	DNA primase	sets RNA primers on fragments of the lagging strand.	7
8984554082	DNA ligase	seals the nucleotides together to form the bond between 2 pieces of DNA. Nucleotides link together in a 5' 3' direction	8
8984554083	Okazaki fragments	short, newly synthesized DNA fragments that are formed on the lagging template strand and are joined together by ligase.	9
8984554095	Composition of chromosome:	DNA > NUCLEOSOMES > CHROMATIN > LOOPED DOMAINS > METAPHASE CHROMOSOME	10
8984554097	Histone proteins	package the DNA into a compact form to become chromatin and allow DNA to fit into nucleus	11
8984554100	Nucleosome	group of histones with DNA coiled around to form a bead.	12
8984554101	how chromatin is formed	With help of 5th histone, H1, histones coil into fibres called chromatin	13
8984554102	looped domains	loops formed from chromatin fibres	14
8984554103	Homologous chromosomes	a pair of chromosomes that have the same size, shape and genes at same location	15
8984554104	Autosomes	first 22 chromosomes, do not include sex chromosomes	16
8984554105	Heterosome	non-identical chromosomes pairing up at meiosis	17
8984554106	locus	The location of a particular gene	18
9005377483	nucleoid	particular region within the cell where prokaryotic chromosomes are found	19
8984554111	Plasmids	small rings of DNA and may also be present in cytoplasm and commonly encode non-essential genes. they replicate independently to the main chromsoomes and can be easily transferred from one bacterium to another and replictae rapidly	20
8984554114	supercoiling	number of proteins act together to fold and condense the DNA so Prokaryotic chromosomes fit into small areas	21
8984554119	Mrna	carries genetic messages from nucleus to ribosomes	22
8984554120	tRNA	carries amino acids from cytoplasm to ribosomes to match with mRNA codons	23
8984554121	Transcription	Occurs in cell nucleus Generates single stranded RNA molecule The copying of RNA from a section of DNA to code for building a protein	24
8984554127	Non-template strand	has same sequence as mRNA (U not T)	25
8984554132	Methylated cap	added at the 5' end of RNA and used as a recognition signal for ribosomes to bind to the mRNA and prevents degradation of mRNA and provides stability	26
8984554136	Poly-A tail	added on 3' which contains 100-200 adenine nucleotides and provides stability	27
8984554138	RNA splicing	coding regions (exons) are kept and regions not translated (introns) are removed from pre-mRNA	28
8984554139	Translation	Occurs at ribosomes and is The conversion of information in mRNA nucleotides into a sequence of amino acids that bond together to build a protein	29
8984554156	Genetic mutations		30
8984554157	Gene mutations: errors in 1 or more nucleotides in the duplicated DNA sequence		31
8984554158	-	May occur in replication or protein synthesis	32
8984554159	Chromosome mutations: changes in the number or structure of chromosomes and added or deleted sections of chromosomes		33
8984554160	Biotechnology		34
8984554161	The use of living things to make new products or systems		35
8984554162	Genetic engineering - changing the genetic sequence of an organism through human use of biotech techniques		36
8984554163	-	Genetically modified organisms/transgenic organisms	37
8984554164	Cutting DNA		38
8984554165	Done by restriction endonucleases/enzymes		39
8984554166	-	Cut DNA into smaller pieces called restriction fragments	40
8984554167	-	DNA is digested by enzymes	41
8984554168	-	Enzymes only cut specific sits - restriction sites	42
8984554169	-	Restriction enzymes occur naturally in bacteria - cut foreign DNA from invading viruses	43
8984554170		R.enzymes bind to restriction site and cut double stranded DNA and may form overhanging/sticky ends - leaves nucleotides exposed	44
8984554171		Blunt ends - cut has occurred at same position in each strand of DNA and there are no overlapping strands	45
8984554172	Recombining DNA		46
8984554173	Combining 2 samples of DNA by DNA ligase joining different pieces together		47
8984554174	-	Acts by forming a phosphodiester bond between 2 fragments of DNA	48
8984554175	-	Joins 3' end to 5' end	49
8984554176	-	DNA ligase used to recombine 2 DNA fragments that have been cut with same enzyme that generates sticky ends and complementary bases are exposed	50
8984554177	-	E.g. EcoR1 can be used to cut both human DNA and bacterial plasmid DNA, leaving sticky ends that are complementary and increase chance of correct 2 ends coming together	51
8984554178	-	Blunt ends can be joined by ligase	52
8984554179		Sticky ends is more efficient	53
8984554180	Amplifying DNA - polymerase chain reaction (PCR)		54
8984554181	To increase amount of DNA, polymerase chain reaction is used		55
8984554182	PCR needs:		56
8984554183	-	Template	57
8984554184	-	DNA polymerase	58
8984554185	-	Buffer solution - salts and other chemicals that helps polymerase function	59
8984554186	-	Nucleotides	60
8984554187	-	2 primers	61
8984554188		Short sequences of single stranded DNA complementary to nucleotide sequences at either end of copying DNA section	62
8984554189		Act as starting point for polymerase	63
8984554190	3 steps of PCR		64
8984554191	1.	Denaturation ('melting stage') - DNA heated to 95c - breaks hydrogen bonds between bases and causes 2 strands to denature	65
8984554192	2.	Annealing - temperature reduced 50-60c - primers anneal together to complementary sequences on opposite ends of each strand - genomic DNA or PCR products	66
8984554193		Allows base pairing ad formation of hydrogen bonds	67
8984554194	3.	Extension - temp raised 72c (optimum for DNA polymerase) where primers start the new DNA strands to be synthesised by polymerase and available nucleotides	68
8984554195		By end, 2 copies of double stranded DNA	69
8984554196	*the cycle is repeated until enough copies of DNA are obtained to work with		70
8984554197	Gel electrophoresis		71
8984554198	Separates fragments of DNA according to size and shape		72
8984554199	-	Agarose gel is melted and poured into flat mould to cool	73
8984554200	-	Wells are created where negatively charged DNA can be loaded	74
8984554201	-	Gel in tray with buffer solution and positive and negative electrodes are attached at each end of gel	75
8984554202	-	Electric current runs and fragments are repelled from negative to positive electrode	76
8984554203	-	Gel acts as sponge	77
8984554204	To view DNA ethidium bromide or other fluorescent dye is added to gel before it sets		78
8984554205		Dye binds to DNA and glows under ultraviolet light - shows pattern of bands	79
8984554206	Each band on the gel contains millions of pieces of DNA		80
8984554207	-	To determine size of DNA fragments - molecular size markers	81
8984554208	Probing for genes		82
8984554209	Gene probing uses a single strand DNA complementary to a gene of interest to identify, isolate or position gene on a chromosome		83
8984554210	-	Tools called gene probes are used to search for specific regions within the genome	84
8984554211		Either have radioactive tag or fluorescent dye tag - Huntington's	85
8984554212		Natural or nucleotides synthesised	86
8984554213		Used in Huntington's disease	87
8984554214	Uses:		88
8984554215	-	Finding fragment of gene after gel electrophoresis	89
8984554216	-	Identify position of gene on chromosomes	90
8984554217	-	Identify allele of specific gene associated with genetic disease	91
8984554218	-	A gene probe binds to target sequences in DNA	92
8984554219		Specific single length of a single stranded DNA of 20-40 nucleotides or 1000 that is complementary to sequence if DNA from specific gene	93
8984554220	-	DNA is heated to separate strands and expose bases	94
8984554221	-	Single strand probes bind to complementary sequences	95
8984554222	Micro array		96
8984554223	-	Allows thousands of genes to be tested at same time	97
8984554224	-	Arrayed on single microscope slide of glass or a silicon chip	98
8984554225	1.	mRNA of cell is extracted and reverse transcribed to DNA	99
8984554226	2.	copied DNA (cDNA) is labelled with fluorescent marker	100
8984554227	3.	labelled cDNA is hybridised (allowed to bind) with probes	101
8984554228	4.	scanner measures amount of fluorescence - stronger fluorescence = more active gene	102
8984554229	DNA sequencing		103
8984554230	A process of determining the nucleotide sequence of a gene determine genetic basis for particular phenotypes		104
8984554231	-	Help identify individuals with deletion mutations e.g. cystic fibrosis	105
8984554232	-	Identify substitution mutations e.g. sickle cell anaemia	106
8984554233	Manually - gel electrophoresis		107
8984554234	Automatically - automatic DNA sequencer		108
8984554235	Sanger method		109
8984554236	1.	4 nucleotides are labelled with 4 different coloured fluorescent dyes	110
8984554237	2.	Laser scans across gel in gel electrophoresis and detects different dyes and the base sequence	111
8984554238	3.	Computer automatically analyses info from the gel to read base sequence #	112
8984554239	Next generation sequencing is faster and cheaper and uses whole genomic DNA as a template greater efficiency		113