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GCSE Science
AQA Exam paper answers
174
Science
11th Grade
04/07/2006

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Term
Why is it necassary to break down proteins properly in the digestive system?
Definition
Proteins are:
  • large
  • insuluable
  • cannot be absorbed
  • Term
    What are the advantages and disadvantages of fertility drugs?
    Definition
  • They can enable women to have children.(benefit)
  • They let people have multiple births.(problem)
  • Term
    What are the advantages and disadvantages of contreceptives?
    Definition
  • They prevent unwanted pregnancies.(benefit)
  • They regulate the menstrual cycle(benefit)
  • They may cause infetility.(problem)
  • May cause mood swings.(problem)
  • Don't protect against STD's.(problem)
  • Increase promiscuity.(problem)
  • Term
    In what ways does the body prevent viruses and harmful bacteria from entering?
    Definition
  • Skin
  • Scabs
  • Mucus
  • Stomach Acid
  • Term
    What type of chemical is released from some white blood cells to attack viruses?
    Definition
    Antibodies
    Term
    Where is the temperature monitored?
    Definition
    In the brain.
    Term
    How do capillaries help the body to keep cool on hot days?
    Definition
  • They dialate...
  • ...allowing blood to flow closer to the surface of the skin
  • resulting in the blood being cooled
  • Term
    What type of organisms reproduce through meiosis?
    Definition
    Humans
    Term
    What type of organisms reproduce through mitosis?
    Definition
    Plants
    Term
    Information is passed __________ across synapses
    Definition
    Chemically
    Term
    Explain how natural selection may cause creatures to have desirable characteristics
    Definition
  • Variation may be caused by mutation...
  • ...which could mean they live their life better ...
  • ...so they will live longer...
  • giving them the chance to breed...
  • ...and pass their DNA down to a new generation with the same characteristic.
  • Term
    What is an allele?
    Definition
    Forms of a gene
    Term
    What does dominant mean?
    Definition
    That only one gene is needed for a characteristic to be inherited
    Term
    What in the body does Huntington's disease affect?
    Definition
    The nervous system
    Term
    How does the carbon monoxide in cigarette smoke affect the normal function of red blood cells?
    Definition
  • The CO combines with haemaglobin...
  • ...more easily than oxygen...
  • ...reducing the cells capacity to transport oxygen.
  • Term
    When bacteria containing the insulin gene multiplies, will all the new cells be able to produce insulin?Why?
    Definition
  • Yes because they all formed from the same original cell...
  • ...by asexual reproduction(mitosis)...
  • ...leaving them all with the copy of the insulin gene.
  • Term
    In the blast furnace, the iron oxide in the iron ore is reduced by carbon monoxide. What does reduced mean?
    Definition
    Oxygen is removed.
    Term
    Why can't a metal like sodium be extracted from its ore using the blast furnace method?
    Definition
    All metals above carbon in the reactivity series (including sodium) cannot be displaced by it.
    Term
    What other metal is added to iron to make stainless steel?
    Definition
    Chromium or Nickel
    Term
    What does thermal decomposition mean?
    Definition
    The break down of a substance using heat.
    Term
    Why is cracking used in the oil industry?
    Definition
    Large hydrocarbons are broken down into smaller molecules which are more useful
    Term
    Suggest a method for seperating mixtures.
    Definition
    (Fractional) Distilation
    Term
    Explain how the position of elements in the periodic table are linked to the electronic structure of their atoms?
    Definition
  • Atoms in the same group have the same number of electrons in their outer shell...
  • ...atoms in the same period all have the same number of shells...
  • ...each succesive atom has one more electron.
  • Term
    How is sedimentary rock changed into metamorphic rock?
    Definition
    The deep buriel and collision of tectonic plates can create high pressures and temperatures, changing the properties of the sedimentary rocks.
    Term
    Explain, in terms of electronic structure, why a ceasium atom is more reactive than a lithium atom.
    Definition
  • The outer shell is further from the nucleus...
  • ...resulting in the outer shell electron being less strongly attracted to it...
  • ...so the outer shell electron is lost more easily.
  • Term
    Explain why, in terms of particles,the rate most reactions increases as the temperature is raised.
    Definition
  • The particles gain more energy as the heat is increaed...
  • ...allowing them to move faster...
  • ...causing more successful collisions.
  • Term
    Why are stableized enymes bettar that unstable enzymes?
    Definition
    They function for a longer period of time.
    Term
    How can an catalyst be immobilized?
    Definition
    They could be fixed or bonded to a surface.
    Term
    In terms of its electronic structure, explain why argon is used in lightbulbs.
    Definition
    It is unreactive because it has a full outer shell, withdrawing the need to gain or lose electons.
    Term
    Which condition of heat and pressure would give the highest percentage of ammonia at equilibreum?
    Definition
  • Because the forward reaction is exothermic, low temperatures would produce the most ammonia.
  • High pressure is needed for the most ammonia to be produced,as it favours the forward reaction
  • Term
    Why does the Haber Process use a temperature of 450° and a pressure of 200 atmospheres?
    Definition
  • 450° and 200 atmospheres are compromise conditions...
  • ...the temperature is high enough to allow the catalyst to work effectively...
  • ...very high pressure can be expensive to maintain.
  • Term
    The structure of silicon is simlilar to the structure of a diamond. Describe silicon's structure, and why it has a high melting point.
    Definition
    It has a giant structure with a large number of strong covalent bonds to break, which requires a lot of energy, hence the high melting point. Each silicon atom is bonded to four others.
    Term
    What equation links together potential difference, current and resistance?
    Definition
    Potential difference= current X resistance V=IxR
    Term
    What type of electromagnetic wave is used to sterilize equipment?
    Definition
    Gamma rays because they destroy bacteria.
    Term
    What type of electromagnetic wave to is send signals to a TV from a remote control?
    Definition
    Infra red
    Term
    Special ink is sometimes used to mark personal items, which can only be detected using ultra violet light. Explain what causes this.
    Definition
    The ink absorbs the ultra violet light, emitting a glowing light.
    Term
    Why do skin cells need to be protected from ultra violet radiation?
    Definition
    UV can kill skin cells, and cause their DNA to mutate to form cancerous cells.
    Term
    What equation links together energy transfer, power, and time?
    Definition
    ENERGY TRANSFER = POWER x TIME
    ENERGY TRANSFERRED=W x h
    Term
    Give 2 practical uses for optical fibres.
    Definition
    In endoscopy and fibre optic decoration lamps.
    Term
    Why does the light ray stay inside optical fibres?
    Definition
    The incident ray is greater than the critical angle, resulting in Total Internal Reflection.
    Term
    In Rutherfield's experiment, how did he manage to prove the 'plum pudding' structure of the atom was incorrect?
    Definition
  • Most of the positive aplpha particles went straight through the empty space of the gold atoms...
  • ...but some were repelled back by the positive nucleus of the gold atoms...
  • ...so Rutherfield concluded that most of an atom was empty space but with most of its mass concentrated in the centre, in a nucleus.
  • Term
    What is an isoptope?
    Definition
    Forms of an element where the number of protons is different, but the atomic mass (number of neutrons) is the same.
    Term
    What equation links together acceleration, change in velocity and time taken?
    Definition
    ACCELERATION= ∆VELOCITY ÷ TIME TAKEN
    acc.=∆V ÷ s TAKEN
    Term
    Why are space shuttles able to stay in orbit around the Earth?
    Definition
    The Earths gravity, holds the shuttle in place, as long as it is travelling at correct orbital speed to allow the shuttle to move in a curve.
    Term
    Why is the underneath of shuttles covered in black tiles?
    Definition
    Black is a good emmiter of radiation.
    Term
    What equation links together distance moved or time taken, force, and work done?
    Definition
    WORK DONE= FORCE x DISTANCE or TIME
    W= N ÷ s or m
    Term
    What equation links together acceleration, change in velocity and time taken?
    Definition
    ACCELERATION= ∆VELOCITY ÷ TIME TAKEN
    acc.=∆V ÷ s TAKEN
    Term
    What equation links together power,work done and time taken?
    Definition
    POWER= WORK ÷ TIME
    W= w ÷ s TAKEN
    Term
    Why does power output always have to be more than accurately required?
    Definition
    Some energy is lost to the surroundings.
    Term
    What equation is used to find the gradient?
    Definition
    y/x
    Term
    What is nuclear fission?
    Definition
  • A nucleus is hit by a neutron...
  • ...causing it to split into smaller neclei, and more neutrons...
  • ...releasing energy.
  • Term
    How does nuclear fission lead to a chain reaction?
    Definition
    Additional neutrons collide with other nuclei causing further fission.
    Term
    Why is generating electricity using nuclear fuels expensive?
    Definition
    Though the fuels themselves are cheap, building and maintaining a nuclear power plant is expensive.
    Term
    Name a benefit of using uranium over coal to produce electricity.
    Definition
    Coal produces more pollutant gases.
    Term
    Explain how a simple generator works.
    Definition
  • A rotating coil cuts through the magnetic fields of a magnet...
  • ...inducing a voltage across the coil.
  • The slip rings allow the coil to rotate...
  • ...and the carbon brushes connect the slip rings to the circuit.
  • Term
    What can be done to induce a higher voltage across a circuit using a simple generator?
    Definition
  • The number of coils can be increased
  • The coil can be rotated faster
  • The strength of magnet can be increased.
  • Term
    Why is electricity transmitted through the national grid as a.c and not d.c?
    Definition
  • Transformers only work for a.c current and have to be used to reduce the current along power lines
  • Less energy is wasted.
  • Term
    How do stars produce energy?
    Definition
    The fusion of nuclei from hydrogen or helium, emits light energy.
    Term
    What evidense suggests that the sun cosists of particles from the explosion of an earlier star?
    Definition
    There are nuclei of heavy elements.
    Term
    What does the term black hole mean?
    Definition
    A mass with high density and strong graviational pull, which pulls in electromagnetic radiation.
    Term
    What is produced as gases from a star spiral into a black hole?
    Definition
    What is produced as gases from a star spiral into a black hole?="Tw Cen MT" SIZE="+5" COLOR="#3366CC">X-rays.
    Term
    What is red shift, and what does it indicate about distant galaxies?
    Definition
  • Red shift is when galaxies move away from Earth at high speed...
  • ...forcing the light to shifted to the red end of the spectrum.
  • The furthest galaxies display the greatest red shift
  • This supports the Big Bang theory.
  • Term
    What equation links potential difference, current, and power?
    Definition
    POWER= POTENTIAL DIFFERENCE x CURRENT
    W= V x i
    Term
    What equation links the number of turns of each transformer coil, to the voltage across each transformer coil?
    Definition
    Voltage across each primary coil ÷ Voltage across each secondary coil
    =
    Number of turns of primary coil ÷ Number of turns of secondary coil
    Term
    Use the theory of plate tectonics to explain sea floor spreading?
    Definition
    Plates are moving away from each other and the gap is filled by basalt rock.
    Term
    What evidense supports sea floor spreading?
    Definition
    Magnetic reversal patterns in oceanic rock.
    Term
    What equation links frequency, wavelength, and speed?
    Definition
    WAVE SPEED= WAVE LENGTH x FREQUENCY
    v= f x λ
    Term
    Which part of the atom emits beta particles?
    Definition
    Neutron in the nucleus.
    Term
    How does the composition of a neutron change after it emits a beta particle?
    Definition
    It becomes a proton.
    Term
    What inside some badges detects radiation?
    Definition
    Photographic film, which when developed goes dark if there is high radiation.
    Term
    Radiation needs to be monitored to prevent what?
    Definition
    Over exposure.
    Term
    What is the equation for photosynthesis?
    Definition
    Carbon Dioxide + Water + Light ------> Glucose + Oxygen.
    Term
    What part of the eye controls how much light enters it?
    Definition
    The pupil.
    Term
    What in the eye does the retina do?
    Definition
    Carries electrical impulses to the brain.
    Term
    How does penicillin help to treat infection?
    Definition
    It destroys bacteria.
    Term
    When might a doctor not prescribe penicillin?
    Definition
  • Bacteri may be resistant
  • May increase resistance
  • Could be a virus, which cannot be treated by penicillin
  • Term
    Name 2 human activities which have increased the amount of carbon dioxide in the Earth's atmosphere.
    Definition
  • Combustion of fossil fuels
  • Deforestation
  • Term
    Why do plants need roots?
    Definition
    To absorb water.
    Term
    Why when growing a cutting, do we cover them with a clear plastic bag?
    Definition
    To create a humid atmosphere, and reduce transpiration.
    Term
    Are new varities of plants grown from seeds or cuttings?
    Definition
    Seeds because
  • they are produced through sexual reproduction...
  • ...where two different gametes fuse together...
  • ...which allows there to be a combination of 2 different genes/allels...
  • ...promoting variation
  • Term
    Which organ produces insulin?
    Definition
    Pancreas
    Term
    How can a high concentration of glucose harm body cells as a result of osmosis?
    Definition
  • Wate movement out of a cell...
  • to an area of low concentration from high concentration...
  • ...Causes the cells to shrink.
  • Term
    What is the function of bile?
    Definition
    To emulsify fat.
    Term
    What type of bacteria decomposes organic matter containing proteins, into ammonium compounds?
    Definition
    Putrifying Bacteria
    Term
    What type of bacteria decomposes ammonium compounds into nitrates?
    Definition
    Denitrifying Bacteria
    Term
    How can large amounts of untreated sewage entering a river cause the fish to die?
    Definition
  • Dead plants are broken down by the bacteria from the sewage which allows more of them to reproduce...
  • ...which all have to respire, removing the oxygen meant for the fish.
  • Term
    What subtances are not normally found in the filtrate and urine from kidneys??
    Definition
  • Glucose
  • Protein (molecules too large)
  • Amino Acids
    Because they are reabsorbed in the filter
  • Term
    Explain how the body reduces the amount of water in urine, when less water is consumed.
    Definition
  • Hypothalamus detects the concentrated blood...
  • ...so the pituatory gland releases ADH...
  • ...a hormone wich increases the reabsorption of water.
  • Term
    Why do some contreceptives contain oestrogen?
    Definition
  • Oestrogen inhibits the release of FSH...
  • ...which ripens eggs...
  • ...therefore the female does not ovulate.
  • Term
    How does the contraction of the inter-costal muscles and the muscles in the diaphragm help to take air into the lungs?
    Definition
  • The diaphragm flattens and the ribs move out...
  • ...causing a volume increase...
  • ...and a pressure decrease.
  • Term
    How does emphysema reduce the amount of oxygen diffused into the blood?
    Definition
    The surface of the lung tissue becomes thicker and surface area decreases.
    Term
    Describe diffusion and when it happens in cells.
    Definition
    Diffusion is the movement of material from high to low concentration concentration.In cells the material inside a cell needs to be>than the material outside the cell for deffusion to occur
    Term
    Plastics are not ___________
    Definition
    Biodegradable
    Term
    What is meant when a molecule is unsaturated?
    Definition
    Can still form double bonds with hydrogen.
    Term
    What does polymerisation mean?
    Definition
    Lots of monomers bond together to form a long chain polymer.
    Term
    In terms of ions, what does oxidation mean?
    Definition
    Electron are lost.
    Term
    What does it mean when a reaction is a redox?
    Definition
    Both oxidation and reduction occur.
    Term
    Give an ionic equation for neutralisation including state symbols.
    Definition
    H+(aq) + OH-(aq)-----> H2o(l)
    Term
    Why were scientists critical of Newland's law of octaves and the periodic table it produced?
    Definition
  • Many elements in the same group had dissimilar properties e.g Cu + K
  • In some cases 2 elements can found in the same place e.g Ce & La
  • No clear division between metals and non metals.
  • Term
    How is Mendeleev's periodic table beeter than Newlands?
    Definition
  • Grouped elements with similar propeties
  • Seperated metals from non-metal
  • Term
    If the forward reaction used to get hydrogen is endothermic, what condition of heat and pressure would give the most?
    Definition
  • High temperature because the reaction takes in energy
  • Low pressure favours a reaction in which more molecules are formed.
  • Term
    Which metals are most likely to be used as catalyst?
    Definition
    Transition
    Term
    Describe the structure of a typical metal.
    Definition
    They are in a lattice with outer electrons free to move through the structure.
    Term
    Why do copper and other metals conduct electricity?
    Definition
    Free electrons are allowed to move around the structure, carrying the current.
    Term
    Why can copper be drawn out into wires or be bent?
    Definition
    The free electrons move, allowing layers in the lattice to slip over each other.
    Term
    Why is copper oxide not as good as pure copper at conducting electricity?
    Definition
    Oxygen atoms disrupt the flow of electrons.
    Term
    Why is copper oxide heated in a hydrogen atmosphere, to make the purest copper possible?
    Definition
    Hydrogen reacts with oxygen.
    Term
    Why is sodium hydrogencarbonate added to cake?
    Definition
    To make it rise.
    Term
    What does extra terrestrial mean?
    Definition
    Not from Earth.
    Term
    Why may scientists have believed that radio pulses came from intelligent life?
    Definition
    Neutron stars were unknown
    Term
    What is the link between a neutron star and a super nova?
    Definition
    A neutron star is the matter left behind as a red giant explodes as a super nova.
    Term
    How can bacteria travel through space to reach our atmosphere?
    Definition
    By comets and meteors
    Term
    How does an ironing board covered in shiny silver colour material make ironing easier?
    Definition
    Silver is a good reflector of heat radiation, so less is lost through the board.
    Term
    Name the sources of background radiation.
    Definition
  • The ground
  • Air
  • Buildings and building equipment
  • Radon
  • Cosmic Rays
  • Rocks (Granite)
  • Term
    What equation links together gravitational field strength, mass and weight?
    Definition
    WEIGHT= MASS x G.F.S
    w= m x g
    Term
    How have stars like the sun formed?
    Definition
  • Remnants from a super nova like dust and gas......have been pulled together by gravity...
  • ...and formed a star when temperatures became hot enough.
  • Helium and hydrogen nuclei fused together...
  • initiating nuclear fission.
  • Energy caused expansion...
  • ...which is balanced by gravitational pull
  • Term
    As an attempt to explain why fossills of the same creatures were found in South America and Africa, why did some say that a bridge had once connected them?
    Definition
  • Animals would have been able to move between the two places
  • Once the bridge had broken, they would have evolved differently
  • Term
    What is the difference between analogue and digital signals?
    Definition
  • Amplitude and frequency vary continuously in analogue signals
  • Digital signals have a series of on and off pulses with set values
  • Term
    Why does the quality of an analogue signal decrease over a long distance but a digital signal signal does not?
    Definition
  • Signals weaken and need amplifying
  • But noise is amplified also in analogue signals
  • Digital signals give noise a low frequency and it is ignored, as electronic circuits remove it.
  • Term
    Why are satellites, used to transmit and recieve radio and television microwaves, put into a geostationary orbit?
    Definition
  • They stay at the same point above the Earth
  • They do not have to keep changing direction
  • Term
    Explain how ultrasonic waves are used to produce images of unborn babies.
    Definition
    They are partly reflected when they hit a boundary between two substances, and the time taken for the reflected wave to return is used to produce the image.
    Term
    Name some uses of ultrasonic waves.
    Definition
  • Scans of unborn babies
  • Cleaning delicate machanisms and jewellery
  • Removing dental plaque
  • Sonar
  • Treating injuries
  • Term
    Name some things that can affect a drivers reaction time.
    Definition
  • Concentration
  • Tiredness
  • Alcohol
  • Drugs
  • Term
    What equation links force, mass and acceleration?
    Definition
    FORCE= MASS x ACCELERATION
    N= kg x ACC.
    Term
    How is heat energy transferred through the particles of metal?
    Definition
    The particles vibrate as heat energy is passed through them, and energy is tranferred through collisions between electrons and ions.
    Term
    Explain what happens to cause a convection current in water.
    Definition
  • As heat energy is transferred through the saucepan, the water at the bottom moves faster...
  • ...causing it to expand and become less dense...
  • ..allowing it to rise through the cold water.
  • Term
    What does thermal radiation mean?
    Definition
    The transfer of energy by infrared radiation.
    Term
    What equation links charge, current and time?
    Definition
    CHARGE= CURRENT x TIME
    I= A x s
    Term
    What equation links together kinetic energy, mass and speed?
    Definition
    KINETIC ENERGY= 1/2 x MASS x SPEED2
    ke= 1/2mv2
    Term
    What is an alpha particle
    Definition
    2 protons and 2 neutrons (the nucleus of a helium atom)
    Term
    Which tpe of radiation may a doctor inject into a body to monitor blood flow?
    Definition
    Gamma beacause it is less dangerous inside the body and is less likely to be absorbed by cells. They can penetrate the body to be detected externally.
    Term
    What does thermal radiation mean?
    Definition
    The transfer of energy by infrared radiation.
    Term
    Describe one way in which an embryo can be cloned.
    Definition
  • Cells can be split apart in the early stages...
  • ...and then implanted into the uterus of a mother.
  • Term
    How does a microwave work?
    Definition
    Water molecules are heated, which causes them to vibrate and to heat up the rest of the food.
    Term
    What happens to cells during meiosis?
    Definition
  • Copies of chromosomes are made...
  • ...and the cell then divides into 4 cells...
  • ...leaving each gamete with a single set of genes
  • Term
    Explain how meiosis and sexual reproduction gives rise to variation.
    Definition
    Fertililization of gametes from 2 different parents with different genes allows a variety of combinations of alleles to form.
    Term
    What is mutation?
    Definition
    A change in DNA.
    Term
    Are all mutations bad?
    Definition
    No because they may increase survival or be neutral.
    Term
    How was Meendelev able to predict the existance of elements before they were discovered?
    Definition
    He arranged the periodic table by relative atomic mass and properties so was able to fill in the gaps.
    Term
    Why is the half life of some radioactive substances important in medicine?
    Definition
    They need the half life to be sure the radioactive substance exists long enough to kill cancerous cells but short enough to minimize damage to surrounding healthy cells.
    Term
    What are the main reasons for deforestation?
    Definition
  • Agriculture
  • Bulidings
  • Roads
  • Term
    Why do MEDC's use more electricity that LEDC's?
    Definition
  • More technology
  • More electricity
  • Term
    How does using a lot of resources damage the Earth?
    Definition
    Pollutants may be produced which encourages the green house effect and global warming?
    Term
    What was the problem about the landfil tax?
    Definition
    Because people were unwilling to pay, they dumped rubbish somewhere else.
    Term
    What are the examples of waste management like reuse, recycle and reduce, being put into practice?
    Definition
  • Reduce-Packaging
  • Recycle-Cardboard, tin cans
  • Reuse-Glass bottles, ink jet cartridges
  • Term
    A catalyst needs only to be heated at the beginning of a reaction if it is__________
    Definition
    Exothermic
    Term
    Describe how ammonium nitrate is made.
    Definition
    Ammonia and nitric acid neutralize each other.
    Term
    How does a circuit breaker work?
    Definition
  • If a high current flows the electromagnet is stronger...
  • ...attracting the iron bolt out which...
  • ...causes the plunger to lift along with the switch...
  • ...resulting in the circuit being diconnected.
  • To reset the system, the plunger must be pushed down.
  • Term
    Explain why organisms high up in the food chain transfer less energy.
    Definition
  • The amount of energy is reduced at each successive stage in a food chain
  • Not all of the prey organism is consumed
  • Energy is lost during 7 life processes.
  • Term
    How are high concentrations of methane and carbon dioxide affecting the Earth?
    Definition
  • Energy from the sun is radiated to Earth...
  • ...which then radiates heat back into space...
  • ...but most of the heat radiation is trapped by carbon dioxide and methane molecules...
  • ...which then causes some of the energy to be re-radiated back to Earth...
  • ...making Earth hotter than usual...
  • ...which in turn leads to climate change and a rise in seal levels.
  • Term
    How do you know when a reaction is exothermic?
    Definition
    The amount of energy from creating the new bonds, is larger than the amount of energy used to break the bonds.
    Term
    What would happen to the reaction in the Haber process if the temperature was increased?
    Definition
  • The rate of reaction would increase
  • But the backward reaction is favoured as it is endothermic and heat is present from the forward reaction...
  • ...resulting in an increase in hydrogen and nitrogen
  • Term
    Describe the orbit and use of a geostationary satellite
    Definition
  • Orbit lasts for 24 hours
  • Used in communications
  • Term
    Describe the orbit and use of a polar satellite
    Definition
  • Orbit lasts for 1.25 days
  • Used to monitor weather.
  • Term
    Name some diadvantages of tidal power
    Definition
  • Visual pollution
  • Destroys habitats
  • Term
    Name some diadvantages of wind power
    Definition
  • Visual pollution
  • Noise pollution
  • Term
    Hormones control the monthly release of an egg from a womens (1)_______. They also control the thickness of the lining of her (2)_______. Hormones that are given to women to stimulate the release of eggs<
    Definition
    1. Ovaries
    2. Womb
    3. Fertility drugs
    4. oral Contreceptives
    Term
    What is the difference between the sex chromosomes of females and males?
    Definition
  • Women have XX
  • Men have XY
  • Term
    How can several cloned embryo's be produced?
    Definition
    By spliting apart the cells of the clonal embryo.
    Term
    Why is it not a good idea for doctors to issue antibiotics without consideration?
    Definition
    The bacteria may become resistant and develop into a greater risk for human or other organisms.
    Term
    How can ultrasonic waves clean delicate mechanisms in fluid?
    Definition
    The vibrations travel hrough the fluid to shake dust particles off.
    Term
    Which part of the blood transports most of the carbon dioxide?
    Definition
    Plasma
    Term
    How were Darwin's and Lamarck's explanation of evolution different?
    Definition
  • Darwin based his theory on the range of variation organisms had...
  • ...and 'the survival of the fittest' meaning that beneficial variation would lead to a longer survival.
  • Lamarck based his theory on the characteristics organisms acquired...
  • ... and that these charcteristics are passed on through genetic inheritance.
  • Term
    What is the difference between P and S waves?
    Definition
    P waves are/can;
  • Longitudinal
  • Faster
  • Travel through liquids + solid

    S waves are/can;
  • Transverse
  • Slower
  • Travel only through solids.
  • Term
    P + S waves are not straight. What does this tell you?
    Definition
  • Wave speed changes...
  • ...and get faster.
  • Term
    What role does sweating play in homeostasis?
    Definition
  • Evaporation of sweat...
  • ...cools the body
  • Term
    Explain the carbon cycle.
    Definition
  • Plants use carbon dioxide to photosynthesize...
  • ...and to form carbohydrates...
  • ...which are eaten by animals...
  • ...who then release carbon dioxide during respiration.
  • Term
    How do hormones improve food production efficiency?
    Definition
  • stimulate root growth
  • Controlling ripening
  • Herbicides
  • Term
    Greater mass requires greater _________.
    Definition
    Force
    Term
    What will happen to the sun as all the hydrogen is used up?
    Definition
  • It will expand because the inward gravitational force will no longer balance the outward force...
  • ...to become a red giant...
  • ...until it contracts and collapses under gravity when fusion stops...
  • ...exploding in a super nova...
  • ...leaving behind a white dwarf.
  • Term
    Describe the structure of alkanes.
    Definition
  • Carbon spine with covalent bonds between each carbon atom
  • Surrounded by hydrogen
  • Saturated
  • General formula CnH2n+2
  • Term
    What are the advantages and disadvantages of fossil fuels?
    Definition
  • Reliable source of energy(benefit)
  • Pollution by carbon dioxide(problem)
  • Term
    What are the advantages and disadvantages of nuclear energy?
    Definition
  • Doesn't produce greenhouse gases.(benefit)
  • Waste can release very dangerous radioactive material.(problem)
  • Term
    What are the advantages and disadvantages of using renewable energy?
    Definition
  • No fuel cost.(benefit)
  • Noise/visual pollution.(problem)
  • Not reliable source of energy except hydroelectric.(problem)
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