Enzymes and Digestion Quiz

Enzymes and Digestion

• Enzymes are proteins that speed up chemical reactions
• Enzymes are biological catalysts
• Enzymes are not used up in the reaction
• Enzymes are specific to their substrates
• The substrate fits into the active site of the enzyme, similar to a lock and key
• Enzymes work best at an optimal temperature and pH
• High temperatures can denature enzymes, making them ineffective
• Enzymes work best at body temperature (36-38°C)
• The optimal pH varies for different enzymes
• The rate of enzyme activity depends on factors including concentration of substrate, enzyme, and surface area

Chemical and Biological Nature of Enzymes

• Enzymes are made of proteins
• Proteins contain elements C, N, O, and H
• The monomers of proteins are amino acids
• Amino acids have an amino group, a carboxyl group, and a variable R-group.

Factors Affecting Enzymes

• Enzyme function is affected by temperature and pH
• Higher temperatures (below 40°C) increase enzyme activity
• Temperatures above 40°C denature enzymes, decreasing their activity
• Too low temperatures decrease enzyme activity
• Different enzymes have different optimal temperatures and pH values
• Surface area and concentration of enzymes affect the rate of reaction

pH

• The optimal pH is different for different enzymes
• Pepsin (stomach enzyme) works best at a pH of 2
• Catalase (found in all cells) does best between pH 4-11

Enzymes are Substrate Specific

• Enzymes are highly specific to their substrates
• Substrates bind to the active site of the enzyme
• This is called the 'induced fit' theory
• The substrate is changed to a different substance which is called a product
• Enzymes can either build up (anabolism) or else break down (catabolism) a substance

Economic Importance of Enzymes

• Enzymes are used in various industries
• Rennin is used to coagulate milk for cheese production
• Cellulase and amylase to remove waxes, oils, and starches from fabrics
• Amylase, protease, lipases, oxidases and cellulases are used in detergents

Holozoic Nutrition

• This is the method of obtaining organic food from other living organisms
• This is how animals obtain nutrients
• The food is digested
• The soluble products are absorbed into the bloodstream
• Indigestible waste is eliminated

Saprophytic Nutrition

• This is the method of obtaining food by decomposing organic matter
• This is how bacteria and fungi obtain nutrients
• They digest organic matter with their secreted enzymes.
• The soluble products are absorbed

Holophytic Nutrition

• This type of nutrition is specific to green plants
• They make their organic food by photosynthesis
• Combining carbon dioxide and water

Holozoic Nutrition in Animals

• Includes ingestion, digestion, absorption, and egestion of food
• Details of structure are given and functions of a few major structures

Ingestion

• The process of taking food into the mouth
• Incisors are used to cut food, canine to tear it apart
• Pre-molars and molars crush and chew the food
• Buccal cavity contains the tongue and teeth inside the mouth
• The pharynx is the throat
• Oesophagus is the food pipe
• Swallowing action is required for moving food down the oesophagus through the pharynx and into the stomach

Digestion in the stomach

• The stomach has elastic walls
• The stomach prepares food for assimilation, the process of transferring molecules into the cells.
• The stomach digests food using pepsin and hydrochloric acid
• A churning effect mixes food with pepsin and hydrochloric acid
• Storage occurs in the stomach before sending food through the rest of the digestive system.

Digestion in the duodenum and the ileum

• Enzymes are produced in the pancreas and liver and released into the duodenum
• Enzymes such as trypsin, amylase and lipase are used to break down proteins, carbohydrates and fats.
• Bile is produced in the liver and stored in the gall bladder, and is released into the duodenum
• Bile suspends fats which allows for easier digestion.
• Further digestion in the ileum is done with enzymes such as maltase, sucrase and lactase to convert carbohydrate into glucose
• Amino acids, glucose, glycerol and fatty acids pass through the villi

Use of digested food

• The blood transports the digested foods around the body
• Assimilation of food occurs in cells
• Glucose is either used immediately or stored as glycogen in the liver or muscles.
• Excess glucose can be stored in fat depots
• Fats are used in cell structures
• Protein is made from amino acids, used in metabolism or stored.

Test your knowledge on enzymes, their functions, and the factors affecting enzyme activity. This quiz covers critical concepts such as the chemical nature of enzymes, their optimal conditions, and specific substrate interactions. Ideal for students studying biology.