other

• Cells can either be prokaryotic or eukaryotic.
• eukaryotic are complex cells and include all animal and plant cells
• Prokaryotic cells are much more simple and are things like bacterial cells
• Eukaryotes are organisms that are made of eukaryotic cells
• A prokaryote is a prokaryotic cell - it is a single celled organism
• animal cell

  A) nucleus

  B) cytoplasm

  C) cell membrane

  D) mitochondria

  E) ribosomes

  
• Animal cells contain::

  • nucleus
  • cytoplasm
  • cell membrane
  • mitochondria
  • ribosomes
• Nucleus - contains genetic material that controls the activities of the cell
• Cytoplasm - gel-like substance where most of the chemical reactions happen, it contains enzymes that control the chemical reactions
• Cell membrane - hods the cell together and controls what goes in or out
• Mitochondria - these are where most of the reactions for aerobic respiration take place. The respiration transfers energy that the cell needs to work
• ribosomes - these are where proteins are made in the cell
• plant cell

  A) chloroplast

  B) nucleus

  C) mitochondria

  D) rigid cell wall

  E) cell membrane

  F) permanent vacuole

  G) cytoplasm

  H) ribosomes

  
• Plant cells have:

  • nucleus
  • cytoplasm
  • cell membrane
  • mitochondria
  • ribosomes
  • rigid cell wall
  • permanent vacuole
  • chloroplasts
• Things only present in plant cells:

  • rigid cell wall
  • permanent vacuole
  • chloroplasts
• rigid cell wall - made of cellulose. It supports the cell and strengthens it
• Permanent vacuole- contains cell sap, a weak solution of sugar and salts
• Chloroplasts - where photosynthesis occurs , to make food for the plant. They contain a green substance called chlorophyll, which absorbs the light needed for photosynthesis
• bacteria cell

  A) chromosomal DNA

  B) cell membrane

  C) flagellum

  D) plasmid DNA

  E) cytoplasm

  F) cell wall

  G) ribosomes

  
• Bacteria cells have:

  cytoplasm

  cell membrane

  cell wall

  chromosomal DNA

  plasmids
• Bacterial cells don't have a 'true' nucleus - instead they have a single circular strand of DNA that floats freely
• microscopes let us see things which we cant see with the naked eye.
• Light microscopes use light and lenses to form an image of a specimen and magnify it. They let us see individual cells and large sub cellular structures
• electron microscopes use electrons instead of light to form an image. they also have a much higher magnification than light microscopes
• resolution is the ability to distinguish between 2 points, so a higher resolution gives a sharper image
• Electron microscopes give a higher resolution than light microscopes
• Magnification + Image size divided by real size
• formula

  A) image

  B) real

  
• Differentiation is the process by which a cell changes to become specialised for its job
• As cells change, they develop different sub cellular structures, and turn into different types of cells. This allows them to carry out specific functions
• Most differentiation occurs as an organism develops
• in most animal cells, the ability to differentiate is then lost at an early stage after they become specialised
• However, lots of plants don't ever lose the ability to differentiate
• The cells that differentiate in mature animals are mainly used for repairing and replacing cells, like skin or blood cells
• Sperm cells are specialised for reproduction. The function of a sperm cell is to get male DNA to the female DNA
• Sperm cells:

  Long tail and streamlined head to help it swim to the egg
• Sperm cells:

  lots of mitochondria in the cell to provide the energy needed
• Sperm cells

  carries enzymes in its head to digest through egg cell membrane
• Nerve cells are specialised for rapid signalling. The function of nerve cells is to carry electrical signals from one part of the body to another
• Nerve cells:

  Long to cover more distance