L2: Cell Types & Subcellular Structures Flashcards
• Explain the concept of ‘the cell’ • Classify different types of cells: prokaryotes, eukaryotes, bacteria, archaea, fungi, plants, animals Outline the basic organisation of eukaryotic cells and give a brief description of the major features and organelles, and the specialised cellular processes that take place in them: plasma membrane, nucleus, rough and smooth endoplasmic reticulum, Golgi apparatus, lysosomes and peroxisomes, mitochondria and chloroplasts, cytosol, cytoskeleton
What are the 3 cell theories?
- All living organisms are made up of 1 or more cells
- The cell is the basic unit of life
- Cells arise from existing cells by division
What are prokaryotes?
Single-cellular without nucleus
What are eukaryotes?
Single/multi-cellular with nucleus
What is the cell (plasma) membrane?
Bilayer of phospholipids, cholesterol & embedded transmembrane proteins
What is a amphipathic molecule?
Have BOTH hydrophobic & hydrophilic parts
4 main roles of the cell (plasma) membrane
- Barrier
- Communication
- Import & Export
- Electrical capacitor
What is the cytoskeleton?
Network of protein fibres
Main roles of the cytoskeleton
- Maintenance of shape
- Cell division
- Movement of particles
What is cytosol?
Fluid portion of the cytoplasm exclusive of organelles & membranes
What does the cytoplasm contain?
- High concentration of proteins
- tRNAs
- Free ribosomes
- Inclusion bodies
Role of the nuclear envelope
Separate contents of the nucleus from the cytoplasm
Function of the nucleus
Site of RNA synthesis & processing
What does the nucleus contain?
Nucleoplasm, chromosomal DNA + histones
Role of the nucleolus
Site of ribosome synthesis
What is the endoplasmic reticulum (ER)?
Network of interconnected membrane vesicles
What is the cisternae?
Flattened membrane vesicle found in the ER & golgi apparatus
Role of the Rough ER (rER)
Synthesis of secreted & transmembrane proteins
Role of the Smooth ER
Synthesis of lipids & steroid hormones
What is the golgi apparatus?
Stack of flattened membrane vesicles
Role of the golgi apparatus
Modification of proteins
Role of mitochondria
- Respiration, ETC
- Krebs cycle
What is the cristae?
High transmembrane protein in the inner mitochondrial membrane crucial for ATP production
Double membrane in mitochondria
Inner membrane folded into cristae
What are lysosomes?
Membrane-bound organelles found in animal cells
Role of lysosomes
Contain enzymes that can break down biological polymers
What are peroxisomes?
Degrade fatty acids & toxic compounds
Function of peroxisomes
Carry out oxidative reactions using molecular oxygen
Equation:
Enzyme catalase neutralises H₂O
2H₂O₂ → 2H₂O + O₂
Equation:
Detoxification of ethanol in the liver
C₂H₅OH + H₂O₂ → CH₃CHO + 2H₂O
