Organisation
Organisation & Digestive System:
3.1 - Tissues and Organs:
Tissues are groups of cells that have similar functions and structure.
• Muscle Tissue – Contracts for movement
• Glandular Tissue – Secretes substances like enzymes and hormones
• Epithetical Tissue – Protects and covers outside of body and organs
Organs – Groups of tissue that carry a specific function
Organ System – Group of organs like digestive system
Adaptations are high SA, rich blood supply, high concentration gradient, and short diffusion path
3.2 - Human Digestive System:
Digestive system changes food from large, insoluble to small and soluble.
• First the mouth mechanically chews food, then the salivary glands release enzymes.
• The stomach mixes the food and liquids.
• The liver releases bile into the small intestine (bile is stored in gallbladder) which emulsifies
lipids into fatty acids and maintains acidic pH of the stomach.
• The small intestine mix food with digestive juices from the pancreas, liver, and intestine, and
the walls of the small intestine absorb water and the digested nutrients into your
bloodstream.
• The large intestine absorbs water.
3.3 - Chemistry of Food:
, Carbohydrates – give us fuel that make reactions of life possible and contain carbon, oxygen and
hydrogen. They are made up of sugars. Some are simple sugars like glucose and some are complex
like cellulose and starch. Carb-rich food include pasta, rice and potatoes.
Lipids – Fats and oils which are an energy store and are important in cell membrane, hormones and
nervous system. Lipids are insoluble in water. They are made up of three molecules of fatty acids
and 1 molecule of glycerol. Lipid-rich foods are oils and butter, cheese and cream.
Proteins – Used to build up cells and tissues and enzymes. Proteins are made of oxygen, hydrogen,
nitrogen and carbon. Protein rich foods are fish, chicken and cheese. Proteins are made of long
chains of amino acids. Proteins are denature depending on the temperature and pH as they lose
their shape. Proteins play a role in the structure of muscle tissue, hormones, antibodies and
enzymes.
3.4 - Catalysts and Enzymes:
Enzymes – biological catalysts made of proteins.
Active site binds to specific substrate molecule and according to the lock and key theory a reaction
occurs and the products are released from the surface of the enzyme.
Metabolic reactions are catalysed by enzymes. Building large molecules from small ones like glucose
made into starch or cellulose or changing molecules like simple sugars e.g. glucose to fructose. Also,
large molecules into small ones like carbs, lipids and proteins into their products during digestion.
3.5 - Factors affecting Enzyme action:
Enzymes work quicker with a higher temperature until 40 degrees+ as enzymes shape begin to
denature and it won’t fit into the substrate.
A change in pH affects the forces holding different parts of the enzyme protein together, therefore
when pH changes the active site shape is changed and the enzymes stop working.
3.6 - How the Digestive System works:
Digestive enzymes are made in glands and lining of digestive system. They operate outside cells and
contact food. The digestive system has a large SA, different pH in areas to allow for maximum
efficiency of enzymes and the digestive enzymes mix food with digestive juices.
Organisation & Digestive System:
3.1 - Tissues and Organs:
Tissues are groups of cells that have similar functions and structure.
• Muscle Tissue – Contracts for movement
• Glandular Tissue – Secretes substances like enzymes and hormones
• Epithetical Tissue – Protects and covers outside of body and organs
Organs – Groups of tissue that carry a specific function
Organ System – Group of organs like digestive system
Adaptations are high SA, rich blood supply, high concentration gradient, and short diffusion path
3.2 - Human Digestive System:
Digestive system changes food from large, insoluble to small and soluble.
• First the mouth mechanically chews food, then the salivary glands release enzymes.
• The stomach mixes the food and liquids.
• The liver releases bile into the small intestine (bile is stored in gallbladder) which emulsifies
lipids into fatty acids and maintains acidic pH of the stomach.
• The small intestine mix food with digestive juices from the pancreas, liver, and intestine, and
the walls of the small intestine absorb water and the digested nutrients into your
bloodstream.
• The large intestine absorbs water.
3.3 - Chemistry of Food:
, Carbohydrates – give us fuel that make reactions of life possible and contain carbon, oxygen and
hydrogen. They are made up of sugars. Some are simple sugars like glucose and some are complex
like cellulose and starch. Carb-rich food include pasta, rice and potatoes.
Lipids – Fats and oils which are an energy store and are important in cell membrane, hormones and
nervous system. Lipids are insoluble in water. They are made up of three molecules of fatty acids
and 1 molecule of glycerol. Lipid-rich foods are oils and butter, cheese and cream.
Proteins – Used to build up cells and tissues and enzymes. Proteins are made of oxygen, hydrogen,
nitrogen and carbon. Protein rich foods are fish, chicken and cheese. Proteins are made of long
chains of amino acids. Proteins are denature depending on the temperature and pH as they lose
their shape. Proteins play a role in the structure of muscle tissue, hormones, antibodies and
enzymes.
3.4 - Catalysts and Enzymes:
Enzymes – biological catalysts made of proteins.
Active site binds to specific substrate molecule and according to the lock and key theory a reaction
occurs and the products are released from the surface of the enzyme.
Metabolic reactions are catalysed by enzymes. Building large molecules from small ones like glucose
made into starch or cellulose or changing molecules like simple sugars e.g. glucose to fructose. Also,
large molecules into small ones like carbs, lipids and proteins into their products during digestion.
3.5 - Factors affecting Enzyme action:
Enzymes work quicker with a higher temperature until 40 degrees+ as enzymes shape begin to
denature and it won’t fit into the substrate.
A change in pH affects the forces holding different parts of the enzyme protein together, therefore
when pH changes the active site shape is changed and the enzymes stop working.
3.6 - How the Digestive System works:
Digestive enzymes are made in glands and lining of digestive system. They operate outside cells and
contact food. The digestive system has a large SA, different pH in areas to allow for maximum
efficiency of enzymes and the digestive enzymes mix food with digestive juices.
