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Science EOY Revision - Coggle Diagram
Science EOY Revision
Biology
Ecosystems
Glossary of Terms
Habitat
A place where plants and animals live
Environment
Everything that surrounds an organism, includingg the physical environment and biotic environment
Physical Environment (Abiotic)
Temperature
Lower temperatures slow down the rate of photosynthesis in plants and growth in organisms
Water
All organisms need water for respiration of transpiration
Air
All organisms require oxygen to respire
Plants require carbon dioxide to phyotosynthesise
Mineral Salts & Salinity
Mineral salts are used to produce essential substances e.g. proteins, vitamins, chlorophyll
pH
Most animals and plants require a specific pH to live
Light
Plants need light for photosynthesis
Living Environment (Biotic)
Relationships:
Predator-prey
One organisms kills the other for food
Parasitism
One organism benefits at the expense of another (
the parasite does harm but not kill
)
Mutualism
Both organisms in this relationship benefit
Population
Made up of organisms of the same kind that live in a particular habitat
Community
Made up of organisms of the same kind that live in a particular habitat
Ecosystem
Made up of the habitat together with the community of organisms living in it
Energy flow
Food chain
Shows the transfer of energy between organisms
e.g. Grass > Rabbit > Tiger
Shows the feeding relationship between organisms
Food web
Network of several interconnected food chains
Balance in a food web
If the population of one organism increases/decreases, the population of its predators will increase/decrease, population of prey decrease/increase
10% rule
Between two
trophic levels
, only
10%
of energy is transferred
Beyond the fourth/fifth trophic level, there is
not enough energy to sustain another trophic level
as only
10% of energy is transferred
between trophic levels
Digestive System
Biological molecules
Carbohydrates
General formula: CmH2nOn e.g. C12H22O11 -
ration of H to O molecules is 2:1
Single sugars: C6H12O6
Glucose
Reducing sugars (see Benedict's test)
Fructose
Galactose
Double sugars: C12H22O11
Maltose
Lactose
Sucrose
Non-reducing sugar
Formed by an anabolic reaction (condensation); Broken down by a catabolic reaction (hydrolysis)
Complex sugars: multiple glucose molecules joined together
Starch
Storage form of glucose
See Iodine Test
Glycogen
Cellulose
Structural form of glucose
Functions
Provide energy for cellular activities
Form supporting structures e.g. cellulose > cell wall in plant cells
Form nucleic acids (RNA, DNA etc.)
Fats
Proteins
Made of C, H, O, N (and S sometimes)
H R O –– H | | |
N –– C –– C === O
| |
H H
Nucleic Acids (not tested)
Reproductive System
Sexual vs Asexual Reproduction
Sexual reproduction requires
one or two parents
, produces
genetically dissimilar offspring
,
gametes must fuse
and
happens slower than asexual reproduction
Asexual reproduction requires just
one parent
, produces
genetically identical offspring
,
gametes do not fuse
and happens
faster than sexual reproduction
Glossary of terms:
Gametes: Sex cells (carry genetic information)
Male: Sperm; Female: Ovum
Gonads: Sex organs (produce sex cells)
Male: Testis; Female: Ovary
Sex hormones: stimulate an event to occur
Oestrogen
Repairs and thickens uterine lining
Progesterone
Maintains thickness of uterine lining during luteal phase
Lutenising hormone
Causes ovulation
Graafian follicle erupts and releases ovum
Follicle stimulating hormone
Stimulate follicles in ovaries to secrete oestrogen
Contraceptive methods: Birth control methods (prevent pregnancy)
Temporary
Behavioural
Abstinence
Avoiding sexual intercourse
100% chance of no STIs
Withdrawal
Remove penis from vagina before ejaculation
Does not protect against STIs
Rhythm
Avoiding unprotected sexual intercourse during fertile period
Low chance of no STIs
Barrier
Condom, Femidom
Prevents semen from entering vagina
Moderate chance of no STIs
Diaphragm
Cover cervix
Does not protect against STIs
Hormonal
Oral contraceptive pill
Prevents ovulation & sperm passage through cervix
Does not protect against STIs
Chemical
Spermicide
Inactivates or kills sperm
Low chance of no STIs
Copper IUD
Plastic frame with copper wires around; copper ions inactivate/kill sperm & devices inflames endometrium
Does not protect against STIs
Only method that prevents implantation of embryo
Intrauterine
Permanent
Surgical
Tubal Ligation
Cut-and-tie oviduct
Vasectomy
Cut-and-tie sperm duct
Sexually transmitted infections (STIs)
Syphilis
Caused by Treponema pallidum
Chancre appears where bacteria entered & lymph nodes swell near area of infection
Symptomless until late stage
Treatment with antibiotics effective in early stages
Can pass through placenta and infect foetus
Deformity of nose and teeth
AIDS
Caused by HIV (virus)
Infects, kills and hijacks white blood cells
Symptomless for up to 10 years
Symptoms:
Persistent fever
Severe prolonged diarrhoea
Kaposi's Sarcoma (Cancer in lymph vessels)
Pneumonia/Tuberculosis
Swelling of lymph nodes
Can pass through placenta
No cure (antivirals only slow down progression of AIDS)
Gonorrhoea
Caused by Neisseria gonorrhoeae
Pus discharge from gonads
Painful burning sensation during urination
Pain and swelling in testes and female abdomen
Treatment with antibiotics effective in early stages
If not treated promptly can cause sterility
Bacteria unable to pass through placenta
Pus discharge during childbirth can cause blindness for child
Spread when
Infected person's bodily fluids come in contact with mucosal membranes
Unprotected sexual intercourse occurs
Needles shared with infected person
Transmitted from mother to foetus
Blood transfused from infected person
Parts of the reproductive system:
Male
Testes
Produce sperm (and testosterone)
Epididymis
Store sperm and allow them to mature
Scrotum
Holds the testes and epididymis
Maintain a lower temperature for optimum sperm maturation
Prostate gland
Produce seminal fluid for sperm to swim in
Promote survival of sperm
Sperm duct
Transports sperm from testes to urethra by peristalsis during ejaculation
Urethra
Transports semen and urine out of body (but not simultaneously)
Penis
Erectile organ that deposits sperm in the vagina during sexual intercourse
Processes during sexual intercourse
Male's penis becomes erect
Erect penis is inserted into vagina (copulation)
Sperm is ejaculated into vagina
Sperm swim through the cervix, uterus and into the oviduct
1 more item...
Fertilisation
Cell Division
Implantation
Development
1 more item...
Female
Ovaries
Produce ovum, oestrogen and progesterone
Oviduct
Location of fertilisation; Transports immobile ovum to uterus
Through peristalsis and sweeping of cilia
Uterus
Foetus' site of development during gestation period
Cervix
Neck of uterus
Dilates during childbirth
Vagina
Sperm are deposited here during sexual intercourse
Vulva
Opening to vagina
Menstrual cycle
Follicular phase
Uterine lining breaks down & menstruation occurs
FSH stimulates secretion of Oestrogen
Uterine lining thickens
1 more item...
Luteal phase (Last 14 days)
High levels of Progesterone to maintain thickness of uterine lining for implantation
Fertile period: Day of ovulation (right before luteal phase) -3 & +2 days; Fertilisation period: Day of ovulation until +2 days; Implantation period: Day of ovulation +2 & +9 days
Physics
Heat
Effects of heat
Contraction
As an object is cooled, the particles
lose kinetic energy
,
vibrate about slower
and are less able to
overcome the forces of attraction
holding the particles together, thus moving closer together
Expansion
As an object is heated, the particles
gain kinetic energy
,
vibrate about faster
and are more able to
overcome the forces of attraction
holding the particles together, thus moving further apart
Bimetallic strips:
Different metals expand and contract at different rates, which means that one metal will expand/contract faster/slower than the other, causing the strip to bend
Transmission of heat
Net transfer occurs when there is a difference in temperature
Heat transmission/transfer involves the transfer of kinetic energy between particles
When there is no difference in temperature, a
thermal dynamic equilibrium
is reached - no net heat flow occurs, but heat is still transferred between the two objects, just at the same rate
Conduction
Definition: Transfer of thermal energy
through a medium without any flow of the medium
Occurs through physical interaction of particles: particles in constant random motion (Brownian motion) collide, transferring kinetic energy from one particle to another
Factors affecting rate of conduction:
Metals are generally better conductors of heat than non-metals
because they have
free-moving delocalised electrons
which can
move and collide quicker
than other particles (atoms, molecules, ions), allowing faster net heat transfer
Between the 3 main states of matter, thermal conductivity for
solids > liquids > gases
. In solids, the particles are
packed tightly together
, increasing the
rate/frequency of collisions
and therefore a higher transfer of kinetic energy
Convection
Definition: Transfer of thermal energy
through a fluid by the movement of the fluid itself
(fluid = liquid or gas)
Convection current
: the
movement of fluid
caused by a
difference in densities
of various parts of the fluid
Factors affecting rate of convection:
Surface area to which heat is transferred to or away from fluid
If heat is spread out across the bottom surface of the fluid, it allows more fluid to gain heat in the same period of time, more water to rise due to reduction in density, more water to sink in greater convection currents
Radiation
Definition: Transfer of thermal energy in the form of
electromagnetic waves
, such as but not limited to infrared radiation,
without the aid of a medium
Radiation
can
occur in a
vacuum
!
All matter above 0 K (absolute zero) emits thermal radiation in all directions)
All matter is capable of absorbing, emitting and reflecting thermal radiation at the same time, though at different rates
Factors affecting rate of radiation:
Colour of surface
Darker, dull surfaces
Better absorbers of thermal radiation
Better emitters of thermal radiation
Poorer reflectors of thermal radiation
Brighter, shiny surfaces
Poorer emitters of thermal radiation
Better reflectors of thermal radiation
Poorer absorbers of thermal radiation
Temperature of surface
Matter at a higher temperature than its surroundings will
emit thermal radiation
to its surroundings
at a higher rate than it absorbs
from its surroundings, resulting in a
net loss of heat
to its surroundings by radiation, causing the matter to start cooling down.
The
rate of emission of thermal radiation decreases
as the matter’s temperature gets closer to that of its surroundings,
towards thermal equilibrium
Surface area
The larger the surface area, the greater the rate of absorption and emission of thermal radiation
SI Unit: Kelvin (K); symbol: T
Forces, Pressure, Work, Energy and Power
Forces and Pressure
Forces
Effects of forces
Move a stationary object
Stop a moving object
Change speed/direction of object
SI Unit: N (newton)
1N of force accelerates a 1kg body by 1/mss
Types of forces
Contact forces
Friction
Air resistance
Normal force
Force acting against another force (e.g. placing a block on a table: Block exerts downward force and table exerts normal force)
Tension
Non-contact forces
Gravitational Force
GF (weight) = mass x g (9.81)
Electrostatic force of attraction/repulsion
Between two charged particles e.g. magnets
Magnetic force
Force exerted on a magnet or magnetic material by another magnet
Balanced and unbalanced forces
Balanced forces: Net force = 0 (e.g. placing a block on a table: gravitational force = 98.1N, normal force = 98.1N)
Object in motion remains in motion at same speed
Object at rest remains at rest
Unbalanced forces: Net force
≠
0 (pushing a ball: pushing force = 1.2N, friction = 0.8N, net force 0.4N in direction of push
Object at rest starts moving
Object in motion changes speed
Pressure
SI Unit: Pa (pascal)
P = F/a (Pressure = Force / Cross sectional area)
Factors affecting pressure
Greater SA, smaller pressure
Greater mass/force/gravitational field strength, greater pressure
Atmospheric and air pressure:
Suction cup
Suction cup pushes the air out while forming an impenetrable barrier, causing
pressure gradient force
to push against the suction cup into the wall and keep it stuck
Drinking from straws:
Sucking the air out > Remove air > Lower air pressure >
PGF
pushing water down and into straw > Drink
Work, Energy and Power
Work Done (W)
SI Unit: J (joule)
Force exerted on object x distance travelled or W = Fd
(1J = 1Nm)
Energy (E)
Ability to do work
Types of energy
Chemical Potential Energy (CPE)
Energy stored in fuels/food
Gravitational Potential Energy (GPE)
Energy stored due to height
GPE = mgh
(GPE = GF x h; GPE = 9.81mh)
Kinetic Energy (KE)
Energy due to motion
KE = mvv/2 (1/2 x m x v^2)
Elastic Potential Energy (EPE)
Energy stored in stretched elastic objects e.g. rubber band
Heat Energy
Products of energy conversion when friction occurs
Sound Energy
Light Energy
Renewable vs non-renewable sources
Renewable: Biofuels/biomass, Geothermal, Hydroelectric, Solar, Wind
Non-renewable: Nuclear, fossil fuels
Law of Conservation of Energy
Energy cannot be destroyed or created, and can only be converted from one form to another
As an object falls, GPE > KE (or when an object is moved upwards KE > GPE)
KE > HE (+SE + LE) due to friction during motion
Power (P)
SI Unit: W (watt)
Rate of work done:
1W = 1J/s
Electrical Systems
Chemistry
Chemical Changes
Compounds and reactions
Chemical equations
Balanced chemical equation for reaction of NaOH and HNO3:
NaOH + HNO3 -> NaNO3 + H2O
Types of chemical equations:
Synthesis
Decomposition
Oxidation of
metals
Combustion
Ionic
Compounds
Lose valence electrons (e-)
to attain electronic configuration of noble gases (e.g. Na in group 1 loses its 1 valence e-)
Forms
positively-charged
ions
(cations)
e.g. Na+ (+ superscripted)
Must memorise: Ag+, Cu+ or Cu2+, Zn2+, Fe2+ or Fe3+, Pb2+ or Pb4+
Written with Roman numerals e,g Pb(IV) whenever the cation has multiple possible charges
Hydrogen loses its only valence e- to form H+ (still called hydrogen)
Covalent substances
Gains valence electrons (e-)
to attain electronic configuration of noble gases (e.g. Cl in group 17 loses its 1 valence e-)
Form
negatively-charged
ions
(anions)
e.g. Cl+ (+ superscripted)
Hydrogen gains 1 valence e- to form H- (hydride)
4 polyatomic ions
: hydroxide OH, nitrate NO3, carbonate CO3, sulphate SO4 (OH, NO, SO, CO, OH NO 1-, SO CO 2-)
If no oxygen atoms end in -ide, if less oxygen atoms end in -ite, if more oxygen atoms end in -ate, if only oxygen then oxide
Acids and bases
3 Acids to
memorise
: hydrochloric acid
HCl
, nitric acid
HNO3
, sulfuric acid
H2SO4
. Can derive carbonic acid H2CO3 also.
Properties:
(shown ONLY upon DISSOCIATION in water)
Turn
moist blue
litmus paper
red
pH 1-6 incl. (universal indicator red, orange, yellow)
Produce H+ ions when dissolved in water e.g. HCl > H
Good conductor of elecricity
Reactions
:
Acid + metal = Salt + H2 (e.g. 2Na + 2HCl = 2NaCl + H2)
Copper, silver and gold do not react in this type of equation
Acid + Base = Salt + Water [Neutralisation] (NaOH + HCl = NaCl + H2O)
Acid + Carbonate = Salt + Water + CO2 (Na2CO3 + 2HCl = 2NaCl + 2H2O + 2CO2)
Bases:
All metal oxides and metal hydroxides, and aqueous ammonia NH3 (aq)
Alkalis: All
Group 1 metal oxides and metal hydroxides and aqueous ammonia
(Na2O, NaOH, NH3 aq) and
all alkalis are insoluble in water
while bases that are non-alkali are soluble in water
Properties:
Turn
moist red
litmus paper
blue
pH 8-14 incl. (universal indicator blue, violet, purple)
Not finished: Digestive and Electrical Systems