biology: cell structure

• What is the function of the plasma membrane?

  It encloses the cell and allows controlled communication and movement of materials.
• What is the structure of the plasma membrane?

  It is made of a double phospholipid layer, cholesterol, and proteins.

  
• What are the two types of proteins associated with the plasma membrane?

  Peripheral membrane proteins and protein channels.

  
• What is cytosol?

  Cytosol is a gel-like substance made of water and proteins.
• What is the difference between cytosol and cytoplasm?

  Cytoplasm is the cytosol plus organelles, located between the membrane and nucleus.
• Where do most reactions in cells occur?

  Most reactions occur in the cytosol.
• What is the function of the endoplasmic reticulum?

  It is a network of interconnected membrane-bound sacs and tubules that modifies and synthesizes proteins and lipids.
• What are the two types of endoplasmic reticulum?

  Rough ER and Smooth ER.

  
• What is the role of rough ER?

  Rough ER modifies proteins and manufactures phospholipids.
• What is the role of smooth ER?

  Smooth ER synthesizes lipids and carbohydrates and detoxifies certain chemicals.
• How do liver cells and muscle cells specialize in their functions related to smooth ER?

  Liver cells break down lipid-soluble toxins, while muscle cells release calcium ions for contraction.
• What is the primary function of mitochondria?

  Mitochondria convert stored energy into ATP.
• How many mitochondria are typically found in a cell?

  The number of mitochondria depends on the type of cell.
• What is the structure of ribosomes?

  Ribosomes are made of special RNA (rRNA) and proteins.
• Where can ribosomes be found in the cell?

  Ribosomes can be found free in the cytosol or associated with rough ER.
• What is the function of the nucleus?

  The nucleus contains DNA, nucleoplasm, and is involved in ribosome assembly.

  
• What is the nuclear envelope?

  The nuclear envelope is a double membrane that is porous.

  
• What is the role of the nucleolus?

  The nucleolus is involved in ribosome assembly.
• What happens to proteins manufactured in rough ER?

  They are modified in the lumen of rough ER and transported out via vesicles if not needed.
• What is the function of the Golgi apparatus?

  The Golgi apparatus sorts, packages, and tags proteins and lipids.
• What does the Golgi apparatus receive from the endoplasmic reticulum?

  It receives transport vesicles from the ER.

  
• What are lysosomes filled with?

  Lysosomes are filled with hydrolytic (digestive) enzymes.
• What can uncontrolled release of lysosomal enzymes lead to?

  It can lead to cell death (necrosis).
• How do immune cells utilize lysosomes?

  Immune cells use lysosomes to selectively kill pathogens through phagocytosis.
• What is the function of the cytoskeleton?

  The cytoskeleton maintains cell shape, motility, and internal movement of organelles.
• What are the three types of cytoskeletal components?

  Microtubules, microfilaments, and intermediate filaments.

  
• What is the role of centrosomes in cell division?

  Centrosomes make microtubules and participate in cell division by moving to opposing poles.
• What are centrioles responsible for during cell division?

  Centrioles replicate and form the mitotic spindle for chromosome separation.
• How do the functions of microtubules differ from microfilaments?

  Microtubules provide structural support and transport, while microfilaments are involved in cell motility.