GCSE Revision Cards: Biology + Physics

Question 1

1. State the equation that links Distance, force and work done
2. State the equation for height, gravitational field strength, gravitational potential energy and mass
3. State the equation that links kinetic energy, mass and velocity
4. State the equation for efficiency
5. State the equation that links Energy, power and time

Answer 1

1. Work done = Force x Distance
2. GPE ( J ) = mass (Kg) x gravity (m/s) x change in height
3. EK ( J ) = 1/2 mass (Kg) x velocity 2 (m/s)
4. Efficiency (%) = useful out / total in x 100
5. Energy ( J ) = power (W) x time (s)

Question 2

1. State the 5 energy stores
2. State the 4 ways energy can be transferred
3. State the most important law for energy

Answer 2

1. GPE, kinetic, EPE, thermal, chemical
2. Heating, waves, electrical current, Force
3. Energy cannot be created or destroyed only transferred

Question 3

1. Define Work
2. Calculate work done if a force of 48N pushes a box 14m
3. Define friction
4. Calculate GPE if a mass (48kg) is raised 4.5m on earth where the gfs is 9.8N/kg
5. Calculate the height of a probe on mars if the gfs is 3.71N/kg, the probe has 1800J and weighs 35kg

Answer 3

1. Amount of force applied over a distance
2. 48 x 14 - 672J
3. Friction always apposes work done 4. 48 x 4.5 x 9.8 = 2,116.8J
4. 1800 / (3.71x 35) = 13.86 m

Question 4

1. a. Calculate the energy stored in a vehicle of mass 4100kg that is driving at 45m/s
   b. Or If its speed was 68km/h
2. a. Calculate the energy stored in a spring when its spring constant = 250N/m and is stretched at 0.25m
   b. If its stretched 68cm

Answer 4

1. a. Kinetic energy = ½ x 4100 x 45 = 4151250J
   b. 68km/h * 1000 = 68000 (m/h) / 60 = 1133.33 m (minute) / 60 = 18.89 m/s ½ x 4100 x 18.892 = 731419.8J
2. a. Elastic potential = ½ x 250 x 0.25 = 10/94j
   b. = ½ x 250 x .682 57.8j

Question 5

1. Describe useful energy
2. Describe wasted energy
3. Describe what happens to wasted energy
4. Describe what eventually happens to useful energy
5. Describe what happens to the energy as it spreads out

Answer 5

1. Energy in the place we want it, in the form we need it
2. Energy that has been dissipated (not useful)
3. Heating the environment
4. It is dissipated
5. It becomes less useful

Question 6

1. Explain why machines waste energy
2. (H) Describe how you can make machines more efficient
3. An electric motor is used to raise a weight. When you supply 48J of energy to the motor, the weight gains 23J of GPE. Calculate:
   a. its efficiency
   b. If it was 45% efficient, how much energy would it gain?

Answer 6

1. Because there is always friction apposing work
2. By lubricating, making smoother, improving aerodynamics
3. a. 23 / 48 x 100 = 48%
   b. 45/100 = 0.45
   0.45 x 48 = 21.6

Question 7

1. Describe where your home gets most energy from
2. Describe the useful and wasted energy produced from each of these appliances:
   TV, kettle, toaster, fridge, mobile phone

Answer 7

1. Electricity, oil and gas
2. TV: Useful – sound, light. Wasted – thermal
   Kettle: Useful – Thermal. Wasted – sound
   Toaster: Useful – thermal. Wasted – light.
   Fridge: Useful – thermal. Wasted – thermal, sound
   Mobile phone: Useful – sound, light. Wasted – thermal

Question 8

1. Describe Power
2. Calculate the power of a motor that:
   a. lifts a weight for 30s and uses 11,000J of energy
   If the machine produced 800w of power, how long would it take?

Answer 8

1. How quickly energy can be applied
2. Calculate the power of a motor that:
   a. 11,000 / 30 = 367W
   b. 11000 / 800 13.75s

Question 9

1. State the equation for Specific heat capacity
2. State 3 conductors and 3 insulators
3. Define thermal conductivity
4. State 3 things that affect the rate of energy transfer
5. Explain why loft insulation is effective at its role
6. Explain why a frying pan is effective at its role

Answer 9

1. Energy (J) = Mass (Kg) x Δ temperature (°C) x SHC (J/Kg.°C)
2. Iron, copper, lead. Wool, air, plastic, fibre glass
3. How quickly energy transfers through an object
4. Material thermal conductivity, thickness, temperature difference
5. Because it is thick and made of fibre glass which has a low thermal conductivity
6. It is thin and made of a material with a high thermal conductivity

Question 10

1. Define SHC
2. Explain why bricks are used in storage heaters
3. Calculate Energy transferred if 45kg increases by 40°C and SHC is 4184 J/kg°C
4. Calculate SHC if 25,000J of energy is transferred to raise it 34°C and its mass is 20kg

Answer 10

1. The amount of energy it takes to raise 1Kg of a substances temperature by 1°C
2. Because they have a very high specific heat capacity
3. Energy (J) = Mass (Kg) x Δ temperature (°C) x SHC (J/Kg.°C)
   ? = 45 x 40 x 4184
   =7531200j
4. SHC (J/Kg.°C) = Energy (J) / (Mass (Kg) x Δ temperature (°C))
   ? = 25,000 / 20 x 34
   =36.76 j/Kg.°C)

Question 11

Write a method for calculating the specific heat capacity of different metals

Answer 11

1. Measure the mass of the block
2. Set up the equipment
3. Measure starting temperature
4. Turn on the heater and start the timer
5. Record voltage and current
6. Measure the temperature every 30 seconds for 10 minutes
7. Record results in a table
8. Calculate energy supplied voltage x current x time
9. Specific heat capacity = energy / mass x change in temperature

Question 12

1. State 5 ways to reduce the amount of infrared radiation emitted from a home
2. Explain why cavities between walls reduces heat loss
3. Explain why cavity wall insulation further decreases energy transfer
4. Explain why foil behind radiators reduces heat transfer

Answer 12

1. Loft insulation, double glazing, cavity wall insulation, draft excluders, carpets, aluminium foil behind radiators
2. Because energy can’t transfer through using conduction, must also use convection
3. Stops large convection currents forming
4. Reflects thermal energy back into room

Question 13

Bio Fuels
1. Describe where the energy comes from
2. State if it is renewable, carbon neutral,
3. State 1 way it has a negative impact on the environment
Nuclear Power
4. Describe where the energy comes from
5. State if it is renewable, carbon neutral,
6. State 1 way it has a negative impact on the environment

Answer 13

1. Organisms doing photosynthesis
2. Renewable and carbon neutral
3. Deforestation to grow crops
4. Chemical energy with the nucleus: (breaking elements using nuclear fission)
5. Not renewable carbon neutral
6. Toxic waste

Question 14

Wind Power
1. Describe where the energy comes from
2. State if it is renewable, carbon neutral,
3. State 1 way it has a negative impact on the environment
4. State 1 reliability problem

Wave Power
5. Describe where the energy comes from
6. State if it is renewable, carbon neutral,
7. State 1 way it has a negative impact on the environment
8. State 1 reliability problem

Answer 14

Wind Power
1. Kinetic energy within the wind due to solar heating
2. Renewable and carbon neutral
3. Can kill birds
4. Not always windy

Wave Power
5. Kinetic energy within the water due to currents
6. Renewable and carbon neutral
7. Damages ecosystems
8. Not always waves

Question 15

Hydroelectric Power
1. Describe where the energy comes from
2. State if it is renewable, carbon neutral,
3. State 1 way it has a negative impact on the environment
4. State 1 reliability problem

Tidal Power
5. Describe where the energy comes from
6. State if it is renewable, carbon neutral,
7. State 1 way it has a negative impact on the environment
8. State 1 reliability problem

Answer 15

Hydroelectric Power
1. GPE stored in water from evaporation by the sun
2. Renewable and carbon neutral
3. Large scale flooding of areas
4. Might have low rainfall

Tidal Power
5. The tidal change in water height caused by the moon
6. Renewable and carbon neutral
7. Damages ecosystems
8. Only have tides at certain times

Question 16

Solar
1. Describe where the energy comes from
2. State if it is renewable, carbon neutral,
3. State 1 way it has a negative impact on the environment
4. State 1 reliability problem

Geothermal
5. Describe where the energy comes from
6. State if it is renewable, carbon neutral,
7. State 1 way it has a negative impact on the environment
8. State 1 reliability problem

Answer 16

Solar
1. The sun (nuclear fusion of elements)
2. Renewable and carbon neutral
3. Needs large areas of land
4. Not always sunny

Geothermal
5. Internal energy of the earth from its formation
6. Renewable and carbon neutral
7. Uses a lot of water can release trapped greenhouse gases from earth’s rocks
8. Very specific site requirements

Question 17

Fossil Fuels
1. Describe where the energy comes from
2. State if it is renewable, carbon neutral,
3. State 1 way it has a negative impact on the environment
4. Describe how Carbon capture and storage technology could be used to reduce levels of CO2

Answer 17

Fossil Fuels
1. Photosynthesis in plants that died and were buried millions of years ago
2. neither
3. release CO2 and other greenhouse gases.
4. Pump CO2 into rocks to form carbonates to remove it from the atmosphere

Question 18

1. Describe 3 advantages of renewable sources
2. Describe 3 disadvantages of renewable sources
3. Define start-up time
4. State a power source which is good for base load (long start up time) and a power source that has a short start up time

Answer 18

1. Will last forever, don’t release greenhouse gases, carbon neutral
2. Costly, need further research, use a lot of water and land
3. How long it takes to change a power stations energy production
4. Nuclear or coal. Natural gas

Question 19

1. Define electrical current
2. Describe the difference between a battery and a cell
3. Explain why a diode is useful in an electronic circuit
4. State the equation for current, charge flow and time

Answer 19

1. Flow of charge
2. A battery is multiple cells
3. Because it prevents current flowing the wrong way and damaging other components
4. Charge flow (C) = current (I) x time (s)

Question 20

1. State how an ammeter must be connected in a circuit
2. State how a voltmeter must be connected in a circuit
3. State the equation for potential difference, energy and charge flow
4. State the equation for Resistance, current and Potential difference
5. State Ohm’s law

Answer 20

1. In series
2. In parallel
3. Energy = P.D x charge flow
4. P.D = Current x resistance
5. Current through a resistor at a constant temperature is directly proportional to the PD across it

Question 21

1. a. State what changes the resistance of a filament lamp
   b. State what happens as this increase
2. State how resistance of a diode varies
3. a. State what changes the resistance of a thermistor
   b. State what happens as this increase
4. a. State what changes the resistance of an LDR
   b. State what happens as this increase

Answer 21

1. a. The filament lamp getting hot
   b. Resistance increases as temperature increases
2. Current forwards has a low resistance, backwards has a high resistance
3. a. Temperature
   b. As temperature increases resistance decreases
4. a. Light
   b. Resistance decreases

Question 22

1. State how current varies around a series circuit
2. Describe what happens to the potential difference in a series circuit
3. Describe how you can calculate the total resistance in a series circuit
4. State what happens to the potential difference as you add more cells.

Answer 22

1. It is the same
2. It is shared
3. Add resistance of each component together
4. It increases

Question 23

1. State how current varies around a parallel circuit
2. Describe what happens to the potential difference in a parallel circuit
3. Describe what happens to the current down one channel if the resistance is higher than the others
4. Describe the relationship between total resistance and number of resistors in parallel circuit

Answer 23

1. Each branch adds up to make the total current
2. The PD across each branch is the same
3. Current decreases
4. As the number of resistors in parallel increases the total resistance decreases

Question 24

1. State the name and describe function of these different circuit components (1)
   a) See ClassCharts link
   b) See ClassCharts link
   c) See ClassCharts link
   d) See ClassCharts link
   e) See ClassCharts link
   f) See ClassCharts link

Answer 24

a. Filament bulb: transfer energy into thermal and light
b. Diode: stop electricity flowing opposite way through circuit
c. Light emitting diode: same as previous and emit a small amount of light
d. Ammeter: measure current
e. Switch: break the circuit
f. Cell: provide power to the circuit

Question 25

1. State the name and describe the function of these different circuit components (2) a) See ClassCharts link b) See ClassCharts link c) See ClassCharts link d) See ClassCharts link e) See ClassCharts link f) See ClassCharts link

Answer 25

a. Variable resistor: vary how much current is reduced in a circuit b. Fuse: to break if to much current flows through the circuit c. Voltmeter: measure the potential difference across a component d. Resistor: reduce the flow of current e. Thermistor: decrease the resistance as temperature increase f. Decrease resistance as light intensity increase

Question 26

1. Define D.C 2. Define A.C 3. State 3 features of the UK mains live wire 4. Describe a mains step up transformers 5. Describe a mains step down transformers 6. Explain the role of these transformers

Answer 26

1. Direct current: only flows in one direction 2. Flows in both directions 3. Alternating, frequency of 50Hz and 230Volts 4. A transformer that increases the potential difference 5. A transformer that decreases the potential difference 6. Reduce energy loss

Question 27

1. State what plugs are made of and why 2. State what wires are made from and why 3. State what each wire is surrounded by and why 4. State what plug pins are made from and why 5. Label the features of a plug, include wire colours and names

Answer 27

1. Plastic: poor conductor of electricity 2. Copper: good conductor of electricity 3. Plastic/ rubber: poor conductor of electricity 4. Brass: good conductor of electricity and it is hard and not reactive 5. a. Earth wire: green b. Neutral wire: blue c. fuse d: live wire: brown

Question 28

1. State the equation for power, energy and time 2. State the equation for power, current and P.D 3. Describe the role of a fuse 4. * State the equation for power resistance and current

Answer 28

1. Energy = power x time 2. Power = current x potential difference 3. To break if too much current flow through it. This would indicate the appliance has malfunctioned and is dangerous. 4. Power = resistance x current2

Question 29

1. State the equation for charge flow, current and time 2. Explain why a resistor gets hot 3. State the equation for efficiency

Answer 29

1. Charge flow = current x time 2. Energy is transferred into thermal store because of the high resistance 3. Useful / total input x 100 OR Small number / big number x 100

Question 30

1. State the equation for density 2. State the equation for latent heat

Answer 30

1. Mass/ volume = density 2. Energy/ mass =latent heat

Question 31

1. State density of a substance of mass 700g and a volume of 0.3m3 2. Define density 3. Describe how to measure the density of an irregular shaped solid 4. Describe how you measure the density of a liquid 5. State the resolution of a metre ruler with a mm scale 6. Explain why an object would float on water

Answer 31

1. 0.7kg x 0.3m = 2.33kg/m3 2. Mass per volume 3. Use a displacement can and measure the water displaced by the object 4. Measuring cylinder 5. 1mm 6. It is less dense than water so has less particles in the same volume

Question 32

1. For solids, liquids, gases state if each: flows, shape changes, volume changes, density compared with the others 2. State the type of change, change of state is 3. Describe conservation of mass 4. Describe the kinetic theory of matter

Answer 32

1. Solid. I. Liquid. I. Gas Flows. No. I. Yes. I. Yes Shape Constant I. Not. I. Not Change. I. I. Volume Constant I Const- I. Not Change I ant I Density High. I. Low. I Low Compared 2. Physical change 3. Mass cannot be created or destroyed 4. All mater above 0 kelvin has thermal energy, thus kinetic energy and is vibrating or moving

Question 33

1. State the changes of state 2. Describe the difference between boiling and evaporating 3. State what must be added to or removed from a substance to change its state 4. Define latent heat 5. State what is happening at each point on the graph

Answer 33

1. A melt, B freeze, C condensate, d evaporate, e sublimate 2. Boiling is the maximum temperate that a liquid will get to. Evaporating is the change of state. 3. Energy 4. Energy required to change state per kg 5. 1: temperature is increasing until it reaches its melting point. 2: Temperature stops increasing while it melts. 3: once all melted, temperature increases until it reaches its boiling point. 4: Temperature stops increasing while it boils. 5: temperature increases once all is boiled

Question 34

1. Define internal energy 2. Describe what happens to the particles of a solid as it is heated 3. Describe the force of attraction in a liquid 4. Describe the force of attraction in a gas

Answer 34

1. Energy stored in a substance through the sum of the kinetic and potential energy 2. They vibrate more 3. Strong enough to keep them touching 4. Very weak

Question 35

1. Define specific latent heat of fusion Lf 2. State the specific latent heat if E = 300cJ and m = 40g (changed to grams) 3. Define specific latent heat of vaporisation Lv 4. State the unit for specific latent heat

Answer 35

1. Energy required to change 1kg of the substance into a liquid 2. Energy = latent heat x mass Latent heat = energy / mass ? = 3J / 0.04kg = 75j/kg 3. Energy required to change a substance to a gas without changing its temperature per kilogram 4. j/kg

Question 36

1. Describe what causes pressure 2. Describe how to increase pressure 3. Explain why you should never heat a sealed container with gas in it. 4. Describe the 2 factors that cause a sealed containers pressure to increase when heated 5. Explain why a smoke particle moves randomly when viewed under a microscope

Answer 36

1. The force and amount of impacts of the atoms on the container 2. Add more particles into the same container or heat the container 3. It can explode 4. Faster collisions with container because they have more energy More frequent collisions because they are moving faster 5. Because it is being hit by molecules of air that we can’t see

Question 37

1. Describe what a radioactive atom is 2. State the 3 types of radiation 3. State what devise is used to measure radiation

Answer 37

1. An atom that emits radiation from its nucleus 2. Alpha, beta, gamma 3. Geiger counter

Question 38

1. State what model was used to describe atoms before 1914 2. State what particle was fired at the gold foil in Rutherford’s experiment 3. State 2 observations of his experiment (one supported the plum pudding model the other didn’t 4. Describe how this changed the model of the atom

Answer 38

1. Plum pudding model 2. Alpha particle/ helium 3. Most passed straight through, some got deflected by large angles 4. It put a nucleus in the middle with nearly all the mass and was positively charged

Question 39

1. Describe what an isotope is 2. State how an atom changes that emits: a. an alpha particle b. a beta particle 3. State where the electron is emitted from during beta decay 4. Complete these decay equations: a. 238 U ——> ? Th +. 4. a 92. ? 2 b. 238 U ——> ? Th. +. 4. a 92. ? 2

Answer 39

1. An element with a different number of neutrons 2. a. Mass goes down by 4 and proton number goes down by 2 b. Mass stays the same and proton number goes up by 1 3. The nucleus 4. a. 234 b. 64 90 30

Question 40

1. Rank order alpha, beta and gamma from most to least: a. Ionising b. Penetrating c. Damaging if inside the body 2. State what can stop each type of atomic radiation 3. Describe what is meant by ionising radiation 4. Explain why this is bad P7.5 Activity and half life 1. Define half life 2. Describe the randomness of decay

Answer 40

1. a. Alpha, beta, gamma b. Gamma, beta, alpha c. Alpha, beta, gamma 2. Alpha, paper or 5cm of air, beta aluminium or 1m of air, gamma thick lead air will never stop it. 3. It strips electrons from elements 4. This is bad because this can happen to DNA, cause mutations and possibly cancer 4. The time taken for the amount of radiation from a substance to half 5. You can’t predict when a single atom will decay but that within a sample how many will in a given time

Question 41

1. State the symbol and unit for each of these a. Distance, mass, time, current, temperature, frequency, force, energy, power, pressure, charge, potential difference, electric resistance Prefixes and converting units 2. Convert 1m2 to cm2 to mm2 3. State 8 metric prefixes starting from 109

Answer 41

1. Distance d metre m, mass m kilogram Kg, time t Second s, current I ampere A, temperature θ °C, frequency f hertz Hz, force F Newton N, energy E joule J, power P Watt W, pressure p pascal Pa, charge C coulomb C, potential difference V Volts V, electric resistance r ohms Ω 2. 1m2 = 100 x 100 = 10,000cm2, 1m2 = 1000 x 1000 = 1,000,000mm2 3. giga G, mega M, kilo K, centi, c, milli m, micro µ nano n

Question 42

1. Define accuracy 2. Define precise 3. Define measurement error 4. Define random error 5. Define systematic error 6. Define zero error 7. Define the symbol Δ and state its name 8. Define resolution 9. Define an anomaly

Answer 42

1. How close values are to true value 2. How close values are to each other. 3. The difference between a measured value and the true value 4. Reasons that cause the results to be spread around the true value, varying from one measurement to the next 5. A consistent error in the measurement 6. Error caused by the equipment not being set to zero 7. delta: change in 8. The degree of accuracy a measuring device gives you 9. A result that does not match with the rest of the data/ line of best fit. Should not be included in the line of best fit or in the mean

Question 43

1. Define Independent variable 2. Define dependent variable 3. Define control variable 4. State which variable goes in the first column of a table 5. State which graph to use if the variable is continuous 6. State which graph to use if the variable is discrete 7. State which axis the dependent and independent variables go on 8. Describe the purpose of a line of best fit

Answer 43

1. The thing I change 2. Depends on what you change 3. Things that must be kept the same 4. Independent variable 5. Line 6. Bar 7. X – independent, Y – dependent 8. To predict values and help remove random errors from data collection.

Question 44

1. State 4 metric units of length smaller than 1m from largest to smallest. 2. State how many of each length are in the one larger. 3. State how you calculate the size of a magnified object 4. State the smallest object that can be seen with each microscope type.

Answer 44

1. centimetre, millimetre, micrometre, nanometre 2. 1000 nanometres = 1 micrometre 1000 micrometre = 1 millimetre 10 millimetres = 1 cm 3. Image / real size = magnification 4. Light microscopes is 200nm Electron microscopes is 0.2nm

Question 45

1. Label the 5 parts of an animal cell 2. Describe each of their functions 3. Label the 3 extra parts of a plant cell 4. Describe each of their functions

Answer 45

a. Cell membrane: controls movement of substances in and out of the cell b. Ribosomes: protein synthesis happens here c. Mitochondria: respiration happens here d. Nucleus: controls cell functions e. Cytoplasm: chemical reactions happen her and is a fluid that other parts are suspended in f. Cell wall: made of cellulose and strengthens cell and gives it support g. Permanent vacuole: filled with sap and keeps the cell rigid h. Chloroplasts: do photosynthesis

Question 46

1. Define Eukaryote 2. Define Prokaryote 3. State what size range eukaryotes are 4. State what size range prokaryotes are 5. Label the features of a bacteria 6. Describe the function of each part of the bacteria

Answer 46

1. A cell with a nucleus 2. A cell without a nucleus 3. 10 - 100 micrometres 4. 0.2 – 2 micrometres a. Cytoplasm: as above b. Slime capsule: extra protection c. Plasmid ring: code for antibiotic resistance d. Cell wall: not made of cellulose e. Flagellum: allow bacteria to move f. Cell membrane: as above g. Generic material: on loop of DNA that is not in a nucleus

Question 47

1. Describe what makes specialised cell different from each other 2. State the name and function of 3 different specialised cells in animals 3. Describe how each is specialised

Answer 47

1. Has differentiated so has different sub cellular structures 2. Nerve cell: transmit electrical impulses: very long, dendrites to connect to other nerve cells, myelin sheath to transmit information fast Muscles cell: contract to allow movement: contain proteins that pull on each other, many mitochondria large store of glycogen Sperm cell: to take male DNA to an egg: has a tail, lots of mitochondria

Question 48

1. State the name and function of 4 different specialised cells in plants 2. Describe how each is specialised

Answer 48

1. Root hair cell: absorb nutrients and water from the ground: very large surface area, lots of mitochondria, large permanent vacuole Photosynthetic cell: to do lots of photosynthesis: lots of chloroplasts Phloem: transports glucose: cell wall breaks down to make a tube with’ sieve breaks’ Xylem: transports water: they die but for long connected tubes

Question 49

1. Define diffusion 2. State the 3 factors that affect diffusion rate 3. Explain why this is important for cells

Answer 49

1. The movement of particles from an area of high concentration towards an area of low concentration: down the concentration gradient 2. Temperature, the difference in concentration, surface area available 3. Glucose, urea and gases such as oxygen all move around the body simply due to diffusion

Question 50

1. Define osmosis 2. Describe what affects the rate of osmosis 3. State the name of these solution (grey inside cell) 4. Explain why osmosis is important in plant cells

Answer 50

1. The movement of water through a semipermeable membrane to reduce the difference in concentration 2. Temperature, the difference in concentration, surface area available 3. A: hypotonic, B: isotonic, C: hypertonic 4. Osmosis gives plants turgor, which keeps leaves and stems stiff and strong

Question 51

1. Define active transport 2. Describe what is needed for active transport to occur. 3. Describe two examples of active transport. 4. Explain why single celled organisms can only get so large 5. Describe how multicellular creatures get around this issue.

Answer 51

1. When a substance is moved against the concentration gradient and energy is used for this. 2. Energy 3. Minerals moving into roots from soil and glucose moving into the blood stream from the small intestines 4. Because their surface area to volume ratio gets to small so they can’t get enough resources in 5. By having organs which have evolved to have extremely large surface areas

Question 52

1. State how many chromosomes are in a human cell and how are they found? 2. State the name of the process where a cell replicates 3. Describe what happens in each of the stages of this process

Answer 52

1. 46 chromosomes in 23 pairs 2. Mitosis 3. Stage 1: DNA inside nucleus gets replicated and make more copies of subcellular structures Stage 2: nucleus splits into 2 halves Stage 3: cell splits into 2 halves

Question 53

1. State where mitosis occurs in plants 2. In regards to cell production Describe how plant cells are different from animal cells 3. Define stem cell 4. Explain why specialised cells are different from each other 5. Describe how most blood cells are produced 6. Describe plant cloning

Answer 53

1. Meristems 2. Cells are produced only at the meristems but are produced throughout its life 3. A cell that can become different cells 4. Because they have different subcellular structures due to genes being switched on or off 5. Produced by adult stem cells that replace dead cells 6. Making identical copies of a plant by cutting and planting a piece of it, the cells will unspecialise and form new cells and tissues

Question 54

1. State the 2 different types of human stem cell 2. Explain why stem cells are useful 3. Describe how plant stem cells can be used

Answer 54

1. Adult and embryo 2. Because they allow us to grow different cells 3. They can be planted to make clones for agriculture and horticulture

Question 55

1. Describe therapeutic cloning 2. Describe the strengths and weaknesses of using adult and embryo stem cells for medicine

Answer 55

1. An embryo is produced with the same genes as the patient so they are not rejected when they are used 2. Adult +: cheaper, less ethical issues, Adult -: risk of disease, less problems they can fix, patients body can reject them Embryonic +: divide and grow rapidly, Embryonic -: possible they can cause cancer, very expensive and difficult, ethical issues

Question 56

1. State what a tissue is 2. State what an organ is 3. State what an organ system is

Answer 56

1. A collection of similar cells 2. A collection of different tissues that work together 3. A collection of organs working together to complete a function

Question 57

1. State the name of each of these parts of the digestive system 2. State what order of organs does food travel through

Answer 57

1. a: Mouth, b: oesophagus, c: liver, d: stomach, gal bladder, large intestines, small intestines 2. mouth, oesophagus, stomach, small intestines, large intestines

Question 58

1. State what carbohydrates are made from 2. State what lipids are made from 3. State what proteins are made from

Answer 58

1. Glucose 2. 3 fatty acids and glycerol 3. Amino acids

Question 59

1. Define enzyme 2. Define catalyst 3. State what enzymes are made form 4. State the name of the part of the enzyme that binds with the substrate

Answer 59

1. A biological catalyst 2. Something that speeds up a reaction 3. Protein 4. Active site

Question 60

1. State what two things effect enzymes activity 2. State the name for when an enzyme gets damaged 3. State if this damage is reversible or not

Answer 60

1. Ph, temperature 2. Denatured 3. Irreversible

Question 61

1. Describe the purpose of digestion 2. State where digestive enzymes are produced 3. State the name of the enzyme that breaks down carbohydrates/ starch 4. State the name of the enzyme that breaks down lipids (fats and oils) 5. State the name of the enzyme that breaks down proteins

Answer 61

1. To break large insoluble foods into smaller soluble ones 2. Glands around the digestive system 3. amylase 4. lipase 5. protease

Question 62

1. State what environment protease works best in 2. State the name of the acid in the stomach 3. Describe the role of bile 4. State the two places carbohydrates are broken down 5. State where proteins are broken down 6. State where lipids are broken down

Answer 62

1. Acidic 2. Hydrochloric 3. To neutralise the stomach acid and emulsify fats 4. Mouth and small intestine 5. Stomach 6. Small intestines

Question 63

1. State where bile is produced 2. State where bile is stored 3. State where amylase is produced 4. State where protease is produced 5. State where lipase is produced

Answer 63

1. Liver and pancreas 2. Gal bladder 3. Salivary glands and pancreas 4. Pancreas 5. Pancreas and stomach

Question 64

1. State the 4 main components of the blood 2. Describe the function of each component 3. State the composition of the blood

Answer 64

1. White blood cells: <1% fight pathogens Red blood cells: 45% transport oxygen around the body Platelets: <1%help blood to clot Plasma: 55% liquid everything is in, some substances dissolve into this.

Question 65

1. State The 3 types of blood vessel 2. Describe features of each blood vessel that support them in their function 3. State what type of circulatory system humans have

Answer 65

1. Arteries, veins, capillaries 2. Arteries: small lumen, thick walls, thick layer of muscle and elastic fibres Veins, large lumen, thin walls, valves Capillaries: very thin walls (single cell thick), tiny vessel with narrow lumen A double circulatory system

Question 66

1. State the function of the heart 2. State the path blood takes through the heart starting with deoxygenated blood from the rest of the body. 3. Describe what a stent is used for

Answer 66

1. To pump oxygenated blood around the body as well as transporting many other substances around the body 2. Vena cava, Right atrium, valve, right ventricle, valve, pulmonary artery, pulmonary vein, left atrium, valve, left ventricle, valve, aorta 3. To open an artery when it has become blocked with cholesterol (fat)

Question 67

1. Describe what can go wrong with heart valves and how this can be fixed 2. Describe what causes the heart to pump 3. Describe how this can be controlled if is irregular 4. Describe when an artificial heart may be used

Answer 67

1. They can leak. Artificial valves can be inserted. 2. A group of cells in the right atrium that receive a signal from the brain to pump 3. An artificial pacemaker 4. Replacing a heart that has stopped working, this is only a temporary solution

Question 68

1. State the name of each part of the breathing system 2. Describe how gases move into and out of the blood 3. State 2 adaptations of the lungs/ alveoli

Answer 68

1. a. nose, b. mouth, c. trachea, d. bronchioles, e. diaphragm, f. intercostal muscle, g. ribs, h. lung, i. bronchioles, j. alveoli 2. they move via diffusion 3. large surface area, good blood supply with capillaries very close to alveoli

Question 69

1. State the name for 3 plant organs 2. Describe how they are specialised to do their function 3.State the different parts of a leaf’s structure

Answer 69

1. Root: large surface area to absorb lots of water and minerals. stem, strong and contains phloem and xylem to transport water and minerals up and glucose down to the roots. Leaf, large surface area, lots of chloroplasts for photosynthesis 2. a. upper epidermis, b. palisade mesophyll, c. spongy mesophyll, d lower epidermis, e many chloroplasts, f. big surface area for gas exchange, g. air space for gases, h. stomata to let gases in, I. guard cells, j. phloem, k. xylem.

Question 70

1. State the name of the two transport systems in a plant 2. Describe the function of each of the systems 3. Define translocation

Answer 70

1. Xylem: transports water and minerals and phloem: transports glucose 2. The movement of glucose from leaves to the rest of the plant.

Question 71

1. Describe how water is lost from leaves 2. State the name given to this 3. Explain why need this to happen 4. State the 4 factors effect this. 5. Describe how each effect this 6. State the name of the devise that measures this in a plant

Answer 71

1. through diffusion out of the stomata openings on the bottom of the leaves. 2. Transpiration 3. Because the stomata have to be open to let CO2 into the leaves for photosynthesis 4. Temperature, light intensity, air flow 5. If these increase transpiration increases 6. Humidity: if this increases transpiration decreases

Question 72

1. Define health 2. Describe how can diet affect your health 3. State 5 life situations that can affect health 4. State two examples of pathogens that make other diseases worse

Answer 72

1. A complete state of physical and mental wellbeing, not simply the absence of disease 2. Can affect both mental and physical health, leading to non-communicable diseases and increased risk if you get communicable diseases 3. Part of the world you live, gender, financial security, ethnic group, level of free health care, number of children and sewage/ rubbish disposal 4. HIV, HPV (human papilloma virus)

Question 73

1. Define communicable diseases 2. Describe how bacteria make you ill 3. Describe how viruses make you ill 4. State 3 ways pathogens are spread

Answer 73

1. Diseases that can be spread from person to person: pathogens. 2. Produce toxins and can directly damage cells 3. The invade cells, once inside they multiply and then kill the cell when they exit 4. By air, direct contact, water

Question 74

1. Describe what Semmelweis discovered 2. State 4 ways to prevent the spread of disease 3. Describe how these methods of prevention work

Answer 74

1. He discovered that childbed fever was caused by an infectious disease that was being passed around on doctors hands 2. Good hygiene, Isolating the infected individuals, destroying/ controlling vectors, vaccination 3. Reduces transmission of pathogen

Question 75

1. Explain why it is difficult to stop viruses spreading 2. State 3 examples of viral infections 3. Describe how each is spread 4. Describe the symptoms of each infection

Answer 75

1. Because once they are inside a cell it can’t be stopped 2. HIV: blood exchange: mild flu symptoms, weakens immune system. Measles: droplets from coughs and sneezes. Fever and red skin rash, leading to blindness and brain damage. Tobacco mosaic virus: spread by contact between plants. mosaic pattern and stunted growth

Question 76

1. State how bacterial diseases are combated 2. Explain why bacterial diseases are starting to kill more people again 3. State two bacterial diseases 4. Describe how each is spread 5. Describe the symptoms of each infection 6. Describe how each can be controlled

Answer 76

1. Antibiotics 2. Because the are developing antibiotic resistance 3. Salmonella: spread by not cooking food properly and or preparing it unhygienically. Fever, abdominal cramps, vomiting and diarrhoea. Prepare food hygienically Gonorrhoea: unprotected sex. Possible yellow/green discharge. Long term can cause infertility. Use protection during sex

Question 77

1. State the name of a fungal disease that effects plants 2. Describe how it is spread 3. Describe the symptoms of the infection 4. Describe how it can be controlled 5. State a disease caused by a protist 6. Describe how it is spread 7. Describe the symptoms of the infection 8. Describe it can be controlled

Answer 77

1. Rose black spot. 2. Spores are carried in the wind. 3. Black spots on leaves 4. Fungicide, removal of infected parts of plant 5. Malaria 6. Mosquitos 7. Episodes of fever and shaking 8. Mosquito nets and repellents

Question 78

1. List 4 defences the human body has against pathogens 2. List 3 ways white blood cells combat infections 3. Describe how each method combats infection

Answer 78

1. Skin, hairs and mucus in air ways, the stomach has strong acid in it. White blood cells kill and pathogens that enter the body 2. Engulf: removes/ destroys that pathogen Antitoxins: toxins make you ill and white blood cells attack/ combat these. Antibodies: they target and attach to a specific bacterium to aid its destruction

Question 79

1. State what an antigen is 2. Describe how antibodies combat infection 3. State what a vaccine is 4. Describe how a vaccination works 5. Explain why herd immunity is important

Answer 79

1. Part of a pathogen that our white blood cells can produce antibodies to destroy 2. They attach to antigens to destroy them and the pathogen but each type of pathogen has unique antigens 3. A dead or inactive version/ piece of a pathogen 4. Some of the vaccine is injected into the patient. The body learns how to destroy that piece and retains that knowledge for future infections 5. So that infants and people who can get vaccinated are also protected

Question 80

1. Describe the purpose of painkillers 2. Describe how antibiotics make you better 3. Describe two issues with antibiotics when treating infections 4. Explain why it is difficult to kill viruses

Answer 80

1. To reduce pain and treat symptoms not the problem 2. They kill the bacterial disease that is making you ill 3. - They are only effective against bacteria - Some bacteria are becoming antibiotic resistant 4. Because they reproduce inside our living body cells

Question 81

1. State where the first drugs came from 2. Describe how new drugs are created 3. Explain why drugs are created in this way now

Answer 81

1. Plants 2. Scientists often start with a plant and isolate the chemical that is useful and then they produce copies of it in a lab 3. Cheaper, faster, more reliable, can produce more and easier to transfer information about making it around the world

Question 82

1. Explain why drugs must be tested before they are given to the public 2. State what drugs are tested on before humans 3. Explain why healthy people are the first to be given the drug in the clinical trial 4. Define placebo 5. Describe what a double-blind trial is

Answer 82

1. To ensure they are not toxic, efficacy of them, dosage, identify side effects 2. Cells, tissues and live animals 3. To check for toxicity and side effects as they are less likely to become seriously ill and they don’t need a cure 4. A drug that does nothing 5. Some patients are given a placebo but them and the doctors do not know who during the study

Question 83

1. Define non-communicable disease (NCD) 2. List 5 risk factors for NCD 3. Describe what a correlation is 4. Explain why a correlation is not always useful 5. Define causal mechanism

Answer 83

1. A disease that cannot be spread from person to person (pathogen) 2. Weight, diet, exercise, genetics, wealth, living situation (city/ urban) 3. A possible link between two factors (variables) 4. Because they are not proof that one causes the other 5. How one factor causes another

Question 84

1. Describe what a tumour is 2. Describe the difference between benign and malignant tumours 3. List 5 causes of cancer 4. Describe the two treatments for cancer

Answer 84

1. An uncontrolled growth of cells caused by a mutation in the cell’s DNA 2. Benign do not spread around the body whereas malignant do 3. Genetics, carcinogens such as tar and asbestos, ionising radiation, viral infections, lifestyle choices such as smoking and alcohol consumption 4. Radiotherapy: targeted dose of ionising radiation to kill specific cells Chemotherapy: chemicals that destroy cancer cells

Question 85

1. List 3 dangerous substances in cigarette smoke 2. Describe the impact each of these has on the body 3. List 3 diseases caused by smoking 4. Explain why smoking during pregnancy is bad

Answer 85

1. Tar, nicotine, carbon monoxide 2. Tar: sticky that clogs lungs and can lead to bronchitis Nicotine: highly addictive Carbon monoxide: takes up space in red blood cells preventing as much oxygen being transported around the body 3. COPD, cardiovascular disease, lung cancer, coronary heart disease, bronchitis 4. The carbon monoxide prevents as much oxygen getting to the foetus, slowing its growth

Question 86

1. List 2 possible results of poor diet 2. Describe the impact of exercise on risk of getting cardiovascular disease 3. Describe the relationship between obesity and type 2 diabetes 4. Define carcinogen 5. Describe the impacts of alcohol on the body 6. Explain why drinking alcohol during pregnancy is bad 7. List 3 sources of Ionising radiation

Answer 86

1. Overweight or underweight or a deficiency in a vitamin/ mineral 2. It reduces it 3. Causal mechanism especially in severely overweight women 4. A substance that causes cancer 5. Causes brain and liver damage 6. Can lead to miscarriages, still births and birth defects 7. - UV light exposure from the sun/ sun beds - Radioactive materials in nature (rocks) - Medical procedures such as x-rays - Nuclear accidents

Question 87

1. State the word equation for photosynthesis 2. State the formula for glucose 3. Explain why photosynthesis is endothermic 4. State where photosynthesis takes place 5. State 6 adaptations that leaves have 6. Describe how 2 of them are important for photosynthesis

Answer 87

1. Carbon dioxide + water à glucose + oxygen 2. C6H12O6 3. Because it takes in energy from the sun 4. Chlorophyll in chloroplasts 5. / 6 Thin: makes diffusion distances short, broad (wide): big surface for light to hit, veins: brings water (xylem) and transports glucose away (phloem), contains chlorophyll: catalyst for photosynthesis, air spaces: space for gases around cells, guard cells: allows regulation of gas exchange.

Question 88

1. State 3 factors that affect the rate of photosynthesis 2. Sketch a graph for each 3. Explain the shape of each graph

Answer 88

1. Light intensity, temperature, CO2 2. See ClassCharts 3. Increasing Light and CO2 increases rate until they are no longer the limiting factor and further increase do not increase the rate of photosynthesis. Increase in temperature increases the rate of photosynthesis until a point after which rate rapidly decreases with temperature increase.

Question 89

1. State 5 uses of glucose by plant 2. Describe the importance of each to plants 3. State what else plants need for one of these processes

Answer 89

1. Respiration: allows plant to do MS GREN Creating cellulose for strengthening cell walls Creating starches for storing energy (vegetables such as carrots and onions) Making lipids for storing energy such as in seeds Producing amino acids which are then built into proteins that aid processes like respiration 2. Nitrate ions

Question 90

1. Describe the purpose of a greenhouse 2. State what other factors farmers are starting to control in greenhouses 3. Explain what farmers must consider before they install greenhouses for crops

Answer 90

1. Maximise the rate of photosynthesis and thus growth and harvest yield (size) by increasing temperature and making the environment more controllable 2. Light intensity and CO2 3. Whether the cost of controlling these factors will sufficiently increase crop yield to improve profit.

Question 91

1. State if respiration is exothermic or endothermic 2. State the word equation for aerobic respiration 3. State the balanced symbol equation for aerobic respiration 4. State where aerobic respiration occurs 5. Explain why some cells have more mitochondria 6. State 3 uses of the energy created through respiration

Answer 91

1. Exothermic 2. Oxygen + glucose à carbon dioxide + water + energy 3. 6O2 + C6H12O6 → 6CO2 + 6H2O 4. The mitochondria of a cell 5. Some cells have more because they are doing more cellular processes so need to produce more energy 6. Kinetic (movement), growth, reproduction (any of the 7 life processes (MRS GREN)

Question 92

1. Describe 3 responses to exercise 2. Explain why each is important

Answer 92

1. a. Heart rate increases: allows more oxygenated blood to be pumped around the body to the muscles that are working and removes waste such as carbon dioxide b. Breathing rate increases: gets more oxygen into your lungs and gets carbon dioxide away quicker c. Glycogen is converted back to glucose: to be used for respiration

Question 93

1. State the word equation for anaerobic respiration 2. State 2 reasons why anaerobic respiration is not as good as aerobic respiration 3. Describe how anaerobic respiration in other organisms is different 4. H Explain why heart rate and breathing rate remain high after exercise

Answer 93

1. Glucose à lactic acid 2. Less energy is released from the breakdown of glucose to lactic acid (incomplete breakdown) It produces lactic acid which causes fatigue 3. Plants and some microorganisms such as yeast produce ethanol and carbon dioxide 4. Because there is an oxygen debt due to the build-up of lactic acid that must be broken down.

Question 94

1. Define metabolism 2. State 5 functions that contribute to metabolism 3. H State 4 functions of the liver 4. H Describe what the role of the liver in removing lactic acid

Answer 94

1. The sum of all of the reaction in the human body 2. - Conversion of glucose to starch, glycogen and cellulose - Formation of lipid molecules - use of glucose and nitrate ions to form amino acids - respiration and photosynthesis reactions - break down of excess proteins into urea 3. Detoxifying poisonous substances breakdown old blood cells and lactic acid converting these into urea 4. lactic acid is transported there and down into carbon dioxide and water