Module 2 Organisation of Living Things

• Cells in unicellular organisms such as bacteria contain one cell, either prokaryotic or eukaryotic, and are the first forms of life.
• Excess water and salts are removed in the Large Intestines.
• Water, salts and vitamins are absorbed into the blood in the Endocrine Glands.
• Hormones are added in the Endocrine Glands.
• A single cell in unicellular organisms carries out all life processes including obtaining nutrients, exchanging gas, removing waste and reproduction.
• Unicellular organisms have a high SA:V ratio which allows for more efficient movement of substances.
• Unicellular organisms require a moist environments for diffusion and osmosis to occur.
• Colonial organisms, such as Volvox, are a group of cells working or organism working collectively is called a colony.
• Colonial organisms may be unicellular or multicellular and cannot exist independently, however in a multicellular organism colonial organisms cannot exist alone.
• Multicellular organisms are communities of cells working together to enable the organism to carry out life processes, including reproduction.
• Multicellular organisms are composed of many different specialised cells, similar cells are grouped together and perform specific functions that combine for the efficient functioning for the organism.
• Multicellular organisms consist of eukaryotic cells.
• Large organisms made up of smaller cells increase SA:V ratio.
• Each specialised cell type in multicellular organisms is structurally suited to a particular function.
• Embryonic cells develop suitable structural changes to best suit their function.
• Specialised cells in multicellular organisms cannot survive independently – they rely on other cells in the organisms to carry out functions they cannot.
• The spongy mesophyll layer in leaves increases surface area and allows gases to move freely within the leaf.
• The surface of cells in leaves is moist, facilitating gas exchange through stomata and lenticels.
• Insects obtain and release air through spiracles and do not have lungs or capillaries, instead, they have branching air tubes called tracheal tubes.
• Guard cells, which contain chloroplasts, are the bean-shaped cells found on both sides of the stomata.
• Gills extract the most oxygen possible out of water and do so through a countercurrent process, ensuring the most oxygen is being diffused from the water (furthest away from equilibrium).
• Leaves are adapted for gas exchange, being large and flat with a high specific area (SAV) ratio.
• Oxygen dissolves in fluid, which can be diffused into the cells and carbon dioxide diffuses out.
• Lenticels are pores through which gaseous exchange happens in woody plants and are found on trunks and branches of trees and woody shrubs.
• The human digestive system includes the mouth, which breaks down food for more efficient action of enzymes.
• Stomata open and close when the guard cells gain or lose water.
• Gas exchange in animals occurs in the lungs, gills, and tracheal system.
• Lungs are gas exchange structures known as alveoli, which have an increased surface area due to folding, a thin lining, moist surfaces, and share a membrane with the capillaries, facilitating the diffusion of gases.
• Stomata are found on the underside of the leaf and occasionally on the upper epidermis.
• Communication between cells is vital in multicellular organisms, this is done via the bloodstream and nervous system in animals and through chemical and physical contact between cells in plants.
• Organelle 􏰀 Cell �� Tissue 􏰀 Organ 􏰀 Organ System 􏰀 Organism
• Mitochondria 􏰀 Cardiac Muscle Cell �� Cardiac Muscle Tissue 􏰀 Heart
• Cardiovascular System 􏰀 Human
• Epithelial Tissue covers body surfaces, protects organs and forms glands, is densely packed in single sheets or layers, doesn’t contain blood vessels, has 2 distinct surfaces exposed to the exterior body cavity or exposed to adjacent tissue, and some are specialised for absorption or secretion.
• Connective Tissue provides support, ensures that all body parts are bound together and protects against damage, and its differences are from the arrangement of cells and specialised structure.
• Rainforest plants have large, thin, flat leaves to absorb as much sunlight as possible and have less concern about water loss due to high humidity.
• Root cells of plants have no chloroplasts and thus cannot photosynthesise, but they can carry out respiration.
• The structure of a leaf allows it to carry out these functions in an efficient and effective manner.
• The shoot system of plants also includes the leaves, which are the site of photosynthesis and transpiration.
• The shoot system of plants, located above ground, provides structural support and a transport pathway.