Bio II Quarter 1 DCA 1-1 (1) PDF

Quarter 1 1  Homeostasis What is homeostasis? Maintenance of an internal balance needed for survival What is an example of homeostasis? Cells are the Basic Unit of Life. Cell Theory: What is it?  Many scientists contributed to the cell theory. The cell t...

Quarter 1 1  Homeostasis What is homeostasis? Maintenance of an internal balance needed for survival What is an example of homeostasis? Cells are the Basic Unit of Life. Cell Theory: What is it?  Many scientists contributed to the cell theory. The cell theory grew out of the work of many scientists and improvements in the microscope. Early studies led to the development of the cell theory. The cell theory has three principles: All organisms are made of cells. All existing cells are produced by other living cells. The cell is the most basic unit of life.  The cell theory grew out of the work of many scientists and improvements in the microscope. Many scientists contributed to the cell theory. More was learned about cells as microscopes improved. The cell theory is a unifying concept of biology.  All cells share certain characteristics. Cell Membrane All cells contain DNA. All cells are enclosed by a membrane. All cells are filled with Cytoplasm cytoplasm. Bacterium (colored SEM; magnification 8800x)  There are two cell types: eukaryotic cells & prokaryotic cells. Eukaryotic cells have a Prokaryotic cells do not nucleus. have a nucleus. Eukaryotic cells have Prokaryotic cells do not membrane-bound have membrane-bound organelles. organelles. nucleus cytoplasm organelles cell membrane Eukaryotic cells share many similarities. Cells have an internal structure.  Cells have an internal structure. The nucleus stores genetic information.  Cells have an internal structure. The nucleus stores genetic information. Many processes occur in the endoplasmic reticulum.  Cells have an internal structure. The nucleus stores genetic information. Many processes occur in the endoplasmic reticulum. There are two types of endoplasmic reticulum.  Cells have an internal structure. The nucleus stores genetic information. Many processes occur in the endoplasmic reticulum. There are two types of endoplasmic reticulum. rough endoplasmic reticulum  Cells have an internal structure. The nucleus stores genetic information. Many processes occur in the endoplasmic reticulum. There are two types of endoplasmic reticulum. rough endoplasmic reticulum smooth endoplasmic reticulum  Cells have an internal structure. Ribosomes link amino acids to form proteins.  Cells have an internal structure. Ribosomes link amino acids to form proteins. Mitochondria supply energy to the cell.  Cells have an internal structure. Ribosomes link amino acids to form proteins. Mitochondria supply energy to the cell. Vacuoles are fluid- filled sacs that hold materials.  Cells have an internal structure. Ribosomes link amino acids to form proteins. Mitochondria supply energy to the cell. Vacuoles are fluid-filled sacs that hold materials. Lysosomes contain enzymes to digest material.  Descriptions of Organelles l Nucl ontros The ceu f the Mitochon cen ter o ning ontai Breaks down sugar dria cell c ot to release energy (n DNA t in and transfer it into a res e n p ryotic molecule (ATP) used prok a to carry out all of the cells) cell’s processes Lysoso Break mes down and detoxify waste material in the cell Riboso mes Golgi Body Processes and packages materials Follows into vesicles to be instructions from removed from the the nucleus to cell. create proteins for use inside and outside of the cell  Descriptions of Organelles Cell Cytopla Wall Rigid structure outside the cell sm Jelly-like membrane. substance that the Provide support for organelles are cell and protection within Cell Membran Barrier between e the inside of the cell and the cell’s environment. Chlorop Protects the cell Photosynthesis occurs within; and regulates last the plant creates its own sugar what comes in and out. Contain chlorophyll which gives them their green color and helps absorb sunlight Vacuol e structure Fluid filled containing nutrients, Think water, and waste. Plants have one large vacuole to about store extra water needed. which of Most animals have several these small vacuoles only exist in plant cells Macromolecules are the foundation of Life! Carbon is found in all things that are, or once were, living. This is true for Macromolecules, which are carbon based & essential for life. Macromolecules can also be referred to as Carbon-Based Molecules or Biomolecules. Many carbon-based molecules are made of many small subunits bonded together. Monomers are molecules that bond together with other identical molecules to form polymers. Monomers are the individual subunits. Polymers are made of many monomers. What is the difference between a monomer and polymer? Carbohydrates are made of carbon, hydrogen, and oxygen. This is a monomer for carbohydrates which is Glucose! C6H12O6 –Remember this!  Function: Carbohydrates are broken down in order to provide energy for the organism. They are an organisms main source of Examples: sugarsenergy. and Monosaccharides are simple starches. sugars. Disaccharides such as lactose (in milk). Polysaccharides include starches, cellulose, and glycogen.  Carbohydrates can be broken down to provide energy for cells. -Some carbohydrates are part of cell structure. Polymer (starch)-sugars Starch is a polymer of glucose monomers that often have a branched structure. Polymer (cellulose)-plants/leaves monomer Cellulose is a polymer of glucose monomers that have a straight, rigid structure Lipids are nonpolar molecules that include steroids (ex. sex hormones), waxes, fats, oils, and cholesterol. Many contain carbon chains called fatty acids. Fats and oils contain fatty acids bonded to glycerol (monomer). All Lipids are hydrophobic. Triglyceride Lipids have several different functions. broken down as a source of energy make up cell membranes used to make hormones  Phospholipids make up all cell membranes. Polar phosphate “head” Nonpolar fatty acid “tails” Phospholipid= phospho- (combining) + -lipid (fatty acid)  Proteins are polymers of amino acid monomers. Involved in nearly all cellular funtions. 20 different amino acids are used to build proteins in organisms. What elements make up this amino acid monomer? Proteins differ in the number and order of amino acids. Proteins are in charge of structuring the body’s tissues and organs. Amino acids interact to give a protein its shape. Incorrect amino acids change a protein’s structure and function. Nucleic Acids are polymers of monomers called nucleotides. Store, transport and express genetic information. Nucleic Acids are polymers of monomers called nucleotides. Nucleotides are made of a sugar, phosphate group, and a nitrogen base.  Nucleic Acids are polymers of monomers called nucleotides. DNA RNA Deoxyribonucleic Acid Ribonucleic Acid DNA stores genetic RNA builds information. proteins. The Cell Membrane 2 Cell membranes are composed of two phospholipid layers. The cell membrane is a barrier that separates a cell from the external environment. The cell membrane has two major functions. forms a boundary between inside and outside of the cell cell membrane controls passage of materials outside cell inside cell Cell membranes are composed of two phospholipid layers. Controls passage of materials There are other molecules embedded in the membrane. carbohydrate protein cell membrane chain cholesterol protein protein channel Cell membranes are composed of two phospholipid layers. Controls passage of materials The cell membrane is selectively permeable. Some molecules can cross the membrane while others cannot. The cell membrane is made up of a phospholipid bilayer.​ Hydrophilic heads​ Hydrophobic tails  Plasma Membrane Structure and Function The plasma membrane separates the internal environment of the cell from its surroundings. The plasma membrane is a phospholipid bilayer with embedded proteins. The plasma membrane has a fluid consistency and a mosaic pattern of embedded proteins. 4- 43 Fluid-mosaic model of membrane structure 4- 44  Cells live in fluid environments, with water inside and outside the cell. Hydrophilic (water-loving) polar heads of the phospholipid molecules lie on the outward-facing surfaces of the plasma membrane. Hydrophobic (water-fearing) nonpolar tails extend to the 4- 45 interior of the plasma  Plasma membrane proteins may be peripheral proteins or integral proteins. Aside from phospholipid, cholesterol is another lipid in animal plasma membranes; related steroids are found in plants. Cholesterol strengthens the 4- 46 plasma membrane.  Functions of plasma proteins Plasma proteins have a variety of functions. Some help to transport materials across the membrane. Others receive specific molecules, such as hormones. Still other membrane proteins function as enzymes. 4- 47  The Permeability of the Plasma Membrane The plasma membrane is differentially permeable. Macromolecules cannot pass through because of size, and tiny charged molecules do not pass through the nonpolar interior of the membrane. Small, uncharged molecules pass through the membrane, following their concentration gradient. 4- 48 Cell Membrane Processes Materials move across membranes because of concentration differences. Two types of movement: Passive Transport Diffusion Osmosis Active Transport Endocytosis Exocytosis  Movement of materials across a membrane may be passive or active. Passive transport does not use chemical energy; diffusion and facilitated transport are both passive. Active transport requires chemical energy and usually a carrier protein. Exocytosis and endocytosis transport macromolecules across plasma membranes using vesicle formation, which requires energy. 4- 50 How molecules cross the plasma membrane 4- 51  Chapter Summary The structure of the plasma membrane allows it to be differentially permeable. The fluid phospholipid bilayer, its mosaic of proteins, and its glycocalyx make possible many unique functions of the plasma membrane. Passive and active methods of transport regulate materials entering and exiting cells. 4- 52  Passive Transport Passive transport does not require energy input from a cell. Molecules can move across the cell membrane through passive transport. Active Transport, Endocytosis, and Exocytosis Cells use energy to transport materials that cannot diffuse across a membrane. High concentration  Low concentration  Active transport requires energy input from a cell and enables a cell to move a substance against its concentration gradient. Passive transport requires no energy from the cell. Active transport is powered by chemical energy (ATP). Active transport occurs through transport protein pumps. Cells use active transport to maintain homeostasis.  A cell can import and export large materials or large amounts of material in vesicles during the processes of endocytosis and exocytosis. Cells use energy to transport material in vesicles. Endocytosis is the process of taking material into the cell. Phagocytosis is a type of endocytosis. The cell engulfs large particles. Plays a large role in fighting infection.  A cell can import and export large materials or large amounts of material in vesicles during the processes of endocytosis and exocytosis. Cells use energy to transport material in vesicles. Exocytosis is the process of expelling material from the cell. 3  Active transport During active transport, ions or molecules are moved across the membrane against the concentration gradient – from an area of lower to higher concentration. Energy in the form of ATP is required for the carrier protein to combine with the transported molecule. 4- 59 Active transport 4- 60  Carrier proteins involved in active transport are called pumps. The sodium-potassium pump is active in all animal cells, and moves sodium ions to the outside of the cell and potassium ions to the inside. The sodium-potassium pump carrier protein exists in two conformations; one that moves sodium to the inside, and the other that moves potassium out of the cell. 4- 61 The sodium-potassium pump 4- 62 4- 63 4- 64 4- 65 4- 66  Exocytosis and Endocytosis During exocytosis, vesicles fuse with the plasma membrane for secretion. Some cells are specialized to produce and release specific molecules. Examples include release of digestive enzymes from cells of the pancreas, or secretion of the hormone insulin in response to rising blood glucose levels. 4- 67 Exocytosis 4- 68  Endocytosis During endocytosis, cells take in substances by invaginating a portion of the plasma membrane, and forming a vesicle around the substance. Endocytosis occurs as: Phagocytosis – large particles Pinocytosis – small particles Receptor-mediated endocytosis – specific particles 4- 69 Phagocytosis 4- 70 Pinocytosis 4- 71 Receptor-mediated endocytosis 4- 72  Diffusion and Osmosis Diffusion is the passive movement of molecules from a higher to a lower concentration until equilibrium is reached. Gases move through plasma membranes by diffusion. 4- 73  Diffusion Molecules diffuse down a concentration gradient from an area of HIGH concentration to LOW concentration. High concentration  Low concentration Process of diffusion 4- 75 4- 76 4- 77  Transport by Carrier Proteins Some biologically useful molecules pass through the plasma membrane because of channel proteins and carrier proteins that span the membrane. Carrier proteins are specific and combine with only a certain type of molecule. Facilitated transport and active transport both require carrier proteins. 4- 78  Facilitated transport During facilitated transport, substances pass through a carrier protein following their concentration gradients. Facilitated transport does not require energy. The carrier protein for glucose has two conformations and switches back and forth between the two, carrying glucose across the membrane. 4- 79  Facilitated Diffusion Some molecules cannot easily diffuse across the cell membrane. Some molecules can only diffuse through transport proteins. Facilitated diffusion is diffusion through transport proteins. Gas exchange in lungs by diffusion 4- 81 Facilitated diffusion of glucose 4- 82  Osmosis The diffusion of water across a differentially permeable membrane due to concentration differences is called osmosis. Diffusion always occurs from higher to lower concentration. Water enters cells due to osmotic pressure within cells. 4- 83  Osmosis Molecules still diffuse down a concentration gradient. Osmosis is the diffusion of water molecules across a semi-permeable membrane. Osmosis demonstration 4- 85 4- 86 4- 87  Osmosis in cells A solution contains a solute (solid) and a solvent (liquid). Cells are normally isotonic to their surroundings, and the solute concentration is the same inside and out of the cell. “Iso” means the same as, and “tonocity” refers to the strength of the solution. 4- 88  Hypotonic solutions cause cells to swell and possibly burst. “Hypo” means less than. Animal cells undergo lysis in hypotonic solution. Increased turgor pressure occurs in plant cells in hypotonic solutions. Plant cells do not burst because they have a cell wall. 4- 89 4- 90  Hypertonic solutions cause cells to lose water. “Hyper” means more than; hypertonic solutions contain more solute. Animal cells undergo crenation (shrivel) in hypertonic solutions. Plant cells undergo 4- 91 plasmolysis, the shrinking of 4- 92 Osmosis in plant and animal cells 4- 93 There are three types of osmotic solutions. 4 Water in the Human Body pH - percent Hydrogen: 0 – 14 Scale  pH (percent Hydrogen) - is a measure of the acidity( H+ ions) or alkalinity (OH- Hydroxide ions) of an aqueous solution. Solutions with a pH less than 7 are said to be acidic (more H= than OH-) and solutions with a pH greater than 7 are basic (more OH- than H+) or alkaline. Pure water has a pH very close to 7, where H+ = OH-. HUMAN BLOOD = 7.35 – 7.45  Water Polarity – Water (H2O) is a "polar" molecule, meaning that it has a (+) and (-)has Water charge. a partial neg. charge on the oxygen atom, & partial positive charges on the hydrogen atoms. Therefore; attracted to each other and or other polar substances.  The + and – attract, creating a Hydrogen bond between different water molecules and other polar substances. Water Polarity – Water (H2O) is a "polar" molecule, it has a (+) and (-) charge. Water has a partial negative charge on the oxygen atom, & partial positive charges on the hydrogen atoms. Cohesion (surface tension) vs Adhesion (capillary action)  COHESION – water molecules attracted and bound together forming bonds, creating surface tension. ADHESION – water molecules attracted to other objects or molecules, because of being polar, causes capillary action. Capillary Action = Water Adhesion