Biology 160
Are we really what we eat?
• Today:
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(5 min) Scientists at work! Review from yesterday
(10 min) Safety
(1 hr 30 min) Lab 01!
(10 min) Break
(10 min) Class website and Discussion assignment
(10 min) small group discussion Reading Guide 02
• Any questions you had?
• Share what cell city jobs you picked and WHY
• Quiz each other on the cellular structures
 (20 min) whole class review on cells and cell structure
 (10 min) small group cell structure activity
Class Website
The difference between an
observation and an inference
Observation
Inference
A verifiable
description or
measurement
An educated
guess based
on observations
or prior knowledge
Could an inference
be incorrect? How
would you test it?
Scientists at Work!
• Observations (looking carefully)
• Observed fibers, veins, color, shape, parts of foods, water upon
cutting
• We’ll make a list of what kind of observations we might make
for Lab 01
• Prior knowledge (experience)
•
•
•
•
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Digestive system breaks down food and distributes nutrients to body.
Onion becomes sweet after cooking and makes you cry.
DNA found in nucleus of cells
These unprocessed foods are made out of plant cells
Proteins, carbs, and lipids are in foods
• Inferences (educated guess)
• Carbs are inside the potato, carbs and protein form the flesh of the red
pepper, proteins are in the skin of the carrot, lipids and proteins might
be found inside sweet potato, but where?
Am I Really What I Eat?
continued…
• Next we’ll start to prepare ourselves to
answer the question, “What does my food
look like under the microscope?”
• Today we’ll learn how to use a microscope
in Lab 01
• Next week we’ll look at our food more
closely in Lab 02 using this revolutionary
tool!
Biology 160
Are we really what we eat?
• Today:






(5 min) Scientists at work! Review from yesterday
(10 min) Safety
(1 hr 30 min) Lab 01!
(10 min) Break
(10 min) Class website and Discussion assignment
(10 min) small group discussion Reading Guide 02
• Any questions you had?
• Share what cell city jobs you picked and WHY
• Quiz each other on the cellular structures
 (20 min) whole class review on cells and cell structure
 (10 min) small group cell structure activity
The Three Domains of Life
 The three domains of life are:
• Bacteria
• Archaea
• Eukarya
Prokaryotes
Eukaryotes
The Three Domains of Life
 The three domains of life are:
• Bacteria
• Archaea
• Eukarya
Prokaryotes
Eukaryotes
At least four kingdoms of Eukarya
-Plantae
-Fungi
-Animalia
-Protists (a group of multiple kingdoms)
Biology 160
Are we really what we eat?
• So far, what evidence do we have to support or refute this question?
Cells!
– The cell is the lowest level of structure that
can perform all activities required for life.
• Cell Theory:
– All living organisms are composed of cells.
– All cells come from other cells.
We can distinguish two major types of cells:
Prokaryotic
Eukaryotic
Photo source: Wikipedia
The
prokaryotic
cell is simple,
small, and
contains no
organelles.
The
eukaryotic
cell is larger
and more
complex
and
contains
organelles.
Prokaryotic and Eukaryotic Cells:
(DNA)
(DNA)
Cytosol
Cytosol
A prokaryotic cell
Two typical kinds
of eukaryotic cells:
- Animal cells
- Plant cells
Prokaryotic and Eukaryotic Cells:
What do all cells have in common?
(DNA)
(DNA)
Cytosol
Plasma membrane
Cytosol
Ribosomes
Chromosomes
made of DNA
Cytosol
A prokaryotic cell
Plasma Membrane
– The plasma membrane separates the living
cell from its nonliving surroundings.
- Regulates traffic
into and out of
the cell
- Allows cell
to interact
with environment
Cell Surfaces
– Plant cells and bacterial cells have cell walls,
• Which help protect the cells, maintain their shape, and keep
the cells from absorbing too much water.
Cell Surfaces
– Animal cells have an extracellular matrix and cell
junctions,
• Which helps hold cells together in tissues and protects and
supports them (not shown).
Try giving your skin a good pull. If your skin is made out of cells,
how do they all stick together? Extracellular matrix and
junctions!
The Nucleus:
Genetic Control of the Cell
– The nucleus is the manager of the cell.
• Genes on the DNA in the nucleus store information
necessary to produce proteins.
Prokaryotes do not have nuclei.
Their genes (on DNA) are in the nucleoid region
How DNA Controls the Cell
– DNA controls the cell by transferring its coded
information into RNA.
• The information in the RNA is used to make proteins.
The Endomembrane System: Manufacturing,
Distributing, and Storing Cellular Products
Not found in bacterial cells!
Smooth ER
– The smooth ER lacks the surface
ribosomes of rough ER and produces
lipids, including steroids.
Rough ER
– The “roughness” of the rough ER is due to
ribosomes that stud the outside of the ER
membrane.
– The functions of the
rough ER include:
• Producing two types of
membrane proteins
– Membrane proteins
– Secretory proteins
• Producing new
membrane
– After the rough ER synthesizes a molecule, it packages the
molecule into transport vesicles. These vesicles head off to
the Golgi Apparatus…
The Golgi Apparatus
– The Golgi apparatus
• Works in partnership with the ER.
• Refines, stores, and distributes the chemical
products of cells.
Lysosomes
– A lysosome is a
membraneenclosed sac that
contains
digestive
enzymes to
break down
macromolecules.
Vacuoles
– Vacuoles are membranous sacs.
• Contractile vacuoles of protists get rid of excess
water.
• Central vacuoles of plants store nutrients, absorb
water, contain some pigments or poisons.
– A review of the endomembrane system
An amazing
system that
manufactures,
distributes, and
stores cellular
products!
Energy Conversion:
Chloroplasts & Mitochondria
– Cells require a constant energy supply to do all
the work of life.
Not found in bacterial cells!
Chloroplasts
– Chloroplasts are the sites of
photosynthesis, the conversion of light
energy to chemical energy.
All little green
circles are
chloroplasts
Cell walls
Mitochondria
– Mitochondria are the sites of cellular
respiration, which involves the production
of ATP from food molecules.
The Cytoskeleton:
Cell Shape and Movement
– The cytoskeleton consists of a network of fibers.
Also, recently found in bacterial cells!
Cytoskeleton
– Mechanical support to
maintain cell shape
– Can change cell
shape to allow
movement
Cilia and Flagella
– Cilia and flagella are motile appendages.
Not found on most plant cells!
– Flagella propel the cell in a whiplike
motion.
– Cilia move in a coordinated back-and-forth
motion.
Plastids
Membrane-bound organelles found only in plants
Amyloplast
stores
starch
(stained
blue with
iodine)
All little green
circles are
Cell walls
chloroplasts
Chloroplast performs
photosynthesis
Chromoplast
stores
pigments
(little orange
circles)
Are we really what we eat?
What do you think?
What is your evidence?
What do we need to learn more about?