Human Physiology - Cells and Molecules of Life PDF

ASD 3003 Human Physiology L1 Cells and Molecules of Life 1 Chemistry of Life 2 Introduction 4 primary food substances are essential to maintain daily life of human Carbohydrates (碳水化合物) Lipids (脂類) Proteins (蛋白質)...

ASD 3003 Human Physiology L1 Cells and Molecules of Life 1 Chemistry of Life 2 Introduction 4 primary food substances are essential to maintain daily life of human Carbohydrates (碳水化合物) Lipids (脂類) Proteins (蛋白質) Water 3 2. Carbohydrates Contain carbon, hydrogen and oxygen Found in rice, bread, fruit, etc. Three classes: Monosaccharides (simple sugars) (單醣類) Disaccharides (double sugars) (雙醣類) Polysaccharides (多醣類) 4 Molecular structure of a monosaccharide  Class Example Made up of Characteristics Major end-product of carbohydrate digestion Glucose (葡萄糖) - Broken down during respiration to release Monosaccharide energy Sweetest simple sugar Fructose (果糖) - Commonly found in fruit and honey Intermediate in the Maltose (麥芽糖) Glucose + Glucose digestion of starch Disaccharide Commonly known as table Sucrose (蔗糖) Glucose + Fructose sugar Major food reserve in Starch (澱粉) Glucose plants Glycogen (糖原/ Major carbohydrate stored Polysaccharide Glucose 肝糖) in animal Makes up the cell wall of Cellulose Glucose plants (纖維素) Indigestible by human 5 3. Lipids (脂類) Made up of carbon, hydrogen and oxygen Insoluble in water but dissolve readily in organic solvents e.g. alcohol, acetone (丙酮) and ethers (乙醚) Two types of lipids: Fats (semi-solid at room temperature) (脂肪) Oils (liquid at room temperature) (油脂) Triglyceride (三酸甘油酯) Subcategory of lipid made up of 3 fatty acid molecules and 1 glycerol molecule 6  Functions of Lipids Food reserve and energy source The fats (usually triglycerides) are important food reserve materials When carbohydrate storage is used up, fats are often used Structural materials Phospholipids (磷脂) are important compounds in the cell membranes Metabolic regulators Some hormones are lipids in nature, e.g. sex hormones Water-proof layer In mammals’ skin, sebaceous glands secrete oil to keep skin or for waterproof Protection Fat surrounding the internal organs e.g. kidney, act as shock 7 absorbance 4. Protein Made up of carbon, hydrogen, oxygen and nitrogen Other elements, such as sulphur (硫磺) and phosphorus (磷), are sometimes present The basic units of protein are called amino acids (胺基酸) Amino acids join together to form a polypeptide (氨基化合物) Polypeptides link together to form a protein 8 9  Denaturation & Renaturation Denaturation (使改變本性) The loss of the specific three-dimensional conformation of a protein molecule Amino acid sequence of the protein remains unaffected This leads to the loss of biological activities of the protein Renaturation The regain of the biological activities of the protein 10 Factors causing protein denaturation Heat or radiation Extreme pH Mechanical force Chemicals e.g. nonpolar solvents and detergents 11 5. Water 75% of human body is made up of water Water is a vital substance 12 Functions of Water Good solvent 溶劑  Medium for metabolic reactions  Dilute waste substances and prevent them from harming the body Temperature regulator Water has a high heat capacity Helps to maintain the body temperature Strong surface tension表面張力 Strong attraction between water molecules Water rises readily by capillary action (毛細作用) 13  Transporter  Waterin the blood carries nutrients from the foods we eat to tissues throughout the body Lubricant 潤滑劑 The synovial fluid helps joints move easily Water moistens food as it passes along the digestive tract, starting from saliva in the mouth and throat that makes swallowing easy, and ending with the passage of water-softened feces through the anus 14 6. ATP ATP (adenosine triphosphate) Source of energy for biological activities of the cell ATP ⇔ ADP + Pi + energy ADP (adenosine diphosphate) Converting ADP to ATP is a method for energy storage until it is needed 15  7. Nucleic Acids Two types of nucleic acids Deoxyribonucleic acid (DNA) 脫氧核糖核酸 Ribonucleic acid (RNA) 核糖核酸 DNA acts as the genetic materials of all organisms Transcription 轉錄 Translation翻譯 DNA RNA Protein 16 8. Mineral Salts and Ions Mineral Functions salts and ions 1) Constituent of bones and teeth 2) It is involved in Calcium blood clotting and muscle contraction Chlorine Maintain the balance between anion and cation Phosphate Constituent of nucleic acids, ATP, bones and teeth Fluorine It is important in improving resistance to tooth decay Iodine It is the component of growth hormone and thyroxine It is the constituent of many enzymes, haemoglobin Iron and Myoglobin 17 Cells & Tissues 18  A generalized human cell showing the principal organelles Rough endoplasmic reticulum Smooth endoplasmic reticulum 19 1. Cell Membrane / Plasma Membrane 細胞膜 Covers the surface of every living cells, enclose (包圍) the cytoplasm Composed of 2 layers of phospholipid molecules  phospholipid bilayer Proteins scatter (散佈) amongst phospholipids, functioning as receptors (受 體) and transport proteins (運輸蛋白) Function: Controls the movement of materials into and out of the cells 20 2. Cytoplasm細胞質 Fluid, jellylike substance between the cell membrane and the nucleus in which organelles are suspended Function: Serves as matrix substance for chemical reactions to occur 21 3. Nucleus細胞核 The largest organelle, it contains the DNA of the cell Functions: Direct the cell’s activities Contains DNA for protein synthesis 22 4. Mitochondrion線粒體 Mitochondria (plural) Function: Release energy from food molecules and transform energy into ATP No. of mitochondria in the cell depends on the cell’s energy needs Rod-shaped (棒形) structure Bound (包圍) by two membranes Example? Outer membrane → smooth Inner membrane → deeply folded 23 5. Endoplasmic Reticulum (ER, 內質網) A network of interconnected membrane throughout the cytoplasm 2 types of ER: Rough ER (RER) Area of ER where ribosomes attached Helps to synthesize proteins made by ribosomes Smooth ER (SER) Area of ER where NO ribosomes attached Helps to synthesize and metabolize carbohydrates, lipids & other non-protein 24 materials Organelle / component Function Plasma (cell) membrane Controls materials in and out of cell Cytoplasm Serves as matrix substance for chemical reactions to occur Endoplasmic reticulum Rough ER: Assist protein synthesis (ER) Smooth ER: Metabolize nonpolar compound Ribosome核醣體 Protein synthesis Golgi Complex Synthesize carbohydrate and pack molecules 高爾基複合體 for secretion Mitochondrion Transform energy from food to ATP Lysosome溶酶體 Digest foreign molecules, and worn and damaged organelles Nucleus Contains DNA and directs cell activity Nuclear membrane Control material in and out of the nucleus 25 Nucleolus Produce ribosomal RNA for ribosomes Levels of Organization in the Body 26 27 Levels of cellular organization Atoms Molecules Cell organelles Cellular E.g. oxygen (O), E.g. proteins, E.g. nucleus, level hydrogen (H) carbohydrates cell membrane Chemical level Cells E.g. neurons, Cell differentiation: the process that muscle cells cell develops into different cell types Organ Systems Tissues E.g. nervous system, Tissue E.g. nervous tissue, system digestive system level muscle tissue level Organs Organismal Organism E.g. heart, liver, Organ level E.g. human! brain, lung level 28  Levels of Organization in the Body Chemical Atoms combined to form molecules Cell Cells are made of molecules Tissue Consists of similar types of cells Organ Made up of different types of tissues (Organ) System Consists of different organs that work closely together Organism 29 Made up of the organ systems The Primary Tissues Muscle Tissue肌肉組織 Nervous Tissue神經組織 Epithelial Tissue上皮組織 Connective Tissue結締組織 30  Skeletal muscle 1. Muscle Tissue For contraction Types Skeletal骨骼肌– attached to bones at both end by tendons肌腱 Cardiac心肌- heart Smooth平滑肌– digestive tract, blood vessels, urinary and reproductive systems Cardiac muscle 31 Smooth muscle 2. Nervous Tissue Composed of neurons神經元(nerve cells) and supporting cells Neuron: for generation and conduction of electrical events and neural signals Supporting cells: support neurons 32  3. Epithelial tissue Two categories: epithelial membrane and glands Epithelial membrane One cell layer (simple membrane) or multiple layers (stratified membrane) which cover the body surfaces and line the cavity (lumen) of hollow organs Three types based on their cell shape: Squamous epithelium e.g. capillary walls, pulmonary alveoli, epidermis of skin Columnar epithelium e.g. lining of digestive tract Cuboidal epithelium e.g. lining of kidney tubules, ducts of exocrine glands Allow constant loss and renewal of cells 33  4. Connective tissue Consists of connective tissue cells and large amount of extracellular material 細胞外物質in the spaces between cells Different types of connective tissue: Connective tissue proper, contain matrix of collagen and tissue fluid Loose connective tissue (or areolar tissue) e.g. dermis of skin Dense connective tissue e.g. tendon, ligament Cartilage軟骨, contain matrix of collagen Bone, contain matrix of collagen and calcium phosphate Blood, contain matrix of plasma Adipose tissue脂肪組織, specialized connective tissue contains numerous fat globules 34  tendon blood bone cartilage Adipose tissue dermis of skin 35 Organ Systems of the Body Circulatory system (循環系統) Cardiovascular system Lymphatic system Respiratory system (呼吸系統) Digestive system (消化系統) Urinary system (泌尿系統) Musculoskeletal system (肌肉骨骼系統) Muscular system Skeletal system Immune system (免疫系統) Sensory system (感覺系統) Nervous system (神經系統) Endocrine system (內分泌系統) Reproductive system (生殖系統) 36 Integumentary system (外皮系統) Cell? Tissue? Organ? System? 37 Chemical Signals化學信號 (used by cells, receptors, target cells, signal transduction pathway 信號轉導通路) 38 Cell Signaling Cells communicate by signaling each other chemically These chemical signals are regulatory molecules (chemical messegers化學信使) released for: Paracrine signaling 旁分泌信號 Synaptic signaling 突觸信號 Endocrine signaling內分泌信號 39  Cells release regulatory molecules that affect nearby cells within an organ. Neurons release regulatory molecules that affect their target cells. 神經遞質 激素 內分泌腺 Endocrine glands release regulatory 40 molecules that travel in blood to target cells.  How to receive chemical messengers? Receptors受體: Protein that specially bind chemical messenger with high affinity to convey signals from the outside of the cell to the inside (signal transduction pathway) Act as transcription factor to alter gene transcription Example of signal transduction pathway for lipid Example of signal transduction pathway 41 insoluble messenger - cAMP system for lipid soluble messenger e.g. steroid hormone Important Words Carbohydrate Protein Glucose Amino acid Fructose Denature Maltose Nucleic acid – DNA, RNA Sucrose ATP Starch Cell membrane Glycogen Cytoplasm Lipids Mitochondria/ Mitochondrion Triglyceride Nucleus 42