topic 1 cell biology

• animal and plant cells are EUKARYOTES
• bacteria cells are PROKARYOTES
• a cell is the smallest unit of life that replicates independently
• plant cells contain a cell wall, chloroplasts and a permanent vacuole but animals cells DONT
• animal cells and plant cells BOTH contain a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes
• parts that make up a cell are called organelles
• a bacteria cell is a unicellular organism that is prokaryotic
• prokaryotes don't have chloroplasts or a nucleus
• cell membrane controls what goes in and out of the cell and controls the movement of substances in the cell
• the nucleus contains the genetic material of the cell and controls the activities of the cell
• the cytoplasm is where chemical reactions take place and where the cell organelles are found
• mitochondia provides cells with the energy they need to carry out their functions
• ribosomes are the site of protein synthesis
• a permanent vacuole contains cell sap (a mix of sugar, salt, water)
• a cell wall supports and keeps the structure of a cell
• chloroplasts provide photosynthesis
• the pathway of a microscope

  light source, stage, microscope slide, object, objective lens, body tube, eye piece lens, eye
• microscopy is the use of an microsope
• equation for magnification 


  image size divided by object size
• resolution is a measure of how detailed the image will be when the resolution is higher the more detailed, clear the photo will be
• the object is the real object or sample that your looking at
• the image in microscopy is what you will see when you look into the mircoscope
• magnification is how many times larger the image is than the object
• positives of using light microscopes

  cheap, easy to use
• negatives of using light microscopes

  rely on light, resolution limited to 0.2um, not good enough to study subcellular structures
• positives of using an electron microscope 


  uses electron instead of light, maximum resolution is 0.2um, 200x better resolution than light microscopes, can be used to study subcellular structures
• negatives of using an electron microscope

  very expensive, hard to use
• image size calculation 


  object size times magnification
• object size calculation 


  image size divided by magnification
• the cell cycle is the steps that take place as the cell grows then divides
• 3 reasons why new cells are required

  growth, development, repair
• steps of mitosis (cell division) 1. DNA condense into chromosomes 2. chromosomes line up in the centre of the cell 3. cell fibre pull the two arms of each chromosome to opposite sides (poles) of the cell 4. the entire cell divides to form identical daughter cells
• cells produced by mitosis are genetically identical
• steps of the cell cycle 1. cellular growth: the cell gets larger and produces more sub-cellular structures 2. DNA replication: chromosomes duplicate, each consist of 2 'arms' 3. more cell growth 4. mitosis: DNA divides into 2 5. division: cell divides into 2
• adult stem cells and embryonic stem cells are found in animals
• plant stem cells are only found in plants
• adult stem cells can

  divide by mitosis, only differentiate into blood cells (white blood cells, red blood cells, platelets)
• two key features of stem cells are

  they can divide by mitosis, they can differentiate into specialised cells
• adult stem cells are found in bone marrow
• embryonic stem cells can

  differentiate into ANY TYPE of cell (nerve cell, skin cell, blood cell)