Second Term Lesson Note for Week Five
Class : SSS 1
Subject : Biology
Topic : Nutrition in Animals
Duration : 40 Minutes
Period : Single Period
Reference Book :
- Modern Biology for Senior Secondary School.
- Lagos State Unified schemes of work for Senior Secondary School, SSS 1 – 3.
- Online Resources
Instructional Material : Chart showing the nutrients in the food eaten by animals.
Learning Objectives : By the end of the lesson learners will be able to :
i. Explain Animal Nutrition
ii. List the classes of food
iii. Define balanced diet and state its importance
iv. Explain digestive enzymes and give examples.
Content :
ANIMAL NUTRITION
Animals generally cannot manufacture their food. Rather, they depend directly or indirectly on plants for their food. Hence they are called Heterotrophs.
Based on their food types, animals are grouped into three :
- Carnivores which feed on flesh or other animals e.g. lion.
- Herbivores which feed on plants e.g goat.
- Omnivores, which feed on both plants and animals e.g man.
CLASSES OF FOOD SUBSTANCES
Foods eaten by animals are generally classified into seven i. e.
- Carbohydrates
- Proteins
- Fat and oil
- Mineral Salt
- Vitamins
- Water
- Roughages
CARBOHYDRATES
This is got from food like bread, yam rice etc. It basically consists of carbon, hydrogen and oxygen.
Carbohydrates are of three types :
- Monosaccharides (Simple sugars) which include glucose, fructose and galactose
- Disaccharides (Reducing sugars) which include maltose, sucrose and lactose.
- Polysaccharides (Complex sugars) e.g starch, cellulose, chitin under the action of enzymes like ptyalin, maltase, lactase etc, and starch yields glucose as product of its digestion. Excess carbohydrate is stored in the body in form of glycogen in muscles and liver. This can be reconverted to glucose during starvation.
Importance of Carbohydrates
It gives animals energy.
It provides heat needed to maintain body temperature
It can be used for lubrication e.g mucus.
It provides the body with a strong framework e.g. exoskeleton in insects.
PROTEINS
These are complex molecules made up of smaller units called amino acids. Protein is made up of carbon, hydrogen, oxygen, nitrogen and sometimes phosphorus and sulphur. Food like egg, meat, fish, beans etc gives you protein. Proteins are broken down into amino acids under the action of enzymes like pepsin, rennin, trypsin and erepsin.
Importance of Proteins
- Growth in young ones.
- Repair of worn-out tissues.
- Production of enzymes.
- Production of hormones.
- It supports reproduction.
- It is for tissue and all formation i.e body building.
FATS & OIL (LIPIDS)
Fats are solid lipids at room temperature while oil is the liquid. Fat and oil consist of carbon, hydrogen and little oxygen. When digested, it gives rise to fatty acids and glycerol. Foods like palm oil, groundnut, Soya beans give fat and oil. Lipids are broken down to fatty acids and glycerol when acted upon by lipase enzymes.
Importance of Fat and Oil
- It gives you energy even more than carbohydrates
- It supplies essential fatty acids to the body.
- It helps in the maintenance of body temperature
- It provides the body with fat-soluble vitamins
MINERAL SALT
These are usually taken in very small quantity in the food we eat except sodium chloride (table salt) and iron tablet, which can be taken directly by man. The lack of these salts results in nutritional deficiency. The minerals include calcium, magnesium, potassium, Phosphorus, sulphur, chlorine, iron, Iodine, fluorine, manganese, copper, cobalt and sodium.
Importance of Mineral Salts
- Regulate body metabolisms
- Components of bones and teeth
- Aids blood formation
- Control chemical reactions in the body
- Aids the formation of enzymes and pigment
VITAMINS
These are organic food substances needed by man and other animals in small quantity for normal growth and development. Lack of or inadequate supply of any of these vitamins results in nutritional deficiency.
Vitamins can be grouped into two:
- Water-soluble vitamins
- Fat soluble vitamins
The water-soluble vitamins include: vitamins B complex and vitamin C. Vitamin B complex include vitamin, B2, B3 , B5, B6 and B12
Fat-soluble vitamins include vitamins A, D, E and K.
VITAMINS, SOURCE FUNCTIONS AND DEFICIENCY SYMPTOMS
SOURCE
FUNCTION
DEFICIENCY SYMPTOMS
Vitamin A
Liver, eggs, fish
milk, palm oil, fish Vegetables
(i) Normal growth of
body cells and skin
(ii) Proper vision of the eye
(i) Night blindness
(ii) Reduced resistance to disease
Vitamin B1
Yeast, milk, beans,
Ground nut
(i) Normal growth
(ii) Proper functioning of heart
and nervous system
Beri-beri (wasting of
Muscles), paralysis
Vitamin B2
Yeast, soya beans,
egg, milk, green
Vegetables
(i) Growth, proper functioning
of the eye
(ii) Formation of co-enzymes
(i) Slow growth
(ii) Dermatitis
Vitamin B3
Yeast, beans, milk,
Vegetables
Formation of co-enzymes for cellular respiration
Pellagra
Vitamin B12
Kidney, liver, fish
Milk
Formation of red blood
Cells
Pernicious
Anaemia
Vitamin C
Fresh fruits and
Green vegetables
(i) Aids wound healing
(ii) Helps to resist infection
Scurvy
Vitamin D
Fish, milk, egg,
Liver, suns
Ultraviolet rays
(i) Increases absorption
Of calcium and phosphorus.
(ii) Calcification and hardening Of bones
Ricket;
Osteomalacia
Vitamin E
Green vegetables,
Egg, butter, liver
Promotion of fertility
In animals
Sterility
Premature abortion
Vitamin K
Fresh green vegetables, liver
Aids blood clotting
Hemorrhage
WATER
This is of utmost importance to all organisms and it is made up of two elements, hydrogen and oxygen. Water can be got from food, river, stream, pond etc. water makes up 75% of the human body.
Importance Of Water
- Metabolic activities of the body of animals.
- Digestion of food.
- Maintenance of body temperature.
- It is a medium of transportation for all nutrients.
- It helps to maintain the osmotic balance in body tissues.
- It helps in excretion of metabolic waste from the body e.g urine.
ROUGHAGES
These are indigestible fibrous materials got from vegetables, fruit, carbohydrates and proteins. Roughages aid digestion, lack of which can lead to constipation.
EVALUATION
1. State three importance of:
A. Carbohydrate
B. Protein
C. Lipids.
2. Mention five disease that may result from the deficiency of vitamins.
BALANCED DIET
Balanced diet is a diet containing a correct proportion of all the food substances.
On a general note, a balanced diet contains 15% protein, 15% fat and oil, 10% vitamin, minerals and water and 60% carbohydrate. Once a food is taken at these proportions, there is a normal growth and development in the body.
FUNCTIONS OF BALANCED DIET
- It makes us healthy.
- It gives ability to be resistant to diseases
- It makes available energy needed to carry out all biological activities.
- It prevents malnutrition and deficiency symptoms. For examples, a diet that lacks protein results into a nutritional disease called kwashiokor in children.
The following are features of protein deficiency in a child :
- Retarded growth.
- Loss of weight.
- Swollen legs effect (oedema).
- Cracked / split stomach and thin legs e.t.c.
EVALUATION
1. State two importance each of :
A. protein
B. carbohydrates
C. vitamins
2. State three importance of balanced diet
DIGESTIVE ENZYMES
Enzymes are organic (protein) catalysts produced by living cells which help to speed up and slow down the rate of chemical reactions. Digestive enzymes aid the breaking down of complex food substances into simple, soluble and diffusible form. Enzymes have the following characteristics.
Enzymes are soluble
Enzymes are protein
They are specific in their actions
Enzymes are sensitive to temperature i. e. they work best between 35oC to 40oC
Enzymes are PH specific
Enzymes brings about reversible reactions
Enzymes needs co-enzymes to activate them and can be inactivated by inhibitors such as mercury and cyanide
CLASSES AND FUNCTIONS OF ENZYMES
Digestive enzymes are classified based on the type of food they act upon. These include
Proteases e. g. pepsin, rennin, trypsin and erepsin. They act on protein.
Amylases e. g. ptyalin, lactase, maltase, sucrose. They act on carbohydrates
Lipases which act on lipids (fats and oils)
EVALUATION
What are enzymes?
Outline five characteristics of enzymes
GENERAL EVALUATION/REVISIONAL QUESTIONS
State two food items each that supply A. Protein B. Lipids C. Mineral salts
List two functions each for protein and lipids.
State the functions of A. Chlorine B. Magnesium C. Iodine.
What are the diseases resulting from deficiency of: A. Sodium B. Calcium C. Iron
State the functions and deficiency symptoms of all the water soluble vitamins
READING ASSIGNMENT
College Biology, chapter 6, page 95 103
WEEKEND ASSIGNMENT
Vitamins are organic food substances required by animals in ____ quantity A. no B. small C. large D. high
The following except one are fat-soluble vitamins A. vitamin A B. Vitamin B C. Vitamin K D. Vitamin E
One of the following food substances is indigestible in man A. protein B. lipids
C. roughages D. carbohydrates
The highest source of energy is from _______ A. carbohydrate B. proteins C. lipids D. vitamins
Rickets (poor bone formation) in children is a deficiency symptom of ____ A. potassium B. calcium C. chlorine D. manganese.
THEORY
Make a table of food tests showing the column of food, the test, observation & inference.
Make a table of important mineral elements in animals, their functions and deficiency symptoms