G. Answer the following questions in brief.
1. What are the postulates of the Cell theory?
2. Make a flow chart to explain the body organization of living beings.
3. How was cell discovered?
4. What do you understand by the term chromosomes?
5. What is cytoplasm? Where is it found?
6. What is the function of the plasma membrane?
7. What role does the endoplasmic reticulum play in the cell?
8. What are lysosomes?
Answers
Answer:
1
There are three postulates of cell theory. The first two points were given be Schwann and schleiden and the last one was given by Redolf Virchow.Following are these points: ... All living cells arise from pre-existing cells by division. The cell is the fundamental unit of structure and function in all living organisms.
All organisms are made of one or more cells.
1. In biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells.
2. Image is attached above.
3. The term “cells” was first coined in 1665 by a British scientist Robert Hooke. He was the first person to study living things under a microscope and examined a thin slice of cork under a microscope and observed honeycomb-like structures. Robert Hooke called these structures as cells.
4. Chromosomes are thread like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
5. Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm. The portion of the cytoplasm that is not contained in the organelles is called the cytosol.
6. The plasma membrane, or the cell membrane, provides protection for a cell. It also provides a fixed environment inside the cell. And that membrane has several different functions. One is to transport nutrients into the cell and also to transport toxic substances out of the cell.
7. Endoplasmic reticulum, a continuous membrane system in eukaryotic cells that plays an important role in the biosynthesis, processing, and transport of proteins.
8. A lysosome is a membrane-bound cell organelle that contains digestive enzymes. Lysosomes are involved with various cell processes. They break down excess or worn-out cell parts. If the cell is damaged beyond repair, lysosomes can help it to self-destruct in a process called programmed cell death.