chap 1 cells

• what is a cell?


  It is a basic unit of life
• name cell organelles found in plant cells

  ribosomes

  nucleus

  mitochondria

  rough endoplasmic reticulum

  smooth endoplasmic reticulum

  vacuole

  golgi body

  cell membrane

  cytoplasm

  chloroplast

  cell wall
• name cell organelles found in animal cells

  ribosomes

  nucleus

  mitochondria

  rough endoplasmic reticulum

  smooth endoplasmic reticulum

  vacuole

  golgi body

  cell membrane

  cytoplasm
• cell membrane controls the movement of substances into and out of the cell
• cytoplasm is the site where most chemical reactions take place such as photosynthesis and cell division
• nucleus (plural: nuclei) controls most of the cell's activities such as cell division
• mitochondrion (plural: mitochondria) is the site of respiration where it releases energy for cellular activities
• ribosomes in the cytoplasm synthesise proteins for use within the cell while ribosomes attached to the rough endoplasmic reticulum synthesise proteins that are exported from the cell
• rough endoplasmic reticulum folds and modifies the protein made by the ribosomes on its surface, which will then be packaged into vesicles and sent to the golgi body
• smooth endoplasmic reticulum synthesises lipids and steroid hormones, and plays a role in detoxification
• golgi body further modifies proteins from the rough endoplasmic reticulum and packages them into transport vesicles which will travel to the cell membrane and fuse with it, releasing their contents outside the cell
• vacuoles in plant cells provide turgor, and store food and mineral salts
• cell wall provides structural support for the plant cell
• chloropyll traps light for photosynthesis
• what is the difference between vacuoles in a plant cell and animal cell

  vacuoles are small and numerous in animal cells while in plant cells, they are few and large

  vacuoles are temporary in animal cells while they are permanent in plant cells
• transport between RER and golgi body:

  
  

  ribosomes attached to RER will synthesise proteins that enter the RER to be folded and modified

  the proteins are then packaged into vesicles and sent to the golgi body to be further modified

  the proteins are packaged into another vesicle and sent to the cell membrane

  the vesicles then fuse with the cell membrane, releasing the contents outside the cell
• what cell organelles can typically be seen under a light microscope ?

  nucleus, plant vacuoles and chloroplasts
• what is differentiation ?

  it is the process where a cell is specialised for a specific function
• adaptation of muscle cells:

  muscle cells have more mitochondria to release more energy needed for contraction
• adaptation of root hair cell:

  root hair cells have long and narrow finger-like protrusions that increases the surface area to volume ratio, allowing the cells to absorb water and mineral salts more efficiently
• adaptation of red blood cells:

  red blood cells have no nucleus so there is more space to contain more haemoglobin, transporting more oxygen

  red blood cells have a circular, biconcave shape, increasing the surface area to volume ratio, allowing oxygen to diffuse in and out of the red blood cell more efficiently

  red blood cells are elastic and flexible, allowing them to squeeze through narrow capillaries
• a cell (eg. liver cell) having extensive rough endoplasmic reticulum, allows for more proteins (eg. enzymes) to be synthesised