Cell Biology PDF

CELL Cell Is the basic unit of life. Classification of Cell Based on their Function Osteocyte Serves as your body's framework and also gives support, movements and protection. Chondrocyte Give flexible support. Neurons Transmit impulse and epithelial cell serve for protection, and absorption. HOW...

CELL Cell Is the basic unit of life. Classification of Cell Based on their Function Osteocyte Serves as your body's framework and also gives support, movements and protection. Chondrocyte Give flexible support. Neurons Transmit impulse and epithelial cell serve for protection, and absorption. HOW DO LIVING ORGANISMS GROW? -> CELL DIVISION TWO WAYS OF CELL DIVISION G1 or Gap 1 There are two checkpoints: DNA damage checkpoint Restriction checkpoint S or Synthesis stage DNA replicates G 2 or Gap 2 This is preparation for mitosis Organelles are replicated. More growth occurs. Prophase- Chromosome condense Microtubules form the nuclear envelope breaks down chromosome centromere centrioles Chromosomes are pulled to center of cell Line up along “metaphase plate” Centromeres divide Spindle fibers pull one set of chromosomes to each pole Precise alignment is critical to division Telophase- Nuclear envelope form around chromosomes Chromosomes uncoil Cytokinesis Two daugther cell are produced. CELLULAR TRANSPORT Terms to Know Concentration – the amount of solute in a solution. Solute – the dissolved substance in a solution. Solution – a mixture in which two or more substances are mixed evenly. Concentration gradient - the gradual difference in the concentration of solutes in a solution between two regions. Function of the Cell Membrane: Cell membrane separates the components of a cell from its environment—surrounds the cell “Gatekeeper” of the cell—regulates the flow of materials into and out of cell—selectively permeable Cell membrane helps cells maintain homeostasis—stable internal balance Types of Cellular Transport 1. Passive Transport- cell doesn’t use energy from high to low concentration Diffusion is the movement of small particles across a selectively permeable membrane like the cell membrane until equilibrium is reached. These particles move from an area of high concentration to an area of low concentration. Osmosis is the diffusion of water through a selectively permeable membrane like the cell membrane Water diffuses across a membrane from an area of high concentration to an area of low concentration. Semi-permeable membrane is permeable to water, but not to sugar Facilitated Diffusion is the movement of larger molecules like glucose through the cell membrane – larger molecules must be “helped” Proteins in the cell membrane form channels for large molecules to pass through Proteins that form channels (pores) are called protein channels Hypertonic Solutions: contain a high concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrivel.  Hypotonic Solutions: contain a low concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the cell to swell and possibly explode. Isotonic Solutions: contain the same concentration of solute as another solution (e.g. the cell's cytoplasm). When a cell is placed in an isotonic solution, the water diffuses into and out of the cell at the same rate. The fluid that surrounds the body cells is isotonic. 2. Active Transport- cell does use energy Protein Pumps from low to high concentration Endocytosis Exocytosis- Forces material out of cell in bulk membrane surrounding the material fuses with cell membrane Cell changes shape – requires energy Effects of Osmosis on Life Osmosis- diffusion of water through a selectively permeable membrane Water is so small and there is so much of it the cell can’t control it’s movement through the cell membrane. Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water)Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)!Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water)Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis)!Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsshrinks Isotonic: The concentration of solutes in the solution is equal to the concentration of solutes inside the cell.Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium)Osmosis Animations for isotonic, hypertonic, and hypotonic solutions CELL DIVISION AND CELL CYCLE Cell division is the process by which a parent cell divides into two or more daughter cells. Two types of cell division MEIOSIS-the type of cell division that creates egg and sperm cells (sex cells) MITOSIS-the process of making new body cells ?Why our cells Divide? 1. Repair APOPTOSIS- Programmed cell death. 2. GROWTH 3. Reproduction (Asexual) -mode of replicating themselves to increase their populations without the use of sex cells to produce a new organisms.Example: Singled Cell Organism-BACTERIA, AMOEBA, ALGAE CELL DIVISION CYCLE STAGES Cell Division can be divided into stages INTERPHASE-Preparation Stage 2. MITOSIS- the Nuclear Division Stage 3. CYTOKINESIS -the Cytoplasmic Division. 1. INTERPHASE-A non-dividing stage. -Preparatory stage before a cell division may proceeds. - 3 PHASES: G1 Phase S Phase G2 Phase 2. MITOSIS-A Dividing stage. -A process of Nuclear Division - 4 PHASES: PROPHASE METAPHASE ANAPHASE TELOPHASE 3. CYTOKINESIS- The Process of Division in cytoplasm