Cell Type, Structure, &
Function
Bio.4 - Biology Science concepts. The
student knows that cells are the basic
structures of all living things with
specialized parts that perform specific
functions and that viruses are different
from cells
What are the characteristics
of life?
Characteristics of life:
•Made of cells
•Use energy - metabolism
•Reproduce
•Respond to stimulus
•Change over time - grow
•Movement of materials
How do we define life?
Cell Theory
•All living organisms are composed of cells
•Cells are the smallest structures that
perform the functions of life
•All cells come from preexisting cells
Theory
•Statements that explain a phenomenon; repeatedly
tested, widely accepted, and used to make
predictions.
What do all cells have in
common?
 All cells have common
structures
 Cell membrane
 Ribosome
 Cytoplasm
 Cells contain DNA
 Cells are basic unit of life
Make a three column chart.
(Title of slide)
Two types of cells
Cell History
Cell size
Prokaryotes Eukaryotes
Prokaryotes
•
•
Eukaryotes
•
•
Two Cell Types
Prokaryotic
•“pro” – BEFORE
•“karyo” – kernel, nucleus
•a cell type BEFORE the
evolution of a nucleus
Eukaryotic
•“eu” – true
•“karyo” – nucleus
•cell with a true nucleus
Cell History
Prokaryotic
Eukaryotic
 Ancient cells
 Modern cells
 Evolved 3.5 bya
 Evolved 1.4 bya
Billion years ago
Stromatolites, ancient bacterial formations
Cell Size
Prokaryotic
 Smaller cells
 1 to 10 µm
 Micrometer –
1/1000 of a meter
Eukaryotic
 Larger cells
 10 to 100 µm
Cell Size Comparison
Cell Organization
Prokaryotic
Simple cells with all
parts in “one room”
Eukaryotic
Complex cells with
many compartments
Location of DNA
Prokaryotic
DNA is loose in the
cytoplasm,called a
nucleiod
Eukaryotic
DNA is protected in
the nucleus
Presence of Organelles
Prokaryotic
Ribosomes
Cell membrane only
Eukaryotic
Many, membrane bound organelles
Cell Structures and Functions
Animal Cell
Type of Organisms
Prokaryotic
Bacteria only!
round
Rod
shaped
Spiral
shaped
Eukaryotic
Plants, Animals,
Fungi, and Protists
Prokaryotes: Bacteria
Size of Organisms
Prokaryotic
 Always unicellular
uni = one
 SUPER SMALL
Eukaryotic
 Mostly multicellular
(more than one cell)
 Range from cell size
(microscopic) to the size
of a sequoia tree (83
m=272 ft)
Cell Reproduction
Prokaryotes
Eukaryotes
Viruses
•Viruses are not considered
living because:
i. they are not made of
cells and
ii. need a host cell to
reproduce
•Viruses are much smaller
than cells
•Viruses and cells both
contain GENETIC MATERIAL
Capsid
What are the functions of the viral
structures?
Capsid – protein shell that
protects genetic information of
virus
What are the functions of the viral
structures?
Genetic information – strands of
DNA or RNA used to make viral
proteins inside infected host cell
Viral Structure - Bacteriophage
Tail – protein shaft that contracts
to inject viral genetic information
into host cell
Viral Structure - Bacteriophage
Tail fibers – proteins that attach
to the outside of a host cell
Viral Structure – Other Types
Membranous envelope – lipids
that attach and
fuse to host cells membrane
Viruses vs. Cellular Life
Viruses
• DNA or RNA as
genetic information
• Need a host to replicate
• Never contain organelles
• Do not convert energy
(metabolize)
Cellular Life
• Only DNA as genetic
information
• Can reproduce
independently
• Eukaryotes contain
organelles
• Convert energy to
perform tasks
How do viruses reproduce?
• Viruses need a host to reproduce
– Goal: create more copies of their genetic material
• Two methods
– Lytic Cycle
– Lysogenic Cycle
Viral Reproduction –
Lytic Cycle
• Lytic Cycle
– Attaches to host
– Injects genetic material into host
– Cellular machinery duplicates genetic material and creates
viral proteins (capsids, tail fibers)
– New viruses are assembled
– New viruses exit the cell by bursting the cellular membrane
• End result – more viruses made, cell dies
Viral Reproduction –
Lytic Cycle
Attachment
Lytic Cycle
Entry
Release
Assembly
Replication
Viral Reproduction –
Lysogenic Cycle
• Lysogenic Cycle
–
–
–
–
–
Attaches to host
Injects genetic material into host
Viral genetic material is inserted into host genome
Viral genetic material lies dormant
When cell reproduces, new copies have viral genetic
information
– Environmental stimulus sends viral DNA into lytic cycle
• End result – more viral genome made, cell lives
Viral Reproduction –
Lysogenic Cycle
Lysogenic Cycle
Attachment
Entry
Separation
Insertion
Reproduction
Viral Reproduction
Lytic Cycle
• New viruses made
• Cellular host dies
Lysogenic Cycle
• Genome copies made
• Cellular host lives
Common Viral Infections
Lysogenic Cycle:
– Herpes
– HPV
– Chicken Pox (can
become shingles)
– HIV
– Hepatitis B
Lytic:
–
–
–
–
–
–
SARS
Common Cold
Influenza
Rabies
AIDS phase of HIV
Tobacco Mosaic Virus
(in plants)
Viral Reproduction
Lytic & Lysogenic Cycles
Cell Type, Structure, &
Function
Bio.4 - Biology Science concepts. The
student knows that cells are the basic
structures of all living things with
specialized parts that perform specific
functions and that viruses are different
from cells
Cells Make Proteins
Structure & Function
What is structure?
A structure is a physical part,
or a description of how
something is built.
What is function?
A function is a job, a purpose,
or a process that needs to be
done.
What are
organelles?
An organelle is a “mini
organ” inside a
eukaryotic cell that
carries out a specific
function.
Cell Membrane
 Lipid bilayer that surrounds the cell
 Embedded proteins control what materials
enter and leave the cell.
Cytoplasm
 Jelly-like fluid inside the cell membrane
 Supports and holds all the organelles
Ribosomes
 Where proteins are assembled
 Translate genes into proteins
Cell Wall
Support, strength, and protection
Found outside plasma membrane;
made out of cellulose
Plant Cell Wall 
Bacteria Cell Wall
Flagella/Cilia
Extensions of the plasma membrane
that allow for movement
Bacteria with many flagella
Nucleus
 Membrane bound area where
chromosomes are found
 Holds the DNA, or genetic information
Nucleolus
Dense region found in the nucleus
where ribosomal RNA is made
Chloroplasts
 Contains chlorophyll
 Site of photosynthesis reactions
 6H2O + 6CO2
sunlight
C6H12O6 + 6O2
Mitochondria
 Produces ATP (energy) for the cell during
cellular respiration
 C6H12O6 + 6O2
6H2O + 6CO2 + ATP
 Composed of inner and outer membrane
Endoplasmic Reticulum
 Membranous stacks with rough and
smooth sections
 Participates in protein synthesis and
membrane synthesis
Golgi
Apparatus
 Modifies and
packages proteins
for secretion by
budding of vesicles
Lysosomes
 Contains enzymes that break down
cell wastes and foods
 Recycle old cell parts
Lysosomes contain
digestive enzymes 
Vacuole
Stores water and pigments in plant cells
Centrioles
 Used to organize chromosomes during cell division
using spindle fibers.
Cells Make Proteins
Cell Type, Structure, &
Function
Bio.4 - Biology Science concepts. The
student knows that cells are the basic
structures of all living things with
specialized parts that perform specific
functions and that viruses are different
from cells