Test your learning outcome
1. What is protoplasm?
2. Are cell membrane, plasma membrane and
cytoplasm membrane, the three different structures
or the same structure?
3. What is the importance of vacuoles present in plant
cells?
4. Give one function each of: (a) plasma membrane,
(b) mitochondria, (c) endoplasmic reticulum,
(d) Golgi apparatus, (e) ribosome, (f) plastids
(9) nucleus, and (h) nucleolus.
5. What is the function of Centrosome in an animal
6. What are cell organelles?
7. Why do plants have more and large vacuoles tha
animal cells?
8. Why plastids are present only in plant cells?
Answers
Answer:
1)Protoplasm is called the living content of the cell. Protoplasm is the entire content of the living cell including the cytoplasm and the nucleus.
2)Yes, the structure of cell membrane is also called as plasma membrane,it is found in all cells and separates the interior of the cell from the outside environment.Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane.The primary function of the plasma membrane is to protect the cell from its surroundings.
3)Vacuole, in biology, a space within a cell that is empty of cytoplasm, lined with a membrane, and filled with fluid. The vacuole plays an important role in the homeostasis of the plant cell. It is involved in the control of cell volumes.
4)(i)The plasma membrane is composed of phospholipids and proteins that provide a barrier between the external environment and the cell, regulate the transportation of molecules across the membrane, and communicate with other cells via protein receptors.
(ii)Mitochondria are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is stored in a small molecule called adenosine triphosphate (ATP).
(iii)The large network of membranous sheets and tubes is called endoplasmic reticulum. They are filled with fluids and carries materials throughout the cell due to which it is also called transport system of the cell.
(iv)* They are involved in synthesis of cell wall,plasma membrane and lysosomes.
* It produces vacuoles which contain cellular secretions eg:enzymes,protein,cellulose etc.
* They act as an area for storage,processing and packaging of various cellular secretions.
(v)Ribosomes are a cell structure that makes protein. Protein is needed for many cell functions such as repairing damage or directing chemical processes. Ribosomes can be found floating within the cytoplasm or attached to the endoplasmic reticulum.
(vi)Plastids are the site of manufacture and storage of important chemical compounds used by the cells of autotrophic eukaryotes. They often contain pigments used in photosynthesis, and the types of pigments in a plastid determine the cell's color.
(vii)A nucleus is a membrane-bound organelle that contains the cell's chromosomes. Pores in the nuclear membrane allow for the passage of molecules in and out of the nucleus.
(viii)The nucleolus is a region found within the cell nucleus that is concerned with producing and assembling the cell's ribosomes. Following assembly, ribosomes are transported to the cell cytoplasm where they serve as the sites for protein synthesis.
5)And the centrosomes organize the microtubules, so it's called the microtubules organizing center. The centrosomes duplicate before cell division, so they then help to organize the microtubules and the cell division process.
6)Cell Organelle and their Functions. The basic structure of cell consist of nucleus, plasma membrane and cytoplasm. Other than this different structures like Endoplasmic Reticulum(ER), Golgi body, Lysosomes, Mitochondria, Plastids and Vacuoles are also present. All of these are cell organelles.
7)The plant has the largest vacuole than animal cells because in plant cells the larger central vacuole performs two functions, one is to store water and the other is to help the plant remain upright. ... In animal cells, vacuoles are smaller but more in number because they do not require vacuole for rigidity or pressure.
8)Plastids are present in plant cells which synthesize and store important chemical compounds. There are many types of plastids such as the chloroplast, chromoplast and leucoplasts. Chloroplasts synthesize green coloured pigments and chromoplast produce pigments of different colours. Leucoplasts are involved in the storage of compounds like starch, proteins or fats.