2013 HSC COURSE

Disease is any condition that adversely affects the function of any part of a living thing.

Health is the wellbeing of the organism.   

The definition of disease above is very broad.  

Disease can cover a wide range of conditions that fit the above definition including minor conditions as well as the more obvious diseases.  

Health varies on a daily basis and is not just the absence of disease.  

Health varies with age and the susceptibility to disease. It is a state of physical, mental and social wellbeing.

  it is possible for a person to be healthy and have a disease at the same time

  the terms are used in general conversation and have different meaning to the scientific definition.

Genes are the units of inheritance. They control the process of protein synthesis. They assist the maintenance of health by regulating the cell cycle and limiting the growth and reproduction of cells.

Genes provide the code for proteins that are needed for growth and repair.

Enzymes, which control all body processes, are proteins and thus have been produced from the codes of genes.  

Mitosis is cell division that produces identical cells. These cells are important for growth and reproduction. Each day millions of cells die and are replaced by the process of mitosis.  

Cell differentiation is the process undergone by the cells that are formed after mitosis. Each cell has the genetic information necessary to produce all types of cells. However, each cell normally differentiates to become a specialised cell, with a specialised structure and function.

Many types of cells have specialised roles in maintaining the health of an organism. For example, there are specialised blood cells that produce antibodies to attack a disease causing micro-organism.

Gene expression refers to the transfer of information from a gene to produce a protein or RNA.

e.g If you cut yourself, the genetic code contained in all your cells is used to form the new tissue to repair the damage from the cut.

Gene expression results in the maintaince and repair of body tissue

There are huge numbers of disease causing organisms.

Most of them are microscopic and can enter the body through any body opening.

The intake of food and water provide an easy way for micro-organisms to enter our bodies.

Therefore, minimising the number of such organisms in our food and water reduces the risk of infection.

Good personal hygiene ensures that body openings, including broken skin, are clean, so that the number of micro-organisms that might gain entry to our bodies is kept low.

Since we cannot see individual micro-organisms we take precautions that we know will help to protect us.

Examples of precautions include, washing hands after going to the toilet, cleaning wounds, boiling water and water treatment of water that doesn't come from a known safe source to make sure untreated sewage does not get into food or water supplies.

biochemistry process in which the DNA of 2 species is compaired. 

Heat is used to break the hydrogen bonds between strands of DNA 

2 seperated strands of seperate animals are allowed to cool togethor, reforming hydrogen bonds between complementary base pairs 

The greater the amount of bonding the more closely related genetically the two animals are 

This is tested by the amount of heat required to break apart the combined strand.

Composed of the pulmonary and systemic system 

Pulmonary system goes from the heart to the lungs and back

Systemic system goes from the heart to the rest of the body and back 

passive transport doesnt require energy. It is the movement of molecules across a concentration gradient 

All water reabsorption in the kidneys by osmosis is passive 

Occurs at prophase 1 

genetic material is swapped between homologous chromosomes resulting in each chromatid being of different genetic make up 

evolution in which species become less and less similar as a result of experiencing different selective pressures 

e.g. Australian marsupials Koalas are herbivores, Womban burrowing herbivores, tassie devil carnivores evolved from a possum like ancestor 

Occurs at metaphase 1 

Chromosomes line up at the equator with homologous chromosomes side by side. 

However the order of the homologous chromosomes is random 

Therefore the genetic makeup of the gametes is random as well 

1. take a thin sample 

2. place on slide 

3. add 2-3 drops of water using a pipette 

4. lower cover slip at a 45 degree angle slowly 

5. use tissue to wipe off excess water 

non invasive method of measuring Hb saturation 

a probe is connected to ear or finger 

2 light waves with different wave lengths are sent. The light is partly absorbed by the Hb depending on the saturation of Hb. 

Through the comparison of the amount of light that make it through from each the Hb saturation may be calculated 

Can be used in recovery, response to medicine, asthma checking, sedation 

1. mendel was not a recognised scientist

2. presented work at a local insignificant science meeting 

3. other scientists did not understand his work or its significance 

4. no knowledge at the time about DNA or chromosomes 

5. idea of dominant and recessive genes went against accepted idea of the blending of characteristics 

1. Gravitational Potential Energy of an object in a gravitational field is the work done in moving an object from an infinite distance to that point
2. Work = Fd = mgd = mgh 

1. Aim: to calculate the acceration due to gravity using a pendulum
2. Hypothesis: The calculation will be a ≈ 9.8ms^-2
3. Risk: the weighted retort stand may be top heavy, causing it to fall off the desk and cause significant damage to those nearby. Therefore weight the retort stand down using a battery pack.
4. Materials: 1x retort stand, 1x protractor, 1x battery pack, 1x metal ball, 1x length of string, 1x scissors, 1x ruler, 1x mass balance, 1x stopwatch
5. Method: 1. measure the mass of the metal ball, m. 2. set up the simple pendulum with string length 1.2m. 3. measure an angle of 20° then release, timing t for 5 swings 4. repeat step 2 and 3 two more times keeping the angle and mass constant. 5. calculate average time and then period, T (time for one swing). 6. repeat steps 2-5 for Length, L, of range 0.2 to 1.2m 7. Graph T² against L and use the gradient o determine the acceleration due to gravity.
6. Graph of T² against L will result in a straight diagonal line. comment: accurate as T² is directly proportional to L (from equation T² = (4π²L)/g) 
7. Results: Using values of T² and equation  T² = (4π²L)/g) calculate a value for g.
8. Discussion: repetitions ensured reliability however a number of errors including the string's mass and air resistance not being taken into account. timing errors from reaction time and measurement errors associated with measuring the 20° angle.
9. Conclusion: Length was the variable effecting T. Equation varified at T recorded ≈ T estimated from equation. Acceleration measured to be 9.78 ms^-2

G = 6.67 x 10^-7 N(m/kg)²

1. Force (F) = Mass (m) x Gravity (a)
2. vector quantity
3. measured in Newtons (N)

1. GPE of an object at a point in a gravitational field = work done in moving the object from a infinite distance to that point. 
2. _{Ep = -(Gm1m2)/r}
3. Ep is highest at infinity when the object escapes the gravitational field (0J) and lowest at the surface of the object providing the field (negative)
4. When an object is lifted against a gravitational field work is done and Ep increases
5. As an object moves towards the source of the field Ep ⇒ Ek 

1. When object is no longer in a gravitational field

1. at infinity (0J)

1. At the surface of the object providing the gravitational field

1. parabolic path due to gravity
2. path seperated into horizontal and vertical componants 
3. ∆x spans equal distances over equal time periods. Therefore Ux = Vx and ∆x = Uxt
4. ∆y spans differing distances over equal time periods due to the effect of gravity. Therefore   Vy² = Uy² + 2a∆y and ∆y = Uyt + 1/2 at²
5. Ux = Ucosα Uy = Usinα also works for R and V

1. Galileo predicted all objects regardless of mass fell at the same rate. i.e. a is constant for all objects (ignoring air resistance)

1. Aim: to predict the range of a projectile given initial height and Vx. 2. Risk: balls on the ground pose a significant safety hazard as people may slip on them and injure themselves. Therefore pick up any balls on the ground immeadiatly. 3. Materials: 1x wooden ramp 1x retord stand 1x boss head and clamp 1x table 1x metal ball 1x cup 1x stopwatch 4 Method: 1.set up apparatus 2. measure sH, the distance from the edge of the ramp to the edge of the table. 2. release the ball from a marked position on the ramp 4. measure the time take for the ball to cover the distance sH 5. repeat 5x and calculate average time take. 6. calculate the Vavg over sH. Vavg = V at edge of the table = Vx 7. measure ∆y and calculate the theoretical time for the ball to reach the floor from the edge of the table. (∆y = Uyt +1/2 at^2 and Uy = 0) 8. using the value for Ux and t predict ∆x (∆x = Uxt) 9. move the ramp foward by a distance sH/2 place cup at predicted ∆x and test theory (sH/2 compensates for decelleration across the desk) 5. results: the ball landed very close to the predicted ∆x (approximately 1/2cm out) 6. discussion: the repetition of results ensured reliablility. measurements were accurate to a 1/2 mm. Experimental error, as the ball came off the ramp it bounced. 7. Conclusion: The range of the projectile motion of the metal ball was estimated accurately using initial hight and Vx. The slight offshot occured as a result of a flaw in the design of the experiment.

1.Vescape is the initial velocity required by an object to rise vertically and just escape the gravitational field of an object i.e. travel to infinity. 2.This is assuming there is no friction with the atmosphere 3. Ek --> Ep 4. Vesc = root(2Gmp/rp) 5. This hypothetical, in rocket launches etc... the heat produced and g forces would be to great.

newton's concept of escape velocity is a thought experiment in which newton invisaged firing a cannon ball horizontally from a very powerful cannon on top of a very high mountain. At lower velocities the trajectories would be parabolic under the influence of gravity. As the velocity at which the cannon ball was fired increased so to would the range of the cannonball. When the velocity was such that (mv^2)/r = (Gm1m2)/r i.e v = root(Gm/r) the cannonball would orbit the earth - as it fell towards the earth under the influence of gravity the earth would curve away from it

1. used to express apparent weight as a proportion of true weight 2. G-force = R/W where R = reaction force (external force acting/apparent weight) and W = true weight (mg on earth) 3. G-force = (+ - a+g)/g