module 2 - 3.3 carbohydrates - glucose, starch and glycogen Flashcards
what 3 elements are carbs made up of?
carbon, hydrogen, oxygen
what is a monosaccharide?
small, simple sugar
what is a disaccharide?
large sugars
what is a polysaccharide?
long chain carbohydrates
what are examples of a monosaccharide?
glucose, fructose and ribose
what are examples of a disaccharide?
lactose and sucrose
what are examples of a polysaccharide?
glycogen, cellulose and starch
what are carbohydrates?
substances used as energy sources and structural materials in organisms
how many carbons does a glucose molecule have?
6
what type of sugar is glucose?
hexose sugar
why is glucose important?
- main energy source for most cells
- main way carbohydrates are transported around the body
- highly soluble
what are the different forms of glucose called?
structural isomers
what are 2 common isomers?
alpha glucose
beta glucose
what is the difference between alpha and beta glucose?
alpha - OH- attached below carbon 1
beta - OH- attached above carbon 1
how are carbons 1,2,3 and 4 positioned?
clockwise (right to left)
which reaction makes disaccharides and polysaccharides?
condensation reaction
how are disaccharides formed?
when 2 monosaccharide molecules join together with a glycosidic bond
what are pentoses?
sugars of DNA
what does DNA stand for?
deoxyribonucleic acid
what do pentose disaccharides contain?
5 carbon atoms (enough to form a ring)
what are 2 important pentose molecules?
ribose and deoxyribose (structural isomers)
what are ribose and deoxyribose important components of?
RNA and DNA
what is the difference between ribose and deoxyribose?
- ribose has 1 H atom and 1 -OH group attached to carbon 2
- deoxyribose has 2 H atoms and no -OH group
what are polysaccharides made of?
polymers containing many monosaccharides linked by glycosidic bonds
what is the structure of starch?
a polysaccharide made of many alpha glucose molecules arranged into 2 different structural units
what are the 2 different structural units of starch?
amylose and amylopectin
what is maltose (malt sugar) formed of?
2 glucose molecules joined by an alpha 1-4 glycosidic bond
what is sucrose (table sugar) formed of?
glucose and fructose molecules joined by an alpha 1-4 glycosidic bond
what is lactose (milk sugar) formed of?
glucose and galactose molecules joined by an alpha 1-4 glycosidic bond
why is starch important?
it is the major carbohydrate storage in plants
what is starch usually stored as?
plastids - intracellular starch grains in organelles
what do plastids contain?
green chloroplasts
colourless amyloplasts
what is starch produced from?
glucose made during photosynthesis
what is glycogen?
animals store carbohydrates as glycogen
what is the structure of glycogen?
contains many alpha 1-6 glycosidic bonds - produces a branched structure
how is glycogen stored?
stored as small granules, particularly in muscles and liver
what is glycogen like compared to starch?
glycogen - more dense, more soluble, breaks down more rapidly
what is a hydrolysis reaction?
used to break down polysaccharides and disaccharides into monosaccharides
what is cellulose?
polysaccharide and is the main part of plant cell walls
how is cellulose different from starch?
cellulose is very strong, and prevents cells from busting when they take excess water
what is the structure of cellulose?
consists of long chains of beta glucose molecules joined by beta glucose 1-4 glycosydic bonds
when is starch broken down?
during respiration for energy
what is starch also a source of?
carbon - for producing other molecules
