LSM1401 Lect02 (1 Frame) - CELL BIOLOGY I Fundamentals of...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CELL BIOLOGY I Fundamentals of Biochemistry LSM1401 Semester 2 2008‐09 Reference Texts Reference Texts Chapters 4, 5 LSM1401 Chapters 1, 2 Chapter 1 Semester 2 2008‐09 Chapter 1 Chapter 1 2 Internet Resources Internet Resources • The Biology Project – http://www.biology.arizona.edu/ p // gy / • CELLS alive! – h // http://www.cellsalive.com/ ll li / • The Virtual Cell Website – http://www.ibiblio.org/virtualcell/ • Virtual Cell Virtual Cell – http://www.life.uiuc.edu/plantbio/cell/ LSM1401 Semester 2 2008‐09 3 Outline • Diversity of Life • Cells • Membrane structure • Prokaryotic Cells • Eukaryotic Cells – Nucleus – Endomembrane system y – Semi‐autonomous organelles – Cytoskeleton – Movement across Movement across membranes LSM1401 Semester 2 2008‐09 4 Diversity of Life Diversity of Life Three‐Domain Classification LSM1401 Semester 2 2008‐09 5 Diversity of Life Diversity of Life • Prokaryotes – Bacteria and Archaea – Single‐celled – No nucleus or organelles No nucleus or organelles • Eukaryotes – Eukarya (plants, fungi, animals, protists) – DNA inside nucleus DNA inside nucleus – Larger and more complex than prokaryotes LSM1401 Semester 2 2008‐09 6 Cells • Main structural components of all cells LSM1401 Semester 2 2008‐09 7 Membrane Structure Membrane Structure • Composed of lipids and proteins LSM1401 Semester 2 2008‐09 8 Membrane Structure Membrane Structure LSM1401 Semester 2 2008‐09 9 Membrane Structure Membrane Structure LSM1401 Semester 2 2008‐09 10 Movement Across Membranes Movement Across Membranes • Membrane crossing mechanisms LSM1401 Semester 2 2008‐09 11 Passive Transport Passive Transport LSM1401 Semester 2 2008‐09 12 Passive Transport Passive Transport LSM1401 Semester 2 2008‐09 13 Passive Transport Passive Transport LSM1401 Semester 2 2008‐09 14 Active Transport Active Transport LSM1401 Semester 2 2008‐09 15 Active Transport Active Transport LSM1401 Semester 2 2008‐09 16 Movement Across Membranes • Endocytosis and y exocytosis – Process by which large particles or substances particles or substances transported into or out of cell out of cell – In vesicles LSM1401 Semester 2 2008‐09 17 Prokaryotic Cell Prokaryotic Cell • Bacteria and Archaea LSM1401 Semester 2 2008‐09 18 Prokaryotic Cell Prokaryotic Cell • N l id region Nucleoid i – Contains single circle of DNA (single chromosome) (single chromosome) • Cell wall surrounds plasma membrane – Consists of peptidoglycan (in bacteria) or proteins (in archaea) – Coated with slime layer (capsule) • Flagella rotate like propellers • Pili extend from cell surface – For adhesion or motion LSM1401 Semester 2 2008‐09 19 LSM1401 Semester 2 2008‐09 20 LSM1401 Semester 2 2008‐09 21 Nucleus • Separates DNA from cytoplasm – Keeps DNA away from potentially damaging p y p y g g reactions in cytoplasm – Organises and copies DNA before cell division Organises and copies DNA before cell division • Major components – Chromatin – Nuclear envelope p – Nucleolus LSM1401 Semester 2 2008‐09 22 Nucleus LSM1401 Semester 2 2008‐09 23 Nucleus • Nuclear envelope – Two layers of membrane with pores y p – Controls access to DNA LSM1401 Semester 2 2008‐09 24 Nucleus • Chromatin – Consists of DNA and proteins p – Condenses to form chromosomes during cell division – One chromosome is one DNA molecule and its associated proteins associated proteins LSM1401 Semester 2 2008‐09 25 Nucleus • Nucleolus – Dense mass of material – Assembly site of Assembly site of ribosome • From proteins and From proteins and RNA LSM1401 Semester 2 2008‐09 26 Endomembrane System • S i Series of interacting organelles between nucleus fi i ll b l and plasma membrane – Restrict enzymatic reactions to specific compartments within cell –M k Makes, sort, and transport lipids and proteins to t dt t li id d t i t various destinations • Components of endomembrane system Components of endomembrane – Endoplasmic reticulum –G l i Golgi apparatus – Vesicles LSM1401 Semester 2 2008‐09 27 Endomembrane System LSM1401 Semester 2 2008‐09 28 Endomembrane System • Endoplasmic reticulum (ER) – Extension of nuclear envelope into cytoplasm p y p – Folded sheets of inter‐connected membranes – Two forms Two forms • Rough ER – Flattened sacs with ribosomes on surface – S th i Synthesises and modifies membrane proteins and proteins d difi b t i d t i destined for secretion (export) • Smooth ER – interconnected tubules with no ribosomes – Synthesises lipids LSM1401 Semester 2 2008‐09 29 Endomembrane System • Golgi body – Set of stacked flattened, curved sacs , – Modifies proteins and lipids received from ER – Sorts finished material by destinations Sorts finished material by destinations • Some within cell – e.g. lysosomes •S Some exported from cell via exocytosis df ll i i – Material arrives and leaves in vesicles • Secretory vesicles merge with cell membrane LSM1401 Semester 2 2008‐09 30 Endomembrane System • Vesicles – Membranous sacs that move through cytoplasm • Secretory vesicles, transport vesicles, lysosomes, peroxisomes, etc – Lysosomes • Contain hydrolytic enzymes • Digest organelles and material engulfed by cell – Peroxisomes • Break down amino acids and fatty acids producing hydrogen peroxide, which is converted to water and oxygen LSM1401 Semester 2 2008‐09 31 Endomembrane System LSM1401 Semester 2 2008‐09 32 Endomembrane System LSM1401 Semester 2 2008‐09 33 Semi‐Autonomous Organelles • Resemble bacteria – Own DNA, RNA, ribosomes – Capable of self‐replication • Endosymbiotic hypothesis – May have evolved from remnants of engulfed ancient remnants of engulfed ancient prokaryotes but not digested • E g mitochondria E.g. – mitochondria, chloroplasts LSM1401 Semester 2 2008‐09 34 Semi‐Autonomous Organelles Semi Autonomous Organelles • Mitochondria – Makes energy molecule, adenosine triphosphate (ATP) – Consists of two membranes – outer and inner membranes – Outer membrane faces cytoplasm – Inner membrane folds back on itself into cristae that Inner membrane folds back on itself into cristae that encloses matrix • Matrix – space within inner membrane containing p g respiratory enzymes • ATP‐making enzymes embedded in inner membrane LSM1401 Semester 2 2008‐09 35 Semi‐Autonomous Organelles Semi Autonomous Organelles LSM1401 Semester 2 2008‐09 36 Semi‐Autonomous Organelles Semi Autonomous Organelles • Chloroplasts – In green plants only g p y – Convert sunlight energy to drive photosynthesis – Consists of two membranes outer and inner Consists of two membranes – outer and inner membranes – Outer membrane faces cytoplasm b f l – Inner membrane encloses semi‐fluid stroma • Forms thylakoids (disc‐like hollow sacs) • Stacked thylakoids form grana LSM1401 Semester 2 2008‐09 37 Semi‐Autonomous Organelles Semi Autonomous Organelles LSM1401 Semester 2 2008‐09 38 Cytoskeleton • Interconnected d network of protein fibres t i fib – Some temporary, some permanent t • Three types – Microtubules – Microfilaments – Intermediate filaments LSM1401 Semester 2 2008‐09 39 Cytoskeleton • Microtubules – Long, hollow cylinders composed of g, y p tubulin subunits – Dynamic – assembling when needed Dynamic assemblingwhen needed, disassembling when not needed – Involved in Involved in • Cell processes – e.g. cell division •M Movement of organelles – t th t f ll together with motor proteins LSM1401 Semester 2 2008‐09 40 Cytoskeleton • Microfilaments – Also called actin filaments – Composed of actin subunits – Involved in Involved in • Maintenance and change of cell shape •M Movement of cell during phagocytosis f ll d i h i – Together with motor proteins – Through formation of pseudopods (false Through formation of pseudopods (false feet) LSM1401 Semester 2 2008‐09 41 Cytoskeleton LSM1401 Semester 2 2008‐09 42 Cytoskeleton • Intermediate filaments – Involved in • Strengthening and maintenance of cell and tissues structures – Six known groups g p • Different animal cell types have different kinds – Most stable cytoskeletal elements LSM1401 Semester 2 2008‐09 43 Cytoskeleton • Cilia and flagella – Whip‐like structures p • From microtubules • In 9 + 2 arrays In 9 2 arrays – Grow from centrioles • Remain in cytoplasm Remain in cytoplasm as basal bodies – For cell movement or For cell movement or movement of fluid LSM1401 Semester 2 2008‐09 44 LSM1401 Semester 2 2008‐09 45 Cytoskeleton LSM1401 Semester 2 2008‐09 46 LSM1401 Semester 2 2008‐09 47 LSM1401 Semester 2 2008‐09 48 ...
View Full Document

This note was uploaded on 01/29/2009 for the course ZAXZ xsacsdc taught by Professor Sdcsd during the Spring '09 term at National University of Singapore.

Ask a homework question - tutors are online