基礎生物實驗 7 - 實驗三理論簡介：Cell Types and Structure
本期內(nèi)容是 細胞種類與結構?的基礎理論部分，實驗手冊與實驗模擬請看后兩期。本部分內(nèi)容來自 University of California, Berkeley - UC Berkeley Extension, 虛擬實驗的內(nèi)容來自 Labster. 本部分內(nèi)容均不會標記為為原創(chuàng)，但由于是UP主購買的課程，因此不接受非授權的轉載，謝謝您的理解。
每一個生物基礎實驗均會分為三部分：第一部分為實驗的生物理論；第二部分為實驗的指導手冊；第三部分為 Labster?的虛擬實驗模擬。第一部分的基本信息由 Ying Liu, Ph.D. 提供，第二部分的實驗手冊來自 Labster, 第三部分的實驗模擬過程由UP主操作。
Lab 3 - Cell Structure: Basic Information
(Theodosius Dobzhansky, Russian biologist, 1973)
將進化的時間按比例化為一年：
Phylogenetic Tree
????Unity: all life on Earth came from one universal ancestor (bacteria, fungi, plants and animals all use DNA as genetic code).
????Diversity: organiSms adapted to local environment, leading to ‘a(chǎn)daptive radiation.’
Prokaryotes and Eukaryotes
????Prokaryotes: -kary = nucleus; pro- = before
????Domains Bacteria and Archaea (0.1 - 5 μm)
????Eukaryotes: -kary = nucleus; eu- = true
????Domain Eukarya (10 - 100 μm)
Prokaryotes vs. Eukaryotes
????Despite structural differences, common metabolic activities
????Eukaryotic cells: more compartmentalization
Microscopes
????Antonie van Leeuwenhoek: manufactured simple microscopes
????????- First to observe and describe bacteria, yeast, protists in rain water, etc. (~1674)
????Robert Hooke: English father of microscopy
????????- Observed ‘cells’ found in a cork (1665)
????? ? - Reaffirmed Leeuwenhoek’s findings later upon improvement of the microscope design
https://th.bing.com/th/id/OIP.s5O1-xc5-_RYh8oxaZCZgQHaJJ?pid=Api&rs=1
Cell Theory
????Matthias Schleiden: Plants were made of cells
????Theodor Schwann: Animals were made of cells
????Rudolf Virchow: Cells were derived from other cells
????Robert Remak: First to describe cells came from other cells
Life in the world - made of two types of cells: eukaryotic and prokaryotic cells.
Prokaryotic Cell
????DNA in the nucleoid region
????Have 70S ribosomes
????Bacterial cell wall contains peptidoglycan
Cyanobacteria
????Photosynthetic prokaryotes
????Also called ‘blue green algae’
????Gave rise to chloroplasts
Eukaryotic Cell Evolution 1:
????- Infolding of plaSma membrane forms the nucleus and the endomembrane system;
????- Nuclear membrane (envelope), ER membrane, Golgi apparatus and plaSma membrane make up a continuous membrane system, with vesicles travel in between.
Endomembrane System
????- EndoplaSmic reticulum (ER) makes lipids and proteins;
????- Golgi apparatus is involved in protein trafficking;
? ??- Lysosomes are where intracellular digestion occurs.
Lysosome
????- Lysosome contains digestive enzymes that can break down large molecules;
????- Phagocytosis: engulfment (food, bacteria, etc.).
Eukaryotic Cell Evolution 2:?
????- Endosymbiosis explains the development of mitochondrion (proteobacterium) and chloroplast (cyanobacterium);
????- Primitive eukaryotic cell engulfed a proteobacterium capable of aerobic respiration, which became a mitochondrion;
????- Later, eukaryotic cell engulfed a cyanobacterium, which became a chloroplast.
????- Mitochondria and chloroplasts both contain their own DNA and ribosomes;
????- Their DNAs are circular (prokaryote) not linear (eukaryote);
????- Their ribosomes are more similar to bacterial ribosomes (70S) not to eukaryotic ribosomes (80S);
????- Both reproduce by binary fission;
????- Mitochondria can be affected by antibiotics.
DNA
????- Prokaryotic DNA: 1 circular DNA;
????- Eukaryotic DNA: multiple linear DNA wrapped around histones to form chromosomes.
Ribosome - in both?eukaryotic and prokaryotic cells
????- Composed of rRNA (60%) and proteins (40%)
????- Prokaryotic ribosomes: 70S (30S + 50S)
????- Eukaryotic ribosomes: 80S (40S + 60S)
Key Cellular Structures
- Smooth ER: synthesis of lipids;
- Rough ER: synthesis of proteins;
- Golgi: sort & deliver secreted & membrane proteins;
- Lysosome: digest food, worn out organelles, etc.
Animal Cell:
Plant Cell:
Cytoskeleton
- Three types of cytoskeleton:
????Actin filaments: long protein strands (thin, 7 nm)
????Intermediate filaments: ropelike strands (10 nm)
????Microtubules: long hollow tubes (thick, 25 nm)
Extracellular Matrix (ECM)
????ECM contains protein fibers (collagen), proteoglycans, (polysaccharides),?etc.?
????Contributes to adherence (bind adjacent cells to form tissue) and signal reception (communication).
Cell Junctions
????- Tight junctions: watertight seal between adjacent cells (skin);
????- DeSmosomes link adjacent cells, provide mechanical strength;
????- Gap junctions: channels between adjacent cells, allowing transport and communication.
Tissue:
????Tissue: a collection of cells of the same type that perform a common function
????There are 4 major tissue types in the body:
????????- Epithelial: covers body surfaces and lines body cavities
????????- Connective: binds and supports body parts
????? ? - Muscular: moves the body and its parts
????????- Nervous: receives sensory information and conducts nerve impulses
Epithelial Cells
????- Polarity: apical side facing the Small intestine lumen; basal side;
????- Tight junctions around the apical region maintain the polarity.
Bone Cells (Osteocytes)
????- Cells (osteocytes) are connective tissues?in chambers called lacunae;
????- Solid and rigid matrix is made of collagen and calcium salts.
????- Osteon: functional unit of compact bone;
????- Canaliculi: canals between the lacunae.
Muscle Cells (Myocytes)
????- Skeletal muscle: long striated fibers, attached to bone, voluntary movement;
????- Sarcomere: contractile unit of muscle.
????- Sarcomere is a structure only present in muscles.
Nerve Cells (Neurons)
- Neuron: 1 axon (long projection) and multiple dendrites (short projections).
感謝閱讀！下一期為實驗手冊 & 下下期將進行 Labster 實驗！
