SPM BIology 2015


8 . Diagram 8.1 shows the digestive system of a cow.

Rajah 8.1 menunjukkan system pencernaan seekor lembu.

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(a) Based on Diagram 8.1, describe the digestion of cellulose in the cow.

Berdasarkan Rajah 8.1, huraikan pencernaan selulosa dalam lembu tersebut.


(b) Explain the digestion of protein in human’s stomach.

Terangkan pencernaan protein dalam perut manusia.

(c) A mother who is nursing a newborn baby healthy food for herself and her baby. Suggest types of food which are suitable and give reason to your answer.

Seorang ibu yang menyusukan bayi yang baru lahir memerlukan makanan yang sihat untuk diri dan anaknya. Cadangan jenis-jenis makanan yang sesuai dan berikan alas an kepada jawapan anda.

Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution


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Answer ( 1 )

    This answer is edited.

    8.a)-The cow’s stomach has four chambers. Rumen, reticulum, omasum then abomasum.

    -Grass eaten moves down the oesophagus into the rumen.

    -In the rumen, symbiotic microorganisms (bacteria and protozoa) secrete cellulase which enzymatically breakdown cellulose into glucose molecules.

    -The digested food then enters the reticulum where cellulose is further hydrolysed by cellulase.

    -This forms cud which is regurgitated back into the mouth to be chewed again.

    -The cud is swallowed and passes straight into the omasum. Here, water from the cud gets removed.

    -Remaining food will then move into the abomasum. The abomasum contains gastric juices which will further digest the food. The food then moves into the small intestine and large intestine for digestion and absorption.


    b)-The stomach wall secretes gastric juices which contains hydrochloric acid and digestive enzymes (pepsin and rennin).

    -The acid helps to denature protein allowing the digestive enzymes to act.

    -Pepsin hydrolyses protein molecules into polypeptides and peptones.

    -Whereas rennin coagulates milk. Soluble caseinogen is converted into insoluble casein. Casein is further hydrolysed by pepsin into polypeptides.



    • carbohydrates

    -mothers would need to consume more carbohydrates such as rice and potatoes. needed for replenishing their energy.

    • whole grains

    -brown rice and oatmeal are important as they provide fibre. Fibre is needed in digestion and prevents constipation.

    • meat

    -meat is high in protein. examples, chicken and fish.

    -important for cell repair. and through breastmilk this protein is important for growing babies for cell production and growth.

    • green leafy vegetables

    -These are rich in iron which is important for the production of red blood cells as mothers who just gave birth have loss a lot of blood.

    -This food also helps to increase breast milk production.

    • water

    -pregnant mothers should consume more water as it is required in milk production.

    -also important for hydration and water balance.

    • milk and cheese

    -these foods are rich in calcium. calcium is an important mineral for babies as they help with bone and teeth formation.

    • citrus fruits like oranges

    -provides vitamin C which improves the absorption of iron and helps with detoxification.

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