Model & System - Nutrients/ Digestion Flashcards
Chemical elements which make up carbohydrates
Carbon, hydrogen and oxygen atoms
Chemical elements which make up fats
Carbon, hydrogen and oxygens
Chemical elements that make up proteins
Carbon, hydrogen, oxygen, nitrogen, sulfur (sometimes)
Glycogen from?
Glucose
Polypeptides and proteins from?
Amino acids
Lipids such as fats from?
Glycerol and fatty aids
Starch test
- use iodine solution
- Observation: Blue Black = starch is present
Reducing sugar test
- use Benedict’s solution (mix sample)
- place test tube in boiling water
- Observation: blue = no reducing present
Green = little reducing sugar present
yellow/ orange = Moderate amount of reducing sugar present
Brick red = a large amount of reducing sugar present
Protein test (biuret test)
- Shake sodium hydroxide together with sample
- copper sulfate solution
- Observation: Blue/ violet = a protein is present
Test for fats (Ethanol emulsion test)
- Add ethanol to sample and shake
- add distilled water and shake agn
- Observation: Mixture forms white emulsion = fat is present
Function of carbohydrates
Source of energy for the body
Carbohydrates: Single sugars
- basic unit of carbohydrates
- can be absorbed into the bloodstream by diffusion
E.g. glucose/fructose
Carbohydrates: Double sugars
- formed when 2 single sugars are joined together
E.g. maltose
Glucose + glucose = maltose
Complex carbohydrates
- made up of many sugar molecules joined together
E.g. starch => plants store glucose in the form of starch
Digestion of carbohydrates
Carbohydrates are broken down by the body into maltose, and is then further broken down to form glucose, the basic unit of carbohydrates
*Carbohydrates=> maltose=> glucose + glucose
Difference in digestion of starch and sugary foods
- sugary foods and drinks can be quickly broken down to form glucose, which can be quickly absorbed into the bloodstream. This provides a short-lasting energy boost
- Starch is a long, complex molecule which is harder to break down into glucose. This means that it releases energy more slowly. As such it is known as a slow-release carbohydrate
Function of fats
- storage of energy in the body
- the body can use fats as a source of energy (only if carbohydrates are exhausted)
- to provide insulation for the body, preventing excessive heat loss
- found in cell membranes
- provide cushioning for vital organs to protect them.
- a way to reduce water loss from skin surface
- some hormones are made from a lipid called cholesterol
Digestion of fats
In the body, fats can be broken down to make smaller molecules such as fatty acids and glycerol
*Fats=> fatty acids + glycerol
Functions of proteins
- Important in growth, development, and repair for worn-out cells
- used in the formation of antibodies to combat diseases
- Forms enzymes that help us speed up the chemical reactions in our body
Structure of proteins
- Amino acids are building blocks of proteins
- Amino acids are joined together to form polypeptides
- When one or more chains of amino acids are folded together in a 3-dimensional figure, it is called a protein
Dietary fibre
- made from cellulose from plant cell walls that your body cannot break down
- it helps the digestive system to move the food we eat through the intestines and push the waste material out of the body
Vitamins
- needed in small amounts
- essential for metabolism
- from fruits and vegetables
Minerals
- vital to good health
- important minerals include:
E.g. Iron=> needed to transport oxygen in the blood
Calcium=>for bones and teeth
Zinc, to help heal wounds
Digestion in digestive organs
Input: Large insoluble food molecules
mouth: physical and chemical digestion
Stomach: physical and chemical digestion
Small intestine: chemical digestion and absorption
Output: small water-soluble food molecules
Processes involved with nutrients: ingestion
Taking in of nutrients by eating or drinking
Processes involved with nutrients: Digestion
Large food molecules are broken down into smaller soluble molecules that can be absorbed into the body cells
Processes involved with nutrients: Absorption
Nutrients move from the small intestine into the blood stream by diffusion
Processes involved with nutrients: Assimilation
The use of nutrients by the cell to provide energy or to make new protoplasm for growth
Processes involved with nutrients: Egestion
The removal of indigested matter from the body
Physical digestion
- chewing and peristalsis
- Chewing in the mouth helps to increase the surface area of the food for enzyme action.
- Peristalsis is a series of muscular wave-like contractions that occurs along the alimentary canal (oesophagus, stomach, small intestine). It helps to push the food along the gut and also enables food to be mixed with digestive juices.
Chemical digestion
Involves the breakdown of large molecules of proteins, starch and fats into small soluble molecules.
These reactions involve digestive enzymes that act as a catalyst to speed up the rate of a reaction.
Digestive enzymes
- speeds up chemical reactions in the body
Different types of enzymes
Starch=> maltose (amylase)
Proteins=> amino acids (protease)
Fats=> fatty acids and glycerol (lipase)
