B1.1 Flashcards
Carbohydrates
Condensation reactions and hyrolysis
What are Marcomolecules?
- A larger molecule made up of many repeating sub-units. (made up of a very large number of atoms and have a relative molecular mass above 10,000 atomic mass units.
- The four macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids.
Condensation reactions and hyrolysis
What are monomers?
- The small, repeating units that marcomolecules are made up of.
- They are building blocks –> the smallest unit that is still classified as that molecule type.
- Marcomolecules are unique due to it being made up of different monomers.
Condensation reactions and hyrolysis
What are Condensation Reactions?
- Involves the formation of the covalent bond between two monomers.
- This happens by removing atoms from each ot the monomers - a hydrogen - from one and a hydroxl group (OH) so that the monomers are reactive.
- The end result is a polymer (first dimer than a polymer once done many times) –> water is formed as a waste product.
- Also referred to as dehydration synthesis/ polymerisation.
Condensation reactions and hyrolysis
What are Hydrolysis Reactions?
- The opposite of condensation reactions —> they start with a polymer and break the bonds, to break the polymer into many monomers.
- Water is also split in the process and the hydrogen and hydroxyl from the water is used to stabilise the new monomers.
Condensation reactions and hyrolysis
Unique features of Carbon
- carbon atoms have 6 electrons with 4 in the outer shell –> very effective at forming covalent bonds with other carbon atoms or different atoms.
- Can actually form four covalent bonds and can form single/ double bonds giving a wide variety or compouds it can form.
- Can effectively form long chains and rings creating very diverse structural compounds.
Condensation reactions and hyrolysis
Polymers are made of Monomers.
- The four main biomolecules (molecules needed for living organisms) –> unique molecules beacuse they each have a different building block (monomer.)
The monomer and polymer combos are:
1) Carbohydrates are made up of monosaccharides
2) Lipds are made up of fatty acids (and glycerol and/or phosphate group.)
3) Proteins are made up of amino acids.
4) Nucleic Acids are made up of nucelotides.
Condensation reactions and hyrolysis
Importance of Condensation Reactions
- They are building reactions, so when tissue is built for the body, condensation reactions are used.
- Protein synthesis is an example of condensation reaction that is the most crucial role of every cell.
- When energy is stored in larger carbohydrates, condensation reactions are occurring.
Condensation reactions and hyrolysis
Water as the Waste Production of Condensation
- During condensation reations, the previously stable monomers must be reactive.
- This is done by removing something from each monomer –> to do so in a way that creates a safe waste product, a Hydrogen is removed from one monomer and a hydroxyl (OH) from the other.
- The two monomers covalently bond where the elements were removed and the H and OH combine to make water —> water is the waste product.
Condensation reactions and hyrolysis
Importance of Hydrolysis Reactions
- when larger macromolecules in human bodies are broken down to use the building blocks, a hydrolysis reaction is occurring. (DIGESTION)
- Polymers are generally consumed and hydrolysis using digestive enzymes breaks food into monomers for use in our bodies.
Condensation reactions and hyrolysis
Role of Water in Hydrolysis Reactions
- Once the bond in a polymer is broken, the monomers would be reactice and not stable in that state –> to prevent the polymers from reconnecting, water is also split.
- The hydrogen will go to one monomer and the hydroxyl to anotherm so that both monomers are chemically stable, when they are seperated.
Carbohydrates
What is a monosaccharide?
- Means ‘one sugar’, the monomer of all carbohydrates
- Most monosaccharides have 5 or 6 carbons and form rings in aqueous solutions.
- Ribose, Deoxyribose and Glucose are important monosaccharides you already have encoountered.
Carbohydrates
What is a polysaccharide?
- Polysaccharide means many sugars.
- when many monosaccharides have chemically bonded together we call it is a polysaccharide.
- “Complex Carbohydrate”
- Polysaccharides can be broken into monosaccharides to provide emergy so consdiered a form of energy storage.
- Also perform important structural functions in cells.
Carbohydrates
What is Cellulose?
- Cellulose is a polysaccharide that makes up the cell walls of plants.
- It is a long chain of glucose molecules but alternates between two different forms of glucose (alpha and beta glugose) which makes it distinct from starch and creates bonds between chains.
- Creates long straight fibres making it an ideal structural polymer.
- More organisms lack the enzyme to digest cellulose so it does not provide energy —> also called a dietary fibre.
Carbohydrates
Pentose vs Hexose Sugars
All sugars contain a carbon backbone.
- A pentose monosaccharide contains 5 carbons –> examples include fructose and ribose. –> their formula is C5 H10 O5.
- A hexose monosaccharide contains 6 carbons —> example is glucose. —> their formula is C6 H12 O6
Carbohydrates
What are Glycoproteins?
- When a carbohydrate is actually chemically bonded to another biomolecule to make a ‘conjugated carbon compound.’
- Glycoproteins are a carbohydrate chain bonded to a protein.
- Found in cell membranes where the carbohydrate chain is attatched to a membrane protein.
- Play an important role in cell to cell recognition and communication.
Carbohydrates
The Polarity of Glucose
- Glucose has 5 hydroxyl (OH) groups and the oxygen and hydrogen in a hydroxyl are bound by a covalant, polar bond.
- The presence of the 5 polar bonds make glucose a polar molecule.
Carbohydrates
Properties of Glucose
Due to it’s polar covalent bonds, glucose has some important chemical properties:
- High molecular stability —> due to covalent bonds
- High solubility in water –> due to polarity
- Easily transportability —> due to solubility
- High energy yield —> result of covalent bonds breaking.
Carbohydrates
Alpha Glucose vs Beta Glucose
Glucose can exist in two different forms.
- They have the same elements but when it forms a ring structure (in aqeous solution), the orientation of the hydroxyl and hydrogen on carbon 1 rotate.
- Most polymers use alpha glucose but beta glucose is important in cellulose.
ALAPHA: HO facing down.
BETA: OH facing up.
Carbohydrates
The Structure of Starch and Glycogen
Starch and glycogen are both long chains of glucose molecules.
- They form coils/ chains which makes them compact storage molecules.
- The bonds between the glucose molecules are easily broken by hydrolysis to free monosaccharides for celluar respiration.
(plants use starch, animals use glycogen.)
Carbohydrates
Amylose and Amylopectin
Starch exists in two forms.
- Amylose: glucoses are connected only to the adjacent glucose (between C1 and C4) to create a linear chain –> that will twist into a helix when long.
- Amylopectin: additional bonding on top of glucoses (between C1 and C6) creates a abranded structure.
About 20% of starch is amylose, and 80% is amylopectin.
Carbohydrates
ABO Glycoprotiens
Our red blood cells have specific glycoproteins on them called ABO anigens.
- Different types of ABO antigens differentiate/ distinguish blood types.
- Our immune system build antibiodies to other blood types and not our own –> reason why it’s essential to only recieve compatible blood during a transfusion as the body only recognises these markers.
