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Anatomy and Physiology
Cell Structure & Function

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mid 1600s – Anton van Leeuwenhoek
-Improved microscope,
observed many living cells
mid 1600s – Robert Hooke
-Observed many cells
-Cells were discovered in 1665
by Robert Hooke
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3
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All living things are made up of cells
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All cells come from preexisting cells through
cell division
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All organisms are composed of cells
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Cells are the smallest living things
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Cells arise only from pre-existing cells
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Cell size is limited
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Surface area-to-volume ratio:
as a cell increases in size, the volume increases
10x faster than the surface area

Microscopes are required to visualize cells:
Light microscopes can resolve structures that are
200nm apart
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2nm apart
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Electron Microscopes
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Images are black and white – may be colorized
Magnifcation up to ~100,000
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Transmission electron microscope (TEM)
2-D image

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Scanning electron microscope (SEM) 3-D
image

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cytoplasm – a semifluid matrix
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Observing Cells (4
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2 microns to 0
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Amoeba Proteus
2
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Bacteria
4
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Red Blood Cell
Handout Layout by: Gomez, BSN1A

-no membrane-bound organelles
Prokaryotic cell walls
-protect the cell and maintain cell shape
Bacterial cell walls
-may be composed of peptidoglycan
-may be Gram positive or Gram negative
Archaean cell walls lack peptidoglycan
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-genetic material is present in the nucleoid
Two types of prokaryotes:
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–bacteria
Prokaryotic cells possess:
-genetic material in the nucleoid
-cytoplasm
-plasma membrane
-cell wall
-ribosomes
Handout Layout by: Gomez, BSN1A

Prokaryotic Cell Structure
Prokaryotic Cells are smaller and simpler in structure
than eukaryotic cells
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Vacuoles
 Membrane-bound sacs for storage, digestion,
and waste removal
 Contains water solution
 Help plants maintain shape

Chloroplast
 Usually found in plant cells
 Contains green chlorophyll
 Where photosynthesis takes place
1
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Genetic material in the form of DNA
Prokaryotes – no membrane around the DNA (no
nucleus)
Eukaryotes – DNA is within a membrane (there is
nucleus)
3
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2)
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Cells need sufficient surface area to allow
adequate transport of nutrients in and wastes
out
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 However, as cell volume increases the surface
area of the cell does not expand as quickly
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 Thus, surface area limits cell volume/size
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- Long and narrow…
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Ribosomes – make proteins

All Cells have:
 an outermost plasma membrane
 genetic material in the form of DNA
 cytoplasm with ribosomes

Handout Layout by: Gomez, BSN1A

Nucleus
Ribosomes
Endomembrane System
 Endoplasmic reticulum – smooth and rough
Golgi apparatus
Vesicles
Mitochondria

Cytoskeleton

Bilayer Facing
Nuclear Pore

Nucleus (4
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Nuclear envelope
Two Phospholipid bilayers with protein
lined pores
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Nucleoplasm
fluid of the nucleus

Series
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of organelles responsible for:
Modifying protein chains into their final form
Synthesizing of lipids
Packaging of fully modified proteins and lipids
into vesicles for export or use in the cell
And more that we will not cover!

DNA is arranged in chromosomes
Chromosome – fiber of DNA with proteins
attached
Chromatin – all of the cell’s DNA and the
associated proteins
Nucleolus- Area of condensed DNA
Where ribosomal subunits are made
Subunits exit the nucleus via nuclear pores
Handout Layout by: Gomez, BSN1A

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Endoplasmic Reticulum (ER)
- Continuous with the outer membrane of the
nuclear envelope
- Two forms - smooth and rough
 Transport vesicles
 Golgi apparatus

(ER)
The ER is continuous with the outer membrane of the
nuclear envelope

FUNCTION:
 Lipids are made inside the SER
 fatty acids, phospholipids, sterols
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Rough endoplasmic reticulum (RER)
-membranes that create a network of channels
throughout the cytoplasm
-attachment of ribosomes to the membrane gives
a rough appearance
-synthesis of proteins to be secreted, sent to
lysosomes or plasma membrane
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Golgi apparatus
-flattened stacks of interconnected membranes
-packaging and distribution of materials to
different parts of the cell
-synthesis of cell wall components
4
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Microbodies
-membrane bound vesicles
-contain enzymes
-not part of the endomembrane system
-glyoxysomes in plants contain enzymes for
converting fats to carbohydrates
-peroxisomes contain oxidative enzymes and
catalase
Handout Layout by: Gomez, BSN1A

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Golgi apparatus receives transport vesicles
from the ER on one side of the organelle
Vesicle binds to the first layer of the Golgi and
its contents enter the Golgi
The proteins and lipids are modified as they
pass through layers of the Golgi
Molecular tags are added to the fully modified
substances
These tags allow the substances to be sorted
and packaged appropriately
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Transport Vesicles
Vesicle = small membrane bound sac
Transport modified proteins and lipids from the ER to
the Golgi apparatus (and from Golgi to final
destination)

PUTTING IT ALL TOGETHER
DNA directs RNA synthesis RNA exits nucleus
through a nuclear pore ribosome protein is made
proteins with proper code enter RER proteins are
modified in RER and lipids are made in SER vesicles
containing the proteins and lipids bud off from the ER
ER vesicles merge with Golgi body proteins and lipids
enter Golgi each is fully modified as it passes
through layers of Golgi modified products are
tagged, sorted and bud off in Golgi vesicles…
Golgi vesicles either merge with the plasma
membrane and release their contents OR remain in
the cell and serve a purpose

Vesicles - small membrane bound sacs
Examples
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Golgi and ER transport vesicles
Peroxisome
- Where fatty acids are
metabolized
- Where hydrogen peroxide is
detoxified
Lysosome
- contains digestive enzymes
- Digests unwanted cell parts and
other wastes

Handout Layout by: Gomez, BSN1A

The lysosome is an example of an organelle made at
the Golgi apparatus
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The vesicle remains in the cell and:
o Digests unwanted or damaged cell parts
o Merges with food vacuoles and digest the
contents
Tay-Sachs disease occurs when the lysosome is
missing the enzyme needed to digest a lipid found in
nerve cells
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Function – synthesis of ATP
3 major pathways involved in ATP production:
1) Glycolysis
2) Krebs Cycle
3) Electron transport system (ETS)
Mitochondria
Structure:
 ~1-5 microns
 Two membranes
o Outer membrane
o Inner membrane - Highly folded
 Folds called cristae
 Intermembrane space (or outer compartment)
 Matrix
o DNA and ribosomes in matrix

Mitochondria
-organelles present in all types of eukaryotic cells
-contain oxidative metabolism enzymes for
transferring the energy within macromolecules to
ATP
-found in all types of eukaryotic cells
-surrounded by 2 membranes
-smooth outer membrane
-folded inner membrane with layers
called cristae
Function – synthesis of ATP
3 major pathways involved in ATP production
1) Glycolysis - cytoplasm
2) Krebs Cycle - matrix
3) Electron transport system (ETS) intermembrane space

-matrix is within the inner membrane
-intermembrane space is located between the
two membranes
-contain their own DNA

TEM

END

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