Major cellular organelles LO1

Question 1

Cytoplasm

Answer 1

• the watery space between plasma membrane and the nucleus
  -composed of cytosol or ICF
• contains the cellular organelles
• contains dissolved solutes

Question 2

The nucleus (the “Control Center”)

Answer 2

• largest organelle
• houses DNA - instructions for protein synthesis

Question 3

Ribosomes

Answer 3

• site of protein synthesis
• free ribosomes: floating in cytosol
  produce proteins for use inside cell
• membrane bound ribosomes:
  attached to endoplasmic reticulum
  produce proteins for export

Question 4

Endoplasmic Reticulum

Answer 4

• interconnected tubes
  continuous with the nucleus
• functions: synthesis, storage,
  transport & detoxification

Question 5

Rough Endoplasmic Reticulum (RER)

Answer 5

• studded with ribosomes
• proteins produced by
  ribosomes on RER are
  packaged and exported out
  of cell

Question 6

Smooth Endoplasmic Reticulum (SER)

Answer 6

• no ribosomes attached
• synthesis of lipids, cholesterol
  and steroid based hormones
• involved in detoxification
• storage of calcium ions

Question 7

Golgi apparatus (“the traffic director”)

Answer 7

• consists of stacks of flattened sacs
• modify, concentrate and
  packages proteins and lipids
  Golgi apparatus (“the traffic director”)
• forms vesicles and distributes them:
  1. within the cell
  2. move and become inserted within the plasma membrane
  3. move to the plasma
  membrane for the content to be exported out of the cell by exocytosis

Question 8

Mitochondria (“the power house”)

Answer 8

• bean-shaped organelle
• enzymes on surface of inner membrane
• function: cellular respiration → releases energy in the form of ATP
  (adenosine triphosphate)

Question 9

Lysosomes (“the demolition crew”)

Answer 9

• membrane enclosed
  spheres (sacs)
• contains lysosomal
  enzymes
• digest biological material
  including proteins and cell
  debris and recycle
  molecules
• dispose of invading
  bacteria, viruses and
  toxins

Question 10

Cellular extensions: Cilia

Answer 10

• cilia are cellular
  extensions on the top of
  cells
• they sweep in a wave like
  manner to move materials
  across the surface of them

Question 11

Cellular extensions: Microvilli

Answer 11

• minute finger like extensions of the plasma membrane that
  project from the cell surface
• they increase the surface
  area of the cell