Topic 2 - cells and control

• What are the steps in the cell cycle?

  interphase,

  mitosis,

  cytokinesis
• What are the stages of mitosis?

  prophase, metaphase, anaphase, telophase
• What happens in interphase?

  Growth of cell and number of mitochondria and ribosomes increase
• What happens in prophase?

  DNA and chromosomes condenses

  nucleus membrane disappears
• What happens in metaphase?

  Chromosomes line up in the middle of the cell
• What happens in anaphase?

  Chromosomes and their copies are pulled by cell fibres to different ends of the cell
• What happens in telophase?

  Nuclear membrane reforms

  Chromosomes decondense
• What happens in cytokinesis?

  Cell membrane pinches un and eventually divides into 2 daughter cells
• What is a haploid?

  cells that have halve the chromosomes eg gametes
• What is a diploid cell?

  Cells that have the original amount of chromosomes
• Where is mitosis most likely to happen?

  Roots and shoots as its where part are actively growing
• What are stem cells?

  Cells that can differentiate /change into any cell are found in meristem cells. Eg root hair cells, guard cells, palisade cells.
• What does pluripotent mean?

  • can make all types of specialised cells in the body. Eg embryonic cells.
• What does multipotent mean?

  Can make multiple types of specialised cells, but not all types. Adult stem cells
• What are embryonic stem cells?


  Cells that can almost any type of cell in the body. They can be found in the embryo stage of development.
• What are adult stem cells?

  cells that can only become a limited range of cell types. these are found in certain places in the body within unspecialised tissues eg bone marrow.
• how can stem cells be used to repair damaged nerve tissue?

  • mitosis
  • Cells can differentiate to become specialised cells
• what is the process of growth in plants?

  • they have specialised growing areas called meristems
  • Plants undergo CELL DIVISION and CELL ELONGATION
  • as plants continue to grow the older meristems become specialised - they DIFFERENTIATE.
• Explain the similarities and differences between growth in plants and in animals

  • growth in plants and animals involve cell division and cell growth
  • Plant cell division is followed by elongation and then differentiation
  • There are constant regions of cell division/ meristem where cells divide to form undifferentiated cells.
  • Plants grow throughout their lives
  • In animal cells, division is followed by differentiation and there is no elongation
  • Once cells have differentiated they can only form more of the same type of cell
  • Growth stops at adulthood in animals
• How can you measure growth?

  • growth charts
• Why are growth charts important?

  • compare with past data collected from other of the same age
  • Issues highlighted and assessed if necessary
• What is cell division?

  • when a cell replicates itself to make daughter/diploid cells.
• What is cell differentiation?

  • when a cell (stem cell) changes into a different type of cell.
• Where can you find embryonic stem cells?

  blastocyst - a very early embryo
• Where are adult stem cells found?

  • foetus
  • Baby
  • Throughout life
• what is a stimulus.

  • any change in the surroundings. This is detected by receptors and into passes along cells as electrical impulses to the central nervous
• What is CNS?

  • the brain and spinal cord
  • Receptors detect a stimulus —> convert it into electrical impulses —>sent to the CNS
  • it coordinates the response of effectors which may be contracting or glands secreting hormones.
  • central nervous system
• What is the difference between reflex and CNS?

  reflex - doesn’t use brain

  CNS - brain processes information and then acts on it
• What is PNS?


  • all nerves in the body
• what is the function the axon in a neuron?

  A single nerve fibre that carries nerve impulses away from a cell body which is insulated by a fatty sheath
• What is the function of the dendrites in a neuron?

  Branched nerve fibres which receive nerve impulses and pass them towards a cell body
• What is a synapse?

  The gap between the neurons
• What are the types of neurons?

  • Sensory neurons - detects stimuli and pass an impulse to the CNS
  • Motor neurons - CNS to the muscles, an impulse along these makes a muscle contract
  • Interneurons (relay neurons)- responsible for thinking and memory
• What are glial cells?

  • helps support and maintain these neurons
• reflexes —> they bypass the brain to achieve the speed it needs to respond to a stimulus
• What happens at synapses?

  chemicals called neurotransmitters diffuse (high to low) across the gap between the neurons and triggers an impulse in the next neuron.
• What are the differences between the 3 neuron?

  • in relay and motor, the direction of nerve impulse is right whilst in sensory, the direction of impulse is left
  • In relay and motor, they have short dendrites whilst in sensory, it has long dendrites
• What are the similarities between the 3 neurons?

  All have:

  • axons
  • Cell body
  • Nucleus
• What are axon terminals?

  The end of an axon where it forms a synapse with another neuron.
• what’s the difference between the dendrites and the axon terminals?

  Dendrites receive electrical impulses to the next neuron.

  Axon terminals receive the neurotransmissions