CELLULAR COMPONENTS & PROCESES CELLS CELLULAR COMPONENTS & PROCESES

MODERN CELL THEORY The cell is the unit of structure and function in living things. All cells arise from preexisting cells. The cells of all living things carry on similar chemical activities. All cells carry on their metabolic activities in organelles.

There are two types of cells: Prokaryotic- cells that DO NOT have a nucleus or other cell ORGANELLES Eukaryotic- cells with a NUCLEUS & cell ORGANELLES Which is more complicated? REMEMBER YOU ARE EUKARYOTIC!

All cells have the following organelles: The parts of a cell that carry out a function are called cell ORGANELLES: All cells have the following organelles: Cell Membrane Cytoplasm Ribosomes Cytoskeleton

Eukaryote cells ALSO have: Nucleus Nucleolus Mitochondria Golgi Body Complex Endoplasmic Reticulum Vacuole Lysosome Centrioles (ANIMAL ONLY) Only Plant Cells have all of the above &: Cell Wall Chloroplast

organelles little “organs” of the cell Organelles are present in BOTH plants and animals Carry out cellular functions!

Nucleus cellular control center Controls cellular activity contains hereditary material (DNA in chromosomes) self duplicating structure -divides when the cell divides

Nuclear membrane surrounds nucleus allowing certain materials to enter and leave

Nucleolus round organelle in the nucleus usually a pair involved with the synthesis of RNA in the ribosomes

Ribosomes sites of protein synthesis in the cytoplasm may be free in the cytoplasm or attached to the endoplasmic reticulum

Endoplasmic reticulum (ER) cytoplasmic channels from the cell membrane to the nuclear membrane associated with the storage, synthesis, and transport of materials within the cell “HIGHWAY” for cell transport

Cytoplasm (protoplasm) fluid like material between the cell membrane and the nucleus over 80 % water “HOLDS” cell organelles in place site of most organelles and cellular chemical reactions

Vacuole membrane bound cytoplasmic spaces containing materials ** Vacuoles are crucial in single-celled organisms Two Types: Food vacuole--store and digest ingested food Contractile vacuole-pumps excess water from cells maintaining homeostasis

Lysosome pouch containing digestive enzymes digest bacteria and some foods entering the cell Breaks down complex molecules into simpler molecules (SLICE) breakdown worn out cell organelles

Mitochondrion "Powerhouse of the cell" carries on cellular respiration (contains respiratory enzymes that make ATP) (energy molecule) may contain DNA--is self duplicating-- divides when the cell divides found in greater #s in active cells

Golgi apparatus (complex) usually located near the nucleus synthesizes, packages, and secretes cellular products Packages waste & harmful materials

Plasma (cell) membrane The cell membrane is SEMI-PERMEABLE selectively regulates the flow of materials to and from the cell--thus maintaining chemical homeostasis within the cell The membrane acts like a BOUNCER only allowing certain things in and out of the cell It is made up of a lipid bilayer double layer of FAT - "Fat sandwich" transport through the plasma membrane likely occurs through these globular proteins (Fluid mosaic model)

Hydrophilic- attracts water Hydrophobic- repels water Why is it important that the cell membrane is made up of small phospholipids?

ANIMAL CELL ORGANELLES ONLY Centriole- a cylindrical structure found in the cytoplasm which appears to function during the division of certain animal cells (usually near the nucleus) Helps animal cells divide

PLANT CELL ORGANELLES ONLY Cell Wall- a nonliving structure which surrounds and supports the cell - composed mostly of cellulose Gives the plant cell structure & support Chloroplasts- green in color-double membrane - contain the green pigment chlorophyll which carries on photosynthesis Uses the sun’s energy to make food for the plant

photosynthesis the conversion of light energy to chemical energy by chlorophyll in chloroplasts Overall Net equation for photosynthesis: 6 Water + 6 Carbon dioxide yields glucose + 6 oxygen (when catalyzed by chlorophyll in the presence of sunlight)

Levels of Tissue Organization cell - unit of structure of all life tissue - composed of groups of similar cells organs - composed of groups of tissues functioning together organ systems - composed of groups of organs functioning together

Types of transport in Cells Passive transport - movement of substances through a membrane from a region of high to a region of low concentration - no energy needed (ATP) - diffusion and osmosis are examples of this Active transport - movement of substances through a membrane from a region of low concentration to a region of high concentration - requires cellular energy (ATP)

Whether passive or active transport is needed depends on the CONCENTRATION GRADIENT The concentration gradient is the difference in the concentration of a substance in two different spaces Concentration - the amount of a particular substance in a contained area compared with the amount of the same substance in another area Translation: Amount of something in a space (water, salt, sugar, iron,)

PROCESSES OF THE PLASMA MEMBRANE There are two types of passive transport: Diffusion and Osmosis The goal of both diffusion and osmosis is to reach EQUILIBRIUM within the cell Equilibrium is a condition in which the movement in one direction is equal to the movement in another direction

Diffusion the tendency of molecules to move from an area of higher concentration to an area of lower concentration (concentration gradient- diff in conc. between 2 regions)

Osmosis movement of water through a membrane from a region of higher to lower con. Solute - substance being dissolved in a liquid (ex. salt) Solvent - substance doing the dissolving (ex. water) Permeability - the extent to which a membrane will allow particular sized molecules to pass Semi-permeable membrane (selectively permeable)-allows some molecules to pass but not others

So, describe how “Kool-Aid”® is made with regard to the terms “solute” and “solvent”. What is the “universal solvent”?

When comparing two solutions there are three possible relationships, We Identify the relationships by determining what would happen if a cell were placed in the solution. Hypertonic- A solution that causes a cell to shrink because of osmosis. Meaning water leaves the cell. Hypotonic- A solution that causes a cell to swell because of osmosis meaning water rushes into the cell. Isotonic-A solution that causes no change in cell size. Meaning there is no movement of water.

If the fluid outside the cell has… Then the outside fluid is… Water moves… Effect on the cell? …less water than is present inside the cell …more water than is present inside the cell …same amount of water as inside the cell

So, answer this question… So, answer this question…. Why do “establishments” offer free popcorn, peanuts, and pretzels to their patrons if they are serving beverages? What changes are taking place in the body to initiate the need for more beverages?

Active Transport- the movement of a substance against the concentration gradient. (uphill) Active transport requires cell to USE ENERGY

Sodium pump - transports three sodium ions out of the cell and two potassium ions into the cell Both are against the concentration gradient The energy needed to perform this activity is supplied by ATP (adenosine tri-phosphate) ATP is a unit of energy made by the cell

Endocytosis- the movement of a substance into the cell by a vesicle Endocytosis- the movement of a substance into the cell by a vesicle. A vesicle is a form of packaging that is used by cells. Exocytosis- the movement of a substance out of the cell by a vesicle. Phagocytosis- cytoplasm of cell surrounds and engulfs particle--ex. ameba and white blood cell Pinocytosis- plasma membrane "pinches in" to permit entry of molecules too large to diffuse through