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Flashcards by Kusum Khatiwada, updated more than 1 year ago
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Created by Ben Goetze
over 9 years ago
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Copied by Kusum Khatiwada
about 8 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 |
| 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 |
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