Food- Flashcards
What is food?
Food is any substance that is used by a living organism to provide energy, materials for repair and maintenance or to control metabolism
What are bio molecules?
Biomolecules are chemicals that are made inside a living thing.
What is the chemical composition of carbohydrates?
All carbohydrates contain the elements carbon, hydrogen and oxygen
What is the general ratio in carbohydrates?
2:1 , hydrogen 12, oxygen 6
What is the chemical composition of glucose?
Glucose = C6, H12, O6
What is a monosaccharide?
A single sugar unit.
Give an example of a monosaccharide.
Glucose, Fructose, Galactose
What are disaccharides?
Is two units of sugar.
Give an example of a disaccharide.
Sucrose, Lactose, Maltose
What are a polysaccharides?
Polysaccharides are many sugar units
Give an example of a polysaccharide.
Cellulose, starch, glycogen, chitin,
What are the roles of cellulose?
It is used in the cell walls of plants.
In humans it is very difficult to digest so we use as fibre in our diet.
Name the four food bio molecules
Carbohydrates, proteins, lipids and vitamins.
What are the six common elements found in food?
Carbon (c), Hydrogen (h), oxygen (o), nitrogen (n), phosphorus (p) and sulfur (s)
Five elements in dissolved salts>
Sodium (Na), Magnesium (Mg), chlorine (Cl), potassium (k) and calcium (Ca)
Name three trace elements.
Iron (Fe), Copper (Cu) and Zinc (Zn)
How do plants make glucose?
Photosynthesis
What sugar is in table sugar?
Sucrose
Name some reducing sugars.
Maltose, glucose, frutose
What is another name for starch?
Amylose
Name the metabolic roles of carbohydrates.
Glucose is broken down in respiration to release energy.
Glucose is made in photosynthesis
What is the structural role of carbohydrates?
Cellulose is used to form plant cell walls.
Why is cellulose hard to digest?
Because it has many cross-bonds.
What is the most abundant chemical in living things?
Water
Give five functions of water.
Makes up the bulk of cytoplasm, also found in tissue fluid and blood.
It is a good solvent that allows cell reactions to take place and transport
Gives cells their correct shape
It is a good absorber of heat, it helps maintain stable temperature
Participates in cell reactions
Give three reasons why water is essential to life.
It is the liquid which all metabolic reactions take place
Basis for transport systems
Environment which many organisms live in
What elements do lipids contain?
Lipids contain carbon, hydrogen and oxygen
Name the two types of lipids
Oils- liquid at room temperature
Fats- solid at room temperature
What is the smallest unit of a lipid called?
Triglyceride
What is composition of a triglyceride?
One molecule of glycerol and three molecules of fatty acids.
What is the composition of a phospholipid?
One molecule of glycerol,
two molecules of fatty acids and one molecule of phosphate
Name three sources of lipids
Red meat, dairy products and vegetable oils.
Function of lipids in diet
Provide energy and source of fat-soluble vitamins.
Structural role of lipids
Stores energy
Heat Insulation
Protection of organs
Cell membranes (phospholipids and lipoproteins)
Metabolic role of lipids?
Broken down in respiration to provide energy
Energy is used to carry out other metabolic reactions
How many amino acids is there?
20
What is the bond between amino acids called?
Peptide bond
How many amino acids are in a peptide bond?
Less than 20
How many amino acids are in a polypeptide bond?
Less than 200
How many amino acids are in a protein?
More than 200
Properties of fibrous proteins?
Little or no folding
Form long fibres
Strong and tough
Eg. Keratin in nails, hair and feathers, myosin in muscles
Properties of globular proteins?
Lots of folding
Form rounded shapes
Eg. Enzymes, antibodies, hormones
Sources of protein
Meat, fish, eggs, nuts, peas, beans,
Structural role of proteins
Fibrous proteins, keratin in nails and hair, myosin in muscles
Metabolic role of proteins
Proteins are used as enzymes to control metabolic reactions
Antibodies are used to fight infections
Hormones regulate body reacctions
Composition of vitamins?
Carbon based,
Only needed in small amounts
The body cannot make them
Give an example of water soluble vitamin.
Vitamin C
its an ascorbic acid
Sources of Vitamin C
Vegetables, fresh fruit, oranges, lemons
Metabolic role of Vitamin C
Formation of connective tissue eg. skin, gums
Growth and maintenance of bones and teeth
Immune system
Help wounds heal
What does lack of vitamin C cause?
Scurvy
Symptoms of scurvy: Bleeding gums Loss of teeth Poor healing of the skin Bleeding under the skin
Name a fat-soluble vitamin.
Vitamin D
Sources of Vitamin D
Liver, milk, egg yolk, fish oils, sunlight
Metabolic role of vitamin D
Helps absorb calcium from the intestine
Needed for healthy teeth and bone formation
What does lack of Vitamin D cause?
Rickets in children
Osteomalacia in adults
Symptoms:
Weak, deformed bones
Bones beak easily
Why are minerals needed by plants and animals?
- To form rigid body structures such as bone and the cement between plant cell walls (both contain calcium)
- To make soft body parts such as muscle (which requires nitrogen and sulfur)
- To form salts in cell and body fluids (tears, saliva and the liquid part of blood all contain sodium.
- To form biomolecules (such as hemoglobin- iron / chlorophyll- magnesium
Give two examples of minerals that plants need-
Magnesium (Mg)
-Salts in the soil, helps form chlorophyll
Calcium (Ca)
-Salts in the soil, helps cell walls attach to each other.
Give two examples of minerals that animals need.
Iron (Fe)
-Liver, meat, green vegetables, helps form hemoglobin
Calcium (Ca)
-Milk, cheese, dairy products, helps form bones and teeth
What is metabolism?
Is the sum of all the reactions in an organism.
What is an anabolic reaction?
When energy is taken in and used to convert smaller molecules into larger ones
eg. photosynthesis
What is a catabolic reaction?
Larger molecules are broken down into smaller ones and energy is released.
eg. respiration
Name all the experiments of this chapter (food)
- To test for reducing sugar
- To test for starch
- To test for lipids
- To test for protein
What do you use to test for reducing sugar?
Benedict’s solution/ fehling’s solution
What colour does benedict’s solution go if reducing sugar is present?
Red/ orange-red/ brick red
What do you use to test for starch?
Iodine
What colour does iodine go when starch is present?
Turns blue-black or purple
What do you use to test for lipids?
Brown paper/ filter paper
What do you to test for protein?
Biuret solution
contains (sodium hydroxide, copper sulfate)
What colour does the biuret solution turn when protein is present?
Purple
What are phospholipids?
Are fat-like substances in which one of the fatty acids is replaced by a phosphate group or has a phosphate group added to it.
