Cells - Biology Notes PDF

## Cells - Basic unit of life - Takes in raw materials and processes them to make new molecules. ### Microscopic Materials: - Light microscope: magnifies 1000x - Electron microscope: magnifies 200,000x - Colored light micrograph produces biw bue can be artificially colored. ### Parts of a Cell...

## Cells - Basic unit of life - Takes in raw materials and processes them to make new molecules. ### Microscopic Materials: - Light microscope: magnifies 1000x - Electron microscope: magnifies 200,000x - Colored light micrograph produces biw bue can be artificially colored. ### Parts of a Cell - Each living cell consists of living material called protoplasm (including nucleus, cytoplasm) ### Nucleus - Surrounded by nuclear membrane. - Contains genetic material for cell division. - Controls cell activities such as growth and repair. - Important for cell division. ### Cytoplasm - Jelly like substance embedded with organelles. - Each organelle has a specific function. - Site where cellular activities occur. ### Cell Membrane - Partially permeable membrane made of lipids and proteins. - Controls substances entering or leaving the cell. ### Cell Wall - Outermost part of the cell made up of cellulose. - Fully permeable to small molecules. ### Smooth Endoplasmic Reticulum - Tube like structure. - Looks smooth as there is some s. - Synthesizes proteins in general (ex. hormones). - Makes & stores lipids and steroids. - Converts harmful substances in the cell to harmless substances through detoxification. ### Golgi Body - Stack of flattened spaces surrounded by membranes. - Made up of vesicles. - Processes fat and proteins made in sER & RER. - Stores and packages them in vesicles which transport them out of the cell. - Stores and packages substances in vesicles for secretion. ### Vacuole - Fluid filled space. - Large and central in plant (contains cell sap, enclosed by PPM). - Small and numerous (enclosed by membrane, exist temporarily). - Cell sap contains dissolved sugars, mineral salts and amino acids. - Vacuole in animal cells store water, food substances. ### Mitochondrion - Small, oval shaped. - Enclosed by a double membrane. - Inner membrane very folded. - Site where aerobic respiration occurs. - Provides energy for cell activities like growth and reproduction (when food substances are oxidized during aerobic respiration). ### Chloroplast - Oval. - Contains chlorophyll which is in stacks of membranes. - The site of photosynthesis. - Essential for photosynthesis. ### Vesicle - Moves from Golgi apparatus. - More molecules, secretes substances, digests materials, regulate pressure. ### Specialized Cells **Differentiation :** How a cell becomes specialized for a specific function **Red Blood Cell** - **Shape:** Circular biconcave shape. Increases SA: V ratio for increased rate of O2 uptake via diffusion, and rate of O2 transport. - **No cell division:** Absence of nucleus: Allows packing of more hemoglobin for increased rate of O2 transport. - **Flexible cell surface membrane:** Allow cell to alter shapes to easily squeeze through narrow capillaries for continuous increased rate of O2 transport. **Muscle Cell** - **Contains hemoglobin:** Binds to oxygen and transport it around the body. - **Contains many mitochondria:** Release more energy via respiration for contraction of the muscle cell. - **Has contractile protein fibers:** Contract and relax to bring about the movement. - **Elongated and cylindrical:** Allows for easy arrangement into parallel arrays which increases the strength of muscle. - **Has many nuclei:** To allow for more synthesis and secretion of skeletal muscle proteins to support increased rate of muscle contraction & cell div, for cell replacement. **Root Hair Cell** - **Long, narrow protrusion:** Increase SA:V to increase rate of absorption of w.m and mineral ions. - **Water potential lower in cell sap:** Maintains a steep water potential gradient to allow w.m to continuously enter the cell by osmosis. - **Numerous mitochondria:** Release more energy via respiration to increase rate of respiration to increase rate of active transport for absorption of minerals and ions. - **Uniformly thin cell wall:** Reduces distance for diffusion to increase rate of absorption of the water and ions. ### Ribosomes - **Animals:** - Small ribosomes make proteins used within the cell. - Onede usually synthesize proteins transported by for export or membranes. - **Plants:** - Large ribosomes make proteins used within the cell, for export or membranes. - Onede usually synthesize proteins transported by for export or membranes. ### Protein Transporting - **Step 1:** Protein vesicles pinched off from RER. - **Step 2:** Travel towards Golgi apparatus and fuse to release their contents. - **Step 3:** Proteins become chemically modified, packaged, and coated by Golgi. - **Step 4:** Secretory vesicles formed from Golgi travel to the cell membrane and fuse. - **Step 5:** Secreted out of cell.