Admissions Test Flashcards
Mixture
A substance made up of two or more substances not chemically bonded together.
Abundance
The percentage of atoms in the universe with a particular mass.
Alkali Metal + Chlorine =
Metal Chloride
Alkali Metal + Water =
Metal Hydroxide + Hydrogen
Reactivity down G1?
Increases
Reactivity down G17?
Decreases
Melting points down G1?
Decreases
Melting points down G17?
Increases
Filtration
Separates insoluble solids from liquids.
Crystallisation
Evaporation separates soluble solids from solutions.
Fractional Distillation
Separates liquids in a mixture with similar boiling points.
Rf value
Distance travelled by solute / Distance travelled by solvent
Mixtures can be separated by…
Physical processes
Chlorine state at room temperature…
Gas
Bromine state at room temperature…
Liquid
Iodine state at room temperature…
Solid
Transition elements I need to know…
Chromium, Manganese, Iron, Cobalt, Nickel, Copper
What substances form ionic bonds?
Metals and Non-metals
Giant Ionic Lattice
Huge 3D network of ions. Regular structure of positive and negative ions alternately arranged and held together by electrostatic forces of attraction.
When can ionic compounds conduct electricity?
When molten or in solution (aq).
What substances form covalent bonds?
Two non-metals.
Melting points of ionic substances?
High
Examples of Giant Covalent Structures…
Graphite, Diamond, Silicon Dioxide
Alloying a metal makes it…
Less reactive and harder.
Nanoparticles
1-100nm, a few hundred atoms.
Nanotube properties
High tensile strength, electrical conductors.
Uses of nanoparticles…
Medical applications, sun creams, deodorant, catalysts, cosmetics, electronics.
Structure of fullerenes is based on…
Hexagonal rings of carbon atoms but they may also contain rings with five or seven carbon atoms.
First fullerene
Buckminsterfullerene (C60) which has a spherical shape.
Fine particles diameter?
100nm - 2500nm
Avogadro’s number
6.022 x 10^23
Moles =
Mass / Mr
Concentration (1) =
Mass / Volume
Convert cm^3 into dm^3…
Divide by 1000
% yield =
Actual yield / Theoretical Yield x 100
Atom economy =
100 x Mr of desired product / Mr of all reactants
Concentration (2)=
Moles / Volume
1 mol of gas at room temperature and pressure occupies…
24 dm^3
Acid + Metal
Salt + Hydrogen
Acid + Metal hydroxide
Salt + Water
Acid + Metal oxide
Salt + Water
Acid + Metal carbonate
Salt + Carbon dioxide + Water
Acid + Metal Hydrogen Carbonate
Salt + Carbon dioxide + Water
Acidic Oxide + Base
Salt + Water
Acid used is HCl…
Metal Chloride
Acid used is H2SO4…
Metal Sulfate
Acid used is HN03…
Metal Nitrate
Mass of one mole of a substance in grams is numerically equal to…
Its Mr
How can metals be placed in order of reactivity?
Add the metals to water or acid and observe which ones react the most vigorously (fizzing).
Metals less reactive than carbon extracted by…
Reduction with carbon
What is removed from a compound in a reduction reaction?
Oxygen
How are metals more reactive than carbon extracted?
Electrolysis
What is an acid?
A substance with a pH less than 7, that releases hydrogen ions in a solution.
HCl
Hydrochloric Acid
HNO3
Nitric Acid
H2SO4
Sulfuric Acid
What is a base?
A substance (metal oxide, hydroxide or carbonate) that will react with an acid in neutralisation reactions.
H+ + OH-
H2O
What is a salt?
A compound formed when some or all of the hydrogen from an acid is replaced by a metal e.g. copper sulfate, copper has replaced the hydrogen from sulfuric acid.
Reactivity Series
Potassium, Sodium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Tin, Lead, Hydrogen, Copper, Silver, Gold, Platinum
When K, Na, Li and Ca react with water…
Fizzes and gives off hydrogen gas.
When Mg, Al, C, Zn and Fe react with water…
Reacts very slowly.
When tin, lead, hydrogen, copper, silver, gold and platinum react with water…
No reaction.
When K, Na, Li and Ca react with acid…
Explodes
When Mg, Al, C, Zn and Fe react with acid…
Fizzes and gives off hydrogen gas.
When tin and lead react with warm acid…
Reacts slowly.
When copper, silver, gold and platinum react with acid?
No reaction.
What type of reaction occurs when acids react with some metals to produce salt and hydrogen gas?
Redox Reactions
Soluble salts can be made from…
Acids by reacting them with solid insoluble substances such as metals, metal oxides, hydroxides or carbonates.
When making soluble salts how much solid do we add?
We add the solid to the acid until no more acid reacts - filter excess solid off to make a salt solution.
What do we do with the salt solution when making soluble salts?
Solution can be crystallised to form solid salts.
Strong acid - ionisation
Strong acids are completely ionised in aqueous solutions.
Examples of strong acids?
HCl, HNO3, H2SO4
Weak acid - ionisation
Weak acids are only partially ionised in aq solutions.
For a given concentration of acid, the stronger the acid…
The lower pH.
Acids are neutralised by…
Alkalis e.g. soluble metal hydroxides, and bases (e.g. insoluble metal hydroxide & metal oxides).
What do aqueous solutions of alkalis contain?
OH-
Electrolysis
Using electricity to break down a substance and extract elements from a compound.
Electrolyte
A liquid or solution containing ions can conduct electricity.
Positive electrode
Anode
Negative electrode
Cathode
Which electrode do positive ions move towards?
Cathode
Which electrode do negative ions move towards?
Anode
Metals are formed at the…
Cathode
Non-metals are formed at the…
Anode
Examples of weak acids?
Ethanoic, Citric, Carbonic acids
When are metals not produced at the cathode?
When the metal is more reactive than hydrogen.
When electrolysing metal halides, where are halogen gases produced?
At the anode.
What is produced at the anode when electrolysing metal sulfates?
Oxygens
Gains electrons at the…
Cathode
Loses electrons at the…
Anode
Electrolysis products of molten iron bromide?
Iron (s) and Bromine (l)
Electrolysis products of zinc oxide?
Zinc and Oxygen
How are metals more reactive than carbon extracted?
By electrolysis.
What is added to aluminium before electrolysis and why?
Cryolite - lowers the m.p. of aluminium.
What are the electrodes made out of during the electrolysis of aluminium?
Graphite
What is formed in the electrolysis of aluminium?
Aluminium at the cathode, Oxygen at the anode.
Products of sodium chloride electrolysis?
Chlorine gas and hydrogen gas.
H20 (l) =
H+ (aq) + OH- (aq)
Products of lead bromide electrolysis?
Lead at the cathode, Bromine at the anode.
When is hydrogen produced at the cathode?
If the metal is more reactive than hydrogen.
Exothermic Reaction
Energy transferred to the surroundings.
Examples of exothermic reactions…
Combustion, respiration, oxidation, neutralisation
Endothermic Reaction
Energy transferred from the surroundings.
Examples of endothermic reactions…
Thermal decomposition, citric acid & sodium hydrogen carbonate
Breaking bonds
Endothermic
Making bonds
Exothermic
What is the voltage produced by a cell dependent upon?
A number of factors including type of electrode and electrolyte.
How is a simple cell made?
By connecting two different metals in contact with an electrolyte.
How do rechargeable cells & batteries work?
Chemical reactions are reserved when an electrical external current is supplied.
What are fuel cells supplied by?
An external source of fuel e.g. hydrogen & oxygen or air.
What happens to the fuel in a fuel cell?
It is oxidised electrochemically within the fuel cell to produce a potential difference.
What do cells contain?
Chemicals which react to produce electricity.
In non-rechargeable cells & batteries what happens?
The chemical reactions stop when one of the reactants have been used up.
Are alkaline batteries rechargeable or non-rechargeable?
Non-reachargeable
Overall reaction in a hydrogen fuel cells?
Involves the oxidation of hydrogen to produce water.
What do hydrogen fuel cells offer?
A potential alternative to rechargeable cells and batteries.
Mean rate of reaction (1) =
Quantity of reactant used / Time taken
Mean rate of reaction (2) =
Quantity of product formed / Time taken
Factors affecting rate of reaction…
Temperature, surface area of a solid, concentration of reactants in solution, pressure of gases.
What do catalysts provide?
Catalysts provide an alternative route for the reaction to take place, which has a lower activation energy.
Le Chatelier’s Principle
The idea that you change the conditions of a reversible reaction at equilibrium, the system will try & counteract the change.
In a reversible reaction, equilibrium moves in the direction of the exothermic reaction…
You will get a greater yield for the exothermic reaction, & a lesser yield for the endothermic reaction.
In a reversible reaction, increasing temperature…
Causes equilibrium to move in the endothermic direction to try to decrease it.
In a reversible reaction, equilibrium moves in the direction of the endothermic reaction…
You will get a greater yield in the endothermic reaction, and a lesser yield in the exothermic reaction.
Changing the pressure of a reversible reaction only affects an equilibrium…
Involving gases.
If you increase the pressure in a reversible reaction…
The equilibrium tries to reduce it - it moves in the direction when there are fewer molecules of gas.
If you decrease pressure in a reversible reaction…
Equilibrium tries to increase it - it moves in the direction where there are no molecules of gas.
Changing the concentration of either the reactants or the products in a reversible reaction means that…
The system will no longer be at equilibrium.
Decreasing the concentration of products in a reversible reaction…
The system tries to increase it again by reducing the amount of reactants.
If you decrease the temperature in a reversible reaction, the equilibrium…
Will move in the exothermic direction to transfer more thermal energy.
The direction of a reversible reaction can be changed by…
Changing the conditions of the reaction.
Equilibrium is reached when…
The forward and reverse reactions occur at exactly the same rate in apparatus which prevents the escape of reactants and products.
If you increase the temperature in a reversible reaction, equilibrium…
Moves in the endothermic direction to try and decrease it.
What does increasing the concentration of reactants in a system make?
A greater yield of products to try and decrease concentration.
Decreasing the concentration of products in a reversible reaction…
The system tries to increase it again by reducing the amount of reactants.
Crude oil
Mixture of hydrocarbons.
Crude oil formation
Formed over millions of years from remains of ancient biomass (mostly planktons that were buried in mud).
Hydrocarbonds
Compound containing atoms of carbon and hydrogen.
Alkane
Hydrocarbon that only has single bonds.
First 6 Alkanes
Methane, ethane, propane, butane, pentane, hexane.
General Formula for alkanes…
CnH2n+2
The longer the hydrocarbon chain length (bp)…
The higher its boiling point.
The longer the hydrocarbon chain length (v)…
The higher the viscosity.
The longer the hydrocarbon chain length (f)…
The lower the flammability.
Fractional distillation of crude oil…
Crude oil is vaporised, different molecules rise up the fractionating column and cool down, condensing at different points along the column.
A fuel…
A substance which when reacted with oxygen releases oxygen.
5 useful fuels from fractional distillation…
Petrol, diesel, kerosene, heavy fuel oil, liquefied petroleum gases.
Other uses of gases from fractional distillation…
Solvents, lubricants, polymers, detergents.
Complete Combustion
Hydrocarbon + Oxygen –> Water + Carbon Dioxide
Cracking…
The process of breaking down a long hydrocarbon into smaller molecules.
Products of cracking?
Short alkanes and alkenes.
Why is cracking useful?
Smaller hydrocarbons are more useful than longer ones.
Two types of cracking?
Catalytic and steam cracking.
Alkenes –>
Hydrocarbons with a double bond - C=C.
What are alkenes used for?
Formation of polymers.
Test for alkenes…
Bromine water - colour change from orange to colourless.
Which one out of alkenes or alkanes are more reactive?
Alkenes are more reactive than alkanes.
First 6 alkenes…
Ethene, propene, butene, pentene, hexene.
General formula for alkenes…
CnH2n
Are alkanes saturated of unsaturated?
Saturated
What is a fraction?
Hydrocarbons with similar boiling points.
Where are short chain hydrocarbons condensed within the fractionating column?
At the top of the column.
What is the crude oil heated to in the fractionating column?
350 degrees
Are longer or shorter hydrocarbons more or less in demand?
Shorter
Homologous Series
Family of organic compounds with same general formula.
Combustion
The reaction of a fuel with oxygen.
What state are alkanes at room temperature?
Gases
What is a fractionating column used to do?
Separate crude oil.
Temperature moving up the fractionating column…
Decreases
Incomplete combustion
Hydrocarbon + Oxygen –> Water + Carbon Monoxide + Carbon (sometimes)
What flame do alcohols burn with?
A blue flame.
How can we test for the presence of water?
White anhydrous copper (II) sulfate will turn to blue hydrate copper (II) sulfate or cobalt chloride paper will turn from blue to pink.
Test for carbon dioxide…
Colourless lime water becomes cloudy.
Methane
CH4
Ethane
C2H6
Propane
C3H8
Butane
C4H10
Pentane
C5H12
Hexane
C6H14
Hydrogenation
An addition reaction where an alkene reacts with hydrogen to form an alkane.
Which halogens can react with alkenes?
Fluorine, Chlorine, Bromine, Iodine
Ethanoic Acid + Sodium Carbonate –>
Sodium Ethanoate + Water + Carbon Dioxide
Ester functional group
COO
Alcohols react with sodium metal to produce…
Sodium alkoxide + Hydrogen gas
Sodium + Ethanol –>
Sodium Ethoxide + Water
What is produced when alcohols are burned?
Carbon dioxide + Water
Carboxylic Acid general formula…
CnH2n+1COOH
Ethanol oxidised…
Ethanol + Oxidising Agent –> Ethanoic Acid + Water
Example of an oxidising agent?
Potassium dichromates
pH of a solution of carboxylic acid…
Less than 7.
Butene isomers…
But-1-ene, But-2-ene
What gas is released when carbonates fizz in a solution of carboxylic acid?
Ester gas
Esters
Fragrant, volatile compounds used in flavourings and perfumes.
Addition polymerisation
Unsaturated monomer molecules open up their double bonds and join to form polymer chains.
Monomers in condensation polymerisation…
Have two functional groups.
Sodium carbonate + ethanoic acid –>
Sodium ethanoate + Water + Carbon dioxide
How many products are formed in addition polymerisation?
1 - the polymer.
How many products are formed in condensation polymerisation?
2 - the polymer and a small simple molecule (usually water but not always.
What groups do an amino acid contain?
A basic amine group and acidic carboxyl group.
Monomers that make up addition polymers have a…
Double carbon bond - C=C.
Smallest & simplest amino acid?
Glycine
Polymers formed from amino acids?
Polypeptides
Isomers of alcohol with 3 carbons…
Propan-1-ol, Propan-2-ol
First 6 carboxylic acid…
Methanoic Acid, Ethanoic Acid, Propanoic Acid, Butanoic Acid, Propanoic Acid, Hexanoic Acid
State of alcohols at room temperature?
Liquid
What can ethanol be formed from?
The fermentation of sugars.
Catalytic cracking…
Alkane heated to form vapours which are passed over a hot powdered aluminium oxide catalyst.
Alcohol functional group?
OH
Steam Cracking…
Hydrocarbon vapours mixed with steam and then heated to very high temperatures.
Catalytic cracking temperature…
550 degrees approx.
Steam cracking temperature…
800 degrees approx.
Are alcohols soluble in water?
Yes
Which type of combustion are alkenes more likely to experience?
Incomplete
What can alkenes undego?
Addition reactions.
Alkene + Hydrogen –>
Alkane
Alkene + Water (steam) –>
Alcohol
Alkene + Halogen –>
Halogenalkane
Functional group of alkenes…
C=C
Methanol
CH3OH
Ethanol
C2H5OH
Propanol
C3H7OH
Butanol
C4H9OH
Pentanol
C5H11OH
Hexanol
C6H13OH
As the length of alcohol molecules increases…
Their solubility increases.
pH of alcohol solution?
7
Alcohols are oxidised to form…
Carboxylic Acids
What is produced when carboxylic acids react with carbonates?
Salt, Water and Carbon Dioxide
Carboxylic Acid + Alcohol –>
Esters
What happens when carboxylic acids dissolve in water?
They produce an acidic solution but because they only partially dissociate in water, they are weak acids.
Ethene + Bromine –>
Dibromoethane
Ethanoic Acid + Sodium Carbonate –>
Sodium Ethanoate + Water + Carbon Dioxide
General formula for alcohols…
CnH2n+1OH
Methanoic Acid
CH2O2
Ethanoic Acid
C2H4O2
Propanoic Acid
C3H6O2
Butanoic Acid
C4H8O2
Pentanoic Acid
C5H10O2
Hexanoic Acid
C6H12O2
Carboxylic Acids react w/ …
Metals to form a salt + hydrogen, react with bases to form salt and water.
Alcohol + Carboxylic Acid –>
Ester + Water
Ethanol + Ethanoic Acid –>
Ethyl Ethanoate + Water
Aq solutions of ethanol are produced when…
Sugar solutions are fermented using yeast.
Chemical Analysis
Process of establishing what chemicals are present in a substance.
Pure Substance
Made of a single element or compound, not mixed with any other substance.
How can pure and impure substances be distinguished?
By their melting & boiling points.
The boiling & melting points of pure substances…
Have a definite value - one specific temperature.
Impure substances change…
State at a range of substances.
Formulation
A complex mixture designed as a useful product + for a specific purpose.
Chromatography
A process to separate the soluble substances from a mixture e.g. dyes.
Stationary Phase
Paper
Mobile Phase
Solvent e.g. water, ethanol.
How many spots do pure substances form on a chromatogram?
1
How many spots do impure substances form on a chromatogram?
2 or more
What does a substance’s Rf value depend on?
Solubility of the solvent - the higher the Rf value, the more soluble the substance.
Hydrogen Test
Lit splint will give a squeaky pop in a test tube of hydrogen.
Oxygen Test
Relights a glowing splint.
Chlorine Test
Bleaches damp litmus paper white.
Flame Test
A test to identify metal ions (cations).
Frame produced from a lithium containing compound…
Crimson
Frame produced from a copper containing compound…
Green
Frame produced from a sodium containing compound…
Yellow
Frame produced from a potassium containing compound…
Lilac
Frame produced from a calcium containing compound…
Orange-red
How can metal ions also be identified?
By Sodium Hydroxide
Which ions produce white precipitates?
Al, Mg, Ca
Which white precipitate dissolves in excess sodium hydroxide?
Al
Cu (II) ions precipitate…
Blue Precipitate
Fe (II) ions precipitate
Green Precipitate
Fe (III) ions precipitate
Brown Precipitate
Carbonate ion test…
Add an acid to generate carbon dioxide gas.
Halide ion test…
Add silver nitrate and nitric acid to generate a solid silver halide precipitate.
Silver Chloride colour…
White
Silver Bromide colour…
Cream
Silver Iodide colour…
Yellow
Sulfate ion test…
Add barium chloride and HCl - forms white precipitate.
Instrumental Analysis
Use of scientific technology to perform chemical analysis.
Instrumental Analysis is…
Accurate, Sensitive, Rapid
Flame emission spectroscopy…
Instrumental analysis tool for identifying metal ions.
Flame emission spectroscopy method…
Sample placed in flame, light emitted is passed through a spectroscope to give a spectrum which can be compared to a reference.
Limewater
Calcium Hydroxide
If a sample contains a mixture of ions…
Some flame colours can be masked.
Two sources of evidence for gases in the early atmosphere…
Gases in porous rocks & atmospheres on other planets.
Volcanoes give off which gases?
Carbon Dioxide, Nitrogen and Water Vapour.
Gases in trace amounts in the early atmosphere…
Methane and Ammonia.
Photosynthesis
Water + Carbon Dioxide –> Glucose + Oxygen
What gas was not present in the early atmosphere?
Oxygen
After algae evolved, what gas increased in the atmosphere?
Oxygen
What is limestone mainly made up of?
Made up of a calcium carbonate.
Where can carbon be locked from the atmosphere?
Fossil fuels and in sedimentary rocks.
Fossil Fuels
Coal, crude oil, natural gas.
Ammonia
NH3
% of Nitrogen in today’s atmosphere?
78%
% of Oxygen in today’s atmosphere?
21%
% of Argon in today’s atmosphere?
0.9%
% of Carbon Dioxide in today’s atmosphere?
0.04%
Main Greenhouse Gases
CO2, CH4, H2O vapour.
Example of active transport…
Uptake of nitrates into plant root cells from the soil.
Which molecules are dissolved in the cytoplasm, not suspended?
Salt ions and sugar molecules.
What happens to chemical energy from respiration before it can be utilised in movement?
Transferred / converted to Ek.
What is it called when water moves out of the cytoplasm of a cell?
It has been crenated.
What is the unit of ultrafiltration in the kidney?
The nephron.
What is the slowest part of the reflex arc?
Synapses.
When is turgor pressure created?
When plant cells fill with water - cell membrane pushed on cell wall.
Where are mitochondria found in sperm cells?
In the mid-section of a sperm cell.
What do egg cells contain to be utilised by the embryo?
Egg cells contain large amounts of food storage for the development of the embryo once fertilisation has taken place.
Can fats and carbohydrates be stored by the body?
Yes.
Where is the genetic material found in a sperm cell?
In a nucleus in the head-section of the sperm.
Effect of hormones?
Generalised.
What main molecule does not pass into the blood of healthy individuals from the kidneys?
Proteins
Can proteins be stored by the body?
No
Example of diffusion…
Urea entering the bloodstream from animal liver cells.
What are synapses limited by?
Rate of diffusion.
What is urea filtered by?
The kidneys.
Which molecules are suspended in the cytoplasm - NOT DISSOLVED?
Fat molecules and proteins.
Lithium Mass Number…
7
Aluminium Atomic Number…
13
Argon Atomic Number…
18
Helium Mass Number…
4
Lithium Atomic Number…
3
Oxygen Atomic Number…
8
Phosphorous Atomic Number
15
Helium Atomic Number…
2
Hydrogen Mass Number…
1
Sulfur Atomic Number…
16
Neon Atomic Number…
10
Hydrogen Atomic Number…
1
Silicon Atomic Number…
14
Boron Atomic Number…
5
Carbon Atomic Number…
6
Magnesium Atomic Number…
12
Caesium Atomic Number…
20
Potassium Atomic Number…
19
Beryllium Atomic Number…
4
Fluorine Atomic Number…
9
Nitrogen Atomic Number…
7
Sodium Atomic Number…
11
Chlorine Atomic Number…
17
Factors affecting diffusion…
Concentration gradient, temperature, surface area, diffusion distance, size.
What does alcohol do regarding ADH?
Alcohol suppresses ADH production, kidneys reabsorb less water so large volumes of diluted urine.
What is the affect of ecstasy on ADH Production?
Increases the production of ADH, so kidneys reabsorb more water, so small volumes of concentrated urine.
Water brought to Earth by…
Icy comets.
CO2 dissolved in oceans + reacted with metal oxides to form…
Metal carbonates
Types of shortwave radiation hitting the Earth’s surface…
UV and visible light.
What main type of radiation is absorbed by greenhouse gases?
Infrared
Shortwave radiation is emitted by…
The sun.
Longwave radiation emitted by the…
Earth’s crust
What percentage of sun’s energy which reaches Earth is reflected…
Back into space.
What are the products of burning fossil fuels?
Releases carbon dioxide & water.
Examples of Carbon Sinks…
Rainforests and oceans.
What is it called when CO2 is pumped into the ground to be absorbed by porous rocks…
Carbon capture and storage.
What is a biofuel?
Fuel derived from plant material.
Biofuels are…
Carbon neutral.
High temperatures in an engine causes…
Nitrogen oxides to be produced.
What is acid rain caused by?
Nitrogen oxides & sulfur dioxide.
How is sulfur dioxide formed?
Formed by sulfur impurities in fossil fuels being burned.
Carbon dioxide is formed by the…
Complete combustion of fuel.
Methane + Oxygen
Carbon Dioxide + Water
Ammonia + Oxygen
Nitrogen + Water
Particulates
Cause global dimming + health problems for humans.
Potable Water
Water that is safe to drink.
Which element can be added to drinking water to sterilise it?
Chlorine
What else can be used to sterilise water?
Ozone (O3) and UV Light.
Sterilising water means to…
Kill any bacteria that may be in the water.
Reverse osmosis
Uses membranes to separate dissolved salts from salty water.
Water can be purified by…
Distillation
Sewage treatment involves…
The removal of organic matter and harmful microorganisms + chemicals.
Sewage treatment screening
Removing large solids + grit.
Sedimentation
Allowing large particles to settle.
Aerobic treatment of water…
Use microbes with oxygen.
Anaerobic digestion…
Breaking down sewage sludge with microbes and oxygen.
Smelting
Extracting metal from an ore.
How can we purify copper?
Electrolysis - extracted by smelting.
Copper can extracted from solutions of copper compounds…
By electrolysis + displacement.
Phytomining
Extracting metal from the ground using plants.
Bioleaching
Using microbes to extract metals from the ground.
What does LCA stand for?
Life cycle assessment.
Disadvantages of using distillation to purify water…
Requires large amounts of energy, expensive.
How can sewage sludge be treated?
By separation, broken down by digestion (anaerobic), and dried.
What can sewage sludge be used for?
Can be used for fertiliser as a fuel to generate electricity.
How is most potable water produced?
By choosing an appropriate source of fresh water, passing the water through filter beds and sterilising.
Why may desalination be required?
In areas where fresh water is limited.
How can desalination be carried out?
By distillation or reverse osmosis.
Disadvantage of desalination?
Large amounts of energy.
What things produce large amounts of waste water?
Urban lifestyles + Industrial processes.
What has to happen to waste water before being released into the environment?
It has to be treated.
Phytomining process…
Uses plants to absorb metal compounds. The plants are harvested and burned to produce ash containing metal compounds.
Bioleaching process…
Uses bacteria to produce leachate solutions that contain metal compounds.
What happens with the metal compounds produced from bioleaching and phytomining?
We can process the to extract the copper by displacement with scrap iron or electrolysis from the solutions.
Why are LCAs carried out?
To assess environmental impact of products in each of a number of stages.
1st stage of LCA…
Extracting and processing raw materials.
2nd stage of LCA…
Manufacturing and packaging.
3rd stage of LCA…
Use and operation during its lifetime.
4th stage of LCA…
Disposal at the end of its useful life, including transport + distribution at each stage.
What does paint over metal act as?
A barrier to water and oxygen.
What is stainless steel resistant to?
Corrosion
Steel coated in magnesium resistant to corrosion…
Provides sacrificial protection - Mg more reactive than Fe.
Metals can…
Oxidise in air.
Metal oxidation occurs at…
Different rates.
Very unreactive elements such as gold may…
Not undergo corrosion at all.
Corrosion
Process which happens when a metal continues to oxidise over a long period of time.
What does corrosion do to metals?
Weakens the metal - who metal could become a metal oxide.
What is rusting?
Form of corrosion - iron or steel reacts with water + oxygen.
Iron + Oxygen
Iron (III) Oxide
What colour is Iron (III) oxide?
Orange-brown
How can rusting be prevented easily?
Keeping water and oxygen away from iron or steel.
What can metals be stored in to prevent rusting?
Can be stored in an atmosphere of nitrogen or argon (inert).
Why can a desiccant be used to prevent rusting?
It absorbs water vapour and therefore the metal remains dry.
Physical barriers against rusting…
Painting, oiling & greasing, coating with plastic.
Electrolyte in electroplating…
Contains ions of the plating metal.
Electroplating
Electrolysis is used to add a thin layer of metal onto an object.
What is at the cathode and anode in electroplating?
Cathode - iron or steel objects, Anode - plating metal.
Example of object electroplated?
Steel cutlery electroplated with the use of a silver anode and silver nitrate solution.
Galvanisation…
Iron coated in zinc. Zinc layer prevents oxygen and water from reaching the iron.
Why does coating iron with zinc protect it?
Zinc is more reactive than iron - sacrificial metal.
Bronze…
Alloy of copper + tin.
Brass…
Alloy of copper + zinc.
Common properties of transition metals…
Able to form stable ions in different oxidation states, they often form coloured compounds, used as catalysts (as ions or atoms).
Steels
Alloys of iron which contain diff. amounts of carbon & additional metal elements.
Properties of steels are affected by…
Different compositions.
What does high carbon steel contain in addition to iron?
Carbon
High carbon steel properties?
Strong & brittle.
Low carbon steel properties?
Softer, more easily shaped.
What does stainless steel contain in addition to iron?
Chromium & nickel.
Stainless steel properties?
Hard, resistant to rusting.
Aluminium does not…
React with water.
Why does Al not react with water?
Protected by a natural layer of aluminium oxide.
What is aluminium resistant to?
Corrosion
Magnalium…
Aluminium + Magnesium alloy.
What glass is usually used?
Soda-lime
How is soda-lime made?
By melting silicon dioxide with sodium carbonate (limestone) - then allow the molten mixture to solidify into glass.
Borosilicate glass?
Another type of glass formed when silicon dioxide heated with boron trioxide.
Difference between borosilicate glass and soda-lime glass?
Higher b.p.
Clay Ceramics
Bricks, China, Porcelain
Forms of poly(ethene)…
Both high and low density forms.
LDPE
Low Density Poly(ethene)
LDPE properties?
Flexible, unreactive, can be made into films.
HDPE
High Density Poly(ethene)
HDPE properties?
Strong, flexible, resists shattering, resists chemical attack.
Thermosoftening plastics…
Melts when heated, do not have cov. bonds between neighbouring polymer molecules.
Thermosetting plastics…
Do not melt when heated, burns and char. Covalent bonds are strong & prevent the plastic melting when heated.
Composite materials…
Made up of two or more different materials which have different properties.
What are composite materials made up of?
Reinforcement and matrix (binds reinforcement together).
Fibre glass
Reinforcement - glass fibres, Matrix - polymer resin.
Reinforced concrete
Reinforcement - steel, Matrix - concrete.
Carbon Fibre reinforced polymers
Reinforcement - polymers, Matrix - polymer resin.
Chipboard
Reinforcement - wood chips, Matrix - resin glue.
How can composite materials be separated?
By physical processes.
Glass ceramics have…
A high melting point, stiff, brittle, poor electrical conductivity, poor thermal conductivity, poor strength, strong under compression.
Metals have…
High melting point, malleable good electrical conductivity, good thermal conductivity, strong.
Plastics have…
Usually a low melting point, usually flexible, poor electrical conductivity, poor thermal conductivity, relatively weak strength.
Composites have…
High m.p, stiff, brittle, poor electrical conductivity, poor thermal conductivity, strong.
What is ammonia?
Important industrial product used in fertilisers, explosives and dyes.
What is ammonia manufactured by?
The Haber Process - reversible reaction.
Haber Process
N2 + 3H2 -><- 2NH3
What can the Haber Process reach?
A dynamic equilibrium.
1st step of the Haber Process
N. extracted from air & H, which is obtained from natural gas, pumped through pipes.
2nd step of the Haber Process
Compressor, increase the mixture of gases to 200 atms.
3rd step of the Haber Process
Pressurised gases heated to 450 degrees, and passed through a tank, containing an iron catalyst.
4th step of the Haber Process
Mixture cooled so that NH3 liquefies and can be removed.
What happens to unreacted nitrogen and hydrogen in the Haber process?
Recycled - saves money & increases overall yield.
Fertilisers
Chemical formulations which contain nitrogen, phosphorus & potassium compounds to promote plant growth.
What are fertilisers containing the three elements - nitrogen, potassium and phosphorous?
NPK fertilisers.
What do fertilisers have to be?
Soluble in water.
Soluble nitrogen forms?
NH4- (ammonium ions), NO3- (nitrate ions).
Soluble phosphate forms?
PO43-
Ammonium nitrate…
NH4NO3 - Nitrogen = essential element.
Phosphate rock can react w/ nitric acid to form…
Calcium nitrate + Phosphoric acid (neutralised w/ ammonia to make ammonium phosphate).
Phosphate rock can react w/ sulfuric acid to form…
Single superphosphate (calcium sulfate + calcium phosphate).
Phosphate rock can react w/ phosphoric acid to form…
Triple Super Phosphate (calcium phosphate).
Ammonium Sulfate…
Salt used as a fertiliser - made by reacting ammonia solution with sulfuric acid.
pH of pure water…
7
How can the pH of water be tested?
Checked with universal indicator paper.
Distilled water…
Contains no dissolved solids = have a pH of 7.
Waste water treatment
Screened by passing through a mesh to remove solids and grits, settle in large sedimentation tanks, liquid effluent produced & a semi-solid sludge. Solid sludge taken away and digested by anaerobic bacteria.
When sludge is anaerobically digested…
There is the absence of oxygen, bacteria produce biogas.
Biogas can be…
Burned for electricity.
Liquid effluent contains…
A large amount of organic molecules and harmful microorganisms.
Aerobic digestion…
In the presence of oxygen, aerobic bacteria digest the organic molecules and harmful microorganisms.
After treatment what can happen to liquid effluent?
Can be safely discharged into the sea.
Phytomining process…
Plants grown on land containing the metal compound that we want - absorb the metal compound - concentrate it in their tissue. Harvested & burned.
Bioleaching process…
Mixed with low-grade ore & the bacteria carry out chemical reactions & produce a solution called a leachate - contains the metal compound we want.
LCAs can be…
Biased
What sometimes needs to happen regarding LCAS?
May need to make estimates or value judgements - not always accurate.
Raw materials obtained by…
Quarrying or mining.
Recycling metals…
Melt them and then recast them into different products.
Hydrogen can be produced by…
Reacting methane w/ steam.
Disproportionation reaction
A reaction in which the same species is simultaneously oxidised and reduced.
Oxidation state
Represents the total number of electrons that the element has either accepted by an element or removed from an element to get to its current form.
Positive Oxidation State
Shows the total number of electrons which have been removed from an element to get to its present state.
Negative Oxidation State
Shows the total number of electrons added to an element to get to its present state.
Oxidation
Involves an increase in oxidation state.
Reduction
Involves a decrease in oxidation state.
An oxidising agent…
Is normally a non-metal or positive ion, cause oxidation reactions to take place & gains electrons from other atoms or ions (is itself reduced).
A reducing agent…
Is usually a metal or negative ion, donates electrons to another element or ion (reducing the other species), is itself oxidised.
Redox Reaction
One in which both oxidation & reduction takes place.
Example of a redox reaction?
Displacement reactions.
Carbonate ion
CO32-
Examples of small covalently bonded molecules…
Water, ammonia, methane.
Metals exist as…
A giant structure of positively charged ions surrounded by delocalised electrons.
What forces can exist between molecules?
Intermolecular forces
What do intermolecular forces need to be overcome in?
Melting & Boiling
pH is a measure of…
A measure of hydrogen ion concentration.
A change of 1 on the pH scale corresponds to…
A change by a factor of 10 in H+ ion concentration.
Monoprotic acids?
Can only donate one proton.
Examples of monoprotic acids?
HCl, CH3COOH (acetic acid), HNO3
Polyprotic acid
Can donate two or more protons.
Examples of polyprotic acids…
H2SO4, H3PO4 (phosphoric acid), C10H16N2O8 (ethylenediaminetetraacetic acid)
Diprotic acids
Can donate two protons e.g. H2SO4.
Triprotic Acids
Can donate three protons e.g. H3PO4
Catalysts do not…
Affect the position of equilibrium.
Catalysts are…
Not used up in a reaction & are chemically unchanged at the end of a reaction.
In an exothermic reaction…
Delta H is negative - negative enthalpy change.
In an endothermic reaction…
Delta H is positive - positive enthalpy change.
If a reversible reaction is exothermic in one direction…
It is endothermic in the other direction.
Direct current…
Used in electrolysis to maintain a consistent, one-way flow of electrons.
Polyamides
Polymers where the repeating units are held together by amide links.
Formula of an amide group?
CONH2
The biodegradability of polymers depends on…
The types of intermolecular forces within the polymer chains.
Biodegradable polymers…
Are broken down by natural processes such as decomposition.
Non-biodegradable polymers…
Can take hundreds of years to break down and can have long-term environmental impacts.
The reactivity of a metal is linked to its…
Tendency to form positive ions & the ease of extraction of the metal.
Fluoridation
The addition of small amounts of fluoride to drinking water to prevent tooth decay.
Selective Breeding steps
1 - Choose parent w/ desired characteristics.
2 - Breed them together.
3 - Choose best offspring.
4 - Continue over many generations.
Purpose of Selective Breeding…
Desirable characteristics.
2 reasons for Selective Breeding?
Produce food crops, produce domesticated animals.
Selectively breed for…
- Disease resistance (food crops).
- More milk/meat (animals).
- Gentle nature (domestic animals).
- Unusual / large flowers.
Disadvantage of selective breeding in animals?
Inbreeding - health issues.
Disadvantage of selective breeding in plants?
Crops - very similar DNA - genetic disease can kill all plants.
What part of the brain controls unconscious activities i.e. heart rate and breathing rate.
Medulla Oblongata
What part of the brain controls intelligence, personality, conscious thought and high-level functions e.g. language and verbal memory?
Cerebrum
What part of the brain controls balance, coordination of movement and muscle activity?
Cerebellum
Accommodation
The process of changing the shape of the lens to focus on near or distant objects.
What lens can be used to treat hyperopia?
Convex spectacle lenses.
What lens can be used to treat myopia?
Concave spectacle lenses.
Other eye treatments…
Contact lenses, laser eye surgery, replacement lenses.
Myopia
Short-sightedness: when distant objects appear blurred, therefore rays of light focus in front of the retina.
Hyperopia
Long-sightedness: when near object looks blurred because rays of light focus behind the retina.
Reasons for hyperopia…
Eyeball too short - distance between lens and retina is too small; a loss of elasticity of the lens - cannot become thick enough to focus - often age-related.
What happens to the pupil in bright light?
Radial muscles relax, circular muscles contract, contracted pupil = smaller.
Reasons for myopia…
Eyeball being too long/elongated, distance between lens and retina = too great; lens beings too thick and curved - light focused in front of the retina.
Suspensory Ligament
Tightens and slackens to control the shape of the lens.
Sclera
Tough, white outer-layer of the eye. Helps protect eye from injury.
What happens to the pupil in dim light?
Radial muscles contract, circular muscles relax, pupil becomes dilated.
How does the eye focus on near objects?
Ciliary muscles contract, suspensory ligaments slacken, so lens is thick and more curved (refracts light rays more strongly).
How does the eye focus on distant objects?
Ciliary muscles relax, suspensory ligaments pulled tight, lens is thinner and flatter - only refracts light rays slightly.
Where is the cell body found on the sensory neurone?
Along/on the neurone fibre.
Where is the cell body found on the motor neurone?
Beginnings of the neurone fibre.
Hormones used in IVF?
FSH, LH
FSH inhibits…
Oestrogen
Oestrogen stimulates…
LH
Where is progesterone produced?
Corpus luteum
Hormones produced in the pituitary gland?
LH + FSH + ADH
Where are auxins produced?
Meristems
Where is ethene gas produced in plants?
Gas produced by ageing parts of the plant.
Gibberellin
Stimulates seed germination, stem growth and flowering.
Ethene
Influences the growth of the plant by controlling cell division - also stimulates enzymes that cause fruit to ripen.
Auxins
Control the growth of a plant in response to light - phototropisms & gravitropisms/geotropisms.
Progesterone
Maintains uterus lining.
Progesterone inhibits…
FSH & LH
FSH
Egg development and maturation.
LH
Ovulation
Oestrogen
Causes uterus lining to rebuild.
If the motor area is stimulated during electrical stimulation, the patient is…
Making involuntary movement.
Using electrical stimulation…
Scientists stimulate different parts of the brain with a weak electric current and ask patients to describe what they experienced.
MRI
Brain imaging technique - magnetic resonance imaging.
EEGs
Created and studied to observe the electrical activity of the brain.
If the visual area is stimulated by electrical stimulation, the patient may…
See a flash of colour.
The brain controls…
Complex behaviour.
How to MRIs work?
Use strong magnetic fields and radio waves to show details of brain structure and function.
Levels of organisation…
Cells - tissues - organs - organ systems.
Role of mitosis in…
Growth by increasing cell numbers, repair of tissues, replacement of worn out cells, and asexual reproduction.
Role of meiosis in…
Reducing the chromosome number.
Full chromosome complement restored in…
Fertilisation
Asexual reproduction involves…
Two parents and offspring are genetically identical when no mutations occur.
Sexual reproduction involves…
Two parents, offspring are genetically different in relation to each other and the parents - leading to increased variation.
Iris reflex
Controls the size of your pupil.
Optic Nerve
Carries impulse between the brain and eye.
Cells found in the retina…
Rod & Cone cells.
How many rod cells are approximately in the retina?
120 million
What is the pancreas?
A coordination centre
CNS
Brain + Spinal Cord
Oestrogen inhibits…
FSH release.
Oestrogen stimulates…
Luteinising hormone
What hormones can be found in contraceptive pills?
Oestrogen and progesterone.
What hormones are issues as fertility drugs?
FSH & LH
Disadvantages of IVF treatment…
Emotional & physically stressful, success rates are not high, can lead to multiple births - putting both the babies and mother at risk.
The endocrine system…
Is composed of glands which secrete chemicals called hormones directly into the bloodstream.
What happens to the amino acids in the liver?
Deaminated to form ammonia.
What happens to ammonia in the blood?
Ammonia is toxic so it is immediately converted to urea for safe excretion.
What hormone controls water levels?
ADH
Where is ADH released from?
Pituitary gland
What does ADH cause?
More water to be reabsorbed back into the blood from the kidney tubules as a result of increased permeability.
How are thyroxine levels controlled?
By negative feedback.
After auxins are produced…
They move backwards to stimulate cell elongation (enlargement) process which occurs in the cells just behind the tips.
Extra auxin promotes…
Growth in the shoot but inhibits growth in the root.
When a shoot tip is exposed to light…
More auxin is accumulated on the side that is in the shade than the side that is in the light.
What does the accumulation of auxins on the shade cause?
Cells to grow faster on the shaded side, to the shoot bends towards the light.
When a shoot is growing sideways…
Gravity produces an unequal distribution of auxin in the tip, with more auxin on the lower side.
When more auxin is concentrated on the lower side of the shoot, what happens?
The lower side grows faster, so the shoot bends upwards.
Excess ______ are removed via the kidneys in the urine?
Water, ions and urea are removed via the kidneys in the urine.
3 uses of auxins?
Killing weeds, growing from cuttings with rooting powder, growing cells in tissue culture.
How can auxins be used to kill weeds?
Most weeds are broad-leaved, which are the type of plants that auxins affect. Auxins disrupt their normal growth patterns, which kills them.
What happens when we grow cuttings using rooting powder containing auxins?
They will produce roots rapidly and start growing new plants, allowing growers to produce clones on plants quickly.
What drugs may need to be taken with a mechanical valve?
Anticlotting drugs.
A biological heart transplant may…
Be rejected from the body.
To reduce the chance of a heart being rejected, what drugs can be taken?
Immunosuppressants.
Which individuals cannot take statins?
People with liver disease or people who are pregnant or breastfeeding.
Tissue
Group of cells with similar structures working together for a specific function.
Amylase is produced in…
Salivary gland & pancreas.
Proteases are produced in…
Stomach, pancreas, small intestine.
Lipases are produced in…
Pancreas & small intestine.
Function of bile?
Emulsifies fats & neutralises food from stomach.
Risks of food tests?
Ethanol is flammable, Biuret is corrosive.
Differentiation
Process where a cell becomes specialised/adapted to perform specific functions.
Stem Cell
Undifferentiated cell with the potential to become specialised.
Cloning
Production of an identical offspring by asexual reproduction/mitosis.
Which diseases can be treated with stem cell treatment?
Paralysis, diabetes, blindness.
Therapeutic Cloning
An embryo is produced with the same genes as the patient.
How can stem cells be used in regards to plants?
Rare species can be cloned to protect from extinction, crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.
Measles can be spread…
By droplet infection.
HIV can be spread…
By sexual contact - exchange of bodily fluids (shared needles, blood transfusions).
What does a plant infected by TMV look like?
Mosaic pattern of discolouration on leaves.
What does TMV cause?
Destroys chloroplasts, so decreases photosythesis.
Name 2 bacterial diseases?
Salmonella, gonorrhoea.
Salmonella bacteria can be found in…
Raw meat, chicken, eggs.
Symptoms of salmonella?
Fever, abdominal cramps, diarrhoea, vomiting.
Symptoms of gonorrhoea?
Yellow/green discharge from penis/vagina, pain on urination.
Long-term effects of gonorrhoea?
Long-term pelvic pain, infertility, ectopic pregnancies.
Name a fungal disease in humans?
Athlete’s foot.
Name a fungal disease in plants?
Rose Black Spot
Malaria spread by…
Female anopheles mosquitoes
Malaria damages…
Blood & liver cells.
Symptoms of malaria?
Fevers and shaking.
How is rose black spot spread?
Carried on the wind or water.
Symptoms of measles?
Fever and red skin rash.
What does rose black spot look like?
Purple or black spots develop on leaves, which often turn yellow and drop early.
Plasma
A component of blood - yellow liquid which carries blood cells, proteins and dissolved substance around the body.
Platelets function?
Blood clotting.
Arteries (compared to veins)…
Thicker walls, more elastic tissue, no valves.
Veins (compared to veins)…
Thinner walls, less elastic tissues, have valves.
Blood flowing in arteries…
Oxygenated (generally), more nutrients, less wastes.
Blood flowing in veins…
Deoxygenated, less nutrients, more wastes.
Double circulatory system.
One part carries blood between the heart and lungs - the other carries blood between the heart and the rest of the body.
Left side of the heart…
Is thicker.
Method to unblock a coronary artery…
Stent
Statins reduce…
Blood cholesterol levels.
What valves are used to replace a damaged heart valve?
Mechanical or biological valves.
Natural Pacemaker…
A group of cells in the right atrium that controls the resting heart rate.
Artificial Pacemaker…
Sends strong, regular electrical signals to the heart to stimulate it to contract properly.
What do artificial hearts do?
Can be used as a temporary treatment while waiting for a heart transplant.
Ribcage…
Protects the heart & lungs.
What is the name of the tissue that covers and protects the surface surface of plants?
Epidermal Tissue
Xylem and phloem are organised…
In bundles, with xylem on the inside and phloem on the outside - the vein.
Potometer used to…
Stimulate transpiration rate.
Organs
Aggregations of tissues performing specific functions.
Coronary heart disease?
Layers of fatty material builds up inside the coronary arteries, narrowing them.
The build up of fatty deposits in the coronary arteries reduces…
The flow of blood through the coronary arteries, resulting in a lack of oxygen for heart muscle.
Stents used to…
Keep the coronary arteries open.
Heart valves may become faulty in some people, preventing…
The valve from opening fully, or the heart valve might develop a leak.
In the case of heart failure…
A donor heart or heart & lungs can be transplanted.
Risks of cardiovascular disease?
Diet, smoking and lack of exercise.
Examples of cardiovascular disease?
Coronary heart disease, heart attacks, heart failure, faulty valves.
Benefits of stents…
Relatively quick surgery, effective for a long time, blood can flow naturally.
Issues with stents…
Requires surgery, the patient could later develop a blood clot near the stent; a thrombosis, does not treat the cause of the issue.
Statins alter…
The balance of cholesterol in the bloodstream, increasing the good cholesterol (HDL) and decreasing the bad cholesterol (LDL).
Cholesterol is…
A type of lipid.
Benefits of statins?
Ensures that blood can keep flowing, increase the vol. of good cholesterol (HDL), but decrease the vol. of bad cholesterol (LDL), lowers the risk of coronary heart disease and other cardiovascular diseases.
Issues with statins?
Need to be taken regularly, can also cause side effects such as headaches, such as headaches, kidney failure & liver problems.
Heart valves may become faulty due to…
Age, heart attacks & infections.
Biological valves…
Come from another human, a pig, or a cow.
Which type of valves last longer?
Mechanical valves.
Homozygous
The individual has two alleles for this gene.
Heterozygous
The individual has two different alleles for this gene.
Genotype
The genetic makeup of an organism for a particular gene.
Phenotype
The displayed characteristic due to the interactions between alleles.
Female genotype
XX
Male genotype
XY
Polydactyly
Genetic condition causing the individual to have extra fingers or toes.
Is polydactyly recessive or dominant?
Dominant condition - PP or Pp (homozygous dominant or heterozygous).
Is cystic fibrosis dominant or recessive?
Recessive - cc (homozygous recessive), would result on cystic fibrosis.
Methods for screening embryos?
Amniocentesis, chorionic villus sampling, IVF
Concerns of screening embryos?
Causing miscarriage, ethical concerns, inaccurate results, expensive.
Benefits of screening embryos?
Know if your child will have a disorder, able to decide if to proceed with a pregnancy or abortion.
Is Huntington’s dominant or recessive?
Dominant
2 gametes in flowering plants?
Pollen and egg cells.
Recessive
The individual needs two copies of their alleles for its phenotype to be seen.
What do injections/implants/skin patches release?
Slowly releases progesterone to inhibit the maturation & release of eggs for a number of months or years.
What do barrier contraceptive methods do?
Prevent the sperm from reaching the egg.
Intrauterine devices…
Prevent the implantation of an embryo or releases hormones.
Dominant
The individual only needs one copy of this allele for its phenotype to be seen.
Auxins used in growing cells in tissue culture…
Auxins are added to the growth medium, along with nutrients, to stimulate the cells to divide to form both roots & shoots.
When a shoot tip is exposed to light…
More auxin accumulated on the side that is in the shade compared to the side that is in the light.
Gibberellin used to control dormancy?
Seeds can be treated with gibberellin to alter dormancy & make them germinate @ times of the year they wouldn’t normally. Can also ensure all seeds in a batch germinate at the same time.
Gibberellins used to induce flowering?
Some plants require certain conditions to flower i.e. longer days, low temperatures. Gibberellins allows plants to flower without a change in their environment, or to grow bigger flowers.
Gibberellins used regarding fruits?
Seedless fruits do not grow as large as seeded fruits, but if gibberellins are added to these fruits, they will grow larger to match the size of the normal varieties.
Ethene influences…
The growth of plants by controlling cell division. It also stimulates enzymes that causes fruit to ripen.
Ethene’s use commercially…
It can be used to speed up the ripening of fruits either when they are still on the plants or during transport to shops.
Disadvantages of dialysis?
Carefully controlled diet / long periods connected to a machine (poor quality of life as immobile when connected).
Concentration of urea in the dialysis fluid…
Zero/none.
2 treatments for kidney failure?
Dialysis and kidney transplant.
Muscle adaptations?
Special proteins for concentration, many mitochondria for energy, store glycogen to release glucose for respiration.
What cells keep the phloem alive?
Companion cells
Surgical contraceptive methods…
Female + Male sterilisation.
Genetic Engineering
1 - Select desired characteristic.
2 - Isolate gene w/ restriction enzymes.
3 - Insert gene into vector - joined by a ligase enzyme.
4 - Replicate
GM crops include…
Crops that are resistant to insect attack or to herbicides. Generally show increased yields.
Concerns of GM crops?
The effect on populations of wild flowers & insects, the effects of eating GM crops on human health have not been fully explored.
Genetic Engineering
Modifying the genome of an organism to give a desired characteristic.
Tissue Culture
Using small groups of cells from part of a plant to grow identical new plants.
What is tissue culture important for?
Preserving rare plant species or commercially in nurseries.
Cuttings
Produce many identical plants from a parent plant.
Embryo transplants
Splitting apart cells from a developing animal embryo before the become specialised, then transplanting the identical embryos into host mothers.
2 examples of genetic engineering in practice…
Bacterial cells engineered to produce insulin, plant crops engineered to be resistant to disease / have bigger & better fruits.
Fossils may be formed from…
Hard parts of animals not decaying properly, conditions didn’t allow decay, minerals replaced parts of the organisms it decayed, traces (e.g. footprints) preserved.
Why is the fossil record incomplete?
Soft bodies of early animals decayed easily, geological activities destroyed fossils.
Extinction can be caused by…
New predators, new diseases, one species outcompeting another.
Example of a disease resistant to antibiotics?
MRSA
Antibiotics should not be…
Prescribed inappropriately e.g. should not be prescribed for viral infections.
People should complete…
Their course of antibiotics.
Agricultural use of antibiotics is…
Restricted
3 types of adaptations?
Structural, behavioural, functional.
Animals may compete for…
Water, mates, territory, food.
Plants may compete for…
Nutrients, water, space, light.
Abiotic factors
Light intensity, temperature, moisture, soil pH, wind intensity, carbon dioxide levels, oxygen levels.
Biotic factors
Food availability, new predators, new pathogens, species outcompeting.
Percentage of biomass transferred from one trophic level to another?
0.1%
Biomass is lost from the food chain because…
Not all of the material is eaten e.g. bones + teeth, energy lost as faeces.
Extremophile
Organism that survives and reproduces in the most difficult conditions.
Functional adaptations?
Internal adaptations, can be related to processes such as reproduction and metabolism.
Extremophiles can live in…
Very high concentrations of salt.
Examples of extreme environments?
Very high temperatures, pressure or salt concentration.
Stable Community
One where all the species and environmental factors are in balance, so that population sizes remain constant.
Aerobic respiration
Exothermic reaction that breaks down glucose to release energy using oxygen.
Aerobic respiration equation?
Glucose + Oxygen –> Carbon Dioxide + Water
Oxygen debt
Amount of oxygen needed to break down lactic acid.
What do plants produce in anaerobic respiration?
Plants produce ethanol and carbon dioxide.
Functions of the liver?
Detoxification, breakdown of old blood cells, remove lactic acid (convert to glucose).
Fermentation
Glucose –> Ethanol + Carbon Dioxide
Anaerobic respiration equation
Glucose –> Lactic Acid
Photosynthesis has…
Endothermic
Correlation
A link between 2.
Causation
One thing leads to another.
Risk factors for developing cancer…
Smoking, obesity, common viruses, UV exposure, genetic factors.
Mothers drinking alcohol during pregnancy can cause…
Fetal alcohol syndrome.
Long-term heavy drinking can lead to…
Liver cirrhosis, liver cancer & brain damage.
Carcinogen in cigarette smoke…
Tar
Tobacco smoke & cardiovascular diseases…
Increased heart rate, damage artery lining, increase risk of clot formation, increase blood pressure.
Smoking effect on fetuses…
Premature birth, low birthweight, still birth.
High fat diet leads to…
Fat deposits in coronary arteries.
Spread of malaria can be stopped by…
Using mosquito nets, using insecticides, removing standing water, take antimalarial drugs.
Nitrate ions in plants…
Make proteins.
Magnesium ions in plants…
Make chlorophyll for photosynthesis.
Symptom of magnesium deficiency in plants?
Antibacterial chemicals/poisons.
Physical adaptations in plants to defend against herbivores?
Thorns/hairy stems & leaves/dropping or curling/mimicry.
Physical barriers against pathogens (plants)…
Cellulose cell wall / tough-waxy cuticle / bark on trees / leaves fall.
Digitalis originates from…
Foxgloves
Aspirin originates from…
Willow Trees
What is used in preclinical testing?
Cells, tissues and live animals used in preclinical testing.
Double-blind trial?
Neither the doctors nor the patients know who gets the real drug / placebo.
Stage 1 of Drug Development
Preclinical testing
Stage 2 of Drug Development
Phase 1 clinical trials - Low doses tested on a few healthy individuals to check for side-effects.
Stage 3 of Drug Development
Phase 2 clinical trials - Low doses tested on a few healthy individuals to check for side-effects.
Stage 4 of Drug Development
Phase 3 clinical trials - Large number of people are tested to check that the drug works.
Producing mAbs…
Inject mouse w/ a pathogen, combining B-lymphocytes w/ tumour cells - creates a hybridoma cell, placed in a petri dish to produce lots of antibodies.
Hybridoma cells can produce…
Lots of antibodies and still divide rapidly by mitosis.
Microorganism that produces penicillin…
Penicillium
What are drugs tested for?
Toxicity, efficacy and dose.
To reduce the risk of measles…
Most young children are vaccinated against measles.
HIV can be controlled with…
Antiretroviral drugs
Treatment for gonorrhoea
Antibiotics.
Treating rose black spot…
Can be treated using fungicides and/or removing and destroying the affected leaves.
To restrict the spread of malaria, we can prevent…
Mosquitoes from breeding together.
How can plant diseases be detected?
Stunted growth, spots on leaves, areas of decay (rot), growths, malformed stems or leaves, discolouration, the presence of pets.
Can identify plant diseases by..
Referencing a gardening manual or website, taking infected plants to a laboratory to identify the pathogen, using testing kits that contain mAbs.
Stunted growth in plants can be caused by…
A nitrate deficiency.
Chlorosis can be caused by…
A magnesium deficiency.
Health
A state of physical and mental wellbeing.
Factors that affect health?
Diet / Stress / Life situations (e.g. hygiene) / pathogens / immune system.
Pathogens spread by…
Air/droplet infection, direct contact, water.
Methods to prevent the spread of disease?
Isolation, maintain good hygiene, destroy vectors, vaccination.
TMV virus spread by…
Direct contact/vectors.
3 Viral diseases
Measles, HIV/AIDS, TMV.
Measles
Can lead to blindness & brain damage.
Most phenotypic features are…
The result of multiple genes rather than a single gene inheritance.
Chromosomes contain…
DNA
Protein synthesis involves the production…
Of proteins from amino acids.
Genetic engineering in a medical sense?
Looking at ways to treat HIV, sickle cell anemia, Huntington’s and CF.
Antibiotic resistance is an example of…
Evolution through natural selection.
Variation can be…
Genetic/inherited (resulting in a range of phenotypes), environmental (affects a range of phenotypes.
Nasal Cavity
Air warmed and filtered as it enters the body.
Trachea
Brings air into the lungs. Supported by rings of cartilage that prevent it collapsing.
Bronchus
Branches off the trachea to bring air into the lungs -supported by cartilage rings.
Bronchiole
Branch off the bronchi.
Alveoli
Small air sacs that are the site of gas exchange.
Lung
Organ where gas exchange occurs.
Ribs
Protect internal organs of the thorax.
Thorax
Part of the body between the neck and abdomen.
Intercostal muscles
Muscles between the ribs that aid breathing.
Diaphragm
Sheet of muscle below the ribs that aids breathing.
Pleural membranes
Thin layers that reduce friction between the lungs and inside of the chest wall during breathing.
Pleural Fluid
Fluid found in the pleural cavity (between the pleural membrane layers). It further reduces friction during breathing.
Inhalation
Intercostal muscles contract, ribs move up and out, diaphragm contracts, moving downwards, thorax increases in vol. and pressure decreases, causing air to enter the lungs.
Exhalation
Intercostal muscles relax, ribs move down and in, diaphragm relaxes, returning to its domed shape, thorax decreases in vol. and pressure increases, forcing air out of the lungs.
What can ECGs be used to do?
Monitor heart activity.
What does ECG stand for?
Electrocardiogram.
ECG
Looks at the electrical activity of the heart which is what controls the heart’s activity. Sensors attached to the body are couple w/ a machine, that gives an ECG reading. Normal and abnormal activity can be identified.
Digestion
The breakdown of large, insoluble molecules of food into smaller, soluble molecules.
Rectum
Stores faeces prior to egestion.
Anus
Where faeces are egested.
Peristalsis
The process by which food moves through the digestive system - a wave of muscle contractions in the gut wall which forces food down the gut.
Absorption
Involves the small, soluble molecules from digestion being taken into the bloodstream through the wall of the intestine.
Ingestion
Intake of substance into the body via the mouth e.g. through eating and drinking.
Assimilation
The movement of digested food molecules into the cells where they are used.
Egestion
The passing of undigested food as faeces through the anus.
Excretion
The removal of waste products from the body and substances that are in excess.
Urinary system
Includes the kidneys, ureters, bladder and urethra.
Lifestyle changes which can be made to manage/treat cardiovascular disease?
Reducing smoking, more exercise, and a balanced diet.
What controls the natural, resting heart rate?
Natural pacemaker.
When can artificial pacemakers be used ?
If the individual has an irregular heartbeat.
Can genetics act as a risk factor to cardiovascular disease?
Yes, there are six genetic variants associated with CHD.
Fatty deposits in the coronary arteries are known as…
Plaques
Coronary Bypass Surgery
Coronary heart disease can be treated using bypass surgery -involves taking a healthy blood vessel from another part of the body and surgically inserting it so the blocked vessels are bypassed.
Anti-coagulants
Prevents arteries becoming blocked, reducing the risk of CHD. Can cause excessive bleeding if a person is wounded.
Anti-platelets
Prevents clots forming in arteries and thus, reduces the risk of CHD.
Anti-hypertensives
Can reduce blood pressure, protecting arteries so that their walls are not damaged and reduces the risks of plaques forming.
Prophylactic Treatment
Preventative treatment
Ecosystem
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
Interdependence
Describes how organisms in a community depend on other organisms for vital services.
Some species live together in a…
Symbiotic relationship
Mutualism
If it provides some benefit or resource to the other species, for instance providing nutrients, it is known as a mutualistic relationship.
Parasitism
Involves taking nutrients from another species, to the detriment of other species.
Commensalism
Is where there is no damage caused to either species, and there is often mutual benefit.
Pyramids of Biomass
Shows the relative biomass @ each trophic level.
Carbon cycle -photosynthesis.
Carbon dioxide is removed from the air in photosynthesis by green plants and algae. Carbon used to make carbs, proteins and fats. Plants are eaten, transferring carbon up the food chain.
Carbon cycle - respiration.
Carbon dioxide is returned to the air when plants, algae and animals respire. Decomposers respire while they return nutrients to the soil.
Carbon cycle - combustion.
Carbon dioxide is returned to the air when wood and fossil fuels are burnt - as they contain carbon from photosynthesis.
When biological material decays…
It produces compost.
Optimum conditions for decomposition?
Temperature, oxygen availability, water availability, number of decay organisms.
Decomposition
The breakdown and digestion of biological material by organisms called decomposers.
Decomposers
Include microorganisms - bacteria and fungi - and detritus feeders.
Microorganisms decompose waste anaerobically to produce…
Methane gas
Methane gas can be burnt as…
Fuel
_____ Generators are used to produce methane…
Biogas.
The sun’s energy causes…
Water to evaporate from the sea and lakes, forming water vapour.
Water vapour is also formed as a result of…
Transpiration.
Water vapour…
Rises and condenses to form clouds.
Specific Heat Capacity Equation
Δ E = m c Δ θ
Specific Latent Heat
E = mL
Specific Latent Heat word equation
Energy to change state = mass x specific latent heat
Magnetic force on a current-carrying conductor
F = BIl
Magnetic force on a current-carrying conductor word equation
Force = magnetic flux density x current x length of conductor in a magnetic field.
Transformer coil equation
Vp / Vs = Np / Ns
Transformer current equation
VpIp = VsIs
Pressure in a fluid…
Pressure = height of column x density of fluid x gravitational field strength
Planets in order from the sun…
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
A planet is…
A body that orbits a star, is massive enough for its own gravity to make it round-shaped - has ‘cleared its neighbourhood’ of smaller objects around its orbit.
Moon
A natural object which orbits a planet.
How old is the universe?
Roughly 13.8 billion years ago.
Nuclear fusion
Two small nuclei fuse together to form one large nucleus - releasing energy in the reaction.
When are all naturally occurring irons up to iron produced?
In fusion in stars.
When are elements heavier than iron produced?
In the supernova.
How are elements heavier than iron distributed?
Across the universe in the supernova explosion.
Orbits of planets…
Circular
Artificial Satellite
Something man-made which is in orbit of the Earth.
In circular orbit…
There is changing velocity despite constant speed as the body constantly changes direction.
If the speed of an orbit changes…
The radius of orbit also changes.
Doppler Effect
Observed frequency of waves emitted by a moving object appear changed.
Red-shift
An observed increase in the wavelength of light from most distant galaxies.
The further away the galaxies…
The faster they are moving and the bigger the observed increase in wavelength.
Big Bang Theory
Suggests the universe began from a very small region that was extremely hot and dense.
Red-shift supports the Big Bang Theory because…
It shows that the universe is expanding - must once have been smaller.
Observations of supernovae suggest…
That the furthest away galaxies are moving away from us even faster.
Absorption spectrum…
A spectrum containing every wavelength of light but with dark lines where certain wavelengths have been absorbed.
Universe is expanding…
Slower than epected.
Scientists predict what % of the universe is dark energy?
68%
Scientists predict what % of the universe is dark matter?
27%
Stars begin life as…
A cloud of dust & gas - a nebula.
What is the next stage in the formation of stars after a nebula?
Gravity causes the nebula to collapse and the temperature rises to millions of degrees celsius - forms a protostar.
If the temperature is high enough in a protostar…
Hydrogen will join in nuclei fusion to form helium. Releases a huge amount of energy. Protostar is now a main sequence star.
What happens to a main sequence star which is the same size as the sun…
Red Giant - White Dwarf - Black Dwarf
Red giant formation…
When its hydrogen fuel source runs out, the outwards force due to fusion is lower than the inward force due to gravity - the star therefore collapses, temp. increases, so helium nuclei join to form heavier elements. Expands to form a reactant.
White dwarf
Red giant stops fusing helium and shrinks to become a white dwarf.
Black dwarf
White dwarf is no longer carrying out nuclear fusion - the temperature of the star decreases until the energy it emits is less significant - Black dwarf star formed.
What happens to a main sequence star greater in size that the sun?
Red Super Giant - Supernova - Black hole or neutron star.
Red Super Giant
Star’ Hydrogen fuel begins to run out - expands to form a Red Super Giant.
Supernova
After it becomes a Red Super Giant, it eventually stops carrying out nuclear fusion & the star goes into supernova.
Black Hole
Large gravitational force - not even light can escape from.
Neutron Star
Made of neutrons densely packed together.
Geostationary Satellite
Orbit once every 24 hours, points to the same point of Earth.
Moon’s orbit around Earth is…
Virtually circular.
A moon…
Natural object which orbits a planet.
Artificial Satellite
Something man-made which is in orbit of the Earth.
Orbit
The curved path of one celestial object or spacecraft around another celestial object.
Planet is trying to move in…
Instantaneous Velocity
Amount of energy carried by a photon depends on…
The frequency of the radiation.
Types of radiation which can cause ionisation (EM spectrum)?
UV, X-rays, Gamma
Ionisation
When radiation hits an atom or molecule, it can sometimes have enough energy to remove an electron and change the atom + molecule.
Detectors
Objects that absorb infrared radiation.
What will absorb / stop beta radiation?
A sheet of aluminium, approx 5mm.
In beta decay, the mass number of the parent nucleus…
Stays the same.
Activity
Rate at which decay occurs.
Range of gamma radiation
Unlimited
Half-life
The time taken for number of radioactive nuclei in a sample to halve or the time taken for count rate (or activity) from a sample to fall to half its initial value.
An irradiated object does not…
Become radioactive itself.
Ionising power of beta radiation…
Moderate
Radioactive Decay
An unstable nucleus changes to become more stable and gives out radiation.
Types of radiation
Alpha, Beta, Gamma
Radius of an atom
0.1nm
Ionising power of radiation
How likely it is to ionise atoms which it comes into contact with.
Emission of radiation from an atom may lead to…
Electrons moving to a lower energy level.
Contamination
The unwanted presence of materials containing radioactive atoms.
What will absorb / stop gamma radiation?
Several cm’s of lead.
Range of Beta radiation in air.
Approximately 1m.
What will absorb / stop alpha radiation?
Paper/skin.
If ionisation happens in DNA, it can…
Cause mutations which may result in cancer.
Ionising Power of Gamma radiation
Low ionising Power
Count rate
Number of decays recorded each second by a Geiger-Muller tube.
Units of activity
Bq - Becquerels
Ionising Power of Alpha radiation
Very High Ionising Power
Range of Alpha radiation
Short - 5 cm in air.
Count rate
Number of counts / time
Activity
Activity of material x mass
Random nature of radioactive decay?
Cannot predict which nuclei will next decay or when it will decay.
Medical radioisotopes have to have a short half-life to…
Reduce damage to tissues / organs.
Braking Distance
The distance travelled in the process of coming to a stop.
Thinking Distance
The distance travelled in the process of braking.
Stopping Distance
Braking Distance + Thinking Distance
Inertia
The property of an object to remain in a constant state unless acted on by an external resultant force.
Walking velocity
1.5 m/s
Running velocity
3 m/s
Cycling velocity
6 m/s
Boyle’s Law
As pressure increases, volume decreases, because they are inversely proportional. As you go down to an area of higher pressure, gas will compress proportionally.
Change of state from liquid - solid?
Solidifying / Freezing
Physical State
A change that does not produce a new substance. If the change is reversed, the substance recovers its original properties.
What is the Kinetic Theory of Matter?
Particle model of solids, liquids & gases which describes their properties.
Random motion
Unpredictable path that an individual gas particle follows.
Internal energy
The total energy in the kinetic & potential stores of all the particles (atoms & molecules) that make up a system.
Horizontal line on a temperature vs time graph…
Represents a change of state.
Reversible Change
A change to a substance, which when reversed, allows the substance to recover its original properties.
Particles in a solid.
Strong forces, regular structure, packed close together and vibrate.
Specific Latent Heat of Vaporisation
The amount of energy required to change one kg of a liquid into a gas (vapour) w/ no change in temperature.
Evaporating
When a liquid changes to a gas below the b.p.
Chemical Change
A change in which the chemical bonds are broken & reformed to form new products.
Gas - density
Least dense state of matter.