B2 - Organisation Flashcards
What is the main function of the digestive system?
To digest food and absorb the nutrients obtained from digestion.
What is the role of the pancreas and the salivary gland in the digestive system?
The pancreas and the salivary gland produce digestive juices containing enzymes.
What is the role of the stomach in the digestive system?
Produces hydrochloric acid, which kills any bacteria present and provides the optimum pH for protease to function.
What is the role of the small intestine in the digestive system?
Site where soluble food molecules are absorbed into the bloodstream.
What is the role of the liver in the digestive system?
Produces bile which emulsifies lipids and allows lipase to work more efficiently.
What is the role of the large intestine in the digestive system?
Absorbs water from undigested food, producing faeces.
What is the role of enzymes in the digestive system?
Act as biological catalysts which speed up the rate of biological reactions.
How does the shape of any enzyme affect its function?
Have a specific active site which is complementary to their substrate.
Metabolism.
The sum of all the reactions in a cell or an organism.
What is the lock and key hypothesis of enzyme function?
The shape of the enzyme active site and the substrate are complementary, so can bind together to form an enzyme-substrate complex.
How does temperature affect enzyme action?
Up to a certain point, increasing temperature increases enzyme action, as molecules have a higher kinetic energy. Above a certain temperature, the shape of the active site is altered and the enzyme becomes denatured, so it can no longer catalyse the reaction. The optimum temperature is around 37 degrees.
How does pH affects enzyme function?
The optimum pH for most enzymes is 7. If the pH is too extreme, the shape of the active site may be altered and the enzyme may no longer work.
Where is Carbohydrase produced?
Salivary gland
Pancreas
Where is Protease found?
Stomach
Pancreas
Small intestine
Where is Lipase found?
Pancreas
Small intestine
Role of Carbohydrases.
Break down carbohydrates into monosaccharides and disaccharides. Amylase breaks down starch into maltose, and maltase breaks down maltose into glucose.
Role of Proteases.
Break down proteins into amino acids.
Role of Lipases.
Break down lipids into fatty acids and glycerol.
How are the products of Digestion used?
Used to build bigger molecules. Glucose is used as a substrate in respiration.
Where is bile made and stored in the body?
Bile is made by the liver and stored in the gallbladder.
What is the role of Bile in the digestive system?
An alkaline substance which neutralises the hydrochloric acid secreted by the stomach.
What is the heart?
An organ that pumps blood around the body.
What is the purpose of the circulatory system?
Carries oxygen and other useful substances to bodily tissues, and removes waste substances.
How does the double circulatory system work?
One pathway carries blood from the heart to the lungs.
One pathway carries blood from the heart to the tissues.
Where does blood pumped by the right ventricle go?
The lungs.
Where does blood pumped by the left ventricle go?
Body tissues.
Why is the double circulatory system important?
It makes the circulatory system more efficient.
How many chambers does the heart have and what are they called?
4 - right atrium, right ventricle, left atrium, left ventricle.
Why is the wall of the left ventricle thicker?
The left ventricle has to pump blood at a higher pressure around the whole body.
What are four main blood vessels associated with the heart?
Aorta (left) - carries oxygenated blood from the heart to the body.
Pulmonary Vein (left) - carries oxygenated blood from the lungs to the heart.
Vena cava (right) - carries deoxygenated blood from the body to the heart.
Pulmonary artery (right) - carries deoxygenated blood from the heart to the lungs.
What is the purpose of valves in the heart?
Prevent the backflow of blood.
What is the purpose of coronary arteries?
Coronary arteries supply the heart muscles with oxygenated blood.
Describe the process of blood flow through the heart.
Blood enters the right atrium via the vena cava, and the left atrium via the pulmonary vein.
The atria contract, forcing blood into the ventricles and causing valves to shut.
After the ventricles contract, blood in the right ventricle enters the pulmonary artery and blood in the left ventricle enters the aorta.
What is the approximate value of the natural resting heart rate?
70 beats per minute.
How is the heart rate controlled?
Controlled by a group of cells in the right atrium which act as a pacemaker. They release waves of electrical activity which cause the heart muscle to contract.