Notes

Variation is due to...


Why do twins look alike but do not have the same characteristics?
this is due to the different combination of maternal and paternal alleles that are gathered from both the mother and the father of the child.One child may have inherited a different paternal allele from the dad whereas the other may have inherited a different allele from the mother (maternal).

genotype- the genetic make-up of the individual (also described as the combination of alleles for a particular individual)
phenotype- the observable characteristics of the organism
alleles - different version of the same gene

TT - homozygous dominant
Tt - heterozygous
tt - homozygous recessive

Huntingdons Disorder- caused by the presence of one faulty dominant allele
late onset, clumsiness,memory loss,lack of concentration or difficulty in concentration
Cystic Fibrosis - caused by the presence of two (both) alleles that are homozygous recessive for the disease to be passed on.
difficulty in breathing,thick mucus build up in the lungs and pancreas and overall difficulty in digesting food

Embryonic - are unspecialised stem cells that can turn into any type of cell
is where a body cell is implanted into an empty and unfertilised egg cell
treat cancers such as leukemia, Alzheimers and liver damage
they are however expensive and have the potential to be blocked by the body that is being treated on.
Adult Stem cells - are unspecialised stem cells that have the potential to turn into many, but not all types of cell.
once again can treat cancers such as leukemia and alzheimers and liver damage
very expensive and hard to get as are found in the bone marrow of a patient.
however will not be rejected by the body

Speed of light - 300 km/s
Comets - appear fuzzier
made up of rock dust and ice
have highly elliptical orbits
Asteroids- strange shapes
appear sharper
found in the asteroid belt
Parallax - the apparent movement a star seems to make relative to the background star when viewed from opposite sides of the Earth's orbit.

Actual Brightness - the measure of intrinsic brightness a star gives off

Star Brightness - a star of known apparent brightness when viewed from earth is compared to a star of known intrinsic brightness to determine the distance of the star.

Parallax negatives - only stars nearby can be measured, the further away a star is, the more difficult and less accurate the measurement will be.

star brightness negatives - different stars have different brightnesses,there is always an uncertainty when using the measurement of star brightness.

Wavelength - the length of one wave.

Frequency - the amount of complete wave cycles a wave goes through per second.

Long wavelength - low pitch, low frequency
Short wavelength- high pitch, high frequency