SACE Stage 2 Biology - Cell Division, Protein Synthesis, Genetic Engineering

Ben Goetze
Flashcards by Ben Goetze, updated more than 1 year ago
Ben Goetze
Created by Ben Goetze almost 6 years ago
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A set of flashcards for the SACE Stage 2 Biology topic on Cell Division, Protein Synthesis and Genetic Engineering

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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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