Prokaryotic cells are considered the least evolved type of cell.
They lack a nuclear membrane and membrane-bound organelles such as Golgi bodies and mitochondria.
Cell Shapes and Functions
Variation in Cell Shapes
The variation in cell shapes is primarily due to the functions that different cells perform.
Cell shapes typically correspond to their specific functions.
Plasma Membrane
Semi-permeable Nature of Plasma Membrane
The plasma membrane is described as semi-permeable or selectively permeable.
This means it allows certain small molecules to pass through while blocking larger molecules.
Plant Cells
Distinct Boundaries of Plant Cells
Plant cells often appear to have clear boundaries under a microscope.
This clarity is due to the presence of a thick cell wall that encases the plasma membrane, providing structural support.
Endoplasmic Reticulum (ER)
Smooth Endoplasmic Reticulum in Specific Cells
The smooth ER is abundant in cells such as the ovaries, testes, and adrenal glands.
This organelle helps in the synthesis and storage of lipids, particularly steroid hormones.
Mitochondria
Presence in Muscle Cells
Muscle cells contain a high number of mitochondria.
Mitochondria are responsible for the production of adenosine triphosphate (ATP), which is utilized in various physiological functions, including muscle movement.
Mitochondria as Powerhouses of the Cell
Mitochondria are referred to as the powerhouses of the cell due to their role in generating most of the cell's high-energy ATP molecules.
Main Function: Cellular Respiration
The primary function of mitochondria is to carry out cellular respiration.
This process is supported by various respiratory enzymes present in the mitochondria.
Potato Tuber Color
White Appearance of Potato Interior
The inside of a potato appears white due to the presence of colorless plastids filled with starch granules.
Chloroplasts and Photosynthesis
Role of Chloroplast Enzymes
Specific enzymes in chloroplasts facilitate the process of photosynthesis by reducing carbon dioxide to form carbohydrates.
Lysosomes
Function of Lysosomes
Lysosomes are considered the cleaning units of the cytoplasm.
They eliminate waste by digesting food particles, damaged mitochondria, microorganisms, and other impurities within the cytoplasm.