TOPIC 2: LABORATORY TECHNIQUES AND SAFETY A laboratory is a room or building specially designed for conducting various scientific experiments. An appropriate school laboratory has the following features: a room with enough space for carrying out scientific experiments; a store for keeping laboratory apparatus, chemicals and reagents; an office for laboratory technician to sit in and design scientific experiments; enough ventilation to let in fresh air and light; wide doors and several exits for emergency evacuation in case of an accident; and a wide table in front of the laboratory room, fitted with sinks for experiment demonstrations by the teacher…
Author: Msomi Bora
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TOPIC 1: INTRODUCTION TO CHEMISTRY The concept of chemistry The Concept of Chemistry Explain the concept of Chemistry Chemistry is a branch of science that deals with the study of nature, properties and composition of matter. Matter can be defined as anything that has weight or mass and can occupy space. Therefore, in chemistry we study materials that make up the earth and universe. These range from living to non-living materials. We apply the knowledge of chemistry to study the composition, behaviour and nature of materials around us. This study enables us to make the best use of these materials…
TOPIC 5 HUMAN IMMUNODEFICIENCY (HIV) ACQUIRED IMMUNE DEFICIENCY SYNDROME (AIDS) AND SEXUALLY TRANSMITTED INFECTIONS (STIS) Relationship Between HIV, AIDS and STIs Defference between HIV, AIDS and STIs Distinguish between HIV, AIDS and STIs HIV/AIDS (Human Immunodeficiency Virus and Acquired Immune Deficiency Syndrome) Acquired means “to get from” this means that AIDS is gotten from other people, “Immune” means “protect”, this means that the body is normally protected against many diseases. Deficiency means “lack: and syndrome means a group of different symptoms of diseases. AIDS is the pandemic disease, which is caused by a certain type of organism called virus. These…
TOPIC 4: EVOLUTION Concept of Organic Evolution The Concept of Organic Evolution Explain the concept of organic evolution Evolution is the gradual development of organisms from simple form to more complex forms over a long duration of time. Evolution is marked by emergence of new species from pre-existing species and the disappearance of some species. The species that disappear are said to become extinct. Key terms used in organic evolution Carbon dating: This is a method of estimating the ages of dead materials of biological origin. Natural Selection: This is selective force occurring in nature, which is responsible for eliminating the unfavourable…
TOPIC 3: CLASSIFICATION OF LIVING THINGS Kingdom Animalia The word ‘animal’ is derived from the Latin word animalis which means ‘having breath’. The Kingdom Animalia is characterized by eukaryotic and heterotrophic organisms. They are multicellular and lack cell wall. They depend directly or indirectly of plants for their food. Food is ingested and digested in their internal cavity and food reserves are stored as glycogen or fat. Nutrition is holozoic, i.e, by ingestion of food. Animals follow a definite growth pattern, the adults have a definite shape and size. Higher forms of animals exhibit well developed sensory and neuromotor mechanism. Most of…
TOPIC 2: GENETICS Concept of Genetics The concept of Genetics Explain the concept of the genetics Genetics is a branch of biology which deals with the study of heredity and variations in organisms. Heredity refers to the transmission of genetic information from one generation to another. That is, the passing on of features or characteristics from parents to offspring or progeny. In humans, for example, features such as hair colour and body shape of the parents can be passed on (inherited) to their children. In genetics, a feature that can be inherited by the offspring from the parent is known as a trait. Thus, features…
TOPIC 1: GROWTH Concept of Growth The concept of Growth Explain the concept of growth Growth is an increase in size/mass or growth. It is the progressive development of living thing, especially the process by which the body reaches its point of complete physical development. The growth process is not a steady one; sometimes growth occurs rapidly, at other times slowly. Individual patterns of growth vary widely because of differences in heredity and environment. When the rate of cell increase is higher than the rate of cell loss, growth is referred to as positive growth. When the rate of cell…
TOPIC 6: REPRODUCTION Concept of Reproduction Reproduction is the ability of living organisms to form new individuals of the same species from those already in existence. Here, the new organisms replace those that have died and so life continues. It can also be defined as the process whereby organisms produce new individuals of the same species. It is one of the important features of living things. The Merits and Demerits of Sexual and Asexual Reproduction Explain the merits and demerits of sexual and asexual reproduction Sexual Reproduction This is a type of reproduction in which new organism is produced when…
TOPIC 5: REGULATION Concept of Regulation The Concept of Regulation Explain the concept of regulation Living organisms are subjected to wide variations in temperature, light, acidity, salinity, wind speeds, availability of water minerals and nutrients. These environmental factors create a shifting external setting to which organisms must adjust or die. The central problem for a living thing is to maintain a steady state internally in the force of an often harsh and fluctuating external environment. Homeostasis is the maintaining of a constant condition of the internal environment of the body by regulatory process. OR It is the maintenance of constant…
TOPIC 4: EXCRETION Concept of Excretion The Concept of Excretion Explain the concept of excretion Chemical reactions occur in the cells of living organisms all the time to carry out the life processes. The sum of these reactions is called metabolism. Metabolism produces useful products as well as toxic (poisonous) by-products. These toxic substances have to be removed as they are harmful if allowed to accumulate. The removal of metabolic waste products from the body of an organism is known as excretion. The major excretory products are carbon dioxide, excess water, and nitrogenous compounds like ammonia, urea, uric acid, etc.…