CLASS-IX-CBSE-SCIENCE-Fundamental Unit Of Life-BIOLOGY

1) Differentiate Bacterial Cell from a Human Cell?

  Cell Wall:

•    In bacteria cell thick defensive cell wall exists covering the entire cell.
•    In human cell, cell wall does not exist.

  Cytoplasmic Bridge:

•    In bacterial cell, no cytoplasmic bridge exists because there is just a single cell.
•    In human cell, cytoplasmic bridges exist which help in inner transportation of cell.

  Shape:

•    Bacterial cell exists in many shapes such as circle, oval etc.
•    Human cell exists only in two shapes which are oval or   spherical.

  Cell Membrane:

• In bacterial cell, cell membrane is fabricated of phospholipid bi-layer. But the membrane has no sterols.
• In human cell, cell membrane is fabricated of lipid bi-layer in the company of phosphate particles. It behaves as hydrophilic to outside and hydrophobic in the internal wall.

  

 Cell Appendages:

• In bacterial cell, cell appendages exist. There is flagellum that helps in movement and pili is used for sexual multiplication.
• In human cell, cell appendages are generally missing. Aside from ciliated cells exist in respiratory tract and gut.

  Nucleus:

• In bacterial cell, nucleus does not exist. Rather nuclear substance such as DNA is available in cytoplasm. No core, professed as prokaryote
• In human cell, major nucleus with its membrane is present. This is purported as a eukaryote type.

   

  Division:

• In bacteria cell, mitosis and meiosis occurs. Mitosis results two cells whereas meiosis results four cells.
• In human cell, all cells experience mitosis. Just ovum and sperm development is done by meiosis. Whereas nerves cells never go for division.

  Movement:

• Bacterial cell can precede onward their own with help of flagella for ordinary needs.
• Human cell does not undergo any movement, with the exception of ova and sperm. However, white blood cell stream in the fluid.

   Conclusion

• From the above article we can conclude that human cell doesn’t have cell wall, cell appendages and no movement is there whereas bacterial cell have these things.

2) Draw a Prokaryotic cell.

3) what is cell division?

• Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle.

    There are two types of cell division: mitosis and meiosis.

• Mitosis is a fundamental process for life. During mitosis, a cell duplicates all of its contents, including its chromosomes, and splits to form two identical daughter cells. Because this process is so critical, the steps of mitosis are carefully controlled by a number of genes. When mitosis is not regulated correctly, health problems such as cancer can result

• Meiosis, ensures that humans have the same number of chromosomes in each generation. It is a two-step process that reduces the chromosome number by half—from 46 to 23—to form sperm and egg cells. When the sperm and egg cells unite at conception, each contributes 23 chromosomes so the resulting embryo will have the usual 46. Meiosis also allows genetic variation through a process of DNA shuffling while the cells are dividing.

4) Give any two functions of Golgi complex.

   Production of hormones:

•  Golgi body in endocrine cells helps in secretion of hormones Storage of protein

•  Vacuoles and vesicles which are the main components of Golgi complex become filled with protein-lipoid material for storage.

5) Why are the inner membranes of the Mitochondria 

deeply folded?

      

• The inner membrane folds over many times and creates layered structures called cristae
• Folds (cristea) of the mitochondria provide a greater surface area (more space) for the chemical reactions of oxidative phosphorylation (process of converting food sugars into energy (ATP)) to take place. Increased surface area allows more proteins that create the electron transport chain during this process to work at making more ATP. More space means more energy “factories” in each mitochondrion and more energy to fuel our cells, organs and systems to sustain life.

6) What does the internal organization of the chloroplast

 contain?

• Chloroplasts can be found in the cells of the mesophyll in plant leaves. 
• There are usually 30-40 per mesophyll cell. The chloroplast has an inner and outer membrane with an empty intermediate space in between. 
• Inside the chloroplast are stacks of thylakoids, called grana, as well as stroma, the dense fluid inside of the chloroplast. These thylakoids contain the chlorophyll that is necessary for the plant to go through photosynthesis. The space the chlorophyll fills is called the thylakoid space.

7) What is membrane biogenesis?

•     Membrane biogenesis is the process that involves cell membrane development with the aid of proteins and lipids.

•     The production of these membranes is driven by the endoplasmic reticulum. 

•     Membranes synthesized by the membrane biogenesis process help to divide the cell into functional and structural compartments.