2.1.2 biological molecules Flashcards
covalent bonding
atoms share a pair of electrons, stronger bonds, between non-metals
ionic bonding
electrons are transferred from one atom to another, slightly weaker bonds, between metal and non-metal
hydrogen bonding
slightly negative region of one polar molecule and slightly positive region of another attract each other to form a weak bond but can collectively form important forces that alter physical properties of molecules
polymer
long chain molecule made up of a large number of repeating units linked together
e.g. protein, DNA, starch
monomer
small basic molecular unit that make up polymers
e.g. amino acids, nucleotides, monosaccharides
monomer: glucose
polymer: polysaccharide (amylose, amylopectin, cellulose, glycogen)
monomer: amino acid
polymer: polypeptide (protein)
monomer: nucleotides
polymer: nucleic acid (DNA, RNA)
all carbohydrates contain…
carbon
hydrogen
oxygen
all proteins contain…
carbon
hydrogen
oxygen
nitrogen
sometimes sulfur
all nucleic acids contain…
carbon
hydrogen
oxygen
nitrogen
phosphorous
all lipids are made of…
carbon
hydrogen
oxygen
glucose
hexose sugar
alpha and beta glucose
uses of water
- as a reactant in cells e.g. photosynthesis, hydrolysis
- provides structural support in cells
- keeps organisms cool to maintain an optimum body temperature
properties of water
- metabolic importance
- high heat capacity
- heat of vaporisation
- cohesive properties
- useful as a solvent
water molecules are made from…
2 oxygen
1 hydrogen
what does it mean that water is a polar molecule?
oxygen atoms are slightly negatively charged
hydrogen atoms are slightly positively charged
explain hydrogen bonding in water
the polarity of water molecules means that a hydrogen atom on one water molecules is attracted to the oxygen atom on another water molecule
hydrolysis reaction
a bond is broken and a water molecule is used up
ATP + H20 –> ADP + P + energy
condensation reaction
a new bond is formed and a water molecule is released
ADP + P + energy –> ATP + H20
what is the latent heat of vaporisation
the amount of energy needed to change 1kg of a liquid to a gas
explain the high heat of vaporisation that water has
as liquid water heats up, the hydrogen bonding makes it difficult to separate the water molecules from each other. this means that a lot of energy is needed for water to evaporate
- when water evaporates, energy is used up - this cools the environment where the evaporation is taking place
- this is why sweating helps with body temperature regulation
what is specific heat capacity?
the amount of heat 1kg of a substance must absorb or lose to change its temperature by 1oC
explain the high heat capacity of water
water has a high heat capacity so takes a long time to heat and cool
- the SHC of water is much larger than sand - land cools faster than the sea
- water is used by warm blooded animals to more evenly disperse heat in their bodies
explain water being a good solvent
- water is a good solvent because ions and polar molecules can easily dissolve in it
- water is a polar molecule - meaning that the positive end of the water molecule attracts negative ions and the negative ends will attract positive ions
what does cohesion mean?
the strong attraction between water molecules due to hydrogen bonds
explain water having cohesive properties
cohesion produces surface tension where water meets air
- water forms droplets when placed on a dry surface
- plant use this to help transport water from their roots to their leaves
explain water as a habitat
- water makes an ideal habitat
- highly stable environment that does not change easily
- provides a stable habitat for many species
explain formation
smaller, biological molecules in an organism’s cells can form larger, molecules that can be used around the body
these biological molecules are important to allow the organism to survive
explain a condensation reaction
forms large, biological molecules
releases water
bonds the smaller components together into larger molecules
products of condensation of amino acids
produces proteins
products of condensation of two monosaccharides
produces disaccharides
products of condensation of fatty acid and monoglyceridess
produces lipids
explain breakdown
- when an organism eats, it ingests large, biological molecules
- these biological molecules are important to allow the organism to survive
- molecules could be used in the cells for important reaction but are too large to be transported into the cells
- large molecules must be broken down first
explain a hydrolysis reaction
- breaks down large, biological molecules
- requires water
- splits larger molecules into smaller components
- smaller molecules can easily diffuse into cells or be transported using protein channels
products of hydrolysis of protein
produces amino acids
products of hydrolysis of carbohydrate
produces disaccharides and monosaccharides
products of hydrolysis of lipids
produces fatty acids and monoglycerides
disaccharide definition
two monosaccharides joined together
examples of monosaccharides
simple sugars
- glucose
- galactose
- fructose
structure of glucose
hexose sugar with the chemical formula C6H12O6
function of glucose
important source of energy in humans
during cellular respiration, the energy released from glucose helps to make ATP
what are isomers?
have the same molecular formula but a different arrangement of atoms in space
e.g. alpha and beta glucose
alpha and beta glucose
carbon atoms are numbered from 1-6 and the OH (hydroxyl) groups are in a different orientation around C1
what is a pentose sugar?
monosaccharides that have five carbon atoms in their structure e.g. ribose