Nutrition and the Human Digestive System

Question 1:(a)(i) After absorption of nutrients in the small intestine, the undigested substances in the colon result in the formation of faeces.Explain the formation of faeces in a human. [4 marks](ii) Malnutrition is a condition due to taking an unbalanced diet in which certain nutrients are lacking, in excess or in the wrong proportions.Explain the … Read more

9.11 Mechanism of Photosynthesis Chloroplasts1.   Photosynthesis occurs in the chloroplasts of mesophyll cells and guard cells of the leaf.2.  A chloroplast consists of two parts, stroma and grana (singular: granum).

Transport of Nutrients by Circulatory System1.   Glucose, amino acids, minerals, vitamins B and C are absorbed into blood capillaries of the villus and carried out of the small intestine to the liver by the hepatic portal vein.2.   The hepatic portal vein transports the nutrients absorbed from the small intestine to the liver for processing and prepared for … Read more

9.5 Absorption and Assimilation of Digested Food1.   Ileum is the major site of nutrient absorption.2.   Soluble nutrients are absorbed by simple diffusion, facilitated diffusion or active transport. Adaptive characteristics of the digestive system1.   The wall of the small intestine is covered with epithelial cells that are specialized to complete the digestive process.2.   The … Read more

9.4.2 Digestion in the Small IntestineDigestion in the Small Intestine1.   The small intestine consists of the duodenum, jejunum and the highly coiled ileum.2.   The duodenum is the first part of the small intestine, receives chyme from the stomach and secretions from the gall bladder and pancreas.Digestion in the duodenum Liver1.   Bile is an alkaline, greenish-yellow … Read more

9.4.1 Human Digestive System1.   The human digestive system comprises of the alimentary canal which starts at the mouth and ends at the anus. 2.  The parts of the human digestive system are:   (a) mouth   (b) oesophagus   (c) stomach   (d) duodenum (first part of small intestine)   (e) ileum (rest of … Read more

9.4 Food Digestion 1.   Digestion is the process that breaks down complex food substances into simpler, soluble molecules that are small enough for the body to absorb.2.   Digestion breaks down  (a) carbohydrates into glucose molecules,  (b) proteins into amino acids, and  (c) lipids into glycerol and fatty acids.3.   Digestion involves both physical and chemical processes.4.   Physical digestion  (a) involves the breaking of … Read more

9.1 Types of Nutrition Autotrophic Nutrition1.  An autotroph is an organism that synthesise complex organic molecules from inorganic molecules such as air and water.2.   Autotrophs are able to synthesise their food by (a)  photosynthesis (b)  chemosynthesis3.  Photosynthesis is the process in which green plants and algae, called photoautotrophs, produce organic molecules from carbon dioxide and water using … Read more

Question 8:The human respiratory systems of humans and grasshoppers have different adaptations to maximise the rate of gaseous exchange. State the similarities and differences between the human respiratory system and the grasshopper breathing system. Answer:Similarities:• The respiratory surface is moist to dissolve oxygen for diffusion.• The respiratory surface is thin for fast gas diffusion.• The … Read more