PART - 2 - Unit V : CH - 19 Chemical Coordination and Integration — BIOLOGY STD 11 Science — Question

Organise a discussion in your class on the topic-Are viruses living or non-living?

What is a centromere? How does the position of centromere form the basis of classification of chromosomes. Support your answer with a diagram showing the position of centromere on different types of chromosomes.

Explain the difference between ligament and tendon.

Write the functions of human kidney.

Structures of the bacterial ribosome have provided a framework for understanding universal mechanisms of protein synthesis. However, the eukaryotic ribosome is much larger than it is in bacteria, and its activity is fundamentally different in many key ways. All ribosomes are composed of two subunits, both of which are built from RNA and protein. Bacterial ribosomes, for example of Escherichia coli, contain a small subunit (SSU) composed of one 16S ribosomal RNA (rRNA) and 21 ribosomal proteins (r-proteins) and a large subunit (LSU) containing 5S and 23S rRNAs and 33 rproteins. In contrast to their bacterial counterparts, eukaryotic ribosomes are much larger and more complex, containing additional rRNA in the form of so-called expansion segments (ES) as well as many additional r-proteins and r-protein extensions.

(1).Ribosomes are present in
(a) Eukaryotes only
(b) Eukaryotes and prokaryotes
(c) Prokaryotes only
(d) Eukaryotes, prokaryotes and viruses

(2) In 70S ribosomes, ‘S’ stands for
(a) SI unit (b) Solubility factor (c) Svedberg unit (d) all of these

(3) 80 S ribosomes occur in
(a) Eukaryotic cells of animals
(b) Eukaryotic cells of animals and plants
(c) Both Eukaryotic cells and prokaryotic cells
(d) all of these

(4) Ribosomes are made up of
(a) RNA only (b) RNA and proteins (c) RNA, DNA and proteins (d) Nucleic acids, proteins and lipids

(5) Polysomes are
(a) multiple units of ribosomes
(b) attachment of many ribosomes to a common mRNA
(c) attachment of many mRNA to a common ribosome
(d) lysosomal aggregations

What is the lymphatic system? Describe the functions of the lymph.

Explain the process of inspiration under normal conditions.

Various parts of the plant such as stems leaves, and even fruits are modified into underground parts to perform various functions such as stems, leaves, and even fruits.
The stems in ginger and banana are underground and swollen due to storage of food. They are called rhizome. Rhizome of ginger is a modification of stem because it bears nodes, internodes, terminal buds, scaly leaves and buds, which give rise to aerial shoots. It is not a root because root does not have nodes and internodes. Also, rhizome does not perform the function of roots i.e. anchorage and absorption, rather it serve as reservoir for storage of food. Similarly, corm is an underground stem in Colocasia (jimikand) The tips of the underground stem in potato become swollen due to accumulation of food and forms tuber.



i. Observe the given flow chart and mention what are the four types of Underground stem modification also mention one example of each. (1)
ii. Ginger is an underground stem but why it is distinguished from a root? (1)
iii. Why do the tips of modified stems in potatoes become swollen? (2)

OR

Are all underground parts of a plant roots? (2)

As what is Equisetum commonly known? Write any four differences between Bryophytes and Pteridophytes.

Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?