Ch.4 Biological Molecules Flashcards
Carbohydrates - Single sugars scientific name
Monosaccharides
Carbohydrates - Monosaccharides common examples
Glucose, fructose (and galactose)
Chem formula: C6 H12 O6
Carbohydrates - Glucose
- Found in plants and animals
- Hexagon-ish shape (refer to notebook)
Carbohydrates - Fructose
- Found in plants, rare in animals
- Pentagon shape (refer to notebook)
Carbohydrates - Double sugars scientific name
Disaccharides
Carbohydrates - Disaccharides common examples
Sucrose, maltose, lactose (sumala)
Carbohydrates - Sucrose
- Found in sugarcane stems, sweet fruits, certain storage roots
- Not found in mammals
- Glucose + Fructose –> Sucrose + Water (GFS)
- Shape in notebook
- Chem formula is C12 H22 O11
- Process can be reversed through hydrolysis
- NOT a reducing sugar
Carbohydrates - Maltose
- Occurs in germinating grains
- Glucose + Glucose –> Maltose + Water
- Shape in notebook
- Chem formula is C12 H22 O11
- Process can be reversed through hydrolysis
Carbohydrates - Lactose
- Glucose + galactose –> Lactose + water
Carbohydrates - Functions
- Source and store of energy
- Form supporting structures eg cellulose cell walls in plants
- Formation of nucleic acids eg DNA
- Make lubricants eg mucus
- Nectar in flowers for pollination
Benedict’s solution test
- Test for the presence of reducing sugars
- Safety note:
1. Do not heat the contents of the test-tube directly w/ a Bunsen flame as hot liquid may spill out and someone nearby mat get hurt
2. Wear safety goggles to protect your eyes
3. Make sure the mouth of the test-tube is pointed away from yourself and others during heating - Heat/water bath needed
- Present: refer to notebook
- Absent: Remains blue
Starch test via iodine solution
- Test for the presence of starch
- Present: Blue-black
- Absent: Remains yellow/brown
Complex carbohydrates - scientific name
Polysaccharides
Polysaccharides - what are they?
Many monosaccharide molecules (eg glucose, fructose) joined to form a long molecule
Polysaccharides - Starch
- Thousand glucose molecules joined together
- Two forms: unbranced (gives the blue-black colour when tested in iodine) and branched
- Structure: refer to notebook
FUNCTION:
- Storage form of carbs in plants
- Can be digested into glucose to provide energy for cell activities
- Found in grains and storage organs of plants eg potato tubers and tapioca
Polysaccharides - Cellulose
- Many glucose molecules joined together
FUNCTION:
- Cell wall in plant cells
- Support structure
- Protects plants from bursting/damage
Polysaccharides - Glycogen
- Branched molecule
- Many glucose molecules joined together
FUNCTION:
- Storage form of carbohydrates in mammals
- Source of energy in cellular respiration to produce ATP
- Stored in the liver and muscles of mammals
Fats + oils scientific name (not lipids)
Triglycerides
Fats - at room temperature
Fats = solid
Oils = liquid
Fat molecules are made out of…
1 Glycerol + 3 Fatty Acids –> Fat molecule + Water
Check notebook for structure
Fat - sources
Salmon, red herring, butter, cheese, olivers
Fat - functions
- Source and store of energy (esp animals)
- Insulating material and prevents excessive heat loss
- Solvent for fat-soluble vitamins and other vital substances eg hormones
- Essential part of cells (cell membrane)
- Reduces water as oily substance secreted by glands forms a thin layer over the skin surface, reducing the rate of evaporation of water
- Reduces rate of heat loss from skin
Ethanol emulsion test
- Test for the presence of fats
- Safety note: Ethanol is flammable so keep away from any open flame
- Present: Cloudy white emulsion
- Absent: Colourless/clear solution
PROCEDURE
1. Add ethanol to food sample
2. Test tube shaken so sample dissolves
- Lipids are soluble in ethanol because lipids and ethanol molecules contain parts that don’t have electrical charge
3. Dissolved sample added to pure, cold, distilled water (lipids insoluble in water)
4. Result
Protein molecules are made out of…
Amino acids –> Polypeptide –> Protein
