Biological Molecules Flashcards
What is a condensation rection?
A reaction that joins 2 molecules together and removes a molecule of water
what specific type of bond gives water its unusual properties?
Hydrogen bonds
Why is water being a liquid at RTP usefull to living things?
it is a liquid at RTP so provides an aquatic habitat as well as being able to make up a majority of living tissues
What are the 7 key properties of water?
Liquid at RTP: major component in tissues and provides a habitat
Density: it gets less dense as it freezes
Solvent: good slovent for many solutes found in living things (NaCl or glucose)
Cohesion and Surface Tension: Caused by hydrogen bonding and allows water to move up Xylem
High Specific Heat Capacity: Requires alot of energy to heat or cool so is good at thermoregulation in organisms and provides stable habitat
High Latent Heat: requires large amount of energy to evapourate so allows mammals to sweat to cool down
Reactant: involved in reactions such as photosynthesis and hydrolysis (digestion of starch, lipids and protiens)
What are the three functions of Carbohydrates?
Energy source (Glucose)
Energy Store (Starch and Glycogen)
Structural Units (Cellulose and Chitin)
What are Monosaccharides?
The simplest types of sugars, they are small molecules that are soluble in polar solvents (water)
can exist as staight chains or in cyclic form
some monosaccharides like glucose are the monomers for more complex carbohydrates like disaccharides or polysaccharides.
Are monosaccharides reducing or non reducing sugars?
All monosaccharides are reducing sugars
What are Disaccharides?
Disaccharides are small polar molecules, that are soluble in polar solvents
Formed when 2 monosaccharides join together in a condensation rection.
examples include maltose, sucrose, and lactose
What is the type of bond formed when a disccharide is made
Glycosidic bond
Are dissacharide reducing or non reducing?
Depends, some disaccharides are reducing and some are non reducing.
e.g Maltose and Lactose are reducing but Sucrose is non reducing.
What are polysaccharides
They are polymers of monosaccharides, made of thousands of repeating units
why are polysaccharides good energy stores?
because they can be broken down into their monosaccharide monomers (like glucose) which are often used in respiration
What are the 2 main examples of polysaccharides as energy stores
Starch and Glycogen
what are the 4 Properties of starch and glycogen that makes them good energy stores
Compact so don’t take up much space and can be stored as large granules
They hold glucose in long chains so can be ‘snipped off’ when needed
Branched chains (glycogen and amylopectin) are more compact meaning more can be ‘snipped off’ when lots of energy is needed at once
Polysaccharides are less soluble in water, if they were soluble then it would reduce water potential and disrupt the normal cell workings
Name 1 example of a structural polysaccharide
cellulose
Which monomer makes up Cellulose
Beta glucose
Which type of reaction forms cellulose
Condensation
Why don’t Beta glucose chains spiral
Because each monomer rotates 180 degrees so the bonds are on opposite sides forming a straight chain
Why is cellulose so strong
Forms 1-4 glyosidic bonds that are very strong
Hydrogen bonds form between chains adding strength
The chains lie parallel like bricks forming microfibrils. which then further bundle to make macrofibrils.
Macrofibrils run in all directions and criss-cross.
Where is cellulose most commonly found?
plant cell walls
Bacteria cell walls
Exoskeletons in insects
Why is cellulose useful in plant cell walls
Plants don’t have a skeleton so each cell must be strong in order to provide structure
There are gaps between the macrofibrils so water and mineral ions are able to pass through making the cell wall fully permeable.
What are the 3 main properties of lipids
Insoluble in water (non polar)
soluble in alcohol
NOT polymers, however do consist of components bound together so are called macromolecules.
what are the 3 main types of lipids in living things
Triglycerides
phospholipids
steroids
What is the structure of a Triglyceride?
Made up of glycerol and fatty acids
3 fatty acids
glycerol is an alcohol with 3 free -OH groups
fatty acids have a carboxyl group (-COOH) which can dissociate its hydrogen to form H+ and COO-
How does and unsaturated fat differ from a saturated fat
Unsaturated fats have 1 or more C=C where as saturated fats have all single bonds.
A C=C causes a kink in the chain which prevent the molecules packing as close together. this is why all plant oils are liquid and animal fats are solid at RTP.
What are the 5 main functions of triglycerides
Energy Source: Can be broken down in respiration, provide much more energy when broken down than a sugar does
Energy Store: Insoluble in water so dont affect the water potential of the cell
Insulation: good thermal insulator, Blubber in whales and penguins
Buoyancy: Fat is less dense than water so keeps aquatic animals afloat
Protection: Fat deposits round vital organs to absorb impacts and prevent damage
Describe the structure of a phospholipid
Same as a triglyceride but
