terms.docx

Tissue culture: - a technique of growing cells, organs or tissues in the laboratory in vitro - examining a section of tissue "growing artificially in the lab"= - grown under controlled physical conditions like sterility, light, pH, temperature, nutrients, humidity, etc. "nutrient...

Tissue culture: - a technique of growing cells, organs or tissues in the laboratory in vitro - examining a section of tissue "growing artificially in the lab"= - grown under controlled physical conditions like sterility, light, pH, temperature, nutrients, humidity, etc. "nutrient rich medium"= - rich in specific nutrients for specific growth of specific tissue, cell or organ (not the whole plant) culture: - growing micro-organisms, tissues, cells or organs on a medium culture medium/growth medium: - any substance that has been used to support the growth of a tissue, cell or organ in a medium - how do we decide which form of medium we need to use? - the medium differs based on what we intend to grow and how we intend to grow it - it could be in a solid, liquid or even semi solid form - it depends on the objective of your experiment - typically if you want to isolate or extract DNA from bacterial cells you use liquid media - similarly if you want to grow growth colonies of bacteria you use solid media contaminant: - growth or presence of unwanted substances or micro-organisms in your culture Aseptic Techniques: - all the procedures that are used to prevent the contamination of a culture are known as aseptic techniques - such as the use of laminar flow and biosafety cabinets as well as ethanol solutions callus: - is a group of unorganised proliferated mass of cells micropropagation: - is the process of the production of a large no. of plants from a small piece of plant in less time using less space - we multiply the no. of plants by using many culturing methods - NOTE: we typically use many starting materials in regular propagation to produce a large no. of plants but in micropropagation we only use a small amount of starting materials pathogen: - a disease causing organism pathogenic: - capable of causing a disease sterile: - a culture free of viable micro-organisms (no life present) Sterile Techniques: - all the procedures or techniques that are used to make things sterile clone: - a plant that is produced asexually from the same plant (a single source plant) hence having no variation clonal propagation: - is the asexual reproduction of plants explant: - is a piece of tissue, cell or organs that is excised from the plant and transferred to the medium in vitro: - the process of growing something in a test tube using a defined medium under controlled conditions in vivo: - the process of growing something naturally such as growing a plant or crop in its natural habitat like a field regeneration: - natural: - where the organisms restore or replace damaged cells or tissues - in natural cases we do not need to instruct the system or the body to regenerate, it happens naturally - humans can restore skin, gut, respiratory and liver cells - starfish can regenerate as a whole - lizards can regenerate through their tails - artificial: - by providing instructions via growth media or controlled conditions - if we want to regenerate roots from a leaf it is not a natural process but rather an imposed or artificial one Growth regulators: - help impose cells to regenerate - we use different concentrations of growth regulators like Cytokinins and Auxins to see what helps the plant grow best - Here is a recap of regulators from BIOT201. Double click to open on a laptop. - Somaclonal Variation: - variations which are unintentionally introduced in the plant that show in the phenotype such as differences in height, color, grain size, texture, etc. - in better words, these unintentional variations arise due to tissue culturing procedures - the reason for why this variation occurs is not known - it cannot be predicted and this happens in nature as well - think of it this way--- you have a pizza party with your friends. You and your friend group ate the same food but you were the only one who got food poisoning. It just happens sometimes. - we do not know if the change is permanent or transferrable; unpredictability is expected - somaclones: - the variants that carry somaclonal variation - recalcitrant: - this term is used to refer to an explant that is stubborn or difficult to handle, not giving a response to any kind of media despite optimised conditions - some plants give quick responses, some take years while others simply don't respond - the latter is usually a recalcitrant - subculture: - the term used when you shift the culture from one media to another - this can be done for refreshing the media to get rid of any metabolites toxins that the explant may have produced that may interfere with the experiment--- nature has its way of interfering - it is also done when the color of the media changes--- this shows that the particular media being used can no longer support the growth of the plant - it can also be done to help us focus on growing other regions of the plant - totipotency: - is the ability of a plant to give rise to other cells - it is a cell characteristic in which the cell has the potential for forming all the cell types as well as the whole organism - recap from BIOT201 - ploidy: - this term is normally used to show the sex chromosome number such as 2n, 3n, etc - we will be using this to refer to how many sets of chromosomes a plant carries - there are different wheat varieties--- chapati is 6n (hexaploidy), pizza dough is 4n (tetraploidy). This leads to changes in taste as well as nutritional value - polyploidy is commonly carried out in plants but not animals due to ethical concerns - increasing ploidy increases vegetative growth or the size of food (this is a generalised assumption) - Shoot Apical Meristem: - it is the region in the growing tip of the shoot and it consists of undifferentiated cells where mitotic activity occurs and they were capable to produce leaves, buds and stems - Meristem: - it is a group or region of actively dividing cells - Apical meristem: - it is located at the tip of the roots and shoots; lateral branches - Meristematic: - having the characteristics of a meristem; having the capability of growing - this is because these cells have high mitotic activity - Meristemoid: - a localised group of meristematic cells that arise in the callus and then give rise to a root or shoot - Undifferentiated: - cells or tissues that do not have specialised or mature structures or functions - they are unspecialised - Dedifferentiation: - occurs only artificially in tissue culture, not in nature - in nature, if this occurs, we call it decomposition - where a specialised cell is unspecialised again - it is the opposite of differentiation - Redifferentiation: - refers to shifting a dedifferentiated callus into a new differentiated cell - differentiated leaf in nature---\> undifferentiated callus ---\> differentiated root in the lab - Differentiation: - the specialisation of immature cells - it is natural and a normal part of the developmental process - in nature, tumor formation in plants can also occur through rapid uncontrolled differentiation of cells - we do this sequence to help improve plants or maybe grow a plant in large numbers in less time, etc. - Petiole: - a leaf stalk or a portion of leaf attached to to the stalk - Morphogenesis: - the process where cells change shape - Adventitious: - this term is used when in some plants, the roots form from the leaves of the or the stems or any other region of the plant, developing from an unusual point of region - we often hear the term "adventitious roots" where roots grow where they normally don't grow even in nature, however, any other part can also grow unusually like this but roots are more common - Polarity: - the orientation in the gravitational field - some plants grow on the basis of charge - roots will spread around positive fields for examples - Primordia: - the earliest detectable stage of an organ is known as the primordia - such as the primordia of the shoots