PROCESSES UNDER PRESSURE
Which process of nutrition ensures that soluble food molecules are incorporated into body cells for growth and repair?
Assimilation
Name the enzyme that begins carbohydrate digestion in the mouth.
Salivary amylase
Name the structure that increases the surface area of the ileum.
Villi
What is the semi-liquid food mixture called after stomach digestion?
Chyme
Which type of teeth is mainly used for grinding food?
Molars
State ONE consequence to the body if absorption in the ileum is inefficient.
Nutrients will not enter the blood or lacteal properly, leading to malnutrition and energy deficiency
Why does pepsin work best in the stomach but not in the small intestine?
Pepsin requires an acidic pH, which is present in the stomach but not the intestine
Why are villi lined with a one-cell-thick epithelium?
To allow rapid diffusion and absorption
Name the enzyme responsible for fat digestion in the small intestine.
Lipase
State ONE function of teeth that is NOT related to digestion.
Speech pronunciation or facial appearance
Explain why digestion must occur before absorption can take place.
Large insoluble food molecules must be broken down into small soluble molecules before they can pass through the intestinal wall
Explain the role of hydrochloric acid in digestion besides enzyme activation.
It kills bacteria and provides the acidic medium for enzyme activity
Explain why glucose enters the blood capillaries but fats enter the lacteal.
Glucose is water-soluble; fats are absorbed as fatty acids and glycerol into the lymphatic system
A patient cannot produce bile. Explain how fat digestion is affected.
Fats are not emulsified, reducing enzyme efficiency
Explain how poor mastication affects digestion in the stomach.
Larger food particles reduce surface area, making enzyme action less efficient
If egestion does not occur efficiently, explain TWO effects on the body.
Build-up of waste causes discomfort, possible toxicity, and disruption of normal digestive processes
Predict what would happen to protein digestion if hydrochloric acid were absent from the stomach.
Pepsin would not be activated, leading to incomplete protein digestion
Explain why epithelial cells of villi contain many mitochondria.
Active transport requires energy (ATP)
Differentiate between egestion and excretion using one example each.
Egestion: removal of undigested food (faeces); Excretion: removal of metabolic waste (urine, sweat)
Explain how plaque formation can indirectly affect digestion.
Tooth decay causes pain, reducing chewing efficiency and, therefore, digestion.
A student claims that digestion and absorption are the same process. Use biological reasoning to prove this statement is incorrect.
Digestion is the breakdown of food, while absorption is the movement of digested nutrients into the blood or lacteal; they are distinct but linked processes
Explain why pancreatic juice and bile must neutralize acidic chyme before digestion continues in the duodenum.
Intestinal enzymes require an alkaline pH; acidic chyme would denature enzymes and slow digestion
Damage to villi is observed in a patient. Predict TWO effects on the body and justify your answer.
Reduced absorption leading to malnutrition, weight loss, and energy deficiency
Explain how the hepatic portal vein supports assimilation in the body.
It transports absorbed nutrients to the liver for processing, storage, or detoxification
A child loses deciduous teeth too early. Explain how this could affect digestion later in life.
Poor chewing efficiency affects digestion; loss of space may misalign permanent teeth