LIVING ORGANISMS are HIGHLY ORGANIZED Cells, the simplest
collection of matter that can live, were first observed by Robert
Hooke in 1665 Antoni van Leeuwenhoek later described cells that
could move He viewed bacteria with his own hand-crafted microscopes
Copyright 2009 Pearson Education, Inc.
Slide 4
The CELL THEORY: The early microscopes provided data to
establish the cell theory All living things are composed of cells
All cells come from other cells (NO Spontaneous Generation)
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INTRODUCTION TO THE CELL Copyright 2009 Pearson Education,
Inc.
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Microscopes reveal the world of the cell A variety of
microscopes have been developed for a clearer view of cells and
cellular structure The most frequently used microscope is the light
microscope (LM)like the one used in biology laboratories We will
use a COMPOUND LIGHT MICROSCOPE Light passes through a specimen
then through 2 glass lenses into the viewers eye Specimens can be
magnified up to 400 times the actual size of the specimen Copyright
2009 Pearson Education, Inc.
Slide 7
Enlarges image formed by objective lens Magnifies specimen,
forming primary image Eyepiece Focuses light through specimen
Ocular lens Specimen Objective lens Condenser lens Light
source
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Microscopes reveal the world of the cell Microscopes have
limitations Both the human eye and the microscope have limits of
RESOLUTIONthe ability to distinguish between small structures
Therefore, the light microscope cannot provide the details of a
small cells structure SOwe can stain the specimen Can you think of
a problem with this??? Copyright 2009 Pearson Education, Inc.
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Human height Length of some nerve and muscle cells 10 m Frog
egg Chicken egg Unaided eye 1 m 100 mm (10 cm) 10 mm (1 cm) 1 mm
Light microscope Electron microscope 100 nm 100 m 10 m 1 m Most
plant and animal cells Viruses Nucleus Most bacteria Mitochondrion
10 nm Lipids Ribosome Proteins Mycoplasmas (smallest bacteria) 1 nm
Small molecules 0.1 nm Atoms
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Prokaryotic cells are structurally simpler than eukaryotic
cells Bacteria and archaea are prokaryotic cells All other forms of
life are eukaryotic cells Both prokaryotic and eukaryotic cells
have a plasma membrane and one or more chromosomes (DNA) and
ribosomes Eukaryotic cells have a membrane-bound nucleus and a
number of other organelles, whereas prokaryotes have no nucleus and
no true organelles Copyright 2009 Pearson Education, Inc.
Slide 13
Prokaryotic Cells Prokaryotic cells are like a studio (one-
room) apartment All functions take place within the plasma membrane
of the cell
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Nucleoid Ribosomes Plasma membrane Cell wall Capsule Flagella
Bacterial chromosome A typical rod-shaped bacterium Pili A thin
section through the bacterium Bacillus coagulans (TEM)
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Eukaryotic cells are partitioned into functional compartments
Eukaryotic cells are like a multiple room apartment Different
functions take place in different organelles Copyright 2009 Pearson
Education, Inc.
Slide 16
Eukaryotic cells are partitioned into functional compartments
Manufacturing of protein molecules involves the nucleus, ribosomes,
endoplasmic reticulum, and Golgi apparatus Copyright 2009 Pearson
Education, Inc.
Slide 17
The nucleus is the cells genetic control center It contains the
information (DNA) to make protein molecules The nuclear envelope is
a double membrane with pores that allow material (messenger RNA) to
flow out of the nucleus It is attached to a network of cellular
membranes called the endoplasmic reticulum Copyright 2009 Pearson
Education, Inc.
Slide 18
Two membranes of nuclear envelope Nucleus Nucleolus Chromatin
Pore Endoplasmic reticulum Ribosomes
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Ribosomes make proteins for use in the cell and outside of the
cell Ribosomes are involved in the cells protein synthesis
Ribosomes are synthesized in the nucleolus, which is found in the
nucleus Copyright 2009 Pearson Education, Inc.
Slide 20
Cytoplasm Endoplasmic reticulum (ER) Free ribosomes Bound
ribosomes Ribosomes ER Small subunit Diagram of a ribosome TEM
showing ER and ribosomes Large subunit
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The endoplasmic reticulum is a biosynthetic factory There are
two kinds of endoplasmic reticulumsmooth and rough Smooth ER lacks
attached ribosomes Rough ER lines the outer surface of membranes
They differ in structure and function However, they are connected
Copyright 2009 Pearson Education, Inc.
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Smooth ER Nuclear envelope Ribosomes Rough ER
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The endoplasmic reticulum is a biosynthetic factory Smooth ER
is involved in a variety of diverse metabolic processes For
example, enzymes produced by the smooth ER are involved in the
synthesis of lipids, oils, phospholipids, and steroids Copyright
2009 Pearson Education, Inc.
Slide 24
The endoplasmic reticulum is a biosynthetic factory Rough ER
makes proteins Once proteins are synthesized, they are transported
in vesicles to other parts of the endomembrane system Copyright
2009 Pearson Education, Inc.
Slide 25
The Golgi apparatus finishes, sorts, and ships cell products
The Golgi apparatus functions in conjunction with the ER by
modifying products of the ER Products travel in transport vesicles
from the ER to the Golgi apparatus One side of the Golgi apparatus
functions as a receiving dock for the product and the other as a
shipping dock Products are modified as they go from one side of the
Golgi apparatus to the other and travel in vesicles to other sites
Copyright 2009 Pearson Education, Inc.
Slide 26
Transport vesicle buds off Secretory protein inside trans- port
vesicle Glycoprotein Polypeptide Ribosome Sugar chain Rough ER 1 2
3 4
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Golgi apparatus Golgi apparatus Receiving side of Golgi
apparatus Transport vesicle from ER New vesicle forming Shipping
side of Golgi apparatus Transport vesicle from the Golgi
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PROTEIN SYNTHESIS In the nucleus, DNA information for protein
synthesis is copied into messenger RNA (mRNA) mRNA leaves the
nucleus; goes to the ribosomes Proteins are synthesized at the
ribosomes Proteins leave the ribosomes in transport vesicles headed
for the Golgi apparatus Proteins are modified at the Golgi
apparatus Modified proteins leave the Golgi apparatus in transport
vesicles headed for their destination (inside or outside of the
cell)
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Nucleus Vacuole Lysosome Plasma membrane Smooth ER Nuclear
membrane Golgi apparatus Rough ER Transport vesicle Transport
vesicle
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Lysosomes are digestive compartments within a cell A lysosome
is a membranous sac containing digestive enzymes The enzymes and
membrane are produced by the ER and transferred to the Golgi
apparatus for processing The membrane serves to safely isolate
these potent enzymes from the rest of the cell These enzymes can be
used to: Digest dead cells Digest food for unicellular organisms
Destroy pathogens (WHITE BLOOD CELLS) Copyright 2009 Pearson
Education, Inc.
Slide 31
Vacuoles function in the general maintenance of the cell
Vacuoles are membranous sacs that are found in a variety of cells
and possess an assortment of functions Examples are the central
vacuole in plants Water is stored here Copyright 2009 Pearson
Education, Inc.
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Nucleus Chloroplast Central vacuole
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Mitochondria harvest chemical energy from food Cellular
respiration is accomplished in the mitochondria of eukaryotic cells
Cellular respiration involves conversion of chemical energy in
foods (GLUCOSE) to chemical energy in ATP (adenosine triphosphate)
Copyright 2009 Pearson Education, Inc.
Slide 35
Mitochondrion Intermembrane space Inner membrane Cristae Matrix
Outer membrane
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Chloroplasts convert solar (sunlight) energy to chemical energy
Chloroplasts are the photosynthesizing organelles of plants
Photosynthesis is the conversion of light energy to chemical energy
of sugar molecules Copyright 2009 Pearson Education, Inc.
Slide 37
Chloroplast Stroma Inner and outer membranes Granum
Intermembrane space
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Cilia and flagella move when microtubules bend While some
protists have flagella and cilia that are important in locomotion,
some cells of multicellular organisms have them for different
reasons Cells that sweep mucus out of our lungs have cilia Animal
sperm are flagellated Copyright 2009 Pearson Education, Inc.
Slide 39
Cilia
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Flagellum
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Eukaryotic cells are partitioned into functional compartments
Although there are many similarities between animal and plant
cells, differences exist Lysosomes and centrioles are not found in
plant cells Plant cells have a rigid cell wall, chloroplasts, and a
central vacuole not found in animal cells Copyright 2009 Pearson
Education, Inc.
Review of Cell Types Bacterial CellPlant CellAnimal Cell Ten
times smaller (1-10 micrometers) 10-100 micrometers One Naked
Chromosome Multiple Chromosomes Cell Wall No Cell Wall No
NucleusNucleus No OrganellesOrganelles No OrganellesChloroplasts;
Central Vacuoles No Chloroplasts or Central Vacuoles No
OrganellesNo Centrioles or Lysosomes Centrioles and Lysosomes