year nine - cells

• What are mitochondria?

  Small organelles found in animal and plant cells
• What is the function of the mitochondria?

  Site of respiration
• What is a ribosome?

  Tiny organelle found in animal and plant cells
• What is the function of the ribosome?

  Making proteins
• What is a membrane bound organelle?

  An organelle with its own membrane
• Give 3 examples of membrane bound organelles

  Nucleus, mitochondria, chloroplast
• What is a eukaryotic cell?

  Cells that have membrane bound organelles
• In a eukaryotic cell, where is DNA found?

  In the nucleus
• Give two examples of eukaryotic cells

  Animal and plant cells
• What is a prokaryotic cell?

  Cells that have no membrane bound organelles
• Give an example of a prokaryotic cell

  Bacterial cell
• What is a plasmid?

  A tiny loop of DNA
• What is cell differentiation?

  The process by which a cell becomes specialised
• What are stem cells

  Undifferentiated cells
• Where are stem cells found in plants?

  Meristematic regions
• Where are stem cells found in animals?

  Bone marrow and embryos
• How do you calculate magnification

  Magnification= image size/actual size
• What does focus mean?

  Making an image sharp enough to be viewed
• How do you focus an image using microscope?

  By turning the focusing knob
• How do you record an image from a microscope?

  Draw what can be seen through the eyepiece
• What is resolution

  The ability to distinguish between two points
• Which type of microscope has the highest resolution?

  An electron microscope
• What is the maximum magnification of a light microscope?

  About x2,000
• What is the maximum magnification of an electron microscope?

  About 2,000,000
• What is the name of the specialised cell carrying male DNA for reproduction?

  Sperm cell
• Why does a sperm cell contain many mitochondria?

  To provide energy from respiration for swimming
• Why does a sperm cell have a long tail?

  To swim to the egg
• What is found in the acrosome in the head of the sperm?

  Digestive enzymes
• Why does the sperm head contain digestive enzymes?

  To break down the wall of the egg cell
• What is the name of the specialised cell in the stem of the plant carrying water?

  Xylem
• How is a xylem cell specialised?

  Dead hollow tubes, rings of lignin
• What is the name of the specialised cell in the stem of the work transporting sugar?

  Phloem
• How is a phloem cell specialised?

  Supported by companion cells, sieve plates between cells
• What is diffusion?

  The net movement of particles in a fluid from an area of high concentration to an area of low concentration
• Give two examples of diffusion in the human body

  Gas exchange in lungs, absorption in the small intestine
• What is a concentration gradient?

  A difference in concentration between two regions
• What four factors affect the rate of diffusion?

  Temperature, concentration gradient, surface area, diffusion distance
• What is the effect of increased temperature on rate of diffusion?  

  Increased  
• What is the effect of increased surface area on rate of diffusion?  

  Increased  
• What is the effect of increased diffusion distance on rate of diffusion?  

  Decreased