cells

• What are centrioles composed of?

  Hollow cylinders containing a ring of microtubules arranged at right angles to each other
• What is the role of centrioles in the cell?

  They are involved in producing spindle fibres for cell division
• What are ribosomes composed of?

  Two subunits
• What is the primary function of ribosomes?

  They are the site of protein production
• What do lysosomes contain?

  Digestive enzymes
• What is the structure of lysosomes?

  They are vesicles bound by a single membrane
• What is the composition of the cell wall in prokaryotic cells?

  Made of peptidoglycan
• What is the function of the capsule in prokaryotic cells?

  It helps the cell to retain moisture and adhere to surfaces
• What is a plasmid?


  A circular piece of DNA
• What is the function of the flagellum in prokaryotic cells?

  It rotates to move the cell
• What are pili?


  Hair-like structures that attach to other bacterial cells
• What are mesosomes?


  Infoldings of the inner membrane which contain enzymes required for respiration
• What are viruses composed of?

  Nucleic acid enclosed in a protective protein coat called the capsid
• What is the function of the lipid layer in some viruses?

  It serves as an envelope that can protect the virus
• How are cells organized in multicellular organisms?

  • Cells are organized into tissues
  • Tissues are organized into organs
  • Organs are organized into systems
• What is the process of cell division called?

  Mitosis
• What is the role of mitosis in the cell cycle?

  To produce identical daughter cells for growth and asexual reproduction
• What is the outcome of mitosis in terms of genetic variation?

  It does not give rise to genetic variation
• What are the three stages of the cell cycle?

  1. Mitosis

  • Four stages: prophase, metaphase, anaphase, telophase

  1. Interphase

  • Cell grows and prepares to divide
  • Chromosomes and some organelles are replicated
  • Chromosomes begin to condense

  1. Cytokinesis

  • Parent and replicated organelles move to opposite sides
  • Cytoplasm divides, producing two daughter cells
• What is the shape of prokaryotic DNA?


  Short and circular
• Where is prokaryotic DNA located?

  In the cytoplasm, free and not associated with proteins
• What is the composition of the prokaryotic cell wall?

  Contains murein, a glycoprotein or peptidoglycan
• What is the function of the prokaryotic cell wall?

  Prevents osmotic lysis and provides rigidity
• What is the structure of the cell surface membrane in prokaryotic cells?

  It is a phospholipid bilayer with embedded proteins
• What is the function of the cell surface membrane?


  Controls the passage of substances across the membrane
• What is the size of small ribosomes in prokaryotic cells?

  70S size
• What is the role of ribosomes in prokaryotic cells?

  Responsible for protein synthesis
• What is the function of a simple flagellum in prokaryotic cells?

  Responsible for the movement of the cell
• What are plasmids in prokaryotic cells?

  Small loops of DNA that can replicate independently
• How can plasmids be used in genetic engineering?

  They can pass on genetic information via conjugation to other bacteria
• What is the function of the capsule in prokaryotic cells?

  Provides protection from desiccation and phagocytes
• What is the role of the cytoplasm in prokaryotic cells?

  It is a solution where many dissolved molecules are found
• What distinguishes prokaryotic cells from eukaryotic cells regarding organelles?

  Prokaryotic cells do not have membrane-bound organelles
• How do prokaryotic cells exchange substances?

  Through passive and active transport across the cell membrane
• What is the significance of the murein in the cell wall of prokaryotic cells?

  It provides structural support and rigidity
• What is the primary component of the prokaryotic cell membrane?

  Phospholipid bilayer
• What is the role of the cytoplasm in prokaryotic cells?

  It is the site of many metabolic reactions
• What is the structure of the plasma membrane?

  It is made of a phospholipid bilayer that contains embedded proteins.
• What is the function of the plasma membrane?

  It is selectively permeable and involved in cell identification.
• What does the nucleus contain?

  It contains chromosomes, which are long DNA molecules associated with histone proteins.