Bio Module 2 - OCR A level

• Prokaryotic cells do not have a nucleus and membrane-bound organelles
• Prokaryotes evolved before eukaryotes
• Eukaryotic cells have a nucleus and membrane-bound organelles
• Eukaryotic organisms include all kingdoms except Monera
• Kingdoms made up of eukaryotic cells: Plant, Animal, Fungi, Protista
• Eukaryotic organisms can be unicellular or multicellular
• All eukaryotic cells have membrane-bound organelles for compartmentalisation
• Cytosol/cytoplasm is the site for cellular activities
• Cell-surface membrane is selectively permeable, controls and regulates cell functions, and increases surface area with microvilli
• Nucleus contains nuclear envelope, pores, nucleolus, chromatin, and condenses into chromosomes before cell division
• Ribosomes are macromolecules made of RNA and proteins, site of protein synthesis
• Endoplasmic reticulum (ER) is a network of sacs, Rough ER has ribosomes and is involved in protein synthesis, Smooth ER is involved in lipid production
• Golgi Apparatus modifies proteins and lipids, packages them into vesicles for transport
• Lysosomes are vesicles containing enzymes for digestion
• Mitochondria are the site for cellular respiration, have two membranes and compartments
• Mitochondria are abundant in muscle cells, different shapes and sizes due to different functions
• Cytoskeleton is made of microfilaments, intermediate filaments, and microtubules for cell structure, support, and transport
• Intermediate filaments help cell resist compression forces
• Microtubules provide support and stability for cell shape
• Microtubules hold organelles in place, such as anchoring the nucleus
• Microtubules are involved in transport within cells during protein synthesis
• Microtubules are used as tracks by motor proteins to transport structures within the cell
• Microtubules are involved in the transport of mRNA within the cell
• Motor proteins use microtubules for the transport of structures within the cell
• Microtubules are involved in the movement of transport vesicles within the lumen of the RER
• Microtubules are involved in the movement of transport vesicles from the RER to the Golgi apparatus
• Microtubules are involved in the movement of vesicles between the RER/SER of the Golgi apparatus
• Microtubules are involved in the movement of secretory vesicles from the Golgi to the plasma membrane
• During mitosis, microtubules allow attachment points for spindle fibers at the poles
• During mitosis, microtubules allow movement of chromosomes to opposite poles
• Cell movement involves microtubules to divide the cell into two after mitosis
• Microtubules are involved in the movement of the plasma membrane, for example, in propelling the cell forward like in sperm
• Microtubules in flagella produce a wafting motion to move substances outside the cell, such as mucus
• Examples of structures formed from microtubules include Centrioles, spindle fibers, and Flagella and cilia
• Features found only in plant cells include Chloroplast, the site of photosynthesis
• Chloroplast is the site of photosynthesis, involving many reactions separated into two stages: Light-dependent reactions and Light-independent reactions
• The origin of the evolution of the chloroplast is likely to be endosymbiosis with evidence such as the presence of specific structures
• Large permanent central vacuole in plant cells contains pigments like anthocyanins and cell sap
• Cellulose cell wall in plant cells provides structural support and strength, increased by the presence of lignin in wood
• Cellulose cell wall provides mechanical support and has high tensile strength