Cell Stucture And Organisation Flashcards
Protoplasm
Made up of nucleus, cytoplasm and cell membrane
Cell surface membrane / plasma membrane
Description:
- Made up of lipids and proteins
- Double-membrane
Function:
- Partially permeable to control substances entering and leaving the cell
Nucleus
Description:
- Consists of a mass of denser protoplasm, surrounded by a membrane — to separate nucleus content from surrounding cytoplasm
- Contains long thread-like structures called chromatin
- Contains nucleolus which play a part in synthesising the subunits of ribosomes
Functions:
- Controls cellular activities such as cell growth and repair of worn out parts
-Essential for cell division
Cytoplasm
- The jelly-like substance that fills the cell
- Where most cellular activities occur
- Contains cellular organelles
Vacuoles
In Animal Cells:
Many small vacuoles that contain water, food substances and digestive enzymes to digest invading bacteria usually exist temporarily
In Plant Cells:
Large concentrated central vacuole containing cell sap (sugars, amino acids, mineral salts) enclosed by a partially permeable membrane called tonoplast
Endoplasmic Reticulum (ER)
- Rough Endoplasmic Reticulum (RER)
- Smooth Endoplasmic Reticulum (SER)
Rough Endoplasmic Reticulum (RER)
Description:
- Has ribosomes attached
- Usually continuous with the nuclear membrane
Functions:
- Ribosomes attached are involved in protein synthesis
-Transports (usually non-functional) proteins via vesicles to Golgi apparatus
Smooth Endoplasmic Reticulum (SER)
Description:
- More tubular and may or may not be connected to RER
- No ribosomes are attached to outer surface
Functions:
- SER synthesises substances such as fats and steroids
- Converts harmful substances into harmful materials (detoxification)
Ribosomes
Description:
- Small round structures that are either attached to the RER or lie freely in the cytoplasm
Functions:
- Synthesise proteins by linking amino acids together
- Ribosomes attached to RER synthesise proteins that are transported out of the cell
- Ribosomes that lie freely in cytoplasm synthesis proteins used within cell
Golgi apparatus / Golgi body
Description:
- Membrane-bound flattened sacs
- Vesicles seen fusing with one side and pinching off from the opposite side
Functions:
- Chemically modifies and repackages substances made by RER
- Modified functional substances are transported via vesicles for secretion out of cell across the cell membrane
Mitochondrion
Description:
- Double-membrane-bound organelle
- Inner membrane is highly folded
Functions:
- Site of aerobic respiration
- RELEASES energy by breaking down glucose in the presence of oxygen for cellular activities
- Double membrane bound with outer smooth and inner forming folds to increase SA
Chloroplast
Description:
- Double-membrane-bound organelle
- Oval / Disc-like structures containing chlorophyll
Functions:
- Light energy absorbed by chlorophyll is converted into chemical energy stored in carbohydrates
Centriole
Description:
- Only found in animal cells
Function:
- Plays a role in cell division
