Chapter 5 – Inside The Cell

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-Chapter 7 –The Cell
Answer the “Key Concept” Questions for Each Section.
Quiz Vocab:
Secs: 1-3
Period 1
Lab (Quiz) date = Wednesday November 12
Test Date
= Friday November 14
Period 4
Lab (Quiz) date = Thursday November 13
Test Date
= Monday November 17
Period 7
Lab (Quiz) date = Friday November 14
Test Date
= Monday November 17
Overview: The Fundamental Units of Life
• All organisms are made of cells
• The cell is the simplest collection of matter
that can live
• Cell structure is correlated to cellular function
• All cells are related by their descent from earlier
cells – New cells produced from existing cells
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Eukaryotic cells have internal
membranes that compartmentalize
their functions
• The basic unit of every organism is one of two
types of cells: prokaryotic or eukaryotic
• Bacteria = prokaryotic
• Protists, fungi, animals, and plants all consist of
eukaryotic cells
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Comparing Prokaryotic and
Eukaryotic Cells
• Basic features of all cells:
–
–
–
–
Plasma membrane
Semifluid substance called cytosol (cytoplasm)
Chromosomes (carry genes)
Ribosomes (make proteins)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• Prokaryotic cells are characterized by having
–
–
–
–
No nucleus
DNA in an unbound region called the nucleoid
No membrane-bound organelles
Cytoplasm bound by the plasma membrane
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-6
Fimbriae
Nucleoid
Ribosomes
Plasma membrane
Cell wall
Bacterial
chromosome
Capsule
0.5 µm
(a) A typical rodshaped
bacterium
Flagella
(b) A thin section
through the
bacterium Bacillus
coagulans (TEM)
• Eukaryotic cells are characterized by having
– DNA in a nucleus that is bounded by a membranous
nuclear envelope
– Membrane-bound organelles
– Cytoplasm in the region between the plasma
membrane and nucleus
• Eukaryotic cells are generally much larger than
prokaryotic cells
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-9a
Nuclear
envelope
ENDOPLASMIC RETICULUM (ER)
Nucleolus
Rough ER
NUCLEUS
Smooth ER
Flagellum
Chromatin
Centrosome
Plasma
membrane
CYTOSKELETON:
Microfilaments
Intermediate
filaments
Microtubules
Ribosomes
Microvilli
Golgi
apparatus
Peroxisome
Mitochondrion
Lysosome
Fig. 6-9b
NUCLEUS
Nuclear envelope
Nucleolus
Chromatin
Rough endoplasmic
reticulum
Smooth endoplasmic
reticulum
Ribosomes
Central vacuole
Golgi
apparatus
Microfilaments
Intermediate
filaments
Microtubules
Mitochondrion
Peroxisome
Chloroplast
Plasma
membrane
Cell wall
Plasmodesmata
Wall of adjacent cell
CYTOSKELETON
Inside The Cell
What’s inside the cell?
What does the cell need to sustain life?
How are Cells different?
Are cells independent or dependent or both?
Are there levels of organization?
Characteristics of Cell
•Cells come in all types of
shapes and sizes
•Spheres, Cubes
and bricks
•Spikes, bulges
and extensions
•Cells come in all
different sizes
•Bacteria are
about 1
micrometer
•Human egg cell
is about 1
millimeter
Inside the Cell
Cytoplasm – What is it?
It’s the substance inside the cell. What’s it contain?
70 percent is water
30 percent is: Proteins, fats, carbohydrates, nucleic acids
and ions.
The exact composition varies among different cells. Why?
The eukaryotic cell’s genetic instructions are
housed in the nucleus and carried out by the
ribosomes
• The nucleus contains most of the DNA in a
eukaryotic cell
• Ribosomes use the information from the DNA to
make proteins
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The Nucleus: Information Central
• The nucleus contains most of the cell’s genes
and is usually the most conspicuous organelle
• The nuclear envelope encloses the nucleus,
separating it from the cytoplasm
• The nuclear membrane is a double membrane;
each membrane consists of a lipid bilayer
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• In the nucleus, DNA and proteins form genetic
material called chromatin
• Chromatin condenses to form discrete
chromosomes
• The nucleolus is located within the nucleus and
is the site of ribosomal RNA (rRNA) synthesis
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-10
Nucleus
1 µm
Nucleolus
Chromatin
Nuclear envelope:
Inner membrane
Outer membrane
Nuclear pore
Pore
complex
Surface of
nuclear envelope
Rough ER
Ribosome
1 µm
0.25 µm
Close-up of nuclear
envelope
Pore complexes (TEM)
Nuclear lamina (TEM)
Ribosomes: Protein Factories
• Ribosomes are particles made of ribosomal
RNA and protein
• Ribosomes carry out protein synthesis in two
locations:
– In the cytosol (free ribosomes)
– On the outside of the endoplasmic reticulum or the
nuclear envelope (bound ribosomes)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-11
Cytosol
Endoplasmic reticulum (ER)
Free ribosomes
Bound ribosomes
Large
subunit
0.5 µm
TEM showing ER and ribosomes
Small
subunit
Diagram of a ribosome
The endomembrane system regulates protein
traffic and performs metabolic functions in the cell
• Components of the endomembrane system:
–
–
–
–
–
–
Nuclear envelope
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Plasma membrane
• These components are either continuous or
connected via transfer by vesicles
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Endoplasmic Reticulum: Biosynthetic
Factory
• The endoplasmic reticulum (ER) accounts for
more than half of the total membrane in many
eukaryotic cells
• The ER membrane is continuous with the
nuclear envelope
• There are two distinct regions of ER:
– Smooth ER, which lacks ribosomes
– Rough ER, with ribosomes studding its surface
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-12
Smooth ER
Rough ER
ER lumen
Cisternae
Ribosomes
Transport vesicle
Smooth ER
Nuclear
envelope
Transitional ER
Rough ER
200 nm
Functions of Smooth ER
• The smooth ER
–
–
–
–
Synthesizes lipids
Metabolizes carbohydrates
Detoxifies poison
Stores calcium
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Functions of Rough ER
• The rough ER
– Has bound ribosomes, which secrete glycoproteins
(proteins covalently bonded to carbohydrates)
– Distributes transport vesicles, proteins surrounded
by membranes
– Is a membrane factory for the cell
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Golgi Apparatus: Shipping and
Receiving Center
• The Golgi apparatus consists of flattened
membranous sacs called cisternae
• Functions of the Golgi apparatus:
– Modifies products of the ER
– Manufactures certain macromolecules
– Sorts and packages materials into transport vesicles
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-13
cis face
(“receiving” side of Golgi
apparatus)
0.1 µm
Cisternae
trans face
(“shipping” side of Golgi
apparatus)
TEM of Golgi apparatus
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