Biological Molecules Flashcards
what are carbohydrates made from?
carbon
hydrogen
oxygen
Types of simple carbohydrates?
monosaccharides
disaccharides
type of complex carbohydrates?
polysacharrides
examples of monosaccharides and their chemical formula?
glucose C6H12O6
fructose C6H12O6
galactose C6H12O6
ribose C5H10O5
triose C3H6O3
monosaccharides equation
Cn H2n On
disaccharides formula
C12 H22 O11
what are isomers?
molecules with the same formula but different structures
what is a Glycosidic bond?
a bond formed between two monosaccharides.
what are the importance of monosaccharides:
sources of energy (glucose)
able to be transported in solution in animals (as glucose in blood)
the equation fro the production of maltose
GLUCOSE + GLUCOSE -. MALTOSE (malt sugar) + WATER
the equation fro the production of sucrose
GLUCOSE + FRUCTOSE SUCROSE (cane sugar) + WATER
the equation fro the production of lactose?
GLUCOSE + GALACTOSE LACTOSE (milk sugar) + WATER
how are Disaccharides formed?
Monosaccharides join together in condensation reactions. A glycosidic bond between them forms and water is removed.
what happens to disaccharides in the presence of water?
they are hydrolysed into monosaccharide monomers. Within cells, these reactions are catalysed by specific enzymes.
what is a Condensation reaction?
joins two molecules together with the formation of a chemical bond and involves the elimination of a water molecule
what are Polysaccharides?
polymers formed by combining monosaccharides together, by glycosidic during condensation reactions. They’re large, insoluble molecules ,suitable as storage
Examples of polysaccharides
- Starch
- Cellulose
- Glycogen
how is starch formed?
joining 200 – 100000 α glucose molecules by glycosidic bonds in a series of condensation reactions.
what are the 2 components of starch
- amylose
- amylopectin
amylose structure?
long , unbranched chain ,that is tightly coiled allowing lots of glucose to be sorted in small place (compact)
amylopectin structure?
branched polymer which increases surface area for enzymes to release sugars for respiration
what does amylase digest?
amylose
amylopectin
The main role of starch is energy storage, something its structure is especially suited for:
- insoluble – doesn’t affect water potential
- large & insoluble – doesn’t diffuse out of cells.
- COMPACT – lots can be stored in a small space.
- Branched form so glucose monomers are released rapidly
is starch found in animal cells?
NEVER found in animal cells. Another polysaccharide serves the same role, called glycogen.
glycogen structure
shorter chains and highly branched. this allows more sugar to be released quickly. its storage in animals, stored as small granules, in muscles & liver
how does the structure of glycogen lead to its function?
branched - increases surface area for rapid hydrolysis back to glucose
insoluble - wont affect water potential
why is cellulose different from starch and glycogen?
it is formed from β glucose molecules, rather than α glucose molecules.
what is the structure of cellulose?
straight, unbranched chains, inverted to another, are called micro fibrils. hydrogen bonds form cross-links between chains giving strength and rigidity
cellulose use in plants?
cellulose cell wall prevents the cell from bursting as water enters by osmosis. It exerts inward pressure that stops water. stems & leaves turgid to increase surface area for photosynthesis.
what is a Hydrolysis reaction?
breaks a chemical bond between 2 molecules & involves the use of a water molecule.
what are starch and glycogen cellulose polymers of
Starch & glycogen are polymers of α-glucose & cellulose is a polymer of β-glucose.
what is hydrogen bonding
electrons within a molecule aren’t evenly distributed, but tend to spend more time at one position. This region is more negatively charged than the rest of the molecule
testing for carbohydrates?
- crush / grind the solid and mix strongly with water
- add benedicts reagent
- heat / boil (<80)
- result is a colour change from blue to brick red
quantitative benedicts test result?
green - low conc
yellow - medium conc
brick red - high conc
what test is for non reducing sugars (e.g. sucrose)
- use a fresh sample
- add HCL (still crush and mix)
- boil , this will hydrolyze sucrose into glucose & fructose
- add sodium hydrogen carbonate to neutralize (cant do Benedicts Test in an acidic solution)
- repeat benedicts test,+ results indicates sucrose in og solution
starch
monomers?
bonds between them?
alpha glucose
1-4 glycosidic bonds in amylose
1-4 & 1-6 in amylopectin
starch structure?
made of 2 polymers
amylose - unbranched helix
amylopectin - branched molecule
starch function?
location?
store of glucose
plant cells (e.g. chloroplast)
cellulose
monomers?
bond between them?
beta glucose
1-4 glycosidic bonds
Making dilutions equation
C1 V1 = C2 V2
What test tests for lipids?
The emulsion test
How do you carry out the emulsion test?
1) dissolve the sample in ethanol (its another non-polar substance)
2) mix well/strongly
3)add water, mix again
4) the presences of a milky emulsion shows that lipids are present
What is a triglyceride?
Type of lipid that consists of 3 fatty acid tails connected to glycerol.
It has an ester bond by a condensation reaction that occurs 3 times to make it