Biological molecules Flashcards
intro + water
what do all biological molecules consist of?
- they are organic
- contain the element carbon
what are carbohydrates made of?
Carbon (C), Hydrogen (H), Oxygen (O)
what are lipids made of?
Carbon (C), Hydrogen (H), Oxygen (O)
what are proteins made of?
carbon, hydrogen, oxygen, nitrogen
what are nucleic acids made of?
Carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P).
what is a monomer?
Smaller units that combine to make a large molecule (polymer).
what is a polymer?
Large molecule made up of many monomers joined together.
what is the process by which monomers join to form a polymer?
polymerisation
what are the monomers and polymers for carbohydrates?
- monosaccharides
- polysaccharides
what are the monomers and polymers for proteins?
- amino acids
- polypeptides
what are the monomers and polymers for nucleic acids?
- nucleotides
- polynucleotides
what do carbon atoms do?
- form covalent bonds
- form 4 bonds
- require large amounts of energy to break
- with oxygen, nitrogen and sulfur
what chains can carbon atoms form?
- single
- braided
- rings
what are macromolecules?
- contain 1000 or more atoms therefore having a high molecular mass
- subunits of polymers have to be the same repeating units
what are condensation reactions?
- chemical reaction AKA dehydration synthesis
- two molecules are joined together covalently
- with the removal of an -OH from one
- removal of an -H from another
- form water.
(The removal of water to form a chemical bond between two molecules.)
hydrolysis reaction
A chemical reaction
- breaks apart a larger molecule
- by adding a molecule of water
- addition of water to break a chemical bond between two molecules.
what is a covalent bond?
sharing of two or more electrons between atoms
how is a nonpolar covalent bond formed?
by sharing electrons equally
how is a polar covalent bond formed?
by sharing electrons unevenly
- atoms becomes more electronegative
why are covalent bonds stable?
high energies are required to break the bonds
how are covalent bonds formed between monomers?
When two monomers are close enough that their outer orbitals overlap this results in their electrons being shared
Describe simple covalent molecules
have few atoms
- low melting points and boiling points
- are gases and liquids at r.t.p
- covalent bonds within molecules are strong
- bonds between molecules are weak and easy to break
define ionic bonding
- transfer of electrons between non metals and metals which form ions that are positively or negatively charged
what does R’ means
- R group
- interchangeable group or molecule depending on type of molecule it is
why are lipids not in the polymer table
- they are not classed as polymers bc they do not have a repeating units
For carbohydrates, describe its structure, bonding and how its monomers interact to create polymers
- made up of monomers called monosaccharides
- monosaccharides contain carbon, oxygen and hydrogen which are bonded together with covalent bonds
- two or more monosaccharides (the monomers) will interact by undergoing a condensation reaction where the monosaccharide monomers will join together and form glycosidic bonds to form the polymer called polysaccharides.
- This reaction will also release a water molecule
For proteins, describe its structure, bonding and how its monomers interact to create polymers
- made up on monomers called amino acids
- amino acids contain carbon, oxygen, hydrogen and nitrogen held together with a covalent bond
- amino acid has a carboxyl group, an amino group and a R group
- amino acids will interact by joining together by undergoing a condensation reaction where two or more amino acids will join together, forming peptide bonds
- They will form the polymer called polypeptides
- There will also be a water molecule released in the reaction
For nucleic acids, describe its structure, bonding and how its monomers interact to create polymers
- made up of monomers called nucleotides
- nucleotides consist of carbon, hydrogen, oxygen, phosphorus, and nitrogen held together by covalent bonds
- the monomers will interact by undergoing a condensation reaction to form phosphodiester bonds and form the polymer called polynucleotides.
- a water molecule will also be released
What is the structure of a water molecule?
- contains 1 oxygen and 2 hydrogen atoms
- shared negative hydrogen electrons are pulled towards oxygen atom
- other side of each hydrogen atom is left slightly positively charged
- unshared electrons give slight negative charge
what is a polar molecule
- a molecule with an uneven distribution of charge
- molecule with regions of negative charge and positive charge
what is hydrogen bond
- slightly negatively charged oxygen atom attracts to slightly positively charged hydrogen atom of other water molecules
what is cohesion
- when water molecules get close together and the opposite parts attract creating hydrogen bonds and are held together
- small molecule bonding together
What is adhesion
when water molecule is attracted and sticks to other molecules
what is water at r.t.p
liquid or gas
what are the properties of water?
- metabolite
- high specific heat capacity
- high latent heat
- solvent
- lubricant and liquid
- strong cohesion and high surface tension
- density
Explain density property of water
- water gets more dense as it gets colder, till 4 degreesC
- from 4 degreesC to freezing point, water molecules align themselves –> less dense
- hydrogen bonds fix polar molecules slightly further apart than average distance in liquid state
- this makes a giant rigid open structure with each oxygen atom at centre of tetrahedron arrangement of hydrogen atoms
- ice at lower temps than 4 is less dense than water + creates insulating layer -> keeps water from freezing below
- means ice floats and maintains aquatic habitat below
explain surface tension and cohesion property
- cohesion = hydrogen bonds between molecules pull them together so they stick (attraction between slightly positive charge of hydrogen atoms of one molecule and slightly negative charge of oxygen atoms of another molecule
- tension = force that tends to stretch something
- at air-water surface, cohesion between water molecules produces surface tension -> hydrogen bonds also pull molecules inwards at surface
- water molecules attracted to surfaces - adhesion
why is strong cohesion important?
- helps water flow => great for transporting substances
- means water has high surface tension when coming into contact with air
- helps sweat droplets to form so they can evaporate from skin to cool organism down
Explain the property of being a liquid
- lubricant
- water molecules move around and hydrogen molecules continually break down and reform between molecules
- hydrogen bonds make it harder for water molecules to escape and become a gas = more energy needed
- low viscosity = can flow easily
explain the property of having a high specific heat capacity
- hydrogen bonds absorb lots of energy = high s.h.c
- water wont experience rapid temperature changes
- takes lots of energy to increase temp bc lots of energy absorbed by hydrogen bonds
- water absorbs/loses relatively large amount of heat before temp changes
- remains fairly stable in body = constant internal body temps
- water temp more stable than land = provides suitable habitat
explain the property of solvent
- so that metabolic processes can occur
- allows transport of substances
- good solvent bc it is a polar molecule so attracts molecules (solutes and ions)
- they cluster around the molecules and help them break and separate, allowing them to dissolve and become solution
explain property of high latent heat
- high latent heat bc lots of energy needed to break hydrogen bonds between molecules
- when water evaporates heat energy (latent heat of vaporisation) helps molecules break away from each other to become gas
- water absorbs lots of energy before turning to gas
- uses lots of energy when evaporating from surface -> cooling effect + lowering temp
- living organisms can use water loss through evaporation to cool down without losing too much water
