• EARTH AND SPACE PROGRAM

• CHEMISTRY PROGRAM

• PHYSICS PROGRAM

• BIOLOGY GENETICS PROGRAMS

• BIOLOGY EVOLUTION PROGRAM

• ASSESSMENTS

Space science

Structure of the Universe

Emu in the sky

Emu is running - April and May

Time to collect eggs

Emu sitting - June and July

Still time to collect eggs

Eggs start to hatch - August

No collecting of eggs

Emu drinking - November

Water holes are full

Uses of emu in the sky

• ceremonies

• time to hunt

The brothers of Kingfish clan where forbidden to eat any kingfish. The brothers caught kingfish after kingfish but had to throw them all back. Eventually one of the brothers became so hungry, he ate the kingfish. The sun women, Walu, saw him and in anger, created a water sprout that lifted the brothers up into the sky.

Cosmic background noise - CMB is the ‘noise’ (radiation) left over from the big bang and represents the temperature of space in the whole universe. The temperature is not the same everywhere, therefore density is not the same everywhere. Discovered May 20, 1964.

Cosmic microwave background - cosmic background microwave background is a form of electromagnetic radiation left over from the Big Bang. As the universe expands, the wavelength of the CMB radiation is stretched, causing it to shift towards longer wavelengths, or lower frequencies, this is known as redshift.

Cosmic background noise provides evidence for the big bang - the fact that we can see the microwaves expand means the waves started at a single point.

The Milky Way - the Milky Way is a galaxy that includes the Solar System. It is a huge collection of stars, dust and gas in a spiral system. Our sun is 25,000 light years away from the centre of the galaxy. We can see the stars and gas clouds of the Milky Way across the skies on Earth. We can also see other galaxies from Earth.

Universe mind map -

Galaxies - galaxies are a collection of gas, dust and billions of stars and their solar system.

Stars - a star is a luminous ball of gas held together by its own gravity. Stars are mostly made of hydrogen and helium.

Difference between a star, a planet, a moon and an asteroid - Stars have nuclear fusion, and they produce light. A moon has a body that orbits a planet, an asteroid orbits a star. A planet is a body that orbits the sun.

Role of gravity in the universe - gravity is the force which holes the universe together. It creates a path of objects around another body.

Unit of measurement in the universe - the unit of measurement used in space is light years. Light years is the distance light travels in one year. One light year equals 9.46 trillion kilometres. For example, if a star that was 20 light years away exploded right now, we will see the explosion 20 years from that time it exploded.

Life cycle of a star

Stars can appear in different colours such as orange, yellow, blue and white and they can vary in sizes. Our sun is small compared to many stars. It is still huge compared to the Earth and other planets.

Hertzprung Russell diagram -

The Hertzsprung-Russell diagram is a graph that plots the luminosity of stars against their surface temperature. It is used to classify stars and understand their evolution (cycle).

Hot, bright stars are located in the upper left corner, while cool, dim stars are located in the lower right corner.

The main sequence, where most stars spend the majority of their lives, runs diagonally from the upper left to the lower right.

The cycle:

Nebula - stars come from clouds of dust and gas called nebulae which are mainly of hydrogen. All star begin their life as part of a nebula.

Protostar - gravity causes the dust and gas in nebulae to become denser and more concentrated. The temperature increases until hydrogen and other light elements undergo nuclear fusion. This produces energy and the core get brighter and hotter until a protostar is born.

Main sequence star - nuclear fusion of hydrogen atoms is a now in full flow and a protostar becomes a main sequence star. This star is much hotter and brighter then before, releasing energy and a flow of radiation from its core. A main sequence star is in equilibrium: it is stable because the forces within it are balanced. Our sun is currently in its main sequence stage… but we are safe. These processes take billions of years.

Cycle of smaller (low mass) stars after the main sequence:

Red giant - helium and other light elements in the star’s core fuse to form heavier elements. This process releases even more energy, causing the star to expand. The star gives off a red light, hence the name “red giant”.

White dwarf - a red giant will eventually run out of its “fuel” of light elements. Nothing else in it will fuse. It will lose its outer layers leaving behind the core of the star. This is so dense and hot that it glows white.

Black dwarf - a white dwarf will eventually cool down enough that it stops glowing white. Stars like the sun then fade out, go cold and enter the stage of a black dwarf.

Cycle of bigger (high mass) stars after the main sequence:

Red super giant - following the main sequence, a star begins to fuse together heavier elements. As it has more fuel, it swells out to a much larger size, giving off a lot more energy.

Supernova - a red supergiant will start to collapse in on itself. This compresses its core more until it reaches a critical point. This causes a massive shockwave or a cataclysmic explosion called a supernova. A supernova event can outshine an entire galaxy for several weeks. The explosion only lasts seconds, in those seconds it can release as much energy as the star has released up to that point. It can be as bright as the light from 10 billion stars

THEN

Neutron star - after a supernova, only the star’s compressed core is left behind. The core has turned into lots of neutrons. The neutron star is extremely dense. A small amount of the neutron star would way more than the earth.

OR

Black hole - the core left from the supernova will continue to collapse and keep getting smaller until the entire star collapses into an infinitely small point. The gravitational field is now so strong, nothing can escape from it, not even light of any electromagnetic radiation.

Visual map of cycle:

More information:

Stellar nebula - stellar nebula are clouds that form new stars. Gravity causes the hydrogen to fuse into helium.

Stars turn into giants/supergiants as they get older - stars turn into giants/supergiants as they get older because helium and other elements in the star’s core fuse to form heavier elements. This process releases even more energy, causing the star to expand.

Larger stars are hotter but live shorter. - larger stars are shorter lived because

they burn more fuel, so they run out of hydrogen sooner than smaller stars do.

Likely progress of our sun through the cycle - it will expand and run out of energy, becoming a white dwarf, then a black dwarf.

Supernova - the size of the red giant depends if the star will go into a supernova or not.

Difference between a neutron star and a white dwarf - a white dwarf is hotter and it is remains of a red giant. A neutron star is full of neutrons and comes from a super red giant.

Black hole - a black hole is remnants of super red giants. When gravity is so string it collapses and becomes a black hole.

The big bang

The big bang - how astronomers explain the way the universe began at a hot, dense, single point, then expanded and stretched into the universe we know today. It is still expanding.

The Doppler effect -

The doppler effect is the change in the wavelength/frequency of a wave as it moves towards and away from an object.

As the wave moves towards you, the frequency increases, the wavelength decreases.

As the wave moves away from you the frequency decreases, the wavelength increases.

The doppler effect can be used to determine how fast stars move.

Red/blue shift -

Red stars are further away from blue stars. yellow stars are not as far away as red stars but not as close as blue stars.

Red and blue shift on the spectrum:

Electromagnetic spectrum - the range of all types of radiation that has both electric and magnetic fields and travels in waves.

Doppler effect - the apparent change in wave length or frequency when the source of waves or the observer is moving responsible for the red shift of distant stars.

Oxford extended understanding

Difference between galaxies and constellations - galaxies are the collection of stars and constellations are the collection of a few stars.

Indigenous people using the sky as a calendar - indigenous people used the sky as a calendar by marking out different shapes and referring to them as different animals. As the animal moves, it indicates to the indigenous people the time of year like a calendar.

Orion - Orion is a constellation. To find Orion, look for 3 big stars close together. They are Orion’s belt. 2 brighter stars North of it represent the shoulders and the 2 stars to the south are feet.

Different stories of Orion - there may be different stories about Orion from indigenous people across Australia because there are many indigenous people spread across Australia and they all have different perspectives of Orion which they might associate with different objects.

Individual stars - we can’t see individual stars because they are too distant to be seen individually.

Main sequence star - any star that has a hot core which fuses H into He to produce energy.

Parallax - change in an object’s position when viewed from 2 different points of view.

After a supernova - after a supernova happens, a neutron star remains. When the neutron star collapses, the gravitational pull and density is so great that it creates a black hole.

Objects that pass by a black hole - objects that bass by black holes will be sucked spirally into the black hole. If you get sucked in a black hole, the closer you get to the black hole, you will be pulled in and you won’t be able to escape. If you were to go into a black hole, you will be stretched while also being compressed. You will be ripped apart when you are stretched and look like “spaghetti”, this is known as spaghettification. The closer you get to the black hole, time gets slower (gravitational time dilation). The event horizon has infinite time dilation because any object that goes in doesn’t pass the horizon (doesn’t come out).

Accretion disc - flattened astronomical objects made of rapidly rotating gas which slowly spirals onto a central gravitating body.

Location of black holes - black holes can be located anywhere.

The sun’s progress in the cycle - when the sun reaches the end of the main sequence, it will expand into a red giant. Helium is dumped in the core. There is a shell of hydrogen around the helium-rich core. Fusion causes it to expand. Hydrogen cools and rises to create a rich outer envelope. Gravity is still pushing inwards.

Comparison of the life cycle of our sun with another star that has 10 times the mass of the sun - since our sun is smaller, it won’t have the ability to create a black hole like other bigger stars. Our sun will become a red giant after the main sequence, after it runs out of He, only its hot, white, and dense core is left, creating a white dwarf. After the white dwarf dies, it becomes a black dwarf. If it were a bigger star than our sun, after the main sequence it will become a super red giant. After the super red giant has run out of He, it will become a supernova. It can either become a neutron star or a black hole after. A neutron star and a black hole is both very dense.

Big bang led to the structure of the universe - The big bang is said to have been extremely hot at the beginning. It expanded extremely condensed material in a ball called a singularity. The singularity started expanding which became our universe. People believed the bid bang had radiation. In 1965 scientists discovered left over energy from the big bang. The energy existed as background radiation (CMB) which is evidence that the big bang happened.

Earth science

The four global spheres -

• lithosphere (solid earth)

• atmosphere (in the air)

• hydrosphere (water)

• biosphere (life)

Interactions and relations between the spheres -

• the biosphere gives material to the lithosphere to be decayed.

• the lithosphere gives a habitat to life in the biosphere.

• the atmosphere affects the lithosphere with things like wind to move dirt, sand etc to different locations over time which changes the topography of the land.

• the atmosphere causes combustion, respiration and photosynthesis in the biosphere.

• the hydrosphere can be a habitat for the biosphere.

• the hydrosphere and atmosphere can create rain.

The carbon cycle -

Greenhouse effect - the greenhouse effect is trapping some of the sun’s radiation naturally to keep the planet at a moderate temperature.

Enhanced greenhouse effect - the enhanced greenhouse effect is where the greenhouse gases in our atmosphere keeps too much of the sun’s heat and causes global warming. This extra gas is created by humans.

Long term carbon sinks - long term carbon sinks are carbon reservoirs that store carbon for a significantly longer than a human life span. Carbon will be slowly released back into the atmosphere/surface environment over many years. Examples of carbon sinks include: the ocean (hydrosphere), trees (biosphere), fossil fuels (lithosphere). These carbon sinks are being impacted by humans. Trees are being wiped out (deforestation) so less trees are able to store carbon. Fossil fuels are being used so we’re releasing more carbon in the air. These are negative impacts as we are filling the atmosphere with carbon which causes global warming because it keeps in more heat/solar radiation from the sun.

Chemistry

Atoms and the Periodic Table

An atom is a small unit of matter.

An element is a pure substance.

Subatomic particles:

The atomic number represents the number of protons in a nucleus.

The number of protons and neutrons control the atomic mass of an atom. It is also the weight of the nucleus.

The atomic number is a whole number and the atomic mass is a number with a decimal.

To calculate the number of neutrons in the atom: atomic mass - atomic number.

E.g Carbon, 12.011 (at. mass) - 6 (at. number) = 6

The atomic mass is not always a whole number because it is the average of its isotopes.

Electrons tell us about the chemical reactions, the atomic mass tell us how heavy the nucleus is.

Isotopes are the many forms of the same element, containing the same number of protons but different numbers of neutrons.

The atomic number is a whole number, not like the atomic mass because the number is the number of protons and they are countable.

Examples of the atomic number, atomic mass, # of neutrons, electrons and protons of an element.

Atomic structure and the Periodic Table

The periodic table as we know hasn’t looked like it does now. It has developed over time as we have learnt more about chemistry.

Some early periodic tables:

The Bohr model is the description of the structure of atoms. It consists of a small nucleus (no protons/neutrons, one nucleus as a whole), with electrons in orbits, placed on the electron shells.

On the periodic table there are periods and groups.

• periods - periods are rows on the the periodic table. The numbers for periods are on the left side of the table. Period numbers represent the number of electron shells.

• groups - groups are columns on the periodic table. The numbers for groups are at the top of the table. Group numbers represent the number of electrons on the valence shell.

• group 1 are alkali metals.

• group 2 are alkaline Earth metals.

• group 3 to group 12 are Transition metals.

• group 17 are halogens.

• group 18 are noble gases.

Electron configuration

Electron configuration refers to the arrangement of electrons - how many are in each shell.

Rules for determining electron configuration:

1. determine the period the element is in. This gives the number of occupied electron shells.

2. determine the group the element is in. This gives the number of valence electrons.

3. all shells, except the outer one, will have the, maximum number possible.

Examples:

The purpose for knowing the electron configuration of an element gives us information about the chemistry or chemical reactions it may be in.

Ions

The term ‘neutral atom’ means that an atom has the same amount of electrons and protons and therefore is neither positive or negative.

** Metals form anions.

Comparison of the number of protons in an atom to the number of electrons in an atom - the number of protons is the same as the number of electrons in an atom.

If an atom:

gains an electron - the charge becomes negative.

loses an electron - the charge becomes positive.

The difference between an atom and an ion is that an atom is neutral, whereas, an ion has either lost or gained one or more electrons so they are not neutral.

The atomic structure of all ions are the same because they will always have full valence shells.

If the atom has less electrons on the valence shell, it will lose electrons. If an atom has more electrons on the valence shell, it will gain more electrons. (Remember: the group they are in represents the number of electrons they have.)

Elements in group 18 do not form ions because their valence shells are full and do not need to lose or gain electrons.

Elements in group 2 all form an ion with a charge

Metals

The atomic structure of metals explains the formation of metal ions and the reactivity of metals.

Groups 1 and 2 form cations by losing 1 or 2 electrons.

Group 1 is more reactive than group 2 because it only has to lose 1 electron while group 2 has to lose 2 electrons.

Alkali metals are more reactive, particularly with water.

As you go down the groups, metals become more reactive. They have more electrons in the shells and may need to lose more or gain more electrons.

Four common properties of metals

3 important groups of metals:

A chemical reaction is when reactants are converted to substances.

Reactivity refers to how easily a substance reacts with other substances (the ability to go under chemical change/reaction).

(Reactivity) How easily they lose electrons when they come in contact with other substances determines the reactivity of a metal. The more electron shells, the more reactive it is.

Metallic bonding

Bonding between metal and metal.

Metallic bonding has a structure that features many ions in a "sea" of electrons. They are cations, arranged geometrically, surround by delocalised elections.

An alloy is a mixture of two or more metals. They may contain non-metals.

Non-metals

Non-metals on the periodic table:

Non-metals form anions except noble gases, hydrogen and calcium.

The reactivity of non-metals decrease as the groups descend because the valence shells are closer to the nucleus which is positive. (A stronger attraction to electrons that are closer to the nucleus, therefore increasing reactivity).

Metalloids have properties of metals and non-metals.

The two important groups of non-metals:

Noble gases are described as ‘inert’ (unreactive), this is because their valence shells are full.

‘Semi-conductors’ only conduct electricity under certain conditions.

Metalloids:

Similarities of metalloids, metals, and non-metals:

Covalent bonding

Bonds between two non-metals.

Low melting points

covalent bonds within molecules are strong BUT there are very weak forces between molecules that don’t require much energy to break or separate them

Two non-metal atoms each share one or more of the unpaired electrons with each other to create covalent bonds that contain two electrons (one from each atom) so that all atoms have full valence shells.

Example:

Covalent molecule (ammonia (NH3)) example:

Ionic bonding

Bonds between non-metals and metals.

Properties of ionic compounds:

• non-conductive as a solid.

• conductive as a liquid because the anions and cations become free to move.

• hard and brittle.

Properties of ionic substances

Ionic compounds swap and drop method:

Only bracket polyatomic ions if you swap to make 2 or more

Polyatomic atoms (molecules of multiple atoms)

Ionic substances typically have much higher melting and boiling points than covalent substances because ionic bonds (electrostatic bonds) take a lot of energy to break.

Examples of ionic compounds

Balanced chemical reactions

Remember: the number of atoms of an element on one side of the equation MUST equal the number of atoms of that element on the other side of the equation.

You CANNOT change any subscript numbers. Changing the subscript number changes the formula of the compound.

You CAN change any large numbers at the start of a compound formula.

Advice for balancing equations:

• draw a table to count up the number of each type of atom/ion on each side of the equation.

• start with elements that only appear in ONE compound on either side.

• balance one element at a time.  Once one is balanced, move on the next. You may need to revisit earlier elements multiple times.

Synthesis and decomposition

Synthesis reactions - the building up of compounds by combining simple substances, normally elements: A+B=AB

Example: Calcium (2Ca) + Oxygen (O2) → Calcium oxide (2CaO)

Decomposition reactions are the breakdown of compounds into simpler substances, either elements or more simple compounds. These reactions often require energy in the form of electricity or heat. Electrolytic decomposition is the breakdown of a compound as a result of an electric current passing through a solution. In decomposition reactions, only a single substance can be represented on the left side of the arrow.

States of matter:

• solid - (s)

• liquid - (l)

• gas - (g)

• aqueous - (aq)

Acids and bases

An acid is a substance that releases hydrogen ions (+) and forms salts by combining with certain metals.

An acid is a substance that releases hydroxide ions (-) and can neutralise acids.

Dissociation: to break up into ions.

Example of dissociation: H2SO4 -in water→ 2H + SO4-2

The strength of an acid/base refers to a measure of how easily an acid/base will dissociate (break up into ions). It is measured as pH 1-14; a pH of 1 is a strong acid and a pH of 14 is a strong base. (How many particles of THAT substance)

Concentration is how much acid/base is in the solution. (How many particles)

Examples

Dissociation tells the difference between a strong acid and a weak acid. If an acid dissociates 100% into ions, it is a strong acid. If the acid does not dissociate 100%, it is a weak acid.

pH is a measure of concentration of H+ ions in a solution, lower pH means a high concentration of H+. In what case might a strong acid have a higher pH (less H+) than a weak acid? A highly dilute strong acid can have a higher pH than a weak acid of sufficient concentration. (Diluting it lowers the pH)

Acid reactions

Acid base reactions are called neutralisation reactions because when they are mixed, they neutralise each other, becoming neither acidic or basic.

You must react an acid with carbonate to produce carbon dioxide gas.

Rates of chemical reactions

For a chemical reaction to occur, particles must collide.

Not all collisions between reactant molecules/ions result in a chemical reaction because for a reaction to occur, the particles must be in the right orientation, have the right amount of energy and actually collide.

Collision theory - this theory describes how and why substances react with each other. Collision theory provides three requirements for chemical reactions to occur;

• correct orientation

• reactants must collide

• sufficient energy to overcome the activation energy required

Rate of reaction - refers to the change in mass of the reactants and products in a given amount of time (usually seconds.

Increasing the rate of reaction can be done with 5 things:

• surface area - increasing the surface area by breaking the reactants into smaller pieces exposes the reactants to more collisions.

• temperature - increasing the temperature increases the kinetic energy so that particles will collide more often and increasing the rate of reaction.

• concentration - increasing concentration (amount of particles) the particles are more likely to collide. Using more concentrated acid will increase the chemical reaction with a carbonate, producing more CO2.

• stirring - stirring keeps reactants moving and they are more likely to collide.

• catalyst - a catalyst is a chemical that increases the rate of reaction but does not get used in the chemical reaction. A catalyst reduces the activation energy needed to start the chemical reaction.

Evolution

Natural selection

Natural selection:

• natural selection is when organisms best suited to their environment survive and reproduce more offspring than those are not suited. Variation, selection, inheritance, time.

Fitness:

• fitness refers to how many offspring an organism produces. An organism with greater fitness produces more off spring.

Survival of the fitness:

• continued existence of a type of organism because that type continues to reproduce.

Process of natural selection:

1. variation:

2. selection:

3. inheritance:

4. time:

Examples of natural selection

Examples:

1. Cacti are a group of plants that typically live in very hot and dry locations. Their spines are actually highly modified leaves (thicker and curled up) and are shaped that way to help prevent loss of water by transpiration.

   • variation: cacti with different six leaves from large to very thin/spine like.

   • selection pressure: temperature and the amount of water.

   • time: over time the population changes to be higher frequency in the alleles for small leaves and low frequency for large leaves.

2. whales evolved from earlier land-dwelling mammals that started spending more time back in the ocean and now have limbs (tail and fins) that are suited to efficient movement through the water.

   • variation: some of the land-dwelling whales with fin like limbs (probably a mutation).

   • selection pressure: water environment (select some to survive).

   • inheritance: the ones with finds survived and reproduced so over time the whale population had fins.

   • time: over time the population changes to be a higher frequency in the alleles for fins and low frequency for limbs.

Speciation

• new species are formed by speciation.​

• speciation: formation of a new and distinct species in the course of evolution.​

• the continents that are now separated were once joined together known as Pangea.​

• isolation is the first step in the formation of new species.​

• a place like Australia has a barrier of se meaning each gene pool was now exposed to different conditions like climate, food and competition.​

• those best adapted survived through process of natural selection.​

• gene pool changed and organisms became more and more different from those left behind.​

• those differences became so great that isolated populations are unable to interbreed and a new species is formed.​

• if environment changes due to human or natural influence they may become extinct like the Tasmanian tiger.​

• the variety of animals we have in our world is due to speciation.​
  

Isolation:

• environmental barriers

• geographical

• reproduction times

Human biology

DNA

DNA:

• carries the code for protein and characteristics.

• deoxyribonucleic acid.

• is made of nucleotides

  → nucleotides are composed of a sugar molecule, phosphate, and nitrogenous base.

  

• double helix or twisted-ladder-shaped.

Nitrogenous bases:

• adenine.

• thymine.

• cytosine.

• guanine.

Gene:

• a short section of your DNA. Carry instructions for cells to make proteins.

Chromosomes:

• condensed, coiled DNA into thread-like structures. DNA coils around histones.

• our chromosomes come from our parents.

• there are 23 pairs of chromosomes in each human cell.

• the first 22 pairs of chromosomes are called autosomes.

• the twenty-third pair is called the sex chromosome. Females have (XX), males have (XY).

• human sex cells are called gametes. There are 23 chromosomes in each gamete. It is this number because at fertilisation, the zygote only has 46.

• 23 chromosomes are called haploids.

Protein:

• the order and the number of bases in the gene determines the size and shape of the protein.

• the size and shape of the protein determines its function.

• PROTEINS → CELLS → TISSUES → ORGANS

DNA replication:

1. An enzyme breaks the H bonds between the base pairs

2. the DNA is now exposed as 2 single strands

3. Another enzyme attaches new nucleotides to the 2 exposed strands

4. Each single strand now becomes a double strand and the DNA has been replicated/doubled

Karyotypes

A karyotype is a photo of a cell set of chromosomes that have been ordered inter their parts.

They are used to check if a person’s chromosomes are correct.

• there are 23 pairs of chromosomes in each human cell.

• the first 22 pairs of chromosomes are called autosomes.

• to check that each chromosome is complete, check that there are no added/missing parts.

Protein

Transcription

• RNA polymerase will connect complimentary bases to the DNA in the nucleus.

• the bases bond together and for a single stranded mRNA.

• mRNA goes out the nucleus and attaches to a ribosome.

Translation

• in the cytoplasm, there are tRNA molecules (they carry amino acids on them).

• the mRNA directs the tRNA which amino acids to bring.

• the tRNA looks for its complimentary base and transfers their amino acid.

• when tRNA is bringing in the amino acids it reads the bases in threes (codons).

• the amino acids start building up and eventually a STOP codon is read and the chain stops.

• once the chain stops, the protein is finished.

DNA/RNA

• DNA has a double helix structure.

• DNA replicates itself.

• DNA has deoxyribose sugar.

• DNA have the bases: adenine, thymine, cytosine, guanine.

• RNA is single stranded.

• RNA cannot replicate itself.

• RNA has ribose sugar.

• RNA have the bases: adenine, uracil, cytosine, guanine.

Mitosis

Mitosis is the division of the genetic material into two new identical daughter cells.

The cell cycle:

Cells in our body are consistently dividing to make new cells.

Cells communicate with each other using chemicals which signals when the cells should start and stop dividing.

Sometimes when the cell has abnormalities, they don’t know when to stop dividing.

As the cells grow and divide, they form an abnormal growth called a tumour.

G1 - new cells grow to full size.

S - the genetic material doubles or replicates.

G2 - the cell getting ready to divide.

Cell division:

1. mitosis: the division of the nucleus.

2. cytokinesis: division of the cytoplasm.

Mitosis process:

1. interphase

• DNA in the cell is copied in preparation for cell division.

2. prophase

• chromosomes condense into X shaped structures, composed of two sister chromatids containing identical genetic information.

• chromosomes move to the equator in a line.

1. metaphase

• chromosomes completely lined up at the equator, end-to-end.

• the centrioles are now at opposite poles of the cell.

• mitotic spindle fibres extending from the poles attaching to sister chromatids.

4. anaphase

• the sister chromatids are pulled apart by mitotic spindles.

• each chromatid at each pole.

5. telophase + cytokinesis

• at each end of the poles, chromosomes are gathered together.

• membrane forms around each set of chromosomes, creating two new nuclei.

• the middle pinches, divides the cell into two daughter cells.

• (cytokinesis) completion of cell division.

Meiosis

Meiosis is the process in formation of gametes.

It is 2x the process of mitosis, creates four daughter cells, not genetically identical.

1. interphase I

• DNA in the cell is copied, making two sets of chromosomes.

• each chromosome is duplicated, forming 2 identical chromatids held at the centromere.

2. prophase I

• chromosomes condense into X shaped structures.

• they pair up.

• membrane around nucleus dissolves, releasing chromosomes.

[DELETED SECTION]

• metaphase I

• chromosome pairs line up at the equator.

• genetic crossover occurs.

• the centrioles are now at opposite poles of the cell.

• meiotic spindle fibres extending from the poles attaching to sister chromatids.

4. anaphase I

• cells divide to form gametes.

• homologous chromosomes (from each parents), pulled to opposite ends by spindles.

5. telophase I

• nuclear membrane develops around each set of of homologous chromosomes.

• forms two haploid daughter cells with half as many chromosomes in the original cell.

6. cytokinesis I

• cell divides into two daughter cells.

• each cell has half as many chromosomes as parent cell.

SECOND ROUND

1. prophase II

• membrane in each daughter cell dissolves away, releasing chromosomes.

• meiotic spindle fibres form again.

2. metaphase II

• chromosomes line up at equator and split.

• no genetic crossover or pairs.

3. anaphase II

• sister chromatids are divided and pulled to each pole.

• four haploid daughter cells are created, each with different genetic makeup.

4. telophase II

• separated sister chromatids reach opposite ends of the poles.

• nuclear membrane develops around each set.

• each daughter cell has one set of chromosomes.

4. cytokinesis II

• the two daughter cells created during telophase II physically divide into four haploid cells.

• each cell is distinct.

Important terms:

• haploid - a cell with a single set of unpaired chromosomes.

• diploid - a cell with two complete sets of chromosomes (homologous).

• somatic cell - any cell of a living organism (not gametes).

• sex cell - organism’s reproductive cells.

Apoptosis

Apoptosis is the process of programmed cell death.

It is used to eliminate unwanted cells.

Relation to cancer

• apoptosis is when cells are programmed to die at a certain time.

• in cancer, apoptotic control is lost, meaning cancer cells are able to survive longer.

Alleles

Alleles are variations/alternatives of a gene.

Alleles, genes, and chromosomes:

• an allele is a variant form of a gene.

• a gene is contained in a chromosome.

Autosomes and sex cells

• autosomes are the first 22 chromosomes.

• gametes are the 23rd pair.

• in an autosomal pedigree, both parents can be carriers.

• in a x-linked pedigree, only the mother can be a carrier.

Incomplete and co-dominance

Incomplete dominance:

• one allele is not dominant over another.

• for an allele to be expressed, both has to be homozygous.

• for example - in snapdragon flowers, RR is red, rr is white, Rr, is pink.

Co-dominance:

• both colours are dominant.

• for example - in chickens, BB is black, WW is white, BW is black/white speckled.

Phenotype/Genotype

• A phenotype is the physical appearance.

• A genotype is the written symbol of that allele.

Haemophilia and red-green colour blindness

Haemophilia

• A father who has haemophilia passes his only X chromosome down to all of his daughters, so they will always get his haemophilia allele and be heterozygous (carriers).

• A father passes down his Y chromosome to his sons; thus, he cannot pass down a haemophilia allele to them.

Physics

Distance/Displacement

Distance - how far an object travels in a set time.

Displacement - the final distance and direction from the starting point of an object.

Quantities:

• Scalar - measures magnitude in numbers and units, e.g. 9km, 60kg, 50 mins.

• Vector - measures magnitude with numbers, units AND direction, e.g. 9km North, 600 Newtons down.

Example questions:

1. an object moves 14 m North and the 14 m south. What distance has it covered? What is its displacement?

• distance is 28m.

• displaced 0m.

2. a person runs 50 m north, the 20 m south and the 30 m west. What is the total distance covered? What is the person's displacement? 

• distance is 100m.

• displacement is 42.42m North.

• Explanation:

Speed/Velocity

Speed (scalar) - distance travelled per unit of time. m/s or ms^-1.

Velocity (vector) - distance travelled per unit of time with direction. m/s or ms^-1 with direction.

Formulae:

• distance = speed*time

• speed = distance/time

• time = distance/speed

Example questions:

1. If a car travels 400 m in 20 seconds, how fast is it going? 

• Speed = 400/20 = 20 m/s.  

2. How much time will it take for a bug to travel 5 metres across the floor if it is travelling at 0.5 m/s? 

• Time = 5/0.5 = 10s.  

3. How far can you get away from your little brother with the squirt gun filled with paint if you travel at 3 m/s and you have 15 seconds before he sees you?

• Distance = 3*15 = 45m 

Acceleration

If you drop a bowling ball and a feather from the same height, which will hit the ground first?

• the bowling ball will hit the ground first because the feather has more air resistance.

What if it was on the moon?

• both would land at the same time because the moon does not have air.

Formulae:

(a - acceleration, v - final velocity, u - initial speed)

Example questions:

Graphing motion

Example:  

Bruce starts walking from his home eastwards towards school.

It takes him two minutes (120 seconds) to cover 180 m.

He then gets a call to meet his friend at the shops, so after a 5 second pause, he turns around and walks 400 m in the opposite direction, which takes him 200 seconds.

They are both in the shop for 1 minute (60 seconds) before leaving again. 

Newton’s first law

An object remains at rest or in constant motion in a straight line unless acted on by a net unbalanced force.

What is inertia?

• inertia is the need for an object to keep on doing what it was already doing.

The larger the mass of an object, the greater it’s inertia

Force on an object:

Newton’s second law

Newton’s second law states that acceleration is directly proportional to force and indirectly related to mass.

Formulae:

• force = mass*acceleration.

• mass = force/acceleration.

• acceleration = force/mass.

What’s the difference between mass and weight?

• mass is the amount of matter measured in kilograms.

• weight is the force of gravity. Mass*gravity.

Newton’s third law

Whenever two object interact, they exert equal and opposite forces on each other.

Examples:

Weight and mass

Mass - measure of how much matter there is in an object (Kg).

Weight - force oh how much gravity pulling on an object (N).

Formulae:

• w = m*g

• m = w/g

• g = w/m

  
  

Examples:

Work and energy

Energy - the ability to do work (J)/(kJ).

Main types of energy:

• kinetic - energy associated with movement.

• potential - energy associated with position (stored energy).

Law of conservation of energy:

• energy cannot be created nor destroyed.

• the total energy of a system remains constant.

Example:

Consider two identical, large boxes placed on the floor. Both of them are heavy and are difficult for you to move. 

You are challenged to EITHER move both boxes 1 m each, OR to move just one box 10 m. 

Work - measure of the amount of energy transferred into moving or rearranging an object.

The relationship between force and work - they are directly proportionate to one another, and as distance increases, work also increases.

The relationship between distance and work - they are directly proportionate to one another, and as distance increases, work also increases.

Examples:

Gravitational potential energy

Formulae:

G = 9.8

• M = GPE/(g*h)

• GPE = m*g*h

• H = GPE/(m*g)

• G = GPE/(m*h)

Examples:

Consider a person at the gym lifting weights from the floor.  

Kinetic energy

Power stations: thermal energy

Steps involved in the generation of electricity in a power station:

1. burn coal/gas to release heat.

2. heat turns water in boiler into steam.

3. steam turns turbine to generate electricity.

4. steam condensed back into water, and fed back into boiler

Temperature:

• a measure of the average kinetic of the particles in a substance.

Heat:

• heat is an energy type that transfers from an object of higher temperature to an object of lower temperature.

Which has more energy, an ice-burg or a cup of coffee?

• ice-burg has higher energy because it has more particles.

Which has a higher temperature?

• the cup of coffee has a higher temperature because the particles are moving faster.

Specific heat capacity:

Consider two saucepans of water sitting on a stove. One is large and contains 5 L of water, the other small and contains only 1 L. The stove applies heat to the saucepans at the same rate. 

Formula:

• Q = mcΔT 

Units used:

• J/kg^oC 

Example: