IGCSE Biology Exam Study Guide2022

The seven characteristics of living organisms -Nutrition : taking in , absorbing, and using nutrients which contain raw materials for energy for growth and tissue repair -Excretion : removal of water products if metabolism , toxic materials and substance -Respiration : the chemical reaction that breaks down food to release energy for metabolism -Sensitivity : the ability to detect or sense stimuli to make an appropriate response -Reproduction : process of making more of the same kind of organism -Growth : an increase in size and dry mass by an increase in cell # or cell size or both -Movement : an action by an organism causing a change in position or place Describe how organisms can be organized - Through the classification system which organizes according to the greater/lesser extent of their similarities to other organisms Define species - A specie is a group of organisms that share the many similar appearances and can breed with each other Define and describe the binomial system The system of classifying organisms using two names - genus and species - which are written in Latin genus (always Capital Letter ) and species (always Small Letter ) example Homo sapiens Explain that classification systems in regards to evolutionary relationships, morphology and anatomy,DNA and amino acids - traditionally base on studies of morphology / anatomy - aims to reflect evolutionary relationships - DNA : The sequences of DNA bases and amino acids aid in provides more accurate classifications Explain the relationship between a recent ancestor and a distant ancestor - Your more recent ancestors will have base sequences of DNA that have higher similarities than those of your distance ancestor List the features in the cells of all living organisms - The cell is the basic unit of structure and function of living organisms - All living organisms are composed of or more cells - Cell arise from pre - existing cells through cell division List the main features of Animals - Cells have a nucleus , but no cell wall or chloroplast - Multicellular (contain many cells ) - Feeds on organic substances made by other living organisms List the main features of Plants ... List the main features of Fungus - Have nucleus - Multicellular - Some can be useful while others are harmful - Do not have chlorophyll or perform photosynthesis - Have cell walls , not made of cellulose - Feed parasitically on organic material (feces , human foods , dead plants or animal )