cell the unit of life solution CBSE NCERT class 11

 cell the unit of life solution CBSE NCERT class 11

Q1. (a)

Q2.(c)

Q3. a-(ii)

       b-(iii)

        c-(i)

Q4. (a)

Q5. mesosomes are infoldings of the plasma membrane found in bacteria - these help information of cell wall, DNA replication, distribution to daughter cell, help in respiration, secretion process, increase the surface area of the plasma membrane and enzymatic content.

Q6. neutral solutes move across the cell membrane through passive transport which does not need the energy to transport it to others which means the concentration gradient is from higher concentration to lower concentration. no, the polar molecules move through active transport which requires energy to move it to the cell membrane through active transport which is from lower concentration to higher concentration.

Q7. the two cell organelles having double membrane-bound structures are plastids and mitochondria. both are important parts of the cells as mitochondria act as a powerhouse of the cell and plastids act giving colors to plants and storing different kinds of food as starch. their functions are the same. diagram from NCERT book.

Q8. Characteristics of prokaryotic cells are as follows:

• The prokaryotic cell is essentially a single–envelope system.
• Prokaryotes lack membrane-bound cell organelles.
• Prokaryotes have 70S ribosomes.
• DNA is naked and lies coiled in the cytoplasm. It is not covered by a nuclear membrane and is termed a nucleoid.
• Nuclear components, like, nuclear envelope, nucleolus, nucleoplasm are absent.
• The cell wall is present in bacteria and cyanobacteria, but absent in mycoplasma.
• Multiplies by asexual reproduction.
• Transcription and translation take place in the cytoplasm.

Q9.multicellular organisms are very complex, they perform various functions which are reversible to nature, these organisms are very intense to perform functions at the instant, they actually do works, they have complex body pattern in which they associated. to function t better, to get the maximum results, these organisms usually divide by various methods, and to organize, balance this whole system, we need a division of labour. which means each and every different particular person performs a different function on their own and does its work. 

Q10. the cell is the structural and functional unit of living organisms, it is the basic unit of our body system, this is because it performs all the function in our body and also provides structural support and do the various complex activity. and capable of having independent existence.

Q11.nuclear pores are pores 

Q12.lysomes and vacuoles, both are endo-membrane systems, these structures are inside the membrane, which bound and safe from the surroundings, they differ from their functions as lysosomes are the materials formed during the packaging of Golgi apparatus, whereas vacuoles are inside the membrane tonoplast which contains extra material of the cell and sap of the cell.

Q13.given in NCERTboook NUCLEUS in pg.138 and centrosome in pg.137.

Q14.the centromere is the structure to which the chromosome is bind to, it is present at the middle of the chromosome which has primary constriction . draw diagram give in NCERT pg .139,8.13 the position of the centromere remains the same, based on the position of the centromere, it is classified as metacentric, sub-metacentric, acrocentric, telocentric, etc.