English Prepositions - For MCAT & ECAT Preparation 2013

 Note: Choose the best/appropriate preposition for the following blanks.

01. She writes ______ a Pen.

a) by
b) to
c) From
d) With

02. She gave me advice _______ my loan.

a) with 
b) To
c) From
d) about

03. Please follow the ________ instructions.

a) Through
b) above
c) beneath
d) behind

04. We are not allowed to watch television when we are _____ dinner.

a) with
b) in
c) on
d) at

05. Try to learn one step ______ a time, rather than three or four _____ once.

a) in , at
b) at , at
c) in , at
d) at , in

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Locomotion In Animalia

Locomotion in Animalia: 

     Locomotory organs of animals are built on a quite different plan than those of the protoctists. Instead of being appendages of a single cell, the locomotory organs of animals are far more developed and work by the co-ordinated action of muscles and skeleton.

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Sex Limited Trait

A sex-limited trait is limited to only one sex due to anatomical differences. Such trait affects a structure or fuction of the body present in only males or only females. These traits may be controlled by sex-linked or autosomal genes. Genes for milk yield in dairy cattle affect only cows. Similarly beard growth in humans is limited to men. A woman does not grow a bread herself but she can pass the genes specifying heavy beard growth to her sons.

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Genes and Alleles - Variation and Gene

Genes: 

     Gene (Or.genos = Birth,race) are the basic units of inheritance consisting of a sequence of DNA that occupies a specific position called locus on a chromosomes and is capable of a biological expression. It is the means by which one or more specific characteristics are passed on from parents to offspring.

Alieles: 

     Gr. allelon = of one anothe): Any pf the possible alternative forms of the same gene, of which every individual inherits two (one from each parent), different combinations of which produce different characteristics.

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Locomotion In Earthworm

Locomotion in Earthworm: 

     Earthworms, being terrestrial, are adapted to locomotion in soil. Their movement is brought about by the contraction of two sets of muscles and their body fluid, serving as a hydrostatic skeleton. Contraction of longitudinal muscles shortens the body and contraction of circular muscles lengthens (elongation) the body. As a result of interaction of muscles contractions and compressed body fluid an earthworms crawls.   

          In addition bristles called setae extending from the body wall in each segment grasp the soil functioning as hold fast to take the grip of the soil.

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Gene Pool

Gene Pool:   

 All the genes / alleles found in a breeding population at a given time are collectively called the gene pool. It is the total genetic information encoded in the genes in a breeding population existing at a given time.

Explanation: 

     A population is any group of interbreeding organisms of the same species that exist in both time and space. 

Concept of 'Breeding Genetics'

    If we imagine population not as a group of individuals, but as a group of individually segregating and randomly assorting alleles, we can understand the concept of 'breanbag genetics'. The alleles are like beans in a bean bag. The entire bean bag full of beans is the gene pool of the population. In the bean bag approach we can imagine the entire gene pool comprising all the alleles for all the different traits at once, or we can just focus on some subset, such as all the alleles for a single trait.

      A sample population of 100 diploid plants, some of which bear red flowers, others bearing white flowers has a sum total of 200 of all the different alleles for flower colour trait as its gene pool.

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