3.4 Eukaryotic Cell Structure

1. Surrounded by nuclear envelope
   1. contains nuclear pores
      1. Allows substances (e.g RNA) to move between the nucleus and cytoplasm
2. contains chromosomes
3. contains nucleolus
   1. Makes ribosomes
4. Controls the cells activities

1. Double membrane
   1. Inner layer folded to form cristae.
2. Inside is the matrix
3. Site of Aerobic respiration where ATP is produced

1. Found in plant cells
2. Surrounded by a double membrane
3. Has membranes inside called thylakoid membranes
   1. Stacked up to form grana
      1. Grana connected by lamellae - think, flat pieces of thlakoid membrane
      2. Large S.A for attachment of chlorophyll, electron carriers and enzymes that carry out the 1st stage of photosynthesis (light absorption).
   2. Contain a photosynthetic pigment called chlorophyll
4. Site where photosynthesis takes place
5. Stroma (a fluid-filled matrix found in chloroplasts)
   1. contains the enzymes needed for 2nd stage of photosynthesis - synthesis of sugars

Anotações:

• Cells that manufacture and store large quantities of Carbs, proteins and lipids have a very expensive ER. Such cells include liver and secretory cell, for example the epithelial cells that line the intestine. :)

1. Rough ER (RER)
   1. A system of membranes enclosing a fluid-filled space. The surface is covered with ribosomes
      1. Provides a large surface area for the synthesis of proteins and glycoproteins
      2. Provide a pathway for the transport of materials, especially proteins, throughout the cell
2. Smooth ER (SER)
   1. Similar to the RER but with no ribosomes
      1. Synthesis, store and transport Lipids and carbohydates

1. Consists of a stack of membranes that make up flattened sacs, or CISTERNAE.
2. Closely in contact with VESICLES. Small rounded hollow structures.
3. Add Carbohydrate to proteins to form glycoproteins
4. Produces secretory enzymes, such as those secreted by the pancreas
5. Secretes carbohydrates such as cellulose
6. Transports, modifies and stores lipids
7. Forms lysosomes

1. Formed when the vesicles produced by the golgi apparatus contain enzymes such as proteases and lipases
2. A round organelles, surrounded by a membrane with no clear internal structure
3. Its basically a type of Golgi vesicle that releases lysozymes
4. Hydrolyse material ingested by phagocytic cells such as white blood cells and bacteria
5. Contains digestive enzymes called lysozymes
6. Release enzymes outside of cell in order to destroy material outside of the cell
7. Completely break down cells after they have died (autolysis)
8. Abundant in phagocytic cells and epithelial cells

1. Small cytoplasmic granules found in all cells
2. They can float freely in the cytoplasm, or are attached to the Rough ER
3. 2 types depending on where they are found: 80S - found in eukaryotic cells, around 25nm in diametre and 70S - found in prokryotic cells, mitochondria and chloroplasts, these are slightly smaller
4. Site of Protein Synthesis

1. A ridgid structure that surrounds cells in plants, algae and fungi
2. Consists of microfibrils of th epolysaccharide cellulose, embedded in a matrix
3. Thin layer called the middle lamella which marks the boundary between adjacent cell walls and cements adjacent cells togeher
4. Provides mechanical strength in order to prevent cell lysis
5. Give mechanical strength to the plant as a whole
6. Allow water to pass along it and so contribute to the movement of water through the plant

1. A fluid-filled sac bounded by a single membrane
   1. Single membrane called the TONOPLAST
2. A plant vacuole contains a solution of mineral salts, sugars, amino acids, wastes and sometimes pigments
3. Support herbaceous plants by making cells turgid
4. The sugars and amino acids may act as a temporary food store
5. The pigments may colour petals to attract pollinating insects