2.2 biological molecules Flashcards
what are the properties of water?
- a solvent
- cohesion, surface-tension
- low density as ice
- stable temperature
- a reactant
what are examples of cations?
- calcium- Ca2+
- ammonium- NH4+
- hydrogen- H+
- potassium- K+
- sodium- Na+
what are examples of anions?
- hydrogencarbonate- HCO3-
- nitrate- NO3-
- hydroxide- OH-
- phosphate- PO4 3-
- chlorine- Cl-
what are calcium ions used for?
- blood clotting
- muscle contraction
- increasing the rigidity of bones, teeth and cartilage.
what are hydrogencarbonate ions used for?
- regulating blood pH
- transporting CO2 in and out of the blood
what are nitrate ions used for?
- the nitrogen cycle
- component of nucleic acids, proteins, vitamins
what are ammonium ions used for?
- maintaining pH
- the nitrogen cycle
- component of nucleic acids, proteins, vitamins
what are hydrogen ions used for?
- photossynthesis
- respiration
- regulating blood pH
what are potassium ions used for?
- controlling body water levels
- muscle contraction
- healthy leaves and flowers in plants
what are sodium ions used for?
- regulate pH and water levels
- muscle contraction
- component of plant vacuoles
what is glucose?
- a monosaccharide with 6 carbon atoms
what is amylopectin?
- componet of starch
- branched chain of glucose molcules
- 1-4 and 1-6 glycosidic bonds
what is amylose?
- componet of starch
- unbranched chain of glucose molcules
- 1-4 glycosidic bonds
- very compact
what is starch?
- a polysaccharide made from amylose and amylopectin. it is the energy store in plants
what is cellulose?
a component of cell walls in plants
what is the structure of cellulose?
- long unbranched chains of beta glucose
what is glycogen?
- main energy store in animals
- branched polysaccharide made from alpha glucose
- 1-4 and 1-6 glycosidic bonds
what are hydroxide ions used for?
- regulating blood pH
what are phosphate ions used for?
- increasing rigidity of bones and teeth
- regulating blood pH
- component of phopsholipids, ATP, nucleic acids and enzymes
what are chloride ions used for?
- transporting C02 in the blood
- regualting blood pH
- producing hydrochloric acid in the stomach
what is the test for reducing sugars?
benedicts solution
blue–>red
what is the test for starch?
iodine solution
yellow-brown–>blue-black
what is the method for testing for non-reducing sugars?
- test for reducing sugars
- boil sample with HCl
- cool the solution
- add sodium hydrogencarbonate to neutralise
- test for teducing sugars again
what is the test for lipids?
emulsion test
cloudy white emulsion forms
what is the test for proteins?
biuret test
light blue–> lilac
what are cations?
positively charged ions
what are anions?
negatively charged ions
how do amino acids act as buffers?
- at low pH amino acids will accept H+ ions, and at high pH they will release H+ ions
what are the functions of proteins?
- form structural components
- enzymes
- antibodies
- hormones
- membranes have protein components
what are peptide bonds?
the bond between 2 amino acids, made in a condensation reaction
what are amino acids?
monomers of all proteins
what are the functions of triglycerides?
- energy source
- energy store
- insulation
- buoyancy
- protection
what are triglycerides?
lipids with one molecule of glycerol and 3 fatty acids
what bond joins tryglycerides?
ester bonds
how are disaccharides and polysaccharides formed?
the condesation of monosaccharides, joined by glycosidic bonds
alpha glucose + alpha glucose —->
maltose
glucose + fructose —->
sucrose
glucose + galactose —–>
lactose
what are unsaturated lipids?
- lipids with C=C bonds and kinks
- low melting points
- found in plants
what are saturated lipids?
- found in animal fats
- dont have C=C bonds
what are phospholipids?
1 glycerol molcule, 2 fatty acids and 1 phosphate group
what can phospholipids form?
- micelles
- phospholipid bilayer
what is a prosthetic group?
a non-protein compent that forms a permanent part of a functioning protein molecule
what is a conjugated protein?
a protein with a prosthetic group
what are examples of fibrous proteins?
keratin
collagen
elastin
what is the structure of fibrous proteins?
- regular, repetitive amino acids sequence
- long, thin fibres
- parallel polypeptide chains held together by crosslinks
what are the properties of fibrous proteins?
- insoluble in water
- metabolically inactive
- structural
what are examples of globular proteins?
- insulin
- pepsin
- haemoglobin
what is the structure of globular proteins?
- spherical shape
- hydrophobic R-groups are turned inwards
- hydrophillic groups are on the outside
what are the properties of globular proteins?
- soluble in water
- metabolically active
- enzymes, hormones, transport proteins
what is the quaternary protein structure?
multiple polypeptide chains bonded together with hydrogen and ionic bonds, disulfide links.
what is the tertiary protein structure?
the folding of the protein with hydrogen and ionic bonds
what is a beta-pleated sheet?
- secondary protein structure
what is the phospholipid bilayer?
inside the phopsholipids can move were there isnno water. On the outside the membrane is selectively permeable to non-polar molecules.
what is an alpha helix?
secondary proetin structure
Keratin
- fibrous protein
- very strong
- waterproof
- found in finger nails, hair, claws etc.
collagen
- fibrous protein
- mechanical strength
- found in bones, cartilage and connective tissues
Haemoglobin
- globular protein
- 4 polypeptide chains each with a haem group
- carries oxygen from the lungs to respiring tissues
Pepsin
- globular protein
- an enzyme that digests proteins in the stomach
elastin
- fibrous protein
- allows skin to stretch, and the lungs to inflate
insulin
- globular protein
- soluble in water
- increases rate of glucose consumption
