3.1.2 carbohydrates Flashcards
3.1.2 carbohydrates
what are the three main functions of carbohydrates
- short term energy storage (convert to ATP to be used )
- long term energy storage
- a structural component
what does carbohydrates mean
Hydrated carbon atoms + hydroxyde groups
what 3 letters does carbohydrates tend to end in
- ose
what is sucrose know as
store bought suger
where are lactose and maltose found
lactose : milk
maltose : beer
what polysaccharides can we digest
glycogen
what is the glycemic index and what does it mean to have a high / low glycemic index
The glycemic index measures how blood glucose levels change following the ingestion of carbohydrate.
a high glycemic index means that suger is relesed really fast over a short period and therefore is unhealthy
vise versa for a low glycemic index
what two disaccharides make:
maltose
2 x glucose
what two disaccharides make:
lactose
galactose and glucose
3 carbon suger is called ?
and function
triose
metabolic reactions
what two disaccharides make:
sucrose
glucose and fructose
5 carbon suger is called ?
and function
pentose
formation of nucliac acids
6 carbon suger is called ?
and function
hexose
main source of energy
draw an A-glycose
compare with web should have hydroxy pointing down
draw an b-glycose
compare with web should have hydroxy pointing up
draw a fructose molecule
compare with web
draw a galactose molecule
compare with web
what are the two isomers of glycose
alpha and beta glycose
what type of reaction joins carbohydrates together
glycosidic bond
condensation reaction
what is hydrolysis
the break down of a chemical bond through water
where does hydrolasis take place
during digestion
how do you test for reducing sugers
what is the order of percipitates
1.add an equal quantaty of benedics reagent to approximatly 2cm3 of test solution
- shake and heat for a few min at 95 celceus in a water bath
3.a precipitate indicates a reducing suger
none ——> large amounts
blue , green / yellow , orange , brick red
between which carbons does glycosidic bonds form
1-4
what is a way of testing for the concentration of sugers
potassium permanginate , when sugers reduce potassium permanginate it goes colour less , by comparing it with know concentrations we can see how long it takes to decolour and there for the concentration of the solution.
what are the main reducing sugers
all monosaccharides , maltose , lactose
sucrose is not a reducing suger
what is the role of starch in plants
insoluble store of glucose in plants
what are the two types of polysaccharides
- storage - starch and glycose
- structural - cellulose
is glycogen soluable
no it is insoluable
what isotope of glycose is amylose made of
Alpha - glycose with1-4 glycosidic bonds
describe the structure of amylose
amylose is a polymer made up of alpha - glycose .
it is linear molecule with no branches
describe the structure of amylopectin
the amylose molecule coils into a helix this is due to the hydrogen bonds , it is also branched (1-6 )
it branches around every 25 alpha glucose s
relate the structure of alylopectin to its dunction
Compact shape takes up little space, but large and insoluble and so does not diffuse out of cells.
Insoluble – therefore does not affect water potential, so water is not drawn into the cells by osmosis.
Easily hydrolysed to glucose for respiration (by amylase)
how whould you test for starch
using iodine solution , it would turn from a yellow solution to a more opaque blue/dark blue solution
what is glycogen made of
alpha glucose
relate the dunction of glycogen to function
Compact shape takes up little space
Insoluble - therefore osmotically inert and does not diffuse outside of cells
Easily hydrolysed to glucose for respiration (by amylase) because more branches than starch and so more of the ends can be worked on simultaneously by enzymes.
Speed of hydrolysis important because animals have a higher metabolic rate than plants.
describe the structure of glycogen
very simular to amylopectin however has more frequent branches
describe the role of glycogen
Role: an insoluble, compact store of glucose in animals, found mainly in muscle and liver
what is the role of cellulose in plants
Role: Structural polysaccharide in plants
what is cellulose made out of
Beta glucose which human bodys cannot digest as we do not have the propper enzymes to do so
describe the structure of cellulose
long parallel chains , unbranched , with hydrogen bonds linking adjacent chains
why do hydrogen bonds form between beta glucose and not alpha glucose
beta glucose cannot react without one flipping over as the -OH on the 1-4 are not next to each other , this is not need for alpha glucose
This difference leads to parallel, straight chains that bundle together because of the formation of H bonds between hydroxyl groups in adjacent chains. These bonds cannot form between alpha glucose units because they are not rotated
describe the structure of a cellulose FIBER
60 -70 cellulose molecules become tightly cross linked to form bundles called Microfibrils. These join together with other microfibrils to form a macrofibril which bundle together to form cellulose fibres. The cell wall has multiple layers of fibres running in different directions to increase strength. Microfibrils are very strong and rigid and give huge structural stability to the plant
