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Description
Flashcards by Ben Goetze, updated more than 1 year ago
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Created by Ben Goetze
over 9 years ago
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| Question | Answer |
| The amount of DNA in a cell doubles before cell division because... | Semi-conservative DNA replication occurs before cell division so both daughter cells carry the full genetic code |
| Binary Fission occurs in | Prokaryotes |
| Binary Fission | The DNA loop replicates and then the cell splits in two. Each resulting cell containing a loop of DNA |
| Order the phases of Mitosis | 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase |
| Prophase | Nuclear Membrane breaks down, chromosomes condense and become visible under a microscope, spindle fibres form |
| Metaphase | Spindle Fibres arrange chromosomes along equator of cell |
| Anaphase | Spindle Fibres cause chromosomes to split at centromere and migrate to poles of cell |
| Telophase | Chromosomes clustered in two sets, one at each pole. Nuclear membrane reforms at each pole. |
| Internal Factors regulating division | Proteins produced by the cell which stimulate mitosis. Often set off by the cell detecting hormones e.g. Human Growth Hormone |
| External Factors regulating division | Nutrients, Cell/Cell Contact, Cell/Environment contact. These stimuli can either inhibit or stimulate cell division depending on factor. e.g High nutrients - Stimulate Low Nutrients - Inhibit |
| Gene Product | A polypeptide - Protein. Examples are MPFs (Mitosis Promoting Factors) that initiate the onset of mitosis. |
| Reasons for growing cells in a laboratory | Research - A supply of cells to experiment on to discover more about cell functioning. Medical - Growing Cells for medical purposes e.g. skin grafting Commercial - Growing plants from tissue samples get ,amy plants with required feature e.g. Flower Colour |
| Dissection | Removal of cells from organism. Enzymes often used to isolate cells in sample |
| Suspension | Placement of Cells in culture medium with required nutrients |
| Cell Culture | Suspension placed in cell culture flask in ideal temperature conditions to stimulate growth and division |
| Uses of Cell Culture | Research - Chemical and Drug testing on cells, using cells instead of animal testing Medicine - Skin Tissue, Anti-body production, Vaccine Production, Tissue for Transplant Agriculture - Rapid production of plants for sale, development of more productive crops |
| The functional Unit of information on the chromosome: | The gene |
| Gene | Sections of DNA on chromosomes that code for particular polypeptides are called genes |
| A gene consists of | A unique sequence of bases that code for a polypeptide or an RNA molecule |
| Amino Acids are coded for by | a sequence of 3 bases or a codon. In fact it is a degenerate code as there is more than one codon for each amino acid |
| The flow of information from DNA to protein | DNA --> RNA --> Protein (Unidirectional in most organisms) |
| Transcription | DNA is unzipped by DNA Helicase, A complimentary strand of mRNA is created from DNA template strand |
| Translation | the mRNA molecule migrates to the ribosome. tRNA anti-codons attached to specific amino acids bond to complimentary mRNA codons and peptide bonds form between adjacent amino acids, forming a Protein. |
| DNA can be extracted from Cells by | disrupting cell and nuclear membranes with detergent and then centrifuging so that DNA settles in a distinct layer |
| Probes | usually a segment of DNA or DNA that carry a code complimentary to a segment of the DESIRED GENE. The probes have a marker attached e.g. Flourescent that show up the location they attach |
| Particular Genes can be selected and removed using probes and restriction enzymes: | DNA is heated, strands part and probes can then bind to a specific gene. Once the gene is located in can be cut from its chromosome using a restriction enzyme. This cuts at a particular base sequence. |
| Bacterial Plasmids | small loops of DNA in the cytoplasm of prokaryotes in addition to their main DNA loop. They can be removed, manipulated and then returned to bacteria. |
| Micro-Injection | A very fine glass tube is used to introduce genes into a cell's nucleus e.g. Transgenic Animals Genes are introduced at the zygote to add genetic features |
| Social Consequences of DNA manipulation: | - Possibility of harm to organism - New gene combinations may have unexpected consequences - Genetically engineered crops can genetically pollute organically grown crops - Herbicide resistant plants have an increased weed potential - Monopolies of biotechnology companies BUT - Increased food production potential - Ability to alleviate genetic disease impacts |
| Sequencing | Working out the order and number of bases on a DNA segment |
| PCR | An artificial form of DNA replication where DNA is heated splitting the hydrogen bonds between bases. This separates the polysaccharide strands so that new ones can form along old, therefore duplicating the DNA. Many cycles of this forms copies of the original sample. |
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