Cell Structure And Function Cell The Unit Of Life 2

Structure of Cilia and Flagella:#

• Cilia and flagella are slender, hair-like organelles found on the surface of many eukaryotic cells.
• They are composed of microtubules arranged in a 9+2 pattern (nine doublet microtubules surrounding two central singlet microtubules).
• Cilia are shorter and usually occur in large numbers on a cell’s surface, while flagella are longer and typically exist singly or in pairs.
• The core structure of cilia and flagella is called the axoneme, and it is responsible for their movement.

Mitochondrion:#

• Mitochondria are double-membraned organelles found in eukaryotic cells.
• They are often referred to as the “powerhouses” of the cell because they are involved in cellular respiration, where ATP (adenosine triphosphate) is generated.
• Mitochondria have their own DNA and ribosomes, indicating their evolutionary origin from endosymbiotic bacteria.

Plastids:#

• Plastids are a group of organelles found in plant cells and some algae.
• The three main types of plastids are chloroplasts, chromoplasts, and leucoplasts.
• Chloroplasts are responsible for photosynthesis, containing chlorophyll pigments for capturing light energy.

Structure of Chloroplast:#

• Chloroplasts are double-membraned organelles found in plant cells.
• They contain a green pigment called chlorophyll, which captures light energy for photosynthesis.
• Chloroplasts have thylakoid membranes arranged in stacks called grana, where light-dependent reactions occur.
• The stroma is the fluid-filled region where the Calvin cycle (dark reactions) takes place.

Ribosomes:#

• Ribosomes are cellular structures involved in protein synthesis.
• They can be found in the cytoplasm or attached to the endoplasmic reticulum.
• Ribosomes consist of a large subunit and a small subunit, both composed of ribosomal RNA (rRNA) and proteins.
• They read mRNA (messenger RNA) and assemble amino acids into polypeptide chains.