BIOLOGICAL MOLECULES Flashcards
what makes water a good solvent
because it’s polar, the slightly positive end of a water molecule will be attracted to the negative ion, and the slightly negative end of a water molecule will be attracted to the positive ion, so the ions will dissolve
why is water being a solvent useful
so that substances are dissolved and can be transported around the body
why is water cohesive
because they’re polar so they stick together
why is water cohesiveness useful
helps it flow, making it good for transporting substances
why does water have a high specific heat capacity and what’s useful about it
hydrogen bonds can absorb a lot of energy which which makes it a good habitat
why is water having a high latent heat of evaporation useful
takes a lot of energy to break the hydrogen bonds so a lot of energy is used up when it evaporates useful for cooling mammals
why is water less dense when solid and how is this useful
makes a lattice shape when frozen due to each water molecule forming four hydrogen bonds, forms an insulating ice layer so that organisms can move underneath
what way round are the o and OH in a B glucose
OH on top and O on the bottom
what are the useful properties of glucose
the main energy source, soluble so can be transported and contains lots of energy
what are monosaccharides joined together by
glycosidic bonds
what is starch
plants store excess glucose as starch, a mix of two polysaccharides of alpha glucose: amylose and amylopectin
describe amylose and how it’s useful
a long unbranded chain of alpha glucose, angles of glycosidic bonds give it a coiled structure like a cylinder, compact do good for storing
describe amylopectin and how it’s useful
a long branched chain of alpha glucose, side branches allow enzymes that break down the molecule to get at the glycosidi c bonds easily, means glucose can be released quickly
what is glycogen and how’s it useful
main energy storage material for animals, store glucose as glycogen, lots of side branches so can be released quickly, and also compact so good for storage
describe cellulose and how it’s useful
major component of cell walls in plants, long unbranched chains of beta glucose which form straight cellulose chains when bonded, which are linked by hydrogen bonds which form fibres called microfibrils, means it gives structural support
what are triglycerides made of
one molecule of glycerol and three hydrophobic fatty acids
how are the glycerol and fatty acids bonded together and how are the bonds formed
ester bonds, condensation reaction
what are phospholipids made of
one molecule of glycerol, two fatty acids, and a hydrophilic phosphate group
what are the properties of triglycerides and why are they useful
- contain lots of energy because of long hydrocarbon tails, good for energy
-insoluble so they don’t cause water to enter the cells by osmosis because of hydrophobic tails
what are the properties of phospholipids and what makes them useful
-hydrophilic heads and hydrophobic tails so they form a double layer
- centre of the barrier is hydrophobic so water soluble substances cant easily pass through, membrane acts as a barrier
what are the properties of cholesterol and what makes it useful
-small size and flattened shape, allows cholesterol to fit in between the phospholipid molecules
-at high temps they bind to hydrophobic tails of the phospholipids causing them to pack more closely together,makes the membrane more rigid
- at low temps prevents phospholipids from packing too close together so increases membrane fluidity
what are amino acids
the monomers in proteins
what is the primary structure
the sequence of amino acids in the polypeptide chain, held together by peptide bonds
what is the secondary structure
hydrogen bonds form between nearby amino acids in the chain which make it coil into an alpha helix or fold into a beta pleated sheet
what is the tertiary structure
further coiling or folding, more bonds form between different parts of the polypeptide chain
what is the quaternary structure
proteins that are made of multiple polypeptide chains are held together by bonds
what bonds hold together the tertiary structure
ionic bonds, disulfide bonds, hydrophobic and hydrophilic interactions, hydrogen bonds
what are some examples of globular proteins
haemoglobin, insulin, and amylase
what is amylase
enzyme that catalyses the breakdown of starch in the digestive system, single chain of amino acids, contains both alpha helix and beta pleated sheets
what are some examples of fibrous proteins
collagen, keratin, elastin
calcium
transmission if nerve impulses and releasd of insulin from the pancreas, bone formation
sodium
generating nerve impulses, muscle contraction, and regulating fluid balance in the body
potassium
generating nerve impulses, muscle contraction, regulating fluid balance in the body, activates enzymes needed for photosynthesis
hydrogen
affects PH and activates enzymes need for photosynthesis
ammonium
absorbed from the soil by plants and important source of nitrogen
nitrate
absorbed from the soil by paints and.important source of nitrogen
hydrogen carbonate
acts as a buffer which helps maintain the PH of the blood
chloride
involved in the chloride shift which helps maintain the PH of the blood during gas exchange, also involved in some nerve impulses
phosphate
involved in photosynthesis and respiration reactions needed for the synthesis of many biological molecules such as nucleotides,phospholipids and calcium phosphate
hydroxide
affects pH of substances
how do you test for proteins
biuret test, add sodium hydroxide solution and then add copper sulfate, purple if present
how to test for lipids
shake with ethanol and pour into water, solution will turn milk if present
how to test for starch
iodine test, add iodine dissolved in potassium iodide solution, turns from browny orange to blue black
how to test for reducing sugar
add benedicts reagent and heat, negative blue, positive green yellow brown and brick red
non reducing sugars
add dilute HCL and heat, then add sodium hydrogen carbonate, add benedicts reagent and heat
