1.2.1/.2 - Carbohydrates 1 and 2 Flashcards
How many bonds can each carbon atom make?
can make up to 4 bonds
define a monomer
small molecule (single unit of a polymer)
define a polymer
a long chain of molecules made of of smaller, repeating monomers joined together by chemical bonds
what is an organic compound?
biological molecules that contain carbon,hydrogen or oxygen atoms (less frequently nitrogen, sulfur and phosphorus)
What are carbohydrates used for?
they are used as an energy source and for storing energy
(also part of the cell wall in plant, fungi and bacteria cells).
What is the basic structure of all carbohydrates?
They are all made up of carbon, hydrogen and oxygen
What are the three main groups of carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
What is a monosaccharide?
a simple sugar
the general formula = (CH2O)n
Give examples of carbohydrates.
Examples of carbohydrates include: sugars starch sucrose glucose
What is a triose sugar?
They have 3 carbon atoms –> therefore n = 3 in the general formula
they are important in the mitochondria (where glucose is broken down into triose sugars during respiration)
What is a pentose sugar?
they have 5 carbon atoms —> therefore n = 5 in the general formula
Ribose and deoxyribose are important in the nucleic acids DNA and RNA (which make up the genetic material)
What is a hexose sugar?
they have 6 carbon atoms —> therefore n = 6 in the general formula
they are the best known monosaccharides
often taste sweet
and include glucose, fructose and galactose
What is ribose?
Draw it’s displayed formulae
- a pentose sugar
- used in RNA backbone
- deoxyribose is used in the DNA backbone
- chemical formula = C5 H10 O5
What is Alpha - glucose?
Draw it’s displayed formulae
- hexose sugar
- an isomer (different form of the same molecule) of glucose
- chemical formula = C6 H12 O6
What is Beta - glucose?
Include its chemical formula
Draw it’s displayed formulae
- hexose sugar
- isomer of glucose
- chemical formula = C6 H12 O6
What is a disaccharide?
two monosaccharides joined together (a double sugar)
How do two monosaccharides join together?
Through a condensation reaction
- removes a molecule of water
- forms a disaccharide
- bond formed between them is a glycosidic bond
(e. g 1,4 glycosidic bond)
Where is sucrose found and what monosaccharides join together?
- stored in plants (e.g sugar cane)
- Alpha glucose and fructose
Where is lactose found and what monosaccharides join together?
- milk sugar (main carbohydrate found in milk)
- alpha glucose and beta glucose
Where is maltose found and what monosaccharides join together?
- malt sugar (found in germinating seeds e.g barley)
- a and a glucose
What is a polysaccharide?
11+ monosaccharides joined by condensation reactions to form glycosidic bonds
What is a oligosaccharide?
3-10 monosaccharides joined together
Draw the hydrolysis of maltose
(maltose drawn + water —> two a-glucose molecules)
Why are polysaccharides such good storage molecules?
- very compact, large numbers can be stored in a cell
- glycosidic bonds are easily broken allowing for the rapid release of monosaccharides
- not very soluble in water, therefore little effect on water potential within a cell
How are glycosidic bonds broken?
Through hydrolysis
- water is added to the bond
- disaccharides are broken into two monosaccharides
- polysaccharides are broken down into shorter chains until eventually they are single sugars
This takes place: during digestion in the gut, in muscle and liver cells
What are the two compounds that make up starch?
Amylose
Amylopectin
What is amylose?
- chain of a-glucose (an A 1,4 glycosidic bond)
- helical structure
- unbranched polymer
- releases glucose more slowly and is a form of energy storage
- used in plants
What is amylopectin?
- chain of a- glucose (in an A 1,4 glycosidic bond and an A 1,6 glycosidic bond)
- highly branched
- releases glucose rapidly as its highly branched (more spaces for amylase to break down)
- used as plant storage
What is glycogen?
- only carbohydrate energy store found in animals
- highly branched
- made of a-glucose (A1,4 and A1,6 glycosidic bonds)
- can be broken down extremely quickly due to having more 1,6 bonds - more branched - therefore is very useful in places such as muscle and liver tissue
- insoluble (more soluble than starch)
What is cellulose?
- insoluble
- made up of b-glucose in a B1,4 glycosidic bond
- one of the monomer units in this needs to turned around 180 so bonding can take place
- means hydroxyl group (-OH) sticks out of both sides and causes a hydrogen bond to form between each layer
- this gives cellulose great strength and support, making it an important structural material in plants (cell walls)
- NO spirals, just long straight layered unbranched chains
