Yr 10 Valid Test Flashcards
Difference between CNS and PNS
Function of nervous system
The central nervous system (CNS) includes the brain and spinal cord, while the peripheral nervous system includes all of the nerves that branch out from the brain and spinal cord and extend to other parts of the body, including muscles and organs.
The nervous system helps all the parts of the body to communicate with each other. It also reacts to changes both outside and inside the body. The nervous system uses both electrical and chemical means to send and receive messages.
How does the CNS operate?
receptors receive stimuli e.g., ears hear sounds, eyes see things, nose smells odours, skin feels heat and pain
• the stimuli are changed into electrical impulses and sent along sensory nerves to the brain
• the brain sends electrical stimuli along motor nerves to the muscles
• the muscles produce a response to the original stimulus e.g., the person runs from danger, blocks their ears from a loud sound, covers their eyes from a bright light
Describe a disease of the nervous system
It’s considered an autoimmune disease in which the body’s immune system attacks its own tissues. In the case of MS , this immune system malfunction destroys the fatty substance that coats and protects nerve fibers in the brain and spinal cord (myelin).As a result, nerve impulses cannot travel properly between the brain and the rest of the body. These symptoms include sensory loss eg. loss of vision, loss of feeling, and motor loss eg. loss of movement, weakness in muscles.
Purpose and process of endocrine system
The endocrine system controls activities in the body using hormones produced in glands. A stimulus is received by a receptor and then the hormones are carried by the blood to target organs where they are used to control growth, sexual development, body heat and levels of chemicals in the body such as glucose, water and salts.
Explanation behind flight or fight response
The fight response involves both the nervous system and the endocrine system. This response can be initiated by shock, anger, passion, anxiety or stress. The nervous system detects fright stimuli, which are transmitted to the brain. The brain stimulates the pituitary gland to release hormones into the bloodstream. In particular, the adrenal glands above the kidneys react and release the hormone adrenalin into the blood. As a result, the pupils dilate, the skin becomes pale, the sense organs become highly sensitive, the heart beats faster, glucose is released into the blood, blood pressure increases and the lungs work more effectively. The body is now ready for action, either for fight or for flight.
Purpose of immune system
The immune system protects the body against infectious diseases. When microorganisms such as bacteria and viruses invade the body, the immune system recognises them and produces antibodies that attack and destroy them
Neutralisation reaction
acid + base → salt + water
hydrochloric acid + sodium hydroxide → sodium chloride + water
Examples
Bee stings contain acid and so they are treated with bicarbonate of soda because it contains a base
that neutralises the acid.
Wasp stings contain a base so they are treated with vinegar because it contains an acid that
neutralises the base.
Acid and carbonate reaction
Acid and metal reaction
acid + carbonate → salt + water + carbon dioxide
Hydrochloric acid + sodium carbonate → sodium chloride + water + carbon dioxide
To test for carbon dioxide use Limewater (a solution of calcium hydroxide. So if we bubble carbon dioxide through the solution it reacts with calcium hydroxide solution to produce a white precipitate of calcium carbonate. We will observe that the limewater will turn milky or cloudy white).
acid + metal → salt + hydrogen
hydrochloric acid + magnesium → magnesium chloride + hydrogen
To test for hydrogen use pop test (bring a lit match to the mouth of the test tube containing the metal + acid, and if it makes a pop sound it contains hydrogen)
Corrosion reaction
Combination reaction
Decomposition reaction
Acid + metal oxide → salt + water
Sulfuric acid + copper oxide → copper sulfate +water
Combination= x + y → xy
Decomposition= xy → x + y
Define products and reactants
Products: A substance present at the end of a chemical reaction
Reactants: A substance that enters into and is altered in the course of a chemical reaction
Define corrosion and galvanising
A natural process in which a refined metal is converted to a more chemically stable form, such as oxide, hydroxide, or sulphide.
The process of applying zinc coating to a more noble metal to prevent corrosion
When is corrosion known as rusting
Rusting is the corrosion of iron
Define electric current
Define conductor
Define insulator
Define resistor
The rate of movement of electric charges in a circuit.
A conductor is a substance that electric current flows through eg. metals, carbon. Conductors are used in electrical wiring to carry electric current to electrical appliances.
An insulator is a substance that electric current does not flow through eg. non-metals. Insulators are used to enclose electrical wiring and some electrical appliances to protect people from electrocution.
A resistor is a substance that electric current can flow through with difficulty and some of its electrical energy is changed into heat and light. They are used in appliances that produce heat and light eg. light globe, toaster, room heater, stove element.
Define voltage
Define current
Define resistance
Voltage
Voltage is the difference in electrical potential between 2 points
As electric charges move through resistors they lose some of their electrical energy as it changes into heat and light. In an electric circuit, the voltage across a lamp or other resistor measures that amount of electrical energy that each electric charge loses as heat or light.
Voltage (V) is measured on a meter called a voltmeter in units called volts (V).
CURRENT
The number of electric charges that move in an electric circuit is called the current. When the current is large, eg 10A, more electric charges move around the electric circuit. When the current is small, eg 0.01A, fewer electric charges move around the electric circuit.
Current (I) is measured on a meter called an ammeter in units called amps (A).
RESISTANCE
Resistance is the limiting of electrical flow in a circuit. If the resistance is high, many of the electric charges have difficulty moving and lose some of their electrical energy as it changes to heat and light. If the resistance is low, the electric charges move easily and lose very little of their electrical energy.
Resistance (R) is measured in units called ohms (W).
Define Ohms Law
A law stating that electric current is proportional to voltage and inversely proportional to resistance.
V
I R
Evidence of evolution
Fossils show that the earliest life forms were simple organisms living in water and that since then organisms have become more complex and have moved onto land. Some fossils show links between groups of organisms. Archaeopteryx is a well known example of a transitional fossil. REPTILE features: long-tail, claws, solid bones, teeth
BIRD features: wish-bone, feathers, attaches for flight muscles on the sternum (breast bone).
The very young embryos of a number of vertebrates such as fish, salamander, turtle, chicken, pig, cow, rabbit and human look very similar and some scientists have concluded that the vertebrates have evolved from a common ancestor
Homologous structures indicate common ancestry, where different environmental pressures have led to different adaptations making them different species. For example, the pentadactyl limb is present in all groups of tetrapods and can be traced back to a pentadactyl ancestor that lived around 340 million years ago. In all tetrapods, the fundamental structures of the limbs are the same, implying a common ancestor, the differences brought upon by different environmental pressures.
Define receptor
Define sensory nerve
Define motor nerve
A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific effect in the cell.
a nerve cell that detects and responds to external signals
a neuron that passes from the central nervous system or a ganglion toward a muscle and conducts an impulse that causes movement.
Define gland
Define immune system
Define antibody
An organ which produces and releases substances that perform a specific function in the body
A complex network of cells, tissues, organs, and the substances they make that helps the body fight infections and other diseases.
A protein made by plasma cells (a type of white blood cell) in response to an antigen
Define indicator
Define acidic
Define base
Define alkaline
A chemical that changes color when exposed to certain conditions and is therefore useful for chemical tests.
A substance which contains hydrogen and dissolves in water to produce one or more hydrogen ions
A substance that has a pH greater than 7 and has hydroxide or carbonate as part of their name.
A base that is soluble in water.
Define ammonia
Define pH
Define neutralisation
colourless, pungent gas composed of nitrogen and hydrogen
a measure of how acidic/basic water is
when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water.
Define circuit
Define series circuit
Define parallel circuit
A closed pathway for electrons to flow through.
A series circuit comprises a path along which the whole current flows through each component.
A parallel circuit comprises branches so that the current divides and only part of it flows through any branch.
Define evolution
Define natural selection
Evolution is the permanent gradual change in the genetic composition of a population over long periods of time due to natural selection
The process by which individuals of a species that are better suited to their environment are more likely to survive and reproduce (while those not so well fitted to survive either die or fail to reproduce).
Explain Darwin’s theory of evolution
• Far more offspring are produced than survive and reproduce.
• These offspring have a range of characteristics.
• Offspring with particular characteristics are better adapted to their environment and so survive
while other offspring perish. This is called natural selection or survival of the fittest.
• The surviving organisms reproduce and pass on the favourable characteristics to their offspring.
Over time the population changes so that most organisms have the favourable characteristics.
Provide an example of evolution
Peppered moths are born either pale coloured or nearly black. In 1850, when scientists first began to study them, there were few factories and very little pollution. The countryside was fresh and clean and the pale coloured moths were well camouflaged when they rested on light coloured tree trunks. The black moths were easily seen and were quickly eaten by birds. The pale coloured moths were much better suited to their environment. They survived and reproduce and so were much more common than the black moths. In the years since 1850, more and more factories were built in northern England and the soot from the factory smokestacks gradually blackened the light coloured tree trunks. The change in the environment meant that the black moths were well camouflaged and birds ate the pale coloured moths instead. Scientists have determined that the body color in the peppered moth is controlled by a single gene. The allele (version of the gene) for dark body color is dominant, which means that a moth possessing at least one such allele will have a dark body. The black moths survived and reproduced and became much more common than the pale coloured moths. Strong anti-pollution laws over the past twenty years have reduced the amount of smoke coming from factories resulting in the tree trunks becoming lighter in colour. The pale coloured moths are once again well camouflaged and more black moths are being eaten by birds.
Define fossils
Factors determining whether a fossil is made or not
Fossils are the remains, impressions or traces of living things
QUICK BURIAL: The organism, its body parts (bones, shells) or its impression must be buried quickly so that it is not damaged by predators and so that it does not decay quickly.
SUITABLE BODY PARTS: Hard body parts such as shells, bones and teeth form fossils but soft parts do not.
UNDISTURBED ROCKS: Fossils form in sediments that are not disturbed by earth movements such as earthquakes and volcanoes. The sediments slowly harden into rocks and the fossils are kept intact.
What is the law of superposition?
The Law of Superposition states that in a series of rock layers the oldest rocks are at the bottom and the youngest rocks are at the top.
Importance of Geological Time scale
The Geological Time Scale shows when different types of plants and animals lived on earth. It divides the earth’s history into a number of periods. The first lifeforms were simple, aquatic organisms. Since then organisms have become larger and more complex and have moved onto land
Define crest Define trough Define wavelength Define amplitude Define frequency
top of a wave
bottom of a wave
distance between two crests or two troughs
distance between the crest and the rest position or the trough and the rest position
the number of waves that pass a fixed point in unit time
How to calculate wave speed
How are waves represented
Frequency X wavelength
Represented by a sine graph
Define electromagnetic waves
What are they made of
waves that are created as a result of vibrations between an electric field and a magnetic field.
Electromagnetic waves are composed of electric and magnetic fields and do not need particles to transfer energy, that is, they can travel through a vacuum.
Electromagnetic waves purposes
radio waves: transmit radio and TV signals, radar in air traffic control
microwaves: cooking, radar speed guns used by police
infrared waves: given off by hot objects, used to take temperature pictures and find people in collapsed buildings
visible: seeing,
light: photosynthesis, photography
UV rays: fluorescent lamps, sterilising
X rays: radiography, treating cancer, finding faults in metals, examining crystals
gamma rays: measure thickness of metals, sterilise medical equipment
Absorption and reflection of colours in light
White light is made up of colours. When light hits a coloured object, that colour is reflected and all other colours in the light are absorbed by the object
Relationship between wavelength and energy
The amount of energy is inversely proportional to the wavelength
What is the Law of Reflection
On reflection from a smooth surface, the angle of the reflected ray is equal to the angle of the incident ray
Define refraction Refraction instances Refraction in differing refractive indexes Define critical angle Define total internal reflection Define refractive index
The bending of a ray when it passes at an angle from one medium into another in which its speed is different
Situations involving refraction:
Any object in the water
Rainbows
Viewing something through glasses
If light enters a substance with a lower refractive index (compared to previous substance) it will speed up and bend away from normal
If light enters a substance with a higher refractive index (compared to previous substance) it will slow down and bend towards the normal
When the angle of refraction is 90 degrees
When light enters a medium at an angle greater than the critical angle, it is reflected, not refracted.
Measure of optical density
Difference between concave and convex
Concave: Faces inwards (think the caved in)
Convex: Faces outwards
Describe TIR in the process in optical fibres
Optical fibres are fibres made of glass through which light travels by a process called total internal reflection. As light travels through the glass fibres, it continually hits the sides which causes it to be reflected back into the glass rather than being refracted out. By repeated reflections, the light travels along the optical fibre
Define cosmology
When did it begin?
The study of distant galaxies and the Universe is called cosmology.
The invention of the telescope in the 16th century allowed galaxies to be viewed and studied a lot clearer than before, resulting in cosmology becoming another branch of science.
Define astronomy
When did it begin?
Astronomy on the other hand is the study of the planets and stars and their movements, which began when ancient man first looked up at the night sky.
Alternative explanation of universe creation.
Issue with explanation
Fred Hoyle (1949) hypothesized that the universe is never-ending and the same everywhere and for all time. The Universe, therefore, has no beginning and no end. As the universe expands new matter is created to keep the correct density at all times so that the universe does not change its look over time.
Is no longer accepted as a possibility, because it cannot explain the presence of background microwave radiation in space.
What is the Big Bang theory?
This theory states that all matter that existed came together in a core or one point, which exploded expanded outwards away from that core in a massive and violent explosion about 15 billion years ago. This ‘explosion’ resulted in dense and less dense areas being formed. The dense areas formed dense gas clouds leading to the formation of stars
Evidence of big bang theory
This was actually the first evidence found that suggested the Big Bang might have happened.
Edwin Hubble looked at lots of galaxies and discovered (using the Doppler effect / red shift) they were almost ALL moving away from the Milky Way (our galaxy)
The only explanation was that they all used to be together once.
If the universe was extremely hot at the beginning, there should still be some remnant of that heat today.
2 Scientists, Penzias and Wilson, found this Cosmic Microwave Background Radiation (CMBR) by accident in 1964.
The universe has had a lot of time to cool, and if the big bang was 13.8 billion years ago, it should have cooled to around 3 degrees Kelvin (around -270°C). Guess what temperature Penzias and Wilson measured?
Fates of the universe
Open Universe: the universe will keep expanding, becoming less and less active as the stars die, eventually dispersing in clouds of dust and gas.
Flat Universe: The universe’s expansion will slow down and eventually stop at a maximum limit.
Closed Universe: The universe’s expansion will slow, stop then start to contract and will collapse back on itself forming a dense mass, which will explode in a second Big Bang. This is affectionately termed the ‘Big Crunch’.
How are stars created?
Stars are formed when nebulae collapse. The particles in these clouds attract each other resulting in an increase in their gravitational pull, therefore pulling in more particles. The temperature of this mass increases until it becomes high enough for nuclear fusion to take place.
Relationship between mass and lifespan of a star
How is a red giant formed?
The mass of a star determines how long its life cycle will be. Larger stars will shine hotter and faster for much less than a smaller, cooler star. When a star’s fuel is used up, it starts to collapse. The core cools but the fusion process moves to the outer regions of the resulting in a colour change from white hot to red hot. The star is now a red giant, which is large but relatively cool.
Life cycle of a star
Average star: stellar nebula, average star, red giant, planetary nebula, white dwarf
Massive star: stellar nebula, massive star, red supergiant, supernova, neutron star or black hole
Link between colour and temperature of a star
The colour of a star is linked to its temperature. Blue stars are the hottest with temperatures about 20 5000C, white stars are about 95000C and red stars are the coolest with temperatures less than 30000C. Our sun is a yellow star with a surface temperature of about 55000C.
Layered structure of the earth
Crust, mantle, outer core, inner core
Name of four spheres
Atmosphere – The envelope of gases surrounding the earth or another planet.
Hydrosphere – The hydrosphere is the combined mass of water found on, under, and above the surface of a planet, minor planet, or natural satellite.
Lithosphere – the rigid outer part of the earth, consisting of the crust and upper mantle.
Biosphere – The worldwide sum of all ecosystems.
Explain the theory of continental drift
In 1915 Alfred Wegener proposed that all of the continents were once joined together into one vast land mass called Pangaea. About 250 million years ago, Pangaea broke into two parts. Laurasia consisted of North America, Europe and Asia. Gondwana (also called Gondwanaland), consisted of South America, Africa, Australia, Antarctica and India. About 200 million years ago, the continents gradually broke apart and separated. Since no explanation existed for its occurrence, it wasn’t widely accepted.
Evidence of continental drift
The shapes of the continents fit together like the pieces of a jigsaw.
Eroded mountain ranges, patterns of scouring by glaciers and deposits of iron ore all match up on
different continents
Similar limestone deposits are found in Australia, Antarctica and southern Africa.
Glossopteris fossils remains in similar rock layers all formed in Antarctica, Australia, South America, Africa and India which lived in wet swampy regions
Mesosaurus remains being found in South America and Africa even though freshwater lakes and ponds don’t exist in Africa
Scratches from glaciers found in central tropical Africa…
Fossils of palm trees found in frozen Alaska
Fossils younger than 150 million years are different on all continents.
Evidence of crust formation
The basalt rock underlying the ocean is youngest at the ridge and gets older the further it is away
from the ridge.
Mid-ocean sediments are thinnest at the ridge and are thicker further away from the ridge.
