Ch3: Food Flashcards
What is nutrition?
The way in which organisms obtain and use food
What are nutrients?
the substances in food that are used by organisms
What are nutrients necessary for?
-Energy
-Growth and repair
-Metabolic reactions
How many elements mainly make food?
Of which, which are called minerals?
14
All except for carbon, hydrogen and oxygen are minerals
What are the 6 most common elements in food?
-Phosphorus
-Hydrogen
-Oxygen
-Nitrogen
-Carbon
-Sulfur
PHONCS
Which elements are trace elements (only required in tiny amounts)?
-Zinc
-Iron
-Copper
ZIC
What elements are present as dissolved salts?
-Sodium
-Magnesium
-Chlorine
-Calcium
-Potassium
Salty Milk Can’t Choose Potatoes
What are biomolecules?
Chemicals that are made inside a living thing
What are the 4 major biomolecules in food?
-Lipids (fats/oils)
-Carbohydrates
-Vitamins
-Proteins
LCVP
link molecules (modules)
What elements are present in carbohydrates?
-Carbon
-Hydrogen
-Oxygen
What is the ratio of the elements for carbohydrates?
Cx(H2O)y Where x = y
What are the 3 types of carbohydrates?
-Monosaccharides
-Disaccharides
-Polysaccharides
Describe monosaccharides
-Single sugar unit
-Smallest type of carbohydrate
-Sweet to taste and soluble in water
-Examples: Glucose, Fructose and, Galactose
Describe disaccharides
-Made of 2 sugar units joined together
-Sweet-tasting and soluble in water
-Examples: Maltose (2 glucose molecules), Sucrose (A glucose joined to a fructose)
Describe polysaccharides
-Made of many sugar units
-Insoluble or slightly soluble in water
-Not sweet-tasting
-Examples: Starch, cellulose, glycogen
Describe starch
-Made of many glucose molecules joined together
-The carbohydrate stored by plants
-Easily digested as only two chemical bonds must be broken to release a glucose
Describe cellulose
-Made of many glucose molecules joined together by cross-bonding
-Very strong
-Very difficult to digest
Describe glycogen
-Made of large numbers of glucose molecules arranged in branched chains
-Animals store glycogen in their liver and muscles
Name 4 sources of carbohydrates
-Bread
-Pasta
-Rice
-Sugars
-Fruits
-Sweets
-Cakes
What is the structural role of carbohydrates?
Cellulose is used to form plant cell walls
What is the metabolic role of carbohydrates?
-Glucose is broken down in respiration to release energy
-Glucose is made in photosynthesis
What are the elements in lipids?
Contain carbon, hydrogen and oxygen (very little oxygen)
What is the structure of lipids?
The smallest lipids have 1 molecule of glycerol linked to 3 fatty acid molecules (triglycerides)
What are phospholipids?
Fat-like substances in which one of the fatty acids is replaced by a phosphate group or has a phosphate group added to it
What are sources of lipids?
-Butter
-Margarine
-Fat on meat
-Fried food
-Cream
-Avocado
-Oil
What are the structural roles of lipids?
-They are an important place to store energy in plants and animals (twice as much as carbohydrates)
-They provide heat insulation and protect organs
-Lipids combine with phosphorus (phospholipids) and with proteins (lipoproteins) to form cell membranes
What is the metabolic role of lipids?
They can be broken down in respiration to release energy
What are the elements in proteins?
Carbon
Hydrogen
Oxygen
Nitrogen
(sometimes small amounts of sulfur, phosphorus and other elements)
Describe the structure of proteins
-Composed of amino acids
-Amino acids are joined by a peptide bond
- How many amino acids exist?
- What is a peptide?
- What is a polypeptide?
- 20
- A peptide has less than 20 amino acids
- A polypeptide has more than 20 amino acids
- What does protein folding do?
- What does incorrect protein folding do?
- Protein folding determines how a protein will work
- Incorrect protein folding produces prions which cause diseases like BSE in cattle and CJD in humans
What is fibrous protein? Give examples
Fibrous protein has little or no folding and are strong and tough
e.g. Keratin in hair, nails, and feathers
What is globular protein? Give examples
Globular proteins have lots of folding and form rounded shapes
e.g. Egg whites (albumin) and enzymes
What are sources of proteins?
-Meat
-Fish
-Eggs
-Nuts
-Milk
-Peas
-Beans
What happens to excess amino acids?
Because amino acids are not stored in the body, excess amino acids are converted into urea in the liver in a process called deamination.
The urea is carried in the blood to the kidneys and excreted in urine
What is the structural role of proteins?
-Fibrous protein found in skin and hair (Keratin)
-Myosin found in muscle
What is the metabolic role of proteins?
-Used as enzymes to control reactions
-Form antibodies to fight infections
-Hormones regulate body reactions
Name a water-soluble vitamin and a fat-soluble vitamin
Water-soluble: Vitamin C
Fat-soluble: Vitamin D
What are sources of vitamin C?
-Vegetables (peppers)
-Fresh fruit (oranges)
What is the metabolic roles of vitamin C?
-Forms connective tissue, bones and teeth
-Involved in wound healing and the immune system
What happens when you are deficient in vitamin C?
Causes scurvy
-Bleeding gums, loose teeth, poor skin healing, bleeding under skin
What are sources of vitamin D?
-When UV Light shines on skin
-Egg yolk
-Liver
-Fish oils
-Milk
What is the metabolic role of vitamin D?
-It helps to absorb calcium from intestine
-Needed for healthy bones and teeth
What happens when you are deficient in vitamin D?
Causes rickets (osteomalacia in adults)
-Weak, deformed bones that break easily
Name 2 minerals plants need and their function
-Magnesium: needed to form chlorophyll
-Calcium: holds cell walls together
Name 2 minerals animals need and their function
-Iron: helps form haemoglobin
-Calcium: helps form bones and teeth
Why is water important for living things?
-Universal solvent- most things dissolve in it
-Transports materials
-Participates in chemical reactions
-Moves in and out of cells to give them the correct shape
-Good absorber of heat, which provides a stable temperature for living things and their reactions
-Component of cytoplasm, tissue fluid and blood plasma
What percentage of cell mass is water?
75%-90%
What is metabolism?
The sum of all the chemical reactions in an organism
What are anabolic reactions?
They use energy to convert smaller molecules to larger molecules
e.g. formation of muscle from amino acids, photosynthesis
What are catabolic reactions?
They release energy when a large molecule is broken down to smaller ones
e.g. Digestion, respiration
How do you test for reducing sugar?
-Control: water + Benedict’s solution
-Test: Diluted honey + Benedict’s solution
-Hot water bath
-If reducing sugar is present- blue to turn brick red
How do you test for starch?
-Control: Water + Iodine
-Test: Starch solution + iodine
-If starch is present the mixture will turn blue-black
How do you test for fat?
-Brown pieces of paper
-Control: 2 drops of water
-Test: 2 drops of oil
-Wait to dry
-If fat is present, there will be a permanent translucent stain when held up to a light source
How do you test for protein?
-Control: water + Sodium hydroxide and copper sulfate solution
-Test: Milk + Sodium hydroxide and copper sulfate solution
-If protein is present, it will be purple
