biology - cells

• animal cell:

  A) cell membrane

  B) cytoplasm

  C) mitochondria

  D) ribosome

  E) nucleus

  
• plant cell:

  A) cell wall

  B) mitochondria

  C) vacuole

  D) cytoplasm

  E) nucleus

  F) chloroplast

  G) cell membrane

  
• Eukaryotic cells: have a nucleus and organelles with membranes around them
• Prokaryotic cells: have no nucleus and have no organelles with membranes around them
• Cell Specialisation:

  Cells with special adaptations that make them good for their role.
• Villi = job

  • Digested food molecules are absorbed into the blood stream.
• Villi = Specific Adaptations:

  • Microvilli increase the surface area of the small intestine allowing for faster absorption of food 
• Sperm Cell = Outline of Role:

  • Male gamete that fertilises an egg cell.
• Sperm Cell = Specific Adaptations:

  • Mitochondria for lots of energy 
•  Egg Cell = Outline of Role:

  • Female gamete 
  • Is fertilised by the sperm cell
• Egg Cell = Specific Adaptations:

  • Contains one copy of chromosomes in the nucleus 
• Ciliated Epithelial Cell = Outline of Role:

  • Found in the respiratory tract or oviduct
• Ciliated Epithelial Cell = Specific Adaptations:

  • Small hairs on the top of the cell move. 
•  Xylem Cell = Outline of Role:

  • Moves water from the roots of a plant to the leaves, where photosynthesis can occur
• Xylem Cell = Specific Adaptations:

  • Hollow to transport large volumes of water
•  Phloem Cell = Outline of Role:

  • Move food substances around the plant.
• Phloem Cell = Specific Adaptations:

  • Particles can move throughout the column in all directions. 
•  Root Hair Cell = Outline of Role:

  • Absorbs water and mineral ions from the soil
• • Root Hair Cell = Specific Adaptations:
  • No chloroplast as no photosynthesis takes place in the roots
•  Red Blood Cell = Outline of Role:

  • Delivers oxygen to cells and collects oxygen from the lungs. 
• Red Blood Cell = Specific Adaptations:

  • No nucleus, to maximise the space for haemoglobin.
  • Flattened disc shape so there is a large surface area.
•  Palisade Cell = Outline of Role:

  • Collects light to allow for photosynthesis
• Palisade Cell = Specific Adaptations:

  • Contains lots of chloroplasts so more light is absorbed
•  Nerve cell = Outline of Role

  • Carries electrical signals around the body
• Nerve cell = Specific Adaptations:

  • Very long and surrounded by a fatty layer to make the signals travel faster
•  Stem Cells

  A stem cell is a cell that has not yet become a specialised cell.
•  Features of stem cells:

  • Can replicate many times 
  • Has the potential to become different types of cell -> for growth & repair
•  There are 2 types of stem cells:

  1. Adult stem cells 

  • Come from bone marrow

  1. Embryonic stem cells  

  • Come from a developing embryo e.g. from IVF
• Stem cells are important because they could be used to treat medical conditions or be used as transplants. 
•  There are 2 types of microscopes:

  Light Microscopes, Electron Microscopes
• Magnification VS Resolution

  Magnification is how much bigger a sample appears to be under the microscope than it is in real life.

  Resolution is the ability to distinguish between two points on an image - the amount of detail.  
• magnification formula:

  A) magnification

  B) size of image

  C) actual size of object

  
• Diffusion

  Diffusion is the movement of particles from a place where they are in high concentration to a place where they are in low concentration. 
•  

  Factors affecting Diffusion

  1. Concentration gradient 
  2. Temperature 
  3. Surface area
  4. Particle size
  5. State of diffusion substance
• Osmosis

  Osmosis is the movement of WATER from a place where they are in high concentration to a place where they are in low concentration across a partially permeable membranes.
• Diffusion and Osmosis both occur with no external energy input
• Concentration Gradient

  The difference in the concentration of a substance between two areas is called the concentration gradient. The steeper the gradient, the higher the difference in substance concentration
• Active transport is the movement of particles against the concentration gradient (from an area of low concentration to an area of high concentration) requiring energy released in respiration from the mitochondria.
• Mitosis

  • The name for making new cloned cells.  The new cells are genetically identical to the original cell.
• • Mitosis is known as asexual reproduction, and is important for growth and repair or tissues