Biology Form 2

Contents

1. 1. Classification of Living Things: Monera, Protoctista and Fungi

   1 tests 17 questions

   Topic lessons

   • Viruses
   • Kingdom Monera: bacteria
   • Kingdom Protoctista
   • Kingdom Fungi
   • Summary

   Recap In Form One we learnt that living things are grouped into five kingdoms. This topic studies three kingdoms of mostly small or simple organisms – Monera , Protoctista and Fungi – and also looks at viruses . Viruses Viruses are extremely small particles (seen only with an electron microscope) made of a nucleic acid…

2. 2. Nutrition 1: Nutrition in Plants

   1 tests 17 questions

   Topic lessons

   • Nutrition and its modes
   • Photosynthesis: the process
   • Leaf structure and adaptations for photosynthesis
   • Factors affecting photosynthesis
   • Experiments on photosynthesis
   • Mineral nutrition in plants
   • Summary

   Meaning of nutrition Nutrition is the process by which organisms obtain food and use it for energy, growth and repair. There are two main modes: autotrophic nutrition , in which organisms make their own food from simple inorganic substances, and heterotrophic nutrition , in which organisms depend on food made by…

3. 3. Nutrition 2: Nutrition in Humans

   1 tests 16 questions

   Topic lessons

   • Food substances and a balanced diet
   • Deficiency diseases and food tests
   • Teeth and their care
   • The digestive system and digestion
   • Absorption, assimilation and egestion
   • Summary

   Food substances Humans are holozoic heterotrophs: we take in food, digest it, absorb it and use it. A balanced diet contains all food substances in correct amounts for a person's age, sex, health and activity. Food substance Use Sources Carbohydrates Main source of energy Ugali, rice, cassava, bananas Proteins Growth…

4. 4. Balance of Nature

   1 tests 15 questions

   Topic lessons

   • Ecological terms and components of an ecosystem
   • Feeding relationships: food chains and food webs
   • Energy flow and ecological pyramids
   • Nutrient cycles
   • Interactions between organisms and human impact
   • Summary

   Basic ecological terms Ecology – study of organisms and their environment. Habitat – the place where an organism lives, e.g. a pond. Population – all members of one species in an area, e.g. all tilapia in a pond. Community – all populations of different species living in an area. Ecosystem – a community together with…

5. 5. Transport of Materials in Living Things 1: Movement of Substances and Transport in Plants

   1 tests 16 questions

   Topic lessons

   • Why living things need transport systems
   • Diffusion and active transport
   • Osmosis
   • Transport tissues in plants: xylem and phloem
   • Water uptake and transpiration
   • Summary

   Why transport is needed Every living cell needs a supply of food, water and oxygen and must get rid of wastes. In small organisms such as Amoeba , diffusion over the body surface is enough because the surface area to volume ratio is large. Large organisms have a small ratio, so they need special transport systems.…

6. 6. Transport of Materials in Living Things 2: Transport in Mammals

   1 tests 17 questions

   Topic lessons

   • The circulatory system and double circulation
   • Composition and functions of blood
   • The mammalian heart
   • Blood vessels, pulse and cardiac output
   • Blood groups, transfusion and the lymphatic system
   • Summary

   The circulatory system In mammals, materials are carried by blood , which is pumped by the heart through blood vessels . Mammals have a double circulation : blood passes through the heart twice in one complete circuit – the pulmonary circulation (heart → lungs → heart) and the systemic circulation (heart → body →…

7. 7. Gaseous Exchange and Respiration

   1 tests 16 questions

   Topic lessons

   • Gaseous exchange, respiration and respiratory surfaces
   • Gaseous exchange in insects and fish
   • The human respiratory system
   • Breathing and the health of the lungs
   • Aerobic respiration
   • Anaerobic respiration and its uses
   • Summary

   Gaseous exchange and respiration – the difference Gaseous exchange is the movement of oxygen into and carbon dioxide out of an organism across a respiratory surface , by diffusion. Respiration (cellular respiration) is the chemical breakdown of food, mainly glucose, inside cells to release energy. Breathing is only the…