1.9 The Digestive System Flashcards
What are heterotrophs?
Organisms that cannot synthesize their own nutrients and need to consume food.
What do heterotrophs require to obtain nutrients?
They need to consume food.
What is the typical diet of heterotrophs composed of?
- Proteins
- Carbohydrates
- Fats
- Nucleic acids
- Water
- Vitamins
- Minerals
What is the main energy source for autotrophs?
Photosynthesis.
What is the role of photosynthetic organisms in food chains?
They are the food source for nearly all other organisms.
What are the four main processes involved in nutrition?
- Ingestion
- Digestion
- Absorption
- Egestion
What is digestion?
The process of breaking down food into simple, soluble chemicals.
Where does digestion start?
In the mouth.
What types of digestion occur in the mouth?
- Mechanical
- Chemical
What enzyme in saliva helps break down carbohydrates?
Amylase.
What do essential nutrients refer to?
Nutrients that cannot be made by the body and must be present in the diet.
What are the macromolecules and their sources?
- Carbohydrates: Cereal, fruit
- Lipids: Dairy, nuts
- Proteins: Meat, eggs
- Nucleic Acids: All organic foods
What is the function of proteases?
They break down proteins into amino acids.
What is the function of amylases?
They finish the chemical digestion of carbohydrates.
What do lipases digest?
Lipids into fatty acids and glycerol.
What are enzymes?
Special proteins that speed up chemical reactions in cells.
What is a substrate in the context of enzymes?
Any substance an enzyme acts on. *locking key
What is peristalsis?
A series of wave-like muscle contractions that move food through the digestive tract.
What is the role of the stomach in digestion?
Stores food, churns it, and mixes it with gastric juices for further digestion.
What does the pancreas produce?
- Alkaline fluid
- Pancreatic juices containing enzymes
What is the function of bile?
Helps digest fat and breaks up lipid droplets.
What is chyme?
The acidic fluid that passes from the stomach to the small intestine.
What is the primary function of the small intestine?
Completes chemical digestion and absorbs nutrients.
What structures increase the surface area for absorption in the small intestine?
Villi and microvilli.
What nutrients are absorbed by the villi?
- Glucose
- Amino acids
- Vitamins
- Lipids
What is the main function of the large intestine?
Absorbs water and concentrates wastes.
What is stored in the rectum before egestion?
Faeces.
True or False: The liver processes blood and metabolizes medicines.
True.
Fill in the blank: The _______ is a flap-like structure that prevents food from entering the trachea.
Epiglottis
