biological molecules Flashcards
how are biological molecules evidence of evolution
all organisms share the same carbon based compounds which suggest animals and plants have a common ancestor
what is a polymer
a polomer is a large complex molecule made up of repeating units of monomers
what is a monomer
monomers are small basic molecular units that can from a polymer
how are polymers made
condensation reactions between monomers
how are polymers turned into monomers
hydrolysis reaction breaking the chemical bond using a water molecule
what are the three monosaccharides
glucose, fructose and galactose
what bond forms between monosaccharides
glycosidic bond
what are the three disaccharides and what are they made from
lactose - galactose and glucose
maltose- a-glucose
sucrose- glucose and fructose
how do you test for reducing sugars
- add benedicts solution
- heat solution in water bath to a boil
- blue to brick red
how do you test for non reducing sugars
- do the benedicts test and get a negative result
- add dilute hcl and heat to a boil
- add sodium hydrogencarbonate
- carry out benedicts again and should go blue to brick red
what is a polysaccharide
two or more monosaccharides are joined by condensation reactions to from glycosidic bonds
why is the structure of starch important to its function
amylose is coiled and long so it can store lots of energy in a small area
amlopectin is long and branched so enzymes can work on the branches quickly and glucose can be released quickly
starch is also insoluble which means it doesnt effect water potential so it doesnt cause water to enter plant cells and cause them to swell.
what is the structure of starch and what are the properties involved
startch is made up of two polysaccharides of alpha glucose amylose and amylopectin
amylose- long, unbranched , coiled due to glycosidic bonds
amylopectin- long , branched
what are the three polysaccharides
starch, glycogen and cellulose
what is the structure of glycogen
made up of alpha glucose and has lots of side branches
what is the structure of cellulose
long, unbranched chains of beta glucose in long straight chains linked togther by hydrogen bonds to from microfibrils
why is the structure of glycogen important to its function
bracnhes mean that stored glucose can be released quickly and its also very compact so can fit lots in a small space so not as heavy so animals dont have to carry lots of weight
why is the structure of cellulose important to its function
the stong microfibrils that are formed provides structural support for cells in cell walls
what is the test for starch
add iodine dissolved in potassium iodide and it should go from browny orange to dark blue
what are the two types of lipids
triglycerides and phospholipids
what is the structure of a triglyceride
has one molcule of glycerol with three fatty acids attatched to it
how are triglycerides formed
triglycerides are formed by condensation reactions and an ester bond is formed between the glycerol and fatty acid
what is the structure of phospholipids
they have one glycerol 2 fatty acids and a phosphate group
what are the properties of triglycerides that help its function
triglycerides are used as energy storage molecules and they have long hydrocarbon tails which contain a lot of energy in a small area
they are also insoluble so they dont affect water potential of the cell and cause water to enter the cells by osmosis
the triglycerides bundle together as insoluble droplets in cells because of the hydrophobic tails
how does the structure of a phospholipid help with its function
phospholipids have hydrophobic tails and hydrophyllic heads so they from a bilayer in water and prevent water soluble substances passing through a membrane
what is the test for lipids
the emulsion test
1. shake the substance with ethanol for a minute
2. pour into water
3. a milky white emulsion will form