* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 3 The Basic Structure of a Cell
Survey
Document related concepts
Cytoplasmic streaming wikipedia , lookup
Cell membrane wikipedia , lookup
Signal transduction wikipedia , lookup
Programmed cell death wikipedia , lookup
Tissue engineering wikipedia , lookup
Cell growth wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell nucleus wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Cytokinesis wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Transcript
Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal Cell Plant Cell Bacterial Cell Cell Structure and Function Cells are a collection of living matter enclosed by a barrier that separates the cell from its surroundings 2 Every Cell Contains: • Membrane – thin layer of material that serves as a covering or lining • Structure containing the cells genetic material 3 Number of Cells • Organisms may be: • Unicellular – composed of one cell • Multicellularcomposed of many cells that may organize Cells May be Prokaryotic or Eukaryotic Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles Eukaryotes include most other cells & have a nucleus and membranebound organelles 5 Prokaryotes •Genetic material is not contained in the nucleus •Less complicated than eukaryotic cells •Bacteria are examples of prokaryotes 6 Eukaryotic Cell • Larger and more complex than prokaryotes • Plants, Animals, Fungi are eukaryotes Contain 3 basic cell structures: • Nucleus – contain genetic info • Cell Membrane • Cytoplasm with organelles 7 Nucleus • Nucleus – a large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA – Controls many of the cells activities 8 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. 9 Basic Structure of a Eukaryotic Cell 10 Two Main Types of Eukaryotic Cells Plant Cell Animal Cell 11 Plant Cell 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 12 Animal Cell Ribosome (attached) Nucleolus Nucleus Nuclear envelope Ribosome (free) Cell Membrane Mitochondrion Rough endoplasmic reticulum Golgi apparatus Smooth endoplasmic reticulum Centrioles 13 Organelles – “little organs” Very small size Can only be observed under a microscope Have specific functions Found throughout cytoplasm 14 Nucleus • “The Control Center” • Contains nearly all the cell’s DNA with the codes for the cells proteins and other molecules • Surrounded by the nuclear envelope – Full of nuclear pores • Chromatin – DNA and proteins spread throughout the nucleus 15 Nucleus • Chromosomes – condensed form of chromatin – Passes on from one generation to the next • Nucleolus – place where ribosomes are assembled 16 Ribosomes • • • • • “Protein Factories” Small particles of RNA and protein Located in the cytoplasm Organelle where proteins are assembled Ribosomes get codes for proteins from nucleus 17 Endoplasmic Reticulum • “Highway System of the cell” • Internal membrane system • Transports– Proteins – Other macromolecules Two types: Smooth Rough 18 Smooth & Rough Endoplasmic Reticulum Smooth ER lacks ribosomes & makes proteins USED In the cell Rough ER has ribosomes on its surface & makes proteins to EXPORT 19 Golgi Apparatus • “The Shippers of the cell” • Closely stacked membranes, resembles stacks of pancakes • Modifies, sorts, and packages proteins from the ER for storage or secretion • Sends proteins to their final destination 20 Lysosomes • “Clean-up Crews” • Small organelles filled with enzymes • Breaks down lipids, carbohydrates, and proteins into smaller molecules that can be reused by the cell • Also breaks down old organelles 21 • • • • • • • Mitochondria Nickname: “The Powerhouse” Function: Energy formation Breaks down food to make ATP ATP: is the major fuel for all cell activities that require energy Two membranes – outer and inner Inherit mitochondria from mother Contains its own DNA 22 • Saclike structure • Stores materials Vacuole – Water, salts, proteins, carbohydrates • Plants have a large central vacuole • Single-celled organisms use a contractile vacuole to maintain homeostasis 23 Cell or Plasma Membrane Cell membrane – Living layer – Controls the movement of materials into and out of the cell – Selectively permeable Cytoplasm of a Cell Cytoplasm Jelly-like substance enclosed by cell membrane Provides a medium for chemical reactions to take place Cytoskeleton • Supporting framework of the cell • Cytoskeleton = cell skeleton • Many components • Microtubules / microfilaments made of proteins. • Move organelles w/in the cell. Cytoskeleton Continued • Microtubules / Microfilaments make up – Cilia – Flagella • Used in cellular locomotion Different kinds of animal cells white blood cell Amoeba red blood cell muscle cell cheek cells sperm nerve cell Paramecium • Now let’s talk about structures only found in PLANT Cells!! Figure 7-5 Plant and Animal Cells Plant Cell Section 7-2 Vacuole Cell Membrane Go to Section: Chloroplast • Organelles that capture energy from sunlight and convert it into chemical energy – Photosynthesis • Two membranes • Contains pigment chlorophyll 31 Eukaryotic Cell Organelles and Function Cell Wall – Function: provides support and protection to the cell membrane – Found outside the cell membrane in plant cells Different kinds of plant cells Onion Epidermal Cells root hair Root Hair Cell Guard Cells Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria 34 Differences between plant cells and animal cells Animal cells Relatively smaller in size Plant cells Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present Differences between Plant Cells and Animal Cells Animal cells Plant cells Vacuole small or absent Large central vacuole Glycogen as food storage starch as food storage Nucleus at the center Nucleus near cell wall Endosymbiont Hypothesis • Lynn Margulis U-Mass. • Found that mitochondria / chloroplasts did not fit the roles of organelles. • They had unusual properties. 3 properties of Mito / Cplasts • Contain own DNA • Both surrounded by 2 membranes – Most organelles only surrounded by one membrane. • Both reproduce separately from the rest of the cell Margulis’s Model • Both Mitochondria / Chloroplasts had ancestors that were free-living organisms. • These formed endosymbiotic relationships with other cells. • Over time offsprings of these organisms lost their independence becoming organelles of larger cells. Further Evidence • Studies of DNA in chloroplasts show that they are much like the DNA prokaryotic cells. • Mitochondria / chloroplasts contain their own ribosomes and make many of their own proteins. • These ribosomes are smaller / chemically different from those in eukaryotic cells. • More closely resemble ribosomes in prokaryotic cells. Levels of organization • Cells are grouped together and work as a whole to perform special functions • Known as “Cell Specialization” Tissue • A group of similar cells to perform a particular function – Animals : epithelial tissue, muscular tissue – Plants : vascular tissue, mesophyll Organ • Different tissues group together to carry out specialized functions – Heart : consists of muscles, nervous tissue and blood vessels – Leaf : consists of epidermis, mesophyll and vascular tissue The Structures of a Leaf (Plant Organ) Chloroplast Palisade Mesophyll Cell Spongy Mesophyll Cell Air Space Stoma The Structures of a Heart (Animal Organ) Organ System • Several organs and tissues work together to carry out a particular set of functions in a co-ordinated way – Human : digestive, respiratory, excretory, circulatory and reproductive systems – Plant : root and shoot systems Human Body Systems Examples of systems : Digestive System Respiratory System Circulatory System Nervous System Reproductive System Examples of a Human Body System Examples of a Human Body System The Respiratory System Levels of Organization CELLS (muscle cells,nerve cells) TISSUES (muscle, epithelium) ORGANS (heart, lungs, stomach) SYSTEMS (circulatory system) ORGANISM (human) It’s You!