E. Answer each of the following questions in few sentences.
1. Write a short note on discovery of cell.
2. Why is nucleus called the brain of the cell ?
3. Who proposed the cell theory? Give its salient features.
4. What is a cell? Why is it called the building block of life?
5. Where are chromosomes found in a cell? State their function.
6. What are pseudopodia in amoeba ? What are their functions ?
7. Why is the cell membrane said to be a semi-permeable membrane?
F. Answer each of the following questions in detail.
1. Differentiate between the following:
(a) Plant cell and Animal cell.
(b) Prokaryotes and Eukaryotes.
(c) Unicellular and Multicellular organismo
Answers
Answer:
1. cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name. ... The cell walls observed by Hooke gave no indication of the nucleus and other organelles found in most living cells
Answer: Please mark me as brainliest
E. Answer each of the following questions in few sentences.
Ans 1 - The cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name. The cell walls observed by Hooke gave no indication of the nucleus and other organelles found in most living cells.
Ans 2- The nucleus is called the "brain" of the cell because it holds the information needed to conduct most of the cell's functions. Other molecules make proteins from that information on a regular basis - each moment of our lives.
Ans 3- The classical cell theory was proposed by Matthias Schleiden and Theodor Schwann in 1839. The three tenets to the cell theory are as described below: All living organisms are composed of one or more cells. The cell is the basic unit of structure and organization in organisms. Cells arise from pre-existing cells.
Ans 4 - A cell is defined as the smallest, basic unit of life that is responsible for all of life's processes. Cells are the structural, functional, and biological units of all living beings. A cell can replicate itself independently. Hence, they are known as the building blocks of life.
Ans 5- Chromosomes are found in the nucleus of the cell. They carry genes and help in inheritance or transfer of characters from parents to offspring.
Ans 6 - The finger-like structures are called pseudopodia. These are the false feet of amoeba. Amoeba encircles the pseudopodia around food particle and takes it inside its body. Pseudopodia are an example of blunt transient processes employed by cells such as amoeba or the neutrophil leucocyte for locomotion and the uptake of food particles and /or other extraneous matter.
Ans 7- The cell membrane consists of a phospholipid bilayer with embedded proteins. The membrane is selectively permeable because substances do not cross it indiscriminately. Some molecules, such as hydrocarbons and oxygen can cross the membrane. Many large molecules (such as glucose and other sugars) cannot.
F. Answer each of the following questions in detail.
Ans 1- (a) A plant cell is surrounded by rigid cell wall whereas animal cell does not have cell wall. Presence of a large vacuole in plant cell, which is small in animal cell. Plant cells are larger than animal cells. Plant cells have plastids whereas animal cells do not have plastids.
(b) The primary distinction between these two types of organisms is that eukaryotic cells have a membrane-bound nucleus and prokaryotic cells do not. The nucleus is where eukaryotes store their genetic information. In prokaryotes, DNA is bundled together in the nucleoid region, but it is not stored within a membrane-bound nucleus. The nucleus is only one of many membrane-bound organelles in eukaryotes. Prokaryotes, on the other hand, have no membrane-bound organelles. Another important difference is the DNA structure. Eukaryote DNA consists of multiple molecules of double-stranded linear DNA, while that of prokaryotes is double-stranded and circular.
(c) Unicellular organisms are made up of only one cell that carries out all of the functions needed by the organism, while multicellular organisms use many different cells to function.