Food & Digestion Flashcards
What is a balanced Diet
A diet consisting of correct proportions of:
- Carbohydrates
- Lipids
- Protiens
- Dietary Fiber
- Water
- Vitamins
- Minerals
What is the function of carbohydrates
To provide energy
What is the function of protiens
For growth and repair
What is the function of Lipids
For insulation and energy.
What is the function of Dietary Fiber
To provide bulk to the food so that the intestines have something to push on when moving food.
What is the function of Vitamins
These are needed in small quantities in order tomaintain health.
What is the function of minerals
These are needed in small quantities in order to maintain health
What is the function of Water
This is required for chemical reactions to take place within the cells.
What are some sources of carbohydrates
Bread, pasta, potatoes, rice
What are some sources of proteins
Eggs, meat, fish, nuts
What are some sources of lipids
butter, oils, nuts
What are some sources of Dietary Fiber
Vegetables, whole grain
What are some sources of Water
Water, Fruits and Vegetables, Jiuce, Milk
What is the function of Vitamin A
Required for Vision, especially night vision. It also makes a chemical in retina that protects the surface of the eye.
What is the function of Vitamin C
Required to produce collagen that is required to make up skin, gums, bones and hair
What is the function fo Vitamin D
This helps the body absorb calcium, which is required in making strong teeth and bones
What is the function of Calcium
Used to make strong teeth and Bones and involved in the clotting of blood.
What is the function of Iron
They are required to make Hemoglobin, the red pigment in blood used to carry oxygen around the body.
What are the sources of Vitamin A
Carrots, green vegetabes, Fish, Cheese, Eggs.
What are the sources of Vitamin C
Citrus Fruit, Strawberries, Green Vegetables.
What are the sources of Vitamin D
Oily Fish, Naturally produced by our bodies when exposed to sunlihgt, Liver, eggs
What are the sources of Calcium
Milk, cheese, eggs
What are the sources of Iron
Red Meat, Green Vegetables like: Spinach.
What is caused by a lack of Vitamin A
Night Blindnesss
What is caused by a lack of Vitamin C
Scurvy
What is caused by the lack of Vitamin D
Rickets
What is caused by a lack of Calcium
Osteoporosis
What is caused by the lack of iron
Aneamia
What are some of the causes of Inaccurate results in finding the energy content
- Incomplete burning of food sample
- Heat loss occurs because not all of the heat is used to heat up the water, insted some will be used to heat up the air, boiling tube and thermometer.
What are the chemical elements present in Carbohydrates
Carbon, Oxygen, Hydrogen
What are the chemical elements present in Proteins
All have: carbon, oxygen, hydrogen and nitrogen. But some also have other elements like: sulphur
What are the chemical elements present in Lipids
Carbon, Oxygen, Hydogen
Basic Unit of Carbohydrates
Simple Sugar molecules
1 Sugar Molecule - Monosacharide
2 Sugar Molecules - Disacharide(Maltose)
Many Sugar Molecules - Polysacharide (carbohydrate or starch)
Basic Unit of Protein
Amino Acids
The proteins are formed according to the way in which the Amino Acids are arranged.
There are 20 different Amino Acids
Basic Unit of Lipids
Triglycerides consisting of 1 Glycerol Molecule connected to 3 fatty acid molecules
Common Safety Precautions
- Wear gloves and Goggles.
How to test for Glucose
Adding benedict solution to a substance and then heating to observe if the solution changes color to brick red. Then it contains glucose.
Why dosent the Glucose test work with Sucrose (normal table sugar)
Because Sucrose is not a reducing sugar, and the test only works with reducing sugars.
How to test for starch
By adding Iodine solution to the substance and then cheking if a blue-black color is produced. This means that startch is present.
How to test for protein
By adding biuret solution to a food sample. A positive result will show a color change to purple/voilet color
How to test for Lipids
Ethanol is added to the food sample and then after a few minutes if a cloudy layer is formed on top, it means that the sample contains ethanol.
Why do we need food
- To supply the body with energy
- To help protect our bodies from pathogens
- To provide materials for growth and repair or tissues
Why is starch used as a storage carbohydrate in plants.
Because it does not dissolve.
Why cannot humans digest cellulose
Because our body does not make the enzyme required to digest Cellulose
Why is cellulose important
Because it provide dietary fiber that provides the gut with something to push on to move the food through the gut.
This prevents constipation and helps prevent serious diseases in the Intestine.
Why is Fat useful
To provide insulation in the body by preventing heat loss and reducing the dame caused to organs by mechanical damage.
What is the difference between Saturated and Unsaturated Fats
Saturated fats contain single bonds, while unsaturated fats contain double bonds.
Unsaturated fats are from Plant oils, but saturated fats are from meat and eggs.
Unsaturated fats are healthier than saturated fats.
What are essential Amino Acids.
These are the 10 Amino Acids that cannot be produced by humans and need to be taken externally.
What is the definition of Digestion
This is the chemical and Mechanical breakdown of food. It breaks down large insoluble molecules into smaller soluble molecules that can be absorbed into the blood.
What is peristalsis
This is the contraction and relaxation of Muscles in the gut causing waves that push food through the gut.
What is the function of the Mouth
This is where the mechanical digestion takes place. The teeth chew on the food and breaks it down into smaller pieces.
The saliva also contains the Amylase enzyme which digests starch into maltose.
The tongue then roles the food into a bolus.
What is the function of the Oesophagus (gullet)
This connects the mouth to the stomach
Peristalsis movement carries the food from the mouth to the stomach
What is the Function of the Stomach
This mechanically digests the food by churning
It also releases the protease enzyme to break down the proteins
It also contains Hydrochloric Acid to kill any bacteria or other pathogens that might be present in the food and it is used to provide a optimum PH for the Protease enzyme.
What is the function of the small intestine
The food finished being digested in the top section of the small intestine called, “The Duodenum” and then enters the ileum to be further digested
The inside of the ileum is slightly alkaline
This is also where the food nutrients get absorbed into the blood through the Villi.
There are a large number of Villi in the small intestine to increase the absorption rate of nutrients.
What is the function of the Large Intestine
This is where the water from the remaining material gets absorbed and it forms a substance called, Faeces.
The Faeces are stored in the Rectum and is removed from the body through the Anus.
What is the function of the Pancreas
It produces 3 types of Enzymes:
- Carbohydrases (Amylase, Maltase)
- Protease
- Lipase
It secretes the enzymes in a fluid into the Duodenum
What are the 3 main types of Digestive Enzymes
- Protease
- Carbohydrase
- Lipase
Uses of Carbohydrases
Amylase is a type of carbohydrase and digests starch into maltose. This maltose is then further digested into glucose in the duodenum.
Uses of Proteases
Pepsin is produced in the Stomach
Tripsin is produced in the pacreas and secreted into the duodenum
Both pepsin and tripsin digest proteins into peptides
Then peptidase digests peptides into Amino Acids.
Uses of Lipase
These are produced in the Pancrease and are secreted into the dudenum.
They break down lipids into fatty acids and glycerol.
Where is bile made and stored
Bile is produced in the Liver and stored in the Gall Bladder.
What are the main roles of Bile
Bile has 2 main Roles:
- Neutralising the HCl that comes from the stomach because the optimum PH in the Small Intestine is higher than the Stomach. This creates an Optimum PH for the Enzyme in the Stomach to act on the food. - Used to break down large lipid globules in the food into smaller ones so that there is an increased surface Area for the enzymes to act on and this increases the reaction rate. This is called, "Emulsification".
How is the ileum adapted for the absorption of nutrients
- The ileum is very long, increasing the time that food spends inside the ileum, which increases the digesting time.
- The ileum i highly folded, which helps in digesting food and provides an increased surface area.
How are Villi adapted for Absorption of Nutrients
- They have a large surface area with Microvilli fi further increasing the surface area.
- Their cell walls are one cell thick, which provides a short distance for absorption. This increases the rate of absorption
- They are well supplied with a network of blood capillaries that transport glucose and amino acids away from the small intestine.
- A lacteal runs from the middle of the villus, which carries fatty acids and glycerol away from the small intestine and into the lymphatic system
What is assimilation
When the soluble food molecules are absorbed from the blood that contains the nutrients of the food, into the cells and tissues to build new parts of the cell.
