CELLS CELLS. CELL THEORY Living things are composed of cells (multicellular organisms) Cells are the...
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Transcript of CELLS CELLS. CELL THEORY Living things are composed of cells (multicellular organisms) Cells are the...
CELLSCELLS
CELL THEORY
Living things are composed of cells
(multicellular organisms)
Cells are the smallest unit of life (single celled organisms – all life
functions)
Cells come from pre-existing cells (binary fission & mitosis)
RELATIVE SIZES• Molecules: 1nm• Membranes: 10nm• Viruses: 100nm• Prokaryotic cells range in
size from 1µm - 10µm• Organelles: up to 10µm• Eukaryotic cells: 10µm -
100µm
Separation Techniques
Lack organized nucleus & membrane enclosed organelles
Nucleoid region – concentration of DNASingle, circular chromosomePlasma membrane, cytoplasm, 70s ribosomesCell wall & capsulePili and flagella
Plasma membrane: present in all cells, phospholipid bilayer, semipermeable, barrier, regulator
Typical Animal Cell
Typical Plant Cell
NUCLEUS• Eukaryotic cells only• Envelope – two
membranes, pores, lamina
• Chromatin - threadlike• Chromosomes – visible
during division• Nucleolus – makes
ribosomes
Ribosomes: protein synthesis2 subunits made of RNA and protein (80S)free (intracellular); attached (extracellular)
Endoplasmic Reticulum
Rough:• Ribosomes• Secretory proteins, vesicles• Membrane factory
Smooth• No ribosomes• Synthesis – lipids (steroids,
phospholipids)• Metabolism – carbohydrates• Detoxification – liver cells• Muscle cells – pumping Ca
ions into cisternal space
Golgi apparatus: stacks of flattened sacs• Manufacturing, warehousing, modifying, sorting, shipping• Extensive in secretory cells, near E.R.• Processes lysosomes
LYSOSOMES - digestiveLYSOSOMES - digestive Suicide sacs Double membrane, hydrolytic enzymes, autophagy,
development Made by Golgi apparatus WBC – phagocytosis Pompe’s disease – accumulation of glycogen Tay Sachs disease – accumulation of lipids
VACUOLES
• Larger than vesicles• Storage, transport,
waste disposal• Central – plants,
growth, tonoplast, cell sap, pigments, poison
• Contractile – fresh water protists
Endomembrane System
Partitions the cytoplasm, metabolism Physical continuity or vesicles Components :
Nuclear envelope Endoplasmic reticulum (rough, smooth) Golgi apparatus Lysosomes Plasma membrane Various vacuoles
Mitochondrion
Power house – ATP production Cellular respiration – Krebs cycle, ETC DNA & ribosomes Double membrane: outer smooth, inner
folds Inner membrane: cristae (↑ surface area) 2 compartments – inner membrane space &
matrix (enclosed by inner membrane)
Chloroplasts
Green plant cells, contain chlorophyll, photosynthesis
Other plastids – amyloplasts, chromoplasts Double membrane – thylakoids, grana, stroma DNA and ribosomes
Peroxisome
• Single membrane
• Breaks down H2O2
• Detoxify alcohol
• Cooperate w/ mito. & chloroplast
CYTOSKELETON
Structural support, motility, regulation Maintain shape (framework), anchor
organelles, mechanical support Cell location, movement of organelles Types:
microtubules: centrioles, cilia, flagella microfilaments: actin & myosin intermediate fibers: more permanent,
lamina, tension bearing
Centrioles
Animal cells only Contain DNA; replicate Right angles Triplet microtubules Cell division
Cilia & Flagella
Cell locomotion, 9 + 2 microtubules Cilia: numerous, short hairs, oars, line
trachea Flagella: 1-2, long, undulating, sperm Basal body: anchors, triplet microtubules Movement comes from within structure One microtubule pair moving along a
neighboring pair.
Cell Wall Primary: thin, flexible, outer layer Secondary: thick, several layers, durable, inner layer Middle lamella: sticky, pectin, glues cells together Plasmodesmata: channels through cell walls, continuous cytoplasm
Extracellular Matrix
Intercellular Junctions
Plasmodesmata: plants Tight junctions: fused, prevent leakage,
epithelium Desmosomes: anchor, fasten cells into
strong sheets Gap junctions: communication,
cytoplasmic channels, muscles, embryonic development