Model & System - Nutrients/ Digestion

Question 1

Chemical elements which make up carbohydrates

Answer 1

Carbon, hydrogen and oxygen atoms

Question 2

Chemical elements which make up fats

Answer 2

Carbon, hydrogen and oxygens

Question 3

Chemical elements that make up proteins

Answer 3

Carbon, hydrogen, oxygen, nitrogen, sulfur (sometimes)

Question 4

Glycogen from?

Answer 4

Glucose

Question 5

Polypeptides and proteins from?

Answer 5

Amino acids

Question 6

Lipids such as fats from?

Answer 6

Glycerol and fatty aids

Question 7

Starch test

Answer 7

• use iodine solution
• Observation: Blue Black = starch is present

Question 8

Reducing sugar test

Answer 8

• 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

Question 9

Protein test (biuret test)

Answer 9

• Shake sodium hydroxide together with sample
• • copper sulfate solution
• Observation: Blue/ violet = a protein is present

Question 10

Test for fats (Ethanol emulsion test)

Answer 10

• Add ethanol to sample and shake
• add distilled water and shake agn
• Observation: Mixture forms white emulsion = fat is present

Question 11

Function of carbohydrates

Answer 11

Source of energy for the body

Question 12

Carbohydrates: Single sugars

Answer 12

• basic unit of carbohydrates
• can be absorbed into the bloodstream by diffusion
  E.g. glucose/fructose

Question 13

Carbohydrates: Double sugars

Answer 13

• formed when 2 single sugars are joined together
  E.g. maltose
  Glucose + glucose = maltose

Question 14

Complex carbohydrates

Answer 14

• made up of many sugar molecules joined together
  E.g. starch => plants store glucose in the form of starch

Question 15

Digestion of carbohydrates

Answer 15

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

Question 16

Difference in digestion of starch and sugary foods

Answer 16

• 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

Question 17

Function of fats

Answer 17

• 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

Question 18

Digestion of fats

Answer 18

In the body, fats can be broken down to make smaller molecules such as fatty acids and glycerol
*Fats=> fatty acids + glycerol

Question 19

Functions of proteins

Answer 19

• 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

Question 20

Structure of proteins

Answer 20

1. Amino acids are building blocks of proteins
2. Amino acids are joined together to form polypeptides
3. When one or more chains of amino acids are folded together in a 3-dimensional figure, it is called a protein

Question 21

Dietary fibre

Answer 21

• 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

Question 22

Vitamins

Answer 22

• needed in small amounts
• essential for metabolism
• from fruits and vegetables

Question 23

Minerals

Answer 23

• 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

Question 24

Digestion in digestive organs

Answer 24

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

Question 25

Processes involved with nutrients: ingestion

Answer 25

Taking in of nutrients by eating or drinking

Question 26

Processes involved with nutrients: Digestion

Answer 26

Large food molecules are broken down into smaller soluble molecules that can be absorbed into the body cells

Question 27

Processes involved with nutrients: Absorption

Answer 27

Nutrients move from the small intestine into the blood stream by diffusion

Question 28

Processes involved with nutrients: Assimilation

Answer 28

The use of nutrients by the cell to provide energy or to make new protoplasm for growth

Question 29

Processes involved with nutrients: Egestion

Answer 29

The removal of indigested matter from the body

Question 30

Physical digestion

Answer 30

• 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.

Question 31

Chemical digestion

Answer 31

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.

Question 32

Digestive enzymes

Answer 32

• speeds up chemical reactions in the body

Question 33

Different types of enzymes

Answer 33

Starch=> maltose (amylase)
Proteins=> amino acids (protease)
Fats=> fatty acids and glycerol (lipase)