Biology

BIOLOGY AS AN INQUIRY IN SCIENCE Science is the study of nature (living and non-living things).  Biology is a science that studies living things in nature. Biology was formed from… Read More »BIOLOGY AND LIVING THINGS

This is a yellow colouration of the skin and eyes. Cause: Presence of excess bile pigments. This happens due to blockage of bile duct or destruction of liver. Symptoms: Yellow… Read More »JAUNDICE: SKIN AND EYES

Role of Liver in Excretion The liver lies below the diaphragm and it receives blood from hepatic artery and hepatic portal vein. Blood flows out of the liver through hepatic… Read More »LIVER EXCRETION

The kidneys are organs whose functions are excretion, osmoregulation and regulation of pH. Kidneys are located at the back of the abdominal cavity. Each kidney receives oxygenated blood from renal… Read More »STRUCTURE AND FUNCTIONS OF THE KIDNEYS

What is Excretion? Excretion is the process by which living organisms separate and eliminate waste products of metabolism from body cells. If these substances were left to accumulate, they would… Read More »EXCRETION AND HOMEOSTASIS IN PLANT AND ANIMAL

Asthma Asthma is a chronic disease characterized by narrowing of air passages. Causes: Allergy Due to pollen, dust, fur, animal hair, spores among others. If these substances are inhaled, they… Read More »DISEASES OF THE RESPIRATORY SYSTEM

Factors that cause a decrease or increase in energy demand directly affect rate of breathing. Exercise, any muscular activity like digging. Sickness Emotions like anger, flight Effects of Exercise on… Read More »FACTORS AFFECTING RATE OF BREATHING IN HUMANS

The breathing system of a mammal consists of a pair of lungs which are thin-walled elastic sacs lying in the thoracic cavity. The thoracic cavity consists of vertebrae, sternum, ribs… Read More »GASEOUS EXCHANGE IN A MAMMAL – HUMAN

An adult frog lives on land but goes back into the water during the breeding season. A frog uses three different respiratory surfaces. These are the skin, buccal cavity and… Read More »GASEOUS EXCHANGE IN AN AMPHIBIAN – FROG

Gaseous exchange in fish takes place between the gills and the surrounding water. The gills are located in an opercular cavity covered by a flap of skin called the operculum.… Read More »GASEOUS EXCHANGE IN BONY FISH (E.G. TILAPIA)

Gaseous exchange in insects e.g., grasshopper takes place across a system of tubes penetrating into the body known as the tracheal system. The main trachea communicate with atmosphere through tiny… Read More »GASEOUS EXCHANGE IN INSECTS

All animals take in oxygen for oxidation of organic compounds to provide energy for cellular activities. The carbon (IV) oxide produced as a by-product is harmful to cells and has… Read More »GASEOUS EXCHANGE IN ANIMALS

Gaseous exchange takes place by diffusion. The structure of the leaf is adapted for gaseous exchange by having intercellular spaces that are filled. These are many and large in the… Read More »GASEOUS EXCHANGE IN LEAVES OF TERRESTRIAL PLANTS

The water lily, Salvia and Wolfia whose stems remain in water are permeable to air and water. Oxygen dissolved in the water diffuses through the stem into the cells and… Read More »AQUATIC PLANT STEMS

Living organisms require energy to perform cellular activities. The energy comes from breakdown of food in respiration. Carbon (IV) oxide is a by-product of respiration and its accumulation in cells… Read More »GASEOUS EXCHANGE IN PLANTS AND ANIMALS

Oxygen is required by plants for the production of energy for cellular activities. Carbon (IV) oxide is required as a raw material for the synthesis of complex organic substances. Oxygen… Read More »GASEOUS EXCHANGE IN PLANTS

Making of beer and wines. Ethanol in beer comes from fermentation of sugar (maltose) in germinating barley seeds. Sugar in fruits is broken down anaerobically to produce ethanol in wines.… Read More »APPLICATION OF ANAEROBIC RESPIRATION

Carbohydrate, mainly glucose is the main substrate inside cells. Lipids i.e. fatty acids and glycerol are also used. Fatty acids are used when the carbohydrates are exhausted. A molecule of… Read More »SUBSTRATES FOR RESPIRATION

COMPARISON BETWEEN ENERGY OUTPUT IN AEROBIC AND ANAEROBIC RESPIRATION Aerobic respiration results in the formation of simple inorganic molecules, water and carbon (Iv) oxide as the by¬products. These cannot be… Read More »ENERGY OUTPUT IN AEROBIC AND ANAEROBIC RESPIRATION

BIOLOGY PRACTICAL ACTIVITIES To Show the Gas Produced When the Food is burned A little food substance e.g., maize flour or meat is placed inside a boiling tube. The boiling… Read More »BIOLOGY PRACTICAL ACTIVITIES