Transcript of Week # 8 Lecture – pp 15-128 Lecture Presentations for Integrated Biology and Skills for Success...
- Slide 1
- Week # 8 Lecture pp 15-128 Lecture Presentations for Integrated
Biology and Skills for Success in Science Banks, Montoya, Johns,
& Eveslage
- Slide 2
- Cells and Their Membranes By the end of the lecture today,
students will be able to: State the cell theory Define cell biology
Describe the different classes of cells in the human body Describe
the functions of the plasma membrane Describe the components of the
plasma membrane and explain the role of each component, including
lipids and proteins Differentiate between microvilli, cilia and
flagellum
- Slide 3
- Modern Cell Theory All organisms are composed of cells and cell
products Cell is the simplest structural and functional unit of
life cells are alive An organisms structure and functions are due
to the activities of its cells Cells come only from preexisting
cells, not from nonliving matter therefore, all life traces its
ancestry to the same original cells Cells of all species have many
fundamental similarities in their chemical composition and
metabolic mechanisms Cell biology study of cells (i.e., their
morphology, physiological properties, organelles, interactions with
the environment, life cycles, division and death)
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- http://www.youtube.com/watch?v=4OpBylwH9D U
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- Cell Shapes about 200 types of cells in the human body Squamous
- thin and flat with nucleus creating bulge Polygonal - irregularly
angular shapes with 4 or more sides Stellate starlike shape
Cuboidal squarish and about as tall as they are wide Columnar -
taller than wide Spheroid to Ovoid round to oval Discoid -
disc-shaped Fusiform - thick in middle, tapered toward the ends
Fibrous threadlike shape Note: some of these shapes are cell
appearance in tissue sections, but not their 3 dimensional
shape
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- Cell Shapes Squamous Polygonal CuboidalColumnar Spheroid
DiscoidFusiform (spindle-shaped) Stellate Fibrous
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- Two Classes of cells in the Human Body Sex cells, also known as
germ cells or reproductive cells, are either sperm cells of males
or oocyte cells of females. Somatic cells are the cells that make
up everything else in the body.
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- Cell Size Human cell size most from 10 - 15 micrometers (m) in
diameter egg cells (very large)100 m diameter barely visible to the
naked eye nerve cell at 1 meter long longest human cell too slender
to be seen with naked eye Limitations on cell size cell growth
increases volume more than surface area surface area of a cell is
proportional to the square of its diameter volume of a cell is
proportional to the cube of its diameter nutrient absorption and
waste removal utilize surface area if cell becomes too large, may
rupture like overfilled water balloon
http://projects.cbe.ab.ca/ict/udlsci/udlscience/biology/cells/saVol/notes
/saVol.htm
http://projects.cbe.ab.ca/ict/udlsci/udlscience/biology/cells/saVol/notes
/saVol.htm
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- Major Constituents of Cell plasma (cell) membrane surrounds
cell made of proteins and lipids composition and function can vary
from one region of the cell to another cytoplasm organelles
cytoskeleton cytosol (intracellular fluid - ICF) extracellular
fluid ECF fluid outside of cell Apical cell surface Microfilaments
Secretory vesicle undergoing exocytosis Golgi vesicles Golgi
complex Lateral cell surface Intermediate filament Lysosome Rough
endoplasmic reticulum Smooth endoplasmic reticulum Microtubule
Plasma membranes Basement membrane Basal cell surface Free
ribosomes Mitochondrion Nucleolus Nuclear envelope Nucleus
Intercellular space Centrosome Centrioles Secretory vesicle
Desmosome Fat droplet Hemidesmosome Terminal web Microvillus
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- Plasma Membrane unit membrane forms the border of the cell and
many of its organelles -appears as a pair of dark parallel lines
around cell (viewed with the electron microscope) plasma membrane
unit membrane at cell surface -defines cell boundaries -governs
interactions with other cells -controls passage of materials in and
out of cell -intracellular face side that faces cytoplasm
-extracellular face side that faces outward (a) Nuclear envelope
Nucleus Plasma membrane of upper cell Plasma membrane of lower cell
Intercellular space 100 nm..
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- Membrane Lipids 98% of molecules in plasma membrane are lipids
Phospholipids 75% of membrane lipids are phospholipids amphiphilic
molecules arranged in a bilayer hydrophilic phosphate heads face
water on each side of membrane hydrophobic tails directed toward
the center, avoiding water drift laterally from place to place
movement keeps membrane fluid
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- Plasma Membrane Oily film of lipids with diverse proteins
embedded Extracellular face of membrane Intracellular face of
membrane (b) Peripheral protein Extracellular fluid Glycolipid
Glycoprotein Carbohydrate chains Transmembrane protein Peripheral
protein Channel Intracellular fluid Cholesterol Proteins of
cytoskeleton Phospholipid bilayer
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- Membrane Protein Functions receptors, second-messenger systems,
enzymes, ion channels, carriers, cell-identity markers,
cell-adhesion molecules Chemical messenger Breakdown products Ions
CAM of another cell (a) Receptor A receptor that binds to chemical
messengers such as hormones sent by other cells (b) Enzyme An
enzyme that breaks down a chemical messenger and terminates its
effect (c) Ion Channel A channel protein that is constantly open
and allows ions to pass into and out of the cell (d) Gated ion
channel A gated channel that opens and closes to allow ions through
only at certain times (e) Cell-identity marker A glycoprotein
acting as a cell- identity marker distinguishing the bodys own
cells from foreign cells (f) Cell-adhesion molecule (CAM) A
cell-adhesion molecule (CAM) that binds one cell to another.
- Slide 14
- http://www.youtube.com/watch?v=y31DlJ6uGgE
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- Extensions of membrane (1-2 m) serves to increase cells surface
area best developed in cells specialized in absorption gives 15 40
times more absorptive surface area on some cells they are very
dense and appear as a fringe brush border milking action of actin
actin filaments shorten microvilli pushing absorbed contents down
into cell Microvilli
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- Actin microfilaments are found in center of each microvilli.
(a) 1.0mm (b) 0.1 Glycocalyx Actin microfilaments Microvillus..
mm
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- Cilia Hairlike processes 7-10 m long single, nonmotile primary
cilium found on nearly every cell antenna for monitoring nearby
conditions sensory in inner ear, retina, nasal cavity, and kidney
Motile cilia respiratory tract, uterine tubes, ventricles of the
brain, efferent ductules of testes beat in waves sweep substances
across surface in same direction power strokes followed by recovery
strokes (a) Mucus Saline layer Epithelial cells 1234567 Power
strokeRecovery stroke (b).
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- Structure of Cilia Cilia (a) 10 m..
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- http://www.youtube.com/watch?v=dXVG- DwOtKU Flagella tail of
the sperm - only functional flagellum whiplike structure with
axoneme identical to cilium much longer than cilium stiffened by
coarse fibers that supports the tail movement is more undulating,
snakelike no power stroke or recovery stroke as in cilia
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- Exit Quiz 1). Name the three fundamental parts of the cell
theory and identify who introduced each of these parts to the
scientific community. 2). Why are the majority of cells observed to
be so small? 3). What are the major components to a cell? What are
the primary functions of each of these components? 4). What are the
seven major functions of proteins in a cell membrane? 5). What are
the fundamental differences between cilia and flagella?