Cell Organelles and their Function

Cell Membrane Cytoplasm More on the cell membrane to come… Semi-permeable Regulates movement in & out Cytoplasm All the material from the nucleus to the cell membrane More on the cell membrane to come…

Nucleus Nucleolus Chromosomes Nuclear Envelope Control center of the cell Nucleolus Located inside the nucleus Ribosomes are made here Chromosomes DNA material seen in the nucleus Made up of Chromatin (DNA and proteins) Nuclear Envelope Encloses the nucleus See next slide for chromatin

Chromatin DNA wrapped around proteins A protein Chromatin condenses to form the chromosomes

Endoplasmic Reticulum Synthesizes and transports proteins (Rough ER) Synthesizes lipids and steroids (Smooth ER) Golgi Apparatus Collects, modifies, sorts, and secretes cell products Vesicle Picks up molecules from golgi apparatus and transports in cell or to other cells manufactures membranes and secretory proteins . In certain leukocytes (white blood cells), the rough ER produces antibodies . In pancreatic cells, the rough ER produces insulin.

Ribosomes Synthesize proteins during translation Free – in cytoplasm Bound – on rough ER

Lysosome Peroxisome Break down cellular waste products and debris Rid cells of hydrogen peroxide and other toxins

Mitochondria Creates energy through cellular respiration

Centrosome In animal cells only Play a role in cell division Help to organize cytoskeleton Animal cells have Centrioles which are paired structures within the centrosome Located near the nucleus

Vacuoles Central Vacuole (in plant cells only) Food vacuoles Contractile vacuoles Holds food, water and minerals Formed when particles are taken into the cell Pump water out of cells

In Plant Cells Only Chloroplast (example of plastid) Cell Wall Plastids – A double membrane bound organelle involved in the synthesis and storage of food, and is commonly found within the cells of photosynthetic organisms, like plants. Chloroplast (example of plastid) Site of photosynthesis in plants only Cell Wall Thick outer covering outside the cell membrane Protects and supports a plant cell

Cytoskeleton A network of protein filaments that organizes structures and activities in the cell. All help to maintain the cell shape and other specific functions See next slides

Components of the Cytoskeleton Microtubules Hollow tubes made of proteins known as tubulins Main Functions Cell motility (cilia and flagella) Chromosome movements in cell division Organelle movements

Components of the Cytoskeleton Microfilaments Two intertwined strands of actin (a protein) Main Functions Changes in cell shape Cytoplasmic streaming Cell motility (pseudopodia) Cell division (cleavage furrow formation)

Components of the Cytoskeleton Intermediate Filaments Fibrous proteins supercoiled into thicker cables Main Functions Anchorage of nucleus and other organelles Formation of nuclear lamina

The Endomembrane System A cell's endomembrane system consists of the rough and smooth endoplasmic reticulum, Golgi apparatus, vesicles and plasma membrane, all working together to transport cellular materials. http://study.com/academy/lesson/the-endomembrane-system-functions-components.html

Cell Membrane Allows materials to move in and out of the cell.

Made of a phospholipid bilayer The “fluid-mosaic model” Of an Animal Cell Made of a phospholipid bilayer Two layers of lipids (they can move. They need to be fluid to work properly). Allow certain materials to pass through dotted with proteins Proteins aide in certain molecules moving through the membrane Gen bio. Lipids and proteins only. Copy of this slide

Phospholipid bilayer of Cell Membrane Water loving Water fearing The arrangement of the phospholipid bilayer allows only certain molecules to pass through the cell membrane. “head region” – likes water “tail region” - does not like water Some large molecules, like sugar Cannot “fit” through this layer Small molecules generally move through easily Also if the molecule is soluble in the “tail” region it will go through faster.

Cell Membrane of an Animal Cell ECM – extracellular matrix (cells attach to this and send signals to one another. Made of protein fibers) Carbohydrate chains –assist in cell signaling Proteins-aid certain molecules moving through the membrane Cholesterol- keeps membrane fluid, from not freezing or becoming too liquid Phospholipid bilayer –allow certain materials to pass through Regeneration of cells – regrowing finger https://www.youtube.com/watch?v=ITxx2sOLW2Y

How do substances move in and out of cells?

How Do Substances Move In and Out of Cells? Diffusion – movement of molecules from greater concentration to lesser concentration. No Energy Required by the cell Passive Transport

DIFFUSION – A type of Passive Transport

How do substances move in and out of cells? 2. Osmosis – movement of water across a membrane from greater to lesser concentration. Examples – water into plant cell, salt on slugs, preserving meats Also passive transport (no energy needed)

Review of terms Solute – what is being dissolved Solvent – What is doing the dissolving Solution – solute + solvent

Types of Solutions Hypertonic - higher concentration of solute Hypotonic - lower concentration of solute Isotonic - equal concentration of solute

Less solute / More water More solute/less water Hand out

Hand out answer

In a solution with lower concentration of solute (more water) In a solution with equal concentration of solute and solvent In a solution with higher concentration of solute

Osmosis and animal cells

“Special Cell Processes” -Examples Salt on slug E.coli http://www.youtube.com/watch?v=9QCxTf0QfTo&feature=related Osmosis on lettuce https://www.youtube.com/watch?v=SrON0nEEWmo Egg osmosis

Facilitated Diffusion Passive Transport No Energy required -Molecules move from Higher concentration to Lower concentration. -Molecules are being “helped” through by proteins The molecules “glide” through, like a boat going through a channel

Active Transport -Requires Energy Molecules are now moving the opposite way we have discussed. Molecules move from a lower concentration to a higher concentration. Uses a transport protein Energy comes from ATP Lower concentration https://www.youtube.com/watch?v=ovHYKlHYpyA Review of diffusion and osmosis Higher concentration

Active Transport-example The Sodium (Na), Potassium (K) pump High Na Low K High K Low Na Yahoo search sodium potassium pump - animation

Bulk Transport across the cell membrane require energy Endocytosis Taking materials into the cell

Bulk Transport across the cell membrane require energy Exocytosis Secreting materials (moving materials from inside the cell to outside the cell) Usually moving products