Leaving Cert Biology Cell Diversity

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Leaving Certificate Biology

Tissue – Group of similar cells that perform a particular function
Plant tissues – Vascular tissue: conducts water and nutrients throughout plant. Dermal: covers and protects, epidermis. Ground: photosynthesis, storage and support. Meristematic: produces new cells by mitosis.
Dermal Tissue – The protective covering of plants; generally a single layer of tightly packed epidermal cells covering young plant organs formed by primary growth.
Vascular Tissue – Plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body. Xylem(water) & Phloem(food)
Animal Tissue – epithelial, connective, muscle, nervous
Connective tissue – Consists of cells dispersed in a matrix, it surrounds and supports body parts. Blood has red cells, white cells and platelets carried in plasma
Nervous Tissue – A body tissue that carries electrical messages back and forth between the brain and every other part of the body.. Neurons are nerve cells
Tissue (Cell) Culture – the growth of cells in/on a sterile nutrient medium(energy source) outside an organism
In vitro/ in vivo – in an artificial environment outside the living organism eg in glass/ happening inside the body of an organism
Applications of Tissue Culture – Plant Breeding/ micropropogation, Cancer research; Monoclonal antibodies eg Herceptin; Skin Grafts
Organ – A structure composed of a number of tissues that work together to carry out one or more functions. A leaf in plants/ a Heart in humans
Plant Organ – Leaf: Dermal Tissue, Vascular Tissue and Ground tissue; all tissues combine to carry out photosynthesis; Also Root; Stem
Animal Organ – Heart; muscular tissue, epithelial tissue, connective tissue, nervous tissue; Also Brain, Liver
Organ System – A number of organs working together to carry out one or more functions
Examples of Animal Organ Systems – Circulatory System (heart, blood vessels, blood)
Digestive system oesophagus, stomach, small intestine, large intestine, anus (in association with the pancreas and liver)
Main conditions necessary for Tissue Culture – Absence of other contaminating micro-organisms; food, vits, minerals; substances (eg hormones) to stimulate growth
Micropropogation – the growth of large numbers of plants
from cells, tissue or small parts of a plant. Used to rapidly produces new genetically identical plants
Monoclonal antibodies – May be used in treating cancer
Organisation of Multicellular living things – cell > tissue > organ > organ system > organism