cell structure and organelles

• What is the structure of the nucleus, and what does it contain?

  • The nucleus is a large organelle surrounded by a nuclear envelope containing pores. It contains chromatin, which is made from DNA and proteins, and a structure called the nucleolus.
• Describe the lysosome and its contents.

  • The lysosome is a round organelle surrounded by a membrane with no clear internal structure. It contains digestive enzymes.
• What is a ribosome, and where is it found?

  • A ribosome is a very small organelle made up of proteins and RNA. It can either float freely in the cytoplasm or be attached to the rough endoplasmic reticulum. It lacks a membrane.
• Differences between the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER)

  • The rough endoplasmic reticulum (RER) is a system of membrane-bound flattened sacs covered with ribosomes, where proteins are folded and processed before being transported to the Golgi apparatus. The smooth endoplasmic reticulum (SER) is similar in structure but lacks ribosomes.
• Explain the function of the Golgi apparatus.

  • The Golgi apparatus is a group of fluid-filled membrane-bound flattened sacs formed by the fusion of vesicles from the endoplasmic reticulum. It further processes proteins received from the RER, then packages them into vesicles for transport around the cell.
• What are the structural features of mitochondria, and what is their function?

  • Mitochondria have a double membrane, with the inner membrane folded to form cristae. Inside is the matrix containing enzymes involved in respiration. Their function is to produce energy for the cell through cellular respiration.
• Where are centrioles found, and what is their composition?

  Centrioles are small hollow cylinders made of microtubules. They are found in animal cells but are only present in some plant cells.
• What are the components of the cell walls in fungi and plants?

  • Chitin is a component of cell walls in fungi, while cellulose is a component of cell walls in plants.