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Cells Cytologists Welcome The Micro and the Macro World Antony van Leeuwenhoek (1632-1723) Size variation Cell Most Cells Size range Cell Biology •1665 - Robert Hooke - cork cells Hooke was reminded of the small rooms or “cells” in a monastery. Cell Biology 1805 - Lorenz Ohen - cell theory – All living things originate from, and are made of cells – Spontaneous Generation debunked 1835 - Matthias Schleiden – Botanist – & Theodor Schwann – Zoologist - Schleiden - all plants are made of cells and the cell is the basic unit of tissue function - Schwann - all animals are composed of cells 1859-Rudolf Virchow - “Ommia cellula e cellula” – “All cells come from cells” Cell Theory All living things are composed of cells Cells are the basic units of structure and function in living things New cells are produced from existing cells. What happens on the Macro Level happens on the Micro Level Cells Prokaryotes Cells that have genetic material that is not contained in the nucleus, No membrane bound organelles All bacteria Archaean Eukaryotes Contain a nucleus in which their genetic material is separated from the rest of the cell, Membrane bound organelles Most life forms Mixture of prokaryotic & eukaryotic characteristics, with some unique properties Kingdom Archaea The archaea very much resemble bacteria, so much so that they were once thought to be a weird group of bacteria. However, by studying archaeal cells on a molecular level, scientists have now come to think that these "weird bacteria" actually are a separate category of life altogether. In fact, in some ways, archaea are more like you than they are like bacteria! Archeaens Distinctives -Extremophiles Many archaeans thrive in conditions that would kill other creatures: boiling water, super-salty pools, sulfur-spewing volcanic vents, acidic water and deep in Antarctic ice. These types of archaea are often labeled "extremophiles," meaning creatures that love extreme conditions. Cell membrane Cytoplasm Prokaryotic Cell Cell membrane Cytoplasm Nucleus Eukaryotic Cell Organelles General Archaean Structure Smooth endoplasmic reticulum Vacuole Ribosome (free) Chloroplast Ribosome (attached) Cell Membrane Nuclear envelope Cell wall Nucleolus Golgi apparatus Nucleus Mitochondrion Rough endoplasmic reticulum Plant Cell Organelle – specialized organs, “little organs” Nucleolus Nucleus Ribosome (attached) Nuclear envelope Ribosome (free) Cell Membrane Mitochondrion Smooth endoplasmic reticulum Rough endoplasmic reticulum Centrioles Golgi apparatus Animal Cell Prokaryotes Eukaryotes Cell membrane Contain DNA Animal Cells Centrioles Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell Wall Chloroplasts Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Organelles in Plant & Animal Cells Nucleus – contains nearly all the cells DNA with coded instructions for making proteins and other important molecules. Nuclear envelope – surround nucleus, composed of two membranes, allow materials to move in and out of the nucleus Organelles in Plants & Animal Cells Chromatin – DNA bound to protein, material you can see in the nucleus Chromosomes – condensed chromatin, contains genetic information that is passed from one generation to the next Nucleolus – where assembly of ribosomes begins Organelles in Plants & Animal Cells Ribosomes – make proteins Endoplasmic reticulum – assemble lipids of the cell membrane, along with proteins and other materials that are exported from the cell Rough ER – contains ribosomes on the outside of the ER Smooth ER – ribosomes are not found of the surface of the ER Organelles in Plants & Animal Cells Golgi apparatus – modify, sort and package proteins and other materials from the ER for storage in the cell or secretion outside the cell, the “UPS guys” of the cell Organelles in Plants & Animal Cells Lysosome – digestion or breakdown of lipids carbohydrates and proteins into small molecules that can be used by the rest of the cell. Vacuoles – store materials such as water, salts, proteins, and carbohydrates. Mitochondria – powerhouse of the cell, contain own DNA, endosymbiotic theory, possible descendent of ancient prokaryotes Organelles in Plants & Animal Cells Cell membrane ER microtubule microfilament ribosomes mitochondria Cytoskeleton – support the cell, involved in maintaining shape and involved in movement Microfilament – threadlike structures made of protein called actin, framework of cell, help with movement Microtubules – hollow structures made up of protein, maintain cell shape, important in cell division help build projections from the cell surface such as cilia, flagella Organelle in Plants Only Chloroplasts – captures the suns energy from sunlight and convert it to chemical energy in a process called photosynthesis Organelle in Animals Only Centrioles – microtubules that aid in cell division Structure of the Cell Membrane Outside of cell Proteins Carbohydrate chains Cell membrane Inside of cell (cytoplasm) Protein channel Lipid bilayer Cell membrane – regulates what enters and leaves the cell, lipid bilayer, mosaic of different molecules Cell Wall Cell Wall - in plants only, provides protection and support for the cell Plants v. Animal Cells PLANTS Chloroplasts Large vacuoles Cell wall No centriole Does not usually have lysosomes ANIMALS No chloroplasts Smaller vacuoles No cell wall Centriole Lysosomes Diffusion Through Cell Boundaries Glucose molecules Diffusion – particles tend to move from an area where they are more concentrated to an area where they are less concentrated until they reach equilibrium, no energy required Protein channel High Concentration Cell Membrane Low Concentration Osmosis Osmosis – diffusion of water through a selectively permeable membrane Facilitated Diffusion Facilitated Diffusion movement of specific molecules across cell membranes through protein channels, does not require energy, only if there is a higher concentration of a particular molecule on one side than the other side Active Transport Molecule to be carried Active transport - requires energy, low concentration to high concentration •Endocytosis •Phagocytosis •Pinocytosis •Exocytosis Energy Molecule being carried Cell Specialization Cell Specialization – cells throughout an organism can develop in different ways to perform different tasks. Levels of Organization Muscle cell Smooth muscle tissue Stomach Atom – Molecule - Organelle – Cell – Tissue – Organ – Organ System Organism Digestive system Enzymes • proteins • lock and key theory, specific • effected by temp. pH… •Can build or break down molecules Catalyst – speeds up the rate of a chemical reaction Chapter 10 Cell Growth and Divisions Section 10-1 Ratio of Surface Area to Volume in Cells Cell Size Surface Area (length x width x 6) Volume (length x width x height) Ratio of Surface Area to Volume Limits to Cell Growth – cannot move nutrients and waste through the cell, “DNA overload” Concept Map Cell Cycle includes G1 phase Interphase M phase (Mitosis) is divided into is divided into S phase G2 phase Prophase Metaphase Anaphase Telophase During Interphase (S phase), each chromosome is replicated, consisting of two identical “sisters” or sister chromatids. Centromere attaches the sister chromatids. The Cell Cycle G1 phase M phase S phase G2 phase Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Metaphase Anaphase Interphase – cell grows and replicates its DNA and centrioles Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Metaphase Anaphase Prophase – chromatin condenses in to the chromosomes, centrioles separate, spindle forms, nuclear envelope disappears plant animal Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Metaphase Anaphase Metaphase – chromosomes line up in the center of the cell, each chromosome is connected at the centromere to the spindle fiber. plant Spindle fibers Asters animal Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Metaphase Anaphase Anaphase – sister chromatids separate into individual chromosomes and are moved apart plant animal Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Metaphase Anaphase Telophase – chromosomes gather at opposite ends of the cell, two nuclear envelopes will form. plant animal Mitosis and Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Metaphase Anaphase Cytokinesis – the cytoplasm pinches in half, each daughter cell has duplicate chromosomes. Control of Cell Division Cells have contact inhibition, they will continue growing until in contact with other cells. Effect of Cycling The sample is injected into a second cell in G2 of interphase. A sample of cytoplasm is removed from a cell in mitosis. RESULT: Caused nondividing cells to divide As a result, the second cell enters mitosis. Cyclins – regulate the timing of the cell cycle in eularyotic cells along with internal and external regulators Cancer Definition / Causes – – – Cancer is the uncontrolled growth of cells Changes in a cells’ DNA can lead to unrestrained cell reproduction Cells are produce a growth factor and never stops dividing OR – Cells do not produce a suppressor protein and it never stops dividing Cancer Normal vs. Cancerous (pages 36-38 in Unit 3 Packet) Shape of cell Normal Cell Cancer Cell Anchorage dependent Contact inhibition Flattened, monolayer yes yes Rounded, globular no no Cancer Tumors - 2 types 1. Benign - slow growing, noninvasive, no metastasis 2. Malignant - rapid growth, invasive, metastatic Stem Cells Stem Cells – undifferentiated cells. In embryonic development form tissues in every part of the body. Stem cells found in adult bone marrow. Stem cells have reversed the effects of paralysis in mice. Hope – cure diabetes, spinal cord injuries, damaged livers… Stem cells obtained from human embryos.
