Theory question 102
Photosynthesis and Plant Nutrition(a) Complete the table below.
Table columns: Element | Function in plants | Effect of deficiency in plants
Rows: Iron; Molybdenum; Potassium; Copper; Nitrogen
(b) Name three classes of organic foods which are essential constituents in the diet of a mammal.
(c) State two roles each of the following structures of the digestive system in humans: (i) buccal cavity; (ii) duodenum; (iii) stomach.
(d) Name the end product of adding dilute hydrochloric acid to sucrose.
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(a) Iron - needed to make chlorophyll; part of respiratory enzymes. Deficiency: chlorosis (yellowing) of young leaves.
Molybdenum - needed by enzymes that fix nitrogen and reduce nitrate (formation of amino acids). Deficiency: pale leaves, stunted growth.
Potassium - needed for protein synthesis, enzyme activity and opening of stomata; flowering and fruiting. Deficiency: yellow/brown, scorched leaf margins; premature death of leaves.
Copper - activates enzymes used in respiration and photosynthesis. Deficiency: wilting, spotted or dying leaf tips.
Nitrogen - needed to make proteins, amino acids and chlorophyll. Deficiency: stunted growth, small yellow leaves.
(b) Any three: carbohydrates; proteins; fats and oils (lipids); vitamins.
(c)(i) Buccal cavity: teeth chew food into small pieces; saliva moistens food and its amylase (ptyalin) starts digesting starch to maltose; tongue rolls food into a bolus for swallowing; tastes food.
(ii) Duodenum: receives bile, which emulsifies fats; receives pancreatic juice whose enzymes (amylase, trypsin, lipase) digest starch, proteins and fats; neutralises acid chyme from the stomach.
(iii) Stomach: stores food for a while; churns food and mixes it with gastric juice; hydrochloric acid kills germs and gives acid medium; pepsin begins protein digestion; rennin curdles milk.
(d) Glucose and fructose (the acid hydrolyses sucrose).
Give each element both a function and a deficiency symptom.