This document summarises the entire IEB syllabus requirements for Life Science, fulfilling the IEB SAGS conditions. Using these notes will ensure outstanding results as they provide excellent information, summarised in a way that is easy to understand. These notes cover practical Biology applicatio...
,Contents
Biology Practical Application................................................................................................................... 3
Essay Writing ........................................................................................................................................... 3
Nucleus and Nucleic Acid ........................................................................................................................ 4
Proteins ............................................................................................................................................... 4
Nucleic acids........................................................................................................................................ 4
The folding of nucleic acids ................................................................................................................. 4
The Discovery of the double helix structure of DNA .......................................................................... 4
DNA replication ................................................................................................................................... 5
Protein synthesis ................................................................................................................................. 5
RNA transcription ............................................................................................................................ 5
RNA translation ............................................................................................................................... 5
Biotechnology ......................................................................................................................................... 6
Recombinant DNA Technology (genetic engineering) ........................................................................ 6
Transferring DNA from donor to host ................................................................................................. 6
Genetically Modified Organism's impact ........................................................................................ 6
Cloning ................................................................................................................................................ 6
Reproductive cloning ...................................................................................................................... 6
Therapeutic cloning ........................................................................................................................ 7
The Human Genome Project............................................................................................................... 7
Genetic Techniques ............................................................................................................................. 7
Polymerase Chain Reaction (PCR) ................................................................................................... 7
Gel electrophoresis ......................................................................................................................... 7
DNA profiling ................................................................................................................................... 7
Gene Therapy .................................................................................................................................. 8
Genetic testing ................................................................................................................................ 8
CRISP (Clustered Regularly Interspaced Short Palindromic Repeats) ............................................. 8
Meiosis .................................................................................................................................................... 9
Genetics ................................................................................................................................................ 10
Trisomy 21 (XY + 21 / XX + 21) .......................................................................................................... 10
Sex determination genetic diseases ................................................................................................. 10
Reproduction ........................................................................................................................................ 12
Human reproduction ........................................................................................................................ 12
Male system ...................................................................................................................................... 12
Female system .................................................................................................................................. 12
Fertilisation ....................................................................................................................................... 14
Contraceptive methods .................................................................................................................... 14
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,Plant reproduction ................................................................................................................................ 15
Artificial means of vegetative propagation....................................................................................... 15
Sexual reproduction in angiosperms ................................................................................................ 15
Speciation.............................................................................................................................................. 17
Evidence for evolution .......................................................................................................................... 17
Evolution ............................................................................................................................................... 18
Genetic drift (remember it is totally random) .................................................................................. 18
Human Evolution .............................................................................................................................. 19
Australopithecus ............................................................................................................................... 19
Hominids ........................................................................................................................................... 19
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,Biology Practical Application
Points to remember:
• Volume can be measured in both ml and cm3 1ml= cm3
• The independent variable is the variable purposefully changed throughout the
experiment, while a dependent variable is the variable which changes as a result of the
changing variable.
• A control experiment is often set up to test whether the dependent variables are attained
as a result of the independent variables chosen. Normally, a control experiment has fewer
controlled variables and is placed in more "natural" conditions.
• When measuring temperature - avoid error of parallax on the thermometer, stir solution
before taking reading and place the thermometer in the middle of the substance.
• Heat using a water bath only when you are required to heat a substance to a temperature
lower than its boiling point.
• When asked - "how did you work carefully to avoid errors?", answer "avoided cross
contamination by washing apparatus', 'avoided error of parallax by measuring apparatus
at eye-level', 'made careful measurements of temperature/substances by carefully using
tools.
• When asked - "how would you ensure your results were reliable", answer 'repeat the
experiment' and 'repeat experiment over a wider range of independent variables'
Essay Writing
Points to remember:
• Must be about 2/3 pages in size
• Use two highlighters to go through the information given, highlighting pros in one colour
and cons in another. Also, use the first minutes of your reading time to read over info.
• Don't use adjectives, emotive writing or first-person/personal pronouns use scientific lang.
• Don't use all the sources, only the ones from reliable sources (i.e. peer reviwed research)
• Make sure you include +/- 16 bits of important information from the sources.
• Make 5 relevant points using your own information.
• Ensure you do not repeat any points previously made! This can be done by carefully
dividing
• motifs into paragraphs and only bringing up each idea once.
• Bring in 5 counter-arguments from the sources. Make it seem as if it is not your opinion
• however- by saying things like "some people think.' or "it has been said that.
• Don't write anything new in the conclusion
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, Nucleus and Nucleic Acid
Proteins
• Macromolecules made up of repeating monomers (amino acids)
• Joining of the 20 possible types of amino acids takes place by condensation synthesis and
creates bonds between the monomers called peptide bonds.
• The order and identity of the amino acids make up the primary structure which then, caused
by attractions of hydrogen bonds, it folds into a helix shape referred to as the secondary
stage and finally, with more bonds now being able to form, it enters its tertiary structure.
• If the temperature or pH supersedes a certain level, the hydrogen bonds break and the
protein unwinds - this is known as denaturation.
Nucleic acids
• Organic nutrients which occur in the nucleus, mitochondrion, cytoplasm and chloroplasts.
• Consists of the monomers called nucleotides. These nucleotides themselves are also made
up of monomers, each with one nitrogenous base, a phosphate and a pentose sugar.
• There are two types of pentose sugar, ribose and deoxyribose.
• There are five types of nitrogenous bases, guanine, cytosine, adenine, (thymine and uracil).
These nitrogenous bases are then divided into either pyrimidine (one ring of carbon) -U, T, C
and purine (two rings of carbon) - A, G.
• The type of nucleotide is named after its nitrogenous base
• RNA's type of pentose sugar is always ribose and the single-stranded RNA occurs in the
cytoplasm, mitochondrion, chloroplasts and nucleus with the nitrogenous bases A, C, U, G.
• DNA's type of pentose sugar is always deoxyribose and the double-stranded DNA Occurs
only in the nucleus, mitochondrion and chloroplasts. Nitrogenous bases A, C, I, G. DNA
usually winds up to form a double helix.
• Note that G and C, and A and T/U are complementary base pairs and are the only possible
combinations. Remember, only a purine and pyrimidine can bond.
The folding of nucleic acids
• DNA is wrapped up in the nucleus around histone proteins and further wound up, ensuring
that frequently used genes are wrapped towards the outside of the chromosome.
• When the DNA is wrapped up around proteins it is referred to as the chromatin network.
When wound up even further, the DNA forms a chromosome - two chromatids joined
together by a centromere. However, this only occurs in cell division.
• A section of the DNA which can code for the manufacture of a protein is called a gene.
• A genome is all an organism's heredity information
• The gene pool is a complete set of unique alleles of a population or species.
The Discovery of the double helix structure of DNA
• James Watson and Francis Crick won the noble prize for their discovery of the correct
structure of DNA, aided by the research directed by Rosalind Franklin and Maurice Wilkins,
• Through X-ray crystallography, they correctly deduced that DNA is a double helix antiparallel
structure with specific base pairings on the inside and a phosphate-sugar backbone on the
outside of the structure.
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