2.1.2 Biological molecules Flashcards
what is water comprised off, what is its formula and ratio?
Oxygen and Hydrogen
H2O
2 H : 1 O
how would you descrive the distribution of charge in a water moelcule
an uneven distribution of charge between delta -ve oxygen and delta +ve hydrogen
what is the sign for delta?
𝛿
why is the charge described as uneven?
it is due to the pairs of electrons in each of the oxygen-hydrogen covalent bnds is not equally shared, as the electrons are more stronhly attraced to the oxygen atonms nucleaus than the hydrogen atoms nucleas
Polar definition
Molecules that have an uneven distribution of charge are reffered to as polar
Draw a diagram of a water moeclule, showing the uneven distribution of charge
what bond is present IN water molecules
Covalent bonds
what bond is present BETWEEN water molecules
Hydrogen bonds
why are water moleules attracted to each other?
The delta -ve oxygen from one water moelucle will be attracted to a delta +ve hydorgen from another water moelcule
other than water, what other polar groups are there?
Hydroxyl, amine and carbonyl
draw a fiagram of several water moleules, showing the partial charges and the hydrogen bonds
are polar moleucles soulbule or insoaluble and why?
Soluble, becuase water molecules will be attracted to, and will for hydrogen bonds with their polar groups
what is cohesion
when a hydrogen bond forms between to water molecules
what is adhesion
when a water moelcules and a different type of polar molecules for hydrogen bonds
can hydrogen form between two polar moleucles when neither are water?
yes, the same exact thing happens, and example would be two celluose molecules
what is the biological word for polar and water-soluble moleulces?
hydrophilic
hydrophilic deffinition
the physical properties of a molecules which attracts water molecules
are non-polar moelcuels soluble in water and why?
no, they are described as hydrophobic measning they repel water, this is due to the fact they have an even distribution of charge across the moelcules, so they cannot form partial chrages, therfore cannot form hydrogen bonds with water. An example of this is lipids
There are 8 main properties of water you must know what are they?
excellent solvent
effective thermal buffer
high latent heat of vaporisation
low density of ice compared to liquid water
choesion between water molecules
high surface tension
incompressibe
transparent
why is transparancy an important property of water?
it allows light water to pass through water, however its ability to do so depends on the wavelength of light.
this is especially important in aquatic plants and other photoynthetic oganisms which rely on ligh energy to drive photosynthesis (which produces glucose)
why is it good for water to be incompressible?
as water is a liquid, it is incompressible meaning it cannot be forced to decrease in volume.
this is important in insects, which have hydrostatic skeleton to supoort their body.
in plants, cell become turgid when the voume of water in the cell cretes pressure exerted on the cell wall, this is called cell turgor which is vital in enabling the leaves of a plant to be held up to intercept sunlight.
why is it good for water to have high surface tension?
hydrogen bonding from the surface wawter molecules to teh water moleucles below them cretes high surcace tenion, and the water on the top acts a a ‘skin’
this is important becuse small animals such as pnd skaters can move across the surface without breaking through.
why is it good for water to have cohesion between molecules?
water mnolcecules stick togetrher wia hyfrogen bonding. this allows waterto for strong, continuous colums withing a vessel/tube.
These colums have high tensile strength due to the high number of hydrogen bonds between the molecules.
liquids within a vessel will flow from one region to another due to gravity or a hydrostatic pressure difference via mass flow
Effecttive transport mediumn
why is it good that ice is less dense than water
this is due to the fact that water molecules forms a regular semi crystaline structure, with stable intermolecular hydrogen bonds, with the moleucles held far apart from each other.
as ice is less dense than water, ice floats on the surface of water.
Ice on the surace of water insulates the water below, reducing the chances the lower regions freeze. Therefore most aquatic organsism can surviuve even if the upper layers freeze, hence this property creates a stable environment for many species.
why is it good water has a high latent heat of vaporisation
at rtp water is a liquid due to the many hydrogen bonds which holds the moelcuesl very close togethre.
As of this lots of energy input is needed in order to xcayse liquid water to change to a gas state.
This is due to the numerous higydrogen bonds which need to be broken
This means when water evaporates it is an effective cooling method since it will take lots of energy away from the body when it turns to a gas. Hence water is acting as a coolant
why is it good for water be an effective thermal buffer?
water has a high specific heat capacity, meanign it takes lots of energy to increase by 1 degree.
this is due to the numerous hydrogen bonds requiring lots of energy to break.
This means that the temperature of water is very stable.
This is important in cells, since enzymes have a narrow optimum temperature range, and in ponds/lakes where there is a thermostable habitat that doesnt fluctuate.
why is it good water is an excellent solvent
water moelcules are polar, ie there is an unven distrivution of charge between the delta -ve oxygen and delta +ve hydrogen. As of this water molecules are able to form hydrogen bonds with otherpolar molecules and can interact with ions.
Water mpolecules are strongly attracted to a complety surround the moelcecule or ion of a soluble ions so they become dispersed and become dissolved.
This is good as molecules and ions can dissloved in things such as blood plasma for transportation
dilution of toxic substances such an ammonia
what is a condensation reaction?
a reaction is which two monomers are joinded together, forming a new bond, and a molecules of water is released during the reaction
what is a hydrolysis reaction
a reaction is which a molecule of water is used to break a bond.
are condesnation and hydrolysis reactions enzyme-catalysed?
yes
what is an enzyme which catalyses a condensation reaction called?
there is not a general name for these enzymes.
what is an enzyme which catalyses a hydrolysis reaction called?
hydrolytic enzyme
what elements are present in carbohydratres?
C, H and O
what elements are present in lipids?
C, H and O (Phospholipids contain P)
what elements are present in proteins?
C, H, O, N and S
what elements are present in nucleic acids?
C, H, O, N and P
what is a carbohydratre?
Biological moleuces whcih contain only the elements carbon, hydrogen, and oxygen, where there are twice as many hydrogen atoms than oxygen atoms
what is the carbohydrate general formula?
CX(H2O)Y
What is the simplest form of a carbohydrate called? and give 2 example
Monosaccharide
fructose
glucose
what is it called when two monosaccharides are bonded together in a condensation reaction? and what is the bond between the molecules called?
disaccharide is formed
glycosidic bond
what is the bond in carbohydrates called?
Glycosidic bond
what are three or more monosacchardies bonded together called?
polysaccharide
they are bonded into a long chain via glysocidic bonds
what is a hexose sugar?
a sugar with 6 carbons
what type of sugar is glucose
a hexose sugar
what is the molecular formula for glucose
C6H12O6
What are the two types of glucose and how do you remember where the hydroxyl (-OH) group is on the carbon 1?
α-glucose = Below
β-glucose = Above
Alpha
Below
Beta
Above
what is the name of the structual variants of molecules?
isomers
Draw α-glucose
draw β-glucose
what are the properties of glucose? and its main role?
they contain a polar hyroxyl group (-OH), meaning the can dissolve in water and form hydrogen bonds.
thhis is good so it can dissolve in blood plasma and be transported around the body
its main role is as an energy source is areobic respirtaion where is is broken down and oxidised to release energy