1 / 43

Cell Form and Function

Cell Form and Function. Dr. Anderson GCIT. Cell Diversity. Connect tissues and transportation – blood, epithelia Body movement – muscles (smooth, striated, cardiac) Storage – adipose (fat cells), hepatocytes Immune Function – WBC’s Communication and information processing – nerve cells

mitch
Download Presentation

Cell Form and Function

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Cell Form and Function Dr. Anderson GCIT

  2. Cell Diversity • Connect tissues and transportation – blood, epithelia • Body movement – muscles (smooth, striated, cardiac) • Storage – adipose (fat cells), hepatocytes • Immune Function – WBC’s • Communication and information processing – nerve cells • Reproduction – Egg and sperm cells

  3. Cell Membrane • Keeps the cell contents separate from the environment (extracellular fluid)

  4. The Fluid Mosaic Model • Cell membrane is made of a phospholipid bilayer • Self-assembling! • Extremely thin

  5. Outside of cell – interstitial fluid Polar Heads Non-polar tails Polar Heads Inside of cell – cytoplasm Polar Heads are phospholipids and the non-polar (hydrophobic) ends are fatty acids

  6. Membrane Proteins Facilitate the transport of material across the membrane Integral (trans-membrane) protein – facilitates transport into and out of the cell

  7. Membrane Proteins • Peripheral protein – can be attached to inside or outside layer of cell membrane • Act as enzymes (outside and inside) or serve to move or support the cell (inside)

  8. Glycoproteins – sugar-bound proteins Glycoproteins – make up a sugary coat that envelops the cells called the glyco-calyx or “sugar cup”

  9. The Glycocalyx • The carbohydrates on the cell surface provide a way for some cells to recognize each other • Sperm and egg • WBC and bacteria or other pathogens

  10. Membrane Junctions • Bind cells together – glycoproteins act as adhesive • Cell membrane structure – tongue-and-groove • Specialized Junctions – • Tight junction • Desmosomes • Gap Junctions

  11. Special Membrane Junctions • Tight Junctions – proteins in the cell membranes that bind cells together • Makes sure nothing passes between cells • Desmosomes - small points of connective proteins that anchor cells together • Found in cells subject to heavy pulling forces • Gap Junctions – an open junction between adjacent cells • Permits chemical communication (transport) between cells

  12. Membrane Transport • Interstitial Fluid – extracellular fluid largely derived from blood, but acellular • Amino acids, wastes, electrolytes, sugars, etc. • Cells need to hold a balance of these solutes between their inside and outside environments • How is this done?

  13. Membrane Permeability • Membranes only allow passage to certain molecules, or only permit movement in one direction • Selectively Permeable – only certain molecules can pass

  14. Active Transport • ATP is used to drive the concentration gradient across the cell membrane • Primary – ATP changes the shape of membrane proteins to shuttle specific materials across • Secondary - uses stored potential energy from primary transport to move substances • Vesicular – vesicles “gulp” materials from outside the cell by pinching off a bubble from the cell membrane

  15. ELMO • Review Pages 74-75 in textbook to explain prior slide in more detail

  16. Vesicular Transport • Endocytosis – cell ingests materials via vesicles • Receptor mediated • Exocytosis – cell expels material into the environment via vesicles • Phagocytosis?

  17. Plasma Membrane – Resting Potential • Many cells work using electrical energy which is derived from ion separation • Muscle cells, nerve cells, etc. • How is this accomplished?

  18. Electric Membrane Potential Cations (postively charged ions (K, Na) build up) + + + + K+ + + + + + K+ pump Anions (negatively charged proteins build up) - - - - - - - - - - -

  19. Cytoplasm • The material between the cell membrane and the nucleus • Three major elements • Cytosol • Organelles • Inclusions

  20. Cytosol • Liquid part of the cytoplasm • Consists of mostly water, but also dissolved substances such as • Salts • Sugars • proteins, • Etc.

  21. Cytoplasmic Organelles • Carry out cellular metabolic processes • Specific to the kingdom of living things (e.g. chloroplasts are only found in plants)

  22. Mitochondria • Powerplants of the cell • Breaks down food and uses this energy to form ATP from ADP (cellular respiration)on inner membranes (cristae) • Have their own DNA, RNA and ribosomes • Huh?

  23. Ribosomes • Made of two RNA-protein subunits that work together to synthesize proteins (protein translation) • Two types • Free ribosomes – make soluble proteins • Membrane-bound organelles – make proteins for packaging or export

  24. Endoplasmic Reticulum (ER) • Membranes in the cytosol that are continuous with the nuclear membrane • Rough ER – lined with ribosomes that produce proteins that are secreted from cells, also make new phospholipids and intracellular membranes • Smooth ER – Embedded with enzymes that catalyze the metabolism of proteins, fats, hormones, toxins and glycogen

  25. Golgi Apparatus • Stacks of membranous sacs in the cytosol • Used to concentrate, modify and/or package proteins and lipids made by the rough ER. • Packaged proteins are called vesicles are sent into the cytosol or outside of the cell (exocytosis)

  26. Lysosomes • Contain activated enzymes that may be capable of digesting all type of biological molecules • The membrane-bound lysosomes contain these dangerous substances, preventing cell damage

  27. Peroxisomes • Contain extremely reactive oxygen species (ROS) that are used to detoxify certain poisons such as alcohol • Also destroy free radicals – highly reactive waste products of metabolism that can disrupt cell processes • In which cells might these be found?

  28. Cytoskeleton • Consists of rods made of tubulin that run through the entire interior of the cell • Microtubules • Microfilaments • Intermediate filaments

  29. Cytoskeleton Components • Microtubules • Determine cell shape and influence organelle dstribution • Microfilaments • A “web” of these filaments attach to the inner surface of the cell membrane and give the cell strength. Also helps change cell shape during mitosis/meiosis • Intermediate Filaments • Give the cell tensile strength by attaching to desmosomes

  30. Centrosomes and Centrioles • Centrosomes – serve to anchor microtubulesand provide attachment points during activities such as cytokinesis, alignment of chromosomes during mitosis (mitotic spindle)

  31. Cilia • Relatively short extensions of tubulin that cover cells • Enables cells to move through their environment, or move the liquid environment around themselves

  32. Flagella • Long extensions of tubulin protein used for propulsion • Many microorganisms possess flagella • Only human cells that possess flagella are sperm cells

  33. Inclusions • Chemical substances that may or may not be present, depending on the cell type. • Pigments • Crystals • Vacuoles • Etc.

  34. The Nucleus • The nucleus is a membrane-bound organelle that serves as the central control system of the cell • All instructions for the cell’s processes are carried on genes that can be found within the DNA housed inside the nucleus

  35. Nucleus • Nuclear Envelope – double layered membrane that surrounds the nucleus • Outer Layer – continuous with ER • Inner Layer – lined with lamina, filaments that hold the nuclear shape • Nuclear pores penetrate both layers, allowing some molecules to flow into and out of the nucleus

  36. Nucleus • Nucleoli – dark-staining regions in the nucleus where ribosomal RNA (rRNA) is made • Chromatin – DNA wound around protein units called histones • This form of DNA allows efficient packing and storage of DNA (a nucleosome) during periods where the cell is not actively dividing

  37. Nucleus - Chromosomes • During cell division, chromatin winds up to form bar-shaped structures called chromosomes • The arrangement of these structures allows the definition of different stages of cell division

  38. Human Karyotype • Chromosome sizes and number can also be used to screen for genetic diseases

  39. DNA Replication Helicase DNA Polymerase DNA Polymerase

More Related