this is for my IB class introducing some parts of Genetics

2.  The study of variation and inheritance among
organisms.
 Variation due to different genes or alleles among
individuals.
 Inheritance is the passing on of these genes or
alleles to offspring.
 New developments in technology has led to Gene
Sequencing (finding the base sequence for genes)
 The biggest example of this is the Human
Genome project (which sequenced the entire
human genome)

3.  Chromosomes = a single piece of coiled DNA and
proteins (in eukaryotes but not prokaryotes).
Humans have 23 pairs of chromosomes.
 Gene = a heritable factor that produces a specific
protein which affects a specific characteristic.
Found in DNA.
 Gene locus: the specific position of a gene on a
chromosome
 Genome = the totality of the genes of an
organism.
 Allele = one specific form of a gene.
◦ Dominant allele = always expressed
◦ Recessive allele = expressed if no dominant allele
present.
◦ Codominant alleles = both expressed

4.  What’s a mutation?
 Recall that DNA codes for protein formation.
 If bases are altered in DNA then transcription
is affected then translation.
 A different amino acid may be coded for.
 A different polypeptide/protein may be
formed.
 Most mutations are deleterious; few beneficial
 What causes mutations?

5.  Caused by A/T base substitution in gene
coding for hemoglobin. Part of the gene is
GTG rather than GAG.
 The altered Gene is then transcribed.
 One of the proteins in the hemoglobin is
changed.
 Creates sickle-shape of red blood cells.
 Such cells are less efficient at transporting
gases.
 However, this gives partial resistance to what
disease?

6. Make a powerpoint
explaining
-what sickle cell
anaemia is
-the mutation that
causes it
The effect on
haemoglobin
The effect on red
blood cells
The effect on Malaria
resistance:

7.  Homozygous: Each of a pair of chromosomes
have same alleles.
 Heterozygous: Each… have different alleles.
 Genotype: Actual genetic make-up of organism.
 Phenotype: The characteristics of organism due
to its genotype.
 Carrier: Organism that carries an allele but
doesn’t show it.
 Test cross: a mating of organisms to see if an
organism has an allele (carrier) or does not.
 Locus: location on chromosome of a gene/allele
 Gene mutation : A change in the structure of a
gene; thus gene creates altered protein (or not).