MEMOS PUT TOGETHER
2016 2018
2017 2019
agriculture and
environmental sciences
, Define the following terms:
Operon – a functioning unit of DNA containing a cluster of genes under the
control of a single promoter
Wild Type - a strain, gene or characteristic which prevails under natural
conditions
Mutant - Resulting from or showing the effect of a mutation
Tunica Albuginea - the fibrous envelope of the corpora cavarnosa penis
Corpus albicans - ovarian scar composed of connective tissue that forms after corpus
lateum degenerates, a process called luteolysis
Membrane Granulosa - The internal coat of the larger ovarian follicles consisting of several
layers of nucleated cells
Fertilisation - the union of a spermatozoal nucleus, of paternal origin, with an
egg nucleus of maternal origin to form the primary nucleus of an
embryo
• Discuss the most important contributions of the following people to the discovery of the
structure of DNA. James Watson, Francis Crick and Erwin Chargaff
Watson and Crick discovered the double helix in 1953, this was the most important
breakthrough in the twentieth-century biology. When they began their work, the structure
of the nucleotides and the way these are linked together to form a polynucleotide were
already known. What was not known was the actual structure of DNA in a living cell. To solve
the structure problem. Watson and Crick used model building-they built a scale model of
what they thought a DNA molecule must look like. Obeying the chemistry law and taking
into account the results of other investigations into the DNA structure. one of this studies
was carried out by Erwin Chargaff. He became interested in the DNA in 1940s when
scientists first realized that FNA might be the genetic material. He decided to use a new