nd of Florida have extra toes (polyda 5. A high proportion of the cats on the Ke
ID: 254096 • Letter: N
Question
nd of Florida have extra toes (polyda 5. A high proportion of the cats on the Key West isla What is the most likely explanation? A) high rate of mutation B) founder effect C) bottleneck effect D) directional selection for extra toes E) sexual dimorphism 6. Many types of plants are capable of pollinating themselves, and producing offispring as a result. Such reproduction is one type of A) binary fission B) cloning C) gene flow D) sexual reproduction E) vegetative propagation 7. The fact that is an important piece of evidence in support of the theory of endosymbiosis. A) some bilaterally symmetrical animals develop their mouths before their anusers B) some trees lose their leaves for winter C) chloroplasts and mitochondria have circular D) the human genome is more similar to the genome E) genes are carried on chromosomes chromosomes chimpanzee genome than it is to the mouse 8. In which of the following pairs are the organisms most closely related, phylogenetically speaking? A) mushroom, pine tree B) cow, yeast C) bacterium, amoeba (ameba) D) sea urchin, octopus E) scorpion, crabExplanation / Answer
Q5) A high proportion of cats on the key island of florida have extra toes ,(Polydactyly) , what is the most liking explanation-
Answer- A - High rate of mutation.
Explanation- Polydactyly is a spontaneous complex phenotypic variation, developed in one generation. In the preaxial form of the Hemingway mutant, the variation is induced by a single point mutation in a noncoding cis-regulatory element for Shh. In such variation one or more complete digits develop at each single limb, having nerves, blood vessels, muscles and ligaments. The physiology of the digits are perfect. The mutation induces the variation, besides mutation there are also other factor responsible like. change in expression of other genes, cell-cell signal exchange, cell differentiation, cell and tissue growth, but mutation is the most likely cause of this .
Q6) Many types of plants are capable of pollinating themselves and producing offspring as a result . such reproduction is one type of -
Answer- D- sexual reproduction.
Explanation- During sexual reproduction the two gametes join together by fusion and the process is called fertilization, to form a zygote, which develops to an embryo .
when plants are capable of pollinating themselves and producing offspring, the process called autogamy that is self-fertilization or self-pollination, here the fusion of male and female gametes occur, which are produced by a single plant . Here they donot depend on poliinating agents.like wind , water or insect to carry the pollens.
Q7) The fact that ______ is an important piece of evidence in support of theory of endosymbiosis.
Answer- C - chloroplasts and mitochondria have circular chromosomes.
Explanation:-
Endosymbiosis theory, is an evolutionary theory regarding the origin of eukaryotic cells from prokaryotic organisms, it was first proposed by Russian botanist Konstantin Mereschkowski in 1905. It says that the organelles distinguishing eukaryote cells evolved by symbiosis of individual single-celled prokaryotes (bacteria and archaea).
The theory says that mitochondria, plastids like chloroplasts, and other organelles of eukaryotic cells represents previously living prokaryotes , around 1.5 billion years ago. Mitochondria appears to be related to Rickettsiales proteobacteria, and chloroplasts to nitrogen-fixing filamentous cyanobacteria.
Among the many evidences supporting the symbiogenesis theory, it is found that the new mitochondria and plastids are formed by binary fission, else cells mightnot have created new ones , the transport proteins called porins are found in the outer membranes of mitochondria, chloroplasts and bacterial cell membrane, another protein cardiolipin is found in the inner mitochondrial membrane and bacterial cell membrane, and it is found that some mitochondria and plastids have single circular DNA molecules similar to the chromosomes of bacteria.
So this is an important piece of evidence supporting endosymbiosis theory.
Q8) In which of the follwing pairs are the organisms most closely related , phylogenetically speaking?
Answer- E-Scorpion and crab.
Explanation- Among all the groups -scorpion and crab are closely related , because they belong to the same Kingdom- Animalia, and phylum- Arthropoda .
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