Download Rates of Reaction

B3 Science Revision
Proteins:
Ribosomes are in the cytoplasm and where protein
synthesis happen.
Four different bases, A,T,G,C.
Proteins are made from lots of amino acids joined together.
Each amino acid is coded by the sequence (order) of three
bases. For example, GGT.
The genetic code needed to make aprotein is carried from
the DNA to the ribosomes by a molecule called mRNA.
•mRNA from DNA is called transcription
•Proteins from mRNA is called translation
Functions include structural (collagen),
hormones (insulin), carrier molecules (haemaglobin) &
enzymes.
Enzymes are biological catalysts which
catalyse chemical reactions
Enzymes use a lock and key mechanism
and will denature which change the the
shape of the active site at high PH and
high temperatures
B3 Science Revision
Anearobic respiration
Glucose → lactic acid
Aerobic Respiration
Glucose + oxygen → carbon dioxide + water
C6H12O6 + 6O2→ 6CO2 + 6H2O
Meiosis
Produces gametes which are haploid (contain one
chromosomes from each pair).
Gametes combine to form a diploid zygote
Genes on the chromosomes combine to control the
characteristics of the zygote.
Mitosis
•Chromosomes in
nucleus are copied
•Chromatids pulled
apart
•Cromosoomes
separate
•Cell divides
Structure of the sperm
‘unzipping’ to form
single strands
New double strands
forming by
complementary base
pairing
Acrosome
Nucleus
Mitochondria
Tail
B3 Science Revision
Pulmonary
artery
Vena Cava
Right atrium
Valve
Aorta
The blood
•Red blood cells have a large surface area to
volume ratio, lack a nucleus and contain
haemoglobin.
oxyhaemoglobin
Pulmonary •Haemoglobin + oxygen
•Arteries transport blood away from the heart,
vein
• they have thick muscular and elastic walls
Left atrium •Veins transport blood to the heart, they have a
large lumen and contain valves
•Capillaries exchanging materials with
Valve
•tissues and are therefore permeable
Plant growth
Animal growth
Grows
continuously
Finite size
Everywhere
Stem cells
Restricted to
meristems
Undifferrentiate dcells that can develop into
different cells.
Gain height by cell
enlargement
Gain height by
Cell division
Two types: embyonic (obtained from embryos)
and Adult (obtained from a human)
Cells can
differentiate
Lose ability to
differentiate
Right ventricle
Left ventricle
Bacteria cell lack a true nucleus, mitochondria
and chloroplasts instead they contain a single
circular strand of chromosome
B3 Science Revision
Genetic engineering
•Selection of desired characteristics
•Isolation of genes resposible
•Insertion of other genes into other programmes
•Replication of organismas
Gene therapy: changing a persons genes
in an attempt to cure disorders
Examples: Genes from carrots and
putting them into rice, producing insulin
and becoming resistant to herbicides,
frost damage or disease to crops.
Selective breeding may lead to
inbreeding due to a reduction in the
gene pool
Tissue culture
Cloning technique used to produce dolly:
Nucleus removed from an egg cell
Egg cell nucleus replaced with the nucleus from the
udder cell.
Egg cell given an electric shock to make it divide
Embryo grows into a clone of the sheep from which the
udder cell came
Rates of Reaction
Collision theory – For a reaction to happen, particles must collide. The rate
of reaction depends on the frequency of collisions. Higher collision
frequency = faster rate of reaction.
Ways to increase the rate of reaction:
• Increasing the temperature (faster particles)
• Increasing the concentration or pressure (particles are more crowded)
• Increasing the surface area by breaking down the solid into smaller
pieces
• Use a catalyst (acts as a surface for the reaction to take place)
Drawing and interpreting graphs
Gradient (change in y/change in x)
= rate of reaction
Steeper line = faster reaction
Reaction stops = horizontal line
Relative Formula Mass (Mr) of a compound (e.g NaCl) is the total mass of
the compound. So the Relative Atomic Mass (Ar) of all the atoms added
together.
Mass is conserved in a chemical reaction so (Mr) of reactants = (Mr) of
products
Calculating masses:
1) Write the balanced symbol equation
2) Work out the Mr for the compounds you want
3) Divide to get 1g, multiply to get all
Atom economy is the percentage of reactants that are turned into useful
products. A high atom economy is better for profits and for the
environment.
Percentage yield is how much is actually produced compared to how much
is predicted. Percentage yield is never 100% because some reactant or
product is lost by evaporation, filtration, transferring liquids, some
Batch or Continuous?
Batch – small scale (e.g pharmaceutical drugs)
Continuous – large scale (e.g Haber process)
Why are new medicines so expensive: 1) Batch is more labour intensive 2)
Research and testing takes many years 3) Raw materials are expensive
(extracting chemicals from plants) 4) Expensive human trials
Extracting chemicals from plants: 1) Crushing 2) Dissolving 3) Chromatography
Nanochemistry
Nanotubes:
Catalysts
Reinforcing
tennis racquets
Diamond:
Very hard, high melting point,
used for cutting tools
Buckminster fullerene:
Used to cage drugs to deliver
to specific targets
Graphite:
Conducts electricity
High melting point
Lubricant.
Endothermic – bond breaking. The energy needed to break old bonds is
greater than energy used to form new bonds.
Exothermic – bond making. The energy released from forming new bonds is
greater than the energy needed to break old bonds.
Measuring the energy content of fuels - you
need to measure (i) how much fuel has burned
(ii) change in temperature of water.
Use equation: energy = mass x SHC x change
in temp.
Mass is the mass of water, SHC is of water.
Energy per gram = energy / mass of fuel burnt.
Collecting reliable results – reduce heat loss to the surroundings, keep
everything apart from the fuel burnt the same, repeat and discount anomalous
results.
Distance/time graphs
Speed/time graphs
Speed = Distance travelled in a certain time
Velocity = distance travelled in a certain direction in a certain time
Acceleration = change in speed in a certain time
For an object travelling at a constant speed:
thrust/gravitational pull is equal to the
friction/air resistance.
Thinking Distance – distance travelled whilst you are reacting. Increases
linearly. Affected by tiredness, drugs or alcohol, greater speed, distractions.
Braking distance – distance taken to stop once brakes have been applied.
Affected by mass of vehicle, brakes, road surface, ice or wet surface, tyres
and speed. If speed doubles, braking distance quadruples because ke = ½ x
m x v2.
P3 Science Revision
Momentum = mass X velocity
When the greater the mass of an object and/of the greater the velocity the
more momentum the object has in the direction of motion
Change in momentum over a longer time reduces the likelihood of injury
Forces can be reduced when stopping (eg. Crumple zones, braking
distances, escape lanes, crash barriers, seatbelts and airbags) by
• Increasing stopping or collision time
• Increasing stopping or collision distance
• Decreasing acceleration
Seatbelts crumple zones and airbags are useful in a crash because they
• Change shape
• Absorb energy
• Reduce energy
P3 Science Revision
Moving objects can:
• Increase speed
• Decrease speed
• Maintain speed
Objects reach a terminal speed:
• Higher speed = more drag
• Larger area = more drag
• Weight (falling object) or driving force (eg. A car)=
drag when travelling at terminal speed
Gravitational field strength or acceleration due to gravity is:
•Unaffected by atmospheric changes
•Varies slightly at different points on the Earths surface
•Will be slightly different on the top of a mountain or down a mineshaft
When an object is above the Earth's surface it has gravitational potential energy
(GPE). The amount of GPE an object has depends on its mass and its height
above the Earth's surface.
The weight of an object is the size of the force of gravity pulling the object
down. When an object falls it transfers GPE to KE (kinetic energy).