Chapter 2- Biological molecules Flashcards
Why is water important?
Helps transport other molecules through the body
Part of photosynthesis
Hydration- 70-80% of the body needs to be water for key chemical reactions to occur
Major habitat
Required for health and metabolism
Why are hydrogen bonds important?
Join individual water molecules together and they will always form between negative oxygen and positive hydrogen
Are important to allow water to flow- they are weak alone but very strong together
What are the main characteristics of water?
Ice is less dense than water- float on top of a liquid
Water has a high specific heat capacity- 4.2J of energy to heat 1g of water by 1 degrees leading to thermostability
Cohesive- attracted to itself and so forms bonds
Adhesive- attracted to other substances and allows to travel up the xylem of a plant
Amphoteric- can act as an acid or a base and allows water to be a pH buffer
Described as a universal solvent- substances that are polar dissolve in it
What are the categories that carbohydrates are organised into?
Monosaccharides- 1 sugar unit
Disaccharides- 2 sugar units
Polysaccharides- 2+ sugar units
What are the different categories further split into?
Triose- 3
Pentose- 5
Hexose- 6
Number of carbohydrates in their structure
What are the main 3 disaccharides and what monosaccharides are they made of?
Glucose, fructose and galactose
Glucose + glucose = maltose
Glucose + galactose = lactose
Glucose + fructose = sucrose
What are the main types of bonds between carbohydrates?
1-4 glycosidic bonds
1-6 glycosidic bonds
What are the 3 main examples of polysaccharides?
Glycogen
Starch
Cellulose
What are the characteristics in gylcogen?
Main energy storage unit in animals
Left-over glucose in the blood will be converted into glycogen
It is insoluble
Formed by repeating alpha glucose joined together
Both 1-4 and 106 glycosidic bonds
Most branched polysaccharide- rapid hydrolysis by enzymes
What are the characteristics of starch?
Main storage for plants
Composed of 2 polysaccharide chains- amylose (1-4) and amylopectin (1-4+1-6)
Only contains alpha glucose
What are the characteristics of cellulose?
Located in plant cell walls as it provides strength and support
Composed of only beta glucose- every other beta glucose is inverted so the hydroxyl group can interact so H2O can form creating a 1-1 glycosidic bond
Incredibly strong as hydrogen bonds form between each microfibril
What is a microfibril?
At least a50 b-glucose connected through condensation reactions
What are the benefits of lipids?
Used for insulation for the organism and individual cells
More energy per gram than any other biological molecule
Waterproofing- hydrophobic so they repel water
What are triglycerides?
Group of lipids called macro-molecules
Composed of 3 fatty acids and a glycerol molecule
Ester bonds form between O of glycerol and C of FA
Formed through a specific condensation reaction called esterification
What are the two types of fatty acids and their differences?
Saturated fatty acids- no double bonds, fully saturated with hydrogen, solid at room temp and the main example is animal fats
Unsaturated fatty acids- not fully saturated with hydrogen, double bonds between carbons do exist which causes the hydrocarbon chain to kink, C-H bonds are often far apart
What are proteins required for and some examples of what they create?
Growth and repair
Examples- hair, skin, nails, muscles, DNA, enzymes
What are proteins made up of?
Amino acids
What is the bond between different amino acids?
Peptide bonds
What is the test for reducing sugars?
1- Reducing sugars can donate electrons and when they do this they become oxidised
2- Sample turns red as it contains glucose as benedicts reagent contains Cu2+ and it donates an electron to the Cu2+
What is the test for non reducing sugars?
1- When testing to see if sucrose is reducing, it remains blue
2- Add HCl as it breaks down the glycosidic bond between glucose and fructose which exposes glucose and turns red
What is the primary structure of proteins?
sequence of amino acids
bond- peptide bond
What is the secondary structure of a protein?
Dependant upon where hydrogen structures form
two different types- a-helix and b-pleated sheet
bonds- peptide bonds and hydrogen bonds
What is the tertiary structure of proetins?
final structure of a single polypeptide chain
interaction between the R-variable groups of each AA involved in a protein
Bonds- peptide bonds, hydrogen bonds, ionic bonds and disulfide bonds
What is the quaternary structure of a protein?
Only occurs if the protein is composed of more than one polypeptide chains
Examples- insulin is made of 2 chains and haemoglobin is made of 4 chains