cell biology

• What is the role of the nucleus in a cell?

  It controls cell activities and contains DNA for protein synthesis.
• What is the function of the cytoplasm?

  It is where chemical reactions take place.
• What does the cell membrane do?

  It controls what goes in and out of the cell and is partially permeable.
• What are ribosomes responsible for?

  They make proteins from amino acids.
• How do mitochondria function in a cell?

  They release energy by respiration.
• What is the composition of the plant cell wall?

  It is made of cellulose.
• What is the function of chloroplasts in plant cells?

  They contain chlorophyll to absorb sunlight for photosynthesis.
• What distinguishes prokaryotic cells from eukaryotic cells?

  Prokaryotic cells have no nucleus or membrane-bound organelles.
• What is the role of circular DNA in prokaryotic cells?

  It controls cell activities and makes proteins.
• What is the approximate size of an animal cell?

  About 10 micrometers.
• What is the approximate size of a plant cell?

  About 50 micrometers.
• What is the approximate size of a prokaryotic cell?

  About 5 micrometers.
• What is cell differentiation and specialization?

  • Process where undifferentiated cells become specialized cells.
  • In animals: nerve cells, muscle cells, sperm cells.
  • In plants: xylem, phloem, root hair cells.
• What happens to specialized cells in animals when they divide?

  They usually repair and replace existing cells.
• What is the function of dendrites in a nerve cell?

  They connect to other nerve cells.
• What is the role of the axon in a nerve cell?


  It carries impulses around the body.
• What is the function of the acrosome in a sperm cell?

  It contains enzymes for penetrating the egg cell membrane.
• What is the function of muscle cells?

  They contract to allow movement of the body.
• What is the composition of xylem cells?

  They are dead cells with no cytoplasm and contain lignin for support.
• What is the role of phloem cells?

  They transport sugars and have living cells with little cytoplasm.
• What is the function of root hair cells?

  They absorb water and mineral ions with a large surface area.
• What are the differences between light microscopes and electron microscopes?

  • Light microscopes: low magnification, low resolving power.
  • Electron microscopes: high magnification, high resolving power.
  • Electron microscopes provide higher resolution images.
• What are the units used to measure sizes in microscopy?

  Millimeters, micrometers, and nanometers.
• How do you convert millimeters to micrometers?

  Multiply by 1000.
• How do you convert micrometers to nanometers?

  Multiply by 1000.
• How do you calculate magnification?

  Magnification = size of image / size of real object.
• What is the cell cycle and its stages?

  • Stage 1: Cell growth and replication of organelles.
  • Stage 2: Mitosis, where chromosomes are separated.
  • Stage 3: Cytoplasm and cell membrane divide to form two cells.
• What are stem cells?

  They are undifferentiated cells that can develop into specialized cells.
• What is the result of fertilization in terms of cell development?

  It results in a small ball of undifferentiated cells.
• What is the significance of embryonic stem cells?

  They have the potential to differentiate into any cell type.
• What is the main characteristic of specialized cells?

  They cannot differentiate into any other type of cell once specialized.
• What happens to the cell during stage two of the cell cycle?

  The cell grows and increases the number of subcellular structures.
• What is formed when DNA replicates during stage two?

  Two copies of each chromosome.
• What is the key event that occurs during mitosis?

  The chromosomes line up along the center and are pulled to each end of the cell.
• What occurs during stage three of the cell cycle?

  The cytoplasm and cell membranes divide to form two genetically identical cells.
• How are the two new cells formed during cell division related to the parent cell?

  They are genetically identical to each other and to the parent cell.
• What are the four key points to remember about cell division?

  • The cell grows and increases subcellular structures.
  • DNA replicates to form two copies of each chromosome.
  • Chromosomes line up and are pulled to each end of the cell.
  • Cytoplasm and cell membranes divide to form two identical cells.
• What are embryonic stem cells?

  Stem cells that are undifferentiated and can differentiate into most other cell types.
• How are embryonic stem cells used in medical research?

  They can be cloned and used to differentiate into specialized cells for treatment.
• Where can adult stem cells be commonly found?

  In bone marrow.