cells and control

• What is the process of cell division called?

  Mitosis
• Why is mitosis important?


  It is important for growth and repair
• What phase must occur before mitosis begins?


  Interphase
• How much time do cells spend in interphase?


  About 90 percent of their time
• What must a cell do during interphase?


  Replicate its DNA and make more organelles
• What is the first stage of mitosis?


  Prophase
• What happens during prophase?

  The nucleus breaks down and spindle fibers appear
• What occurs during metaphase?


  The spindle fibers pull the chromosomes to the middle of the cell
• What does the letter 'M' in metaphase stand for?


  Middle
• What happens during anaphase?


  The spindle fibers pull the chromatids to each end of the cell
• What is a chromatid?


  One half of a chromosome
• What occurs during telophase?


  The nucleus reforms
• What is the final stage of mitosis?


  Cytokinesis
• What does cytokinesis result in?


  Two daughter cells
• What type of cells does mitosis produce?


  Identical cells
• What are mutations?


  Errors in DNA that can occur during replication
• How can mutations affect mitosis?


  They can cause mitosis to happen uncontrollably, creating a tumor
• What does growth mean in biological terms?


  To increase in size or number
• How do plant cells typically grow?


  They elongate and divide at the roots
• What does elongation mean in the context of plant growth?


  Cells stretch out to help the plant get bigger
• How do animal cells typically grow?


  They typically just divide
• What are percentile charts used for?


  To measure growth and compare it against other organisms
• What does it mean if an organism is in the 50th percentile?


  50% of the organisms are smaller and 50% are larger
• What are stem cells?


  Unspecialized cells that can differentiate into specialized cells
• What is cell differentiation?


  The process where unspecialized cells turn into specialized cells
• What is a specialized cell?


  A cell adapted to do a particular job
• What is an example of a specialized cell?


  A nerve cell that is very long to carry impulses
• What are embryonic stem cells?


  Stem cells found in the early embryo
• Why can embryonic stem cells turn into any type of specialized cell?


  They are the original cells we start with
• What are animal stem cells?


  Stem cells that are partially specialized
• What is an example of an animal stem cell?


  A stem cell found in the bone marrow
• Why do animals not need to create new cells all the time?


  They stop growing and only need to replace certain cells
• What are meristem cells?


  Stem cells found in plants
• Why can meristem cells turn into any type of cell in a plant?


  Plants continue to grow throughout their lives
• How can stem cells be used in medicine?


  They can be stimulated to produce needed cells for curing diseases
• What are some problems with using stem cells in medicine?


  They could create a tumor or be rejected by the immune system
• What is the nervous system responsible for?


  Sending and receiving information in the body
• What are the two parts of the nervous system?

  The central nervous system and the peripheral nervous system
• What makes up the central nervous system?


  The brain and spinal cord
• What makes up the peripheral nervous system?


  All the other neurons