BIOLOGY 3 Marks Question

When alien species are introduced in a particular ecosystem, they become invasive. Alien species compete for food and other resources which threatens survival of native species. For example:
- The Nile Perch introduced in lake Victoria in East Africa led to the gradual extinction of more than 200 species of Cichild fish in the lake. Introduction of African cat fish (Clarias gariepinus) for aquaculture purpose is posing threat to the indigenous catfish in our rivers.
- Invasive weed species like water hyacinth (Eicchornia), carrot grass (Parthenium) have posed a threat to our native species.

a. Amoebiasis; an infection of the large intestine caused by a protozoan, Entamoeba histolytica
b. Source of infection:
i. Cysts from the faeces of infected person
ii. Contaminated raw vegetables, fruits and other food stuffs.
iii. Through contaminated water.
c. The infection can be avoided by
i. Proper sanitary disposal of faecal matter.
ii. Perfect sanitation and protection of water and vegetables from pollution.
iii. Washing hands regularly.

(i)	Mouth parts of cockroach and butterfly	homology
(ii)	Hearts of rabbits and human beings	analogy
(iii)	Eyes of octopus and mammals	analogy
(iv)	Sweet potato and potato	analogy
(v)	Stings of honey bee and scorpion	analogy
(vi)	Tendrils of Lathyrus and tendrils of Gloriosa	analogy

a. S is the species richness
A is the area
C is a constant
Z is the regression constant.
b. If the species-area relationships are analysed among very large areas like the entire continents, the value of Z, i.e., slope of line lies in the range of 0.1 to 0.2.

Eli Lilly company prepares proinsulin chain A and B using separate DNA sequences corresponding to A and B, chains of human
insulin and introduced them in the plasmid of E. coli to prepare insulin chains, chains A and B produced separately, extracted and
combined by disulphide bond produces mature insulin.
The one important difference between the insulin produced by human pancreas and the one produced by Eli Lilly is that human insulin has an additional C peptide.

The association between the bumblebee and its favourite orchid Ophrys is of Commensalism. The extinction or change of one would certainly affect the other as if there are lesser bees, pollination may suffer and the orchid population may get decreased. On the other hand, if there are fewer orchids then bees may not be able to transfer the pollen.

a. Loss(deletion) or gain (insertion / duplication /addition) or change in position of DNA segments / chromosome cause the mutation.
b. Mutation due to change in a single base pair of DNA is point mutation, while insertion or deletion of one or two bases changes the reading frame from the point of insertion or deletion is frameshift mutation.

i. Transcription unit

ii. RNA strand transcribed from the above transcriptional unit