FOOD Flashcards
What is the definition of nutrition?
The way in which an organism obtains and uses its food.
What are nutrients?
Chemical substances present in food that are used by organisms.
NOTE: ESSENTIAL FOR METABOLISM AND CONTINUITY OF LIFE
What are the three functions of food?
1) Provide energy.
2) Produce chemicals that are needed for metabolic reactions.
3) Raw materials for growth + repair of organisms
What are the six main elements found in food?
Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus and Sulfur.
What are the five elements that are present in dissolved salts?
Sodium, Chlorine, Magnesium, Potassium and Calcium.
Name three trace elements.
Iron, Zinc, Copper
What do these trace elements do?
Combine together in different ratios to create biomolecules.
What are biomolecules?
Chemicals that are made inside a living thing.
What are the four main types of biomolecules?
Carbohydrates, Lipids (Fats and Oils), Proteins and Vitamins
What is the Hydrogen: oxygen ratio?
2:1
General formula for carbohydrates is:
C x (H2O) y
What are the main elements present in carbohydrate?
Carbon, Hydrogen and Oxygen.
Formula for glucose is:
C6 H12 O6
What are the three types of carbohydrates?
Monosaccharides, Disaccharides and Polysaccharides
How do you distinguish monosaccharides?
One sugar unit.
Soluble in water.
Have a sweet taste.
Types of monosaccharides.
Glucose: made by plants during photosynthesis
Fructose: found in fruit
How do you distinguish disaccharides?
Two sugar units combined.
Soluble in water.
Have a sweet taste.
Found in table sugar, sugar cane, and milk.
Types of disaccharides.
Glucose + Fructose = Sucrose
Glucose + Galactose = Lactose
Glucose + Glucose = Maltose
How do you distinguish polysaccharides?
Chain of sugar units linked together.
Insoluble in water.
Do not have a sweet taste.
Found in potatoes, pasta, flour, and vegetables.
Types of polysaccharides.
Starch (as an energy store in plants)
Glycogen (as an energy store in animals)
Where is glycogen found?
Muscles and liver.
Uses and functions of carbohydrates:
Metabolism, Photosynthesis, Storage and Structure.
Metabolism in relation to carbohydrates:
Aerobic respiration (with oxygen).
Glucose is broken down into carbon dioxide and water.
Energy is released - CATABOLISM
Photosynthesis in relation to carbohydrates:
Carbon dioxide and water are combined using light energy to create glucose.
Chlorophyll is required for reaction - ANABOLISM
Storage in relation to carbohydrates:
Carbohydrates are stored in the form of starch in plants.
Stored in the form of glycogen in animals.
Structure in relation to carbohydrates:
Cellulose (polysaccharide) is found in plant cell walls.
Chitin (polysaccharide) is found in the exoskeleton of an insect.
What is an anabolic reaction?
It uses energy to convert small molecules into larger molecules
What is a catabolic reaction?
It releases energy when large molecules are broken down into smaller molecules.
What elements do lipids contain?
Carbon, Hydrogen, and Oxygen
Fats are ________ at ____ temperature (__degrees Celsius).
Oils are ______ at this temperature.
solid
room temperature
liquid
What are fats and oils made of?
One molecule of glycerol linked to three fatty acid molecules - triglyceride.
Phospholipids are where…
One of the fatty acids is replaced by a phosphate group.
Phospholipids are important structures where?
In cell membranes.
Saturated fats are usually found in:
Animal food sources-> beef, poultry, and eggs.
Unsaturated fats are usually found in:
Olive oil, seeds, and fish.
What are the functions of lipids?
1) As an energy store in the body
2) Protection of organs and as heat insulation.
3) Lipids combine with phosphorus and proteins to form cell membranes.
What are the elements present in proteins?
Carbon, Hydrogen, Oxygen and Nitrogen.
Sometimes proteins contain:
Phosphorus and Sulfur
Proteins are made from sub units called…
Amino acids
How many common amino acids are found in protein?
20
What’s the name for a small number of amino acids, usually less then 20?
Peptide
What are peptide bonds?
Bonds between two amino acids.
What peptide has more than 20 amino acids?
Polypeptide.
What is protein?
It’s a very long polypeptide, at least 200 amino acids.
Different ___ combinations produce _______ _____which ____ and take ______ shapes.
AA
Different proteins
Fold
Unique
What plays a central role in a proteins function?
The shape of the protein.
Examples (proteins) :
Enzymes, Hormones, Myosin.
Sources of protein:
Chicken, eggs, nuts, beans.
Name two polypeptide chains.
Fibrous protein and globular protein.
Fibrous protein:
1) Structural protein.
2) Example of it: Keratin and Myosin.
Globular protein:
1) Example of it: Enzymes and Hormones.
Functions of protein:
1) Used for growth and repair
2) Only used as an energy in the event of starvation.
3) 1 gram of protein provides 17kJ of energy.
Structural role of protein:
1) Found in various body tissues e.g. skin and muscle.
2) Structural proteins are embedded with phospholipids to make cell membranes.
3) Other examples: collagen.
Metabolic role of protein:
Enzymes - amylase
Hormones - insulin
The two vitamin groups:
Fat soluble vitamins( A, D, E, K)
Water soluble vitamins (B, C)
Where is vitamin C found?
Citrus fruits.
What is vitamin C required for?
For the formation of connective tissies.
Vitamin C has role in
Growth, maintenance of bones and teeth, and healing wounds and the immune system.
Vitamin C deficiency disease:
Scurvy - bleeding of gums.
Vitamin D is found in:
Milk.
It is made by ____ exposed to the _______
Skin
Sunlight
Function of Vitamin D:
It helps to absorb calcium
It is needed for bone formation and strong teeth.
Vitamin D deficiency in children (explain):
Rickets - deformed bones that easily break.
Vitamin D deficiency in adults (explain):
Osteomalacia - deformed bones that easily break.
What mineral helps plants form chlorophyll?
Magnesium
What mineral helps plant cell walls attach to each other?
Calcium
What mineral helps form hemoglobin in animals?
Iron
What mineral helps form bones and teeth in animals?
Calcium
Water is a ______ of _______ and ____ _____.
Component
Cytoplasm
Body fluids
Functions of water:
1) Transports dissolved substances
2) Plays a role in chemical reactions e.g. photosynthesis and digestion
3) Gives plants cells shape and rigidity.
4) Absorbs heat - helps stabilize the temperature of organisms.
Describe how you carried out the reducing sugars test?
I dissolved glucose in water in a test tube. I added an equal volume of Benedict’s solution. Benedict’s original colour is blue. I then set up a separate tube with equal volumes of water and Benedict’s solution to act a as control. I heat the test tubes in a boiling water bath. If reducing sugars is present the solution will turn a brick red and if there is no rs present then it will remain blue.
Describe how you carried out the test for starch.
I added a few drops of iodine to starch dissolved in water. Iodine’s original colour is red-yellow. I added a few drops of iodine to some water to act as a control. If starch is present the colour turns a blue-black if starch is absent the colour will remain yellow-red.
How did you carry out the test for lipids?
I labeled a piece of brown paper as liquid and rubbed a small amount of butter on the paper. I repeated the process using a few drops of water on a piece of paper labeled water. I then left both pieces of paper to dry. Lipids produce a permanent stain on the paper while water dries out.
How did you carry out the test for protein?
I dissolved protein in water and added sodium hydroxide until the solution cleared. I then added a few drops of copper sulfate which is bluebut. As a control I added sodium hydroxide and biuret solution to water. If the solution turns a violet colour then protein is present but if the protein is not present the colour remains blue.,
