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| 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 |
