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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 structuresCell membraneRibosomeCytoplasm
Cells contain DNA
Cells are basic unit of life
Make a three column chart.
(Title of slide) Prokaryotes
Eukaryotes
Two types of cells Prokaryotes• •
Eukaryotes• •
Cell History
Cell size
Two Cell TypesProkaryotic•“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
Ancient cells
Evolved 3.5 bya
Billion years ago
Eukaryotic
Modern cells
Evolved 1.4 bya
Stromatolites, ancient bacterial formations
Cell SizeProkaryotic
Smaller cells
1 to 10 µm
Micrometer – 1/1000 of a meter
Eukaryotic
Larger cells
10 to 100 µm
Cell OrganizationProkaryotic
Simple cells with all parts in “one room”
Eukaryotic
Complex cells with many compartments
Location of DNAProkaryotic
DNA is loose in the cytoplasm,called a nucleiod
Eukaryotic
DNA is protected in the nucleus
Presence of OrganellesProkaryotic
Ribosomes
Cell membrane only
Eukaryotic
Many, membrane -bound organelles
Type of OrganismsProkaryotic
Bacteria only!
Eukaryotic
Plants, Animals, Fungi, and Protistsround Rod
shaped
Spiral shaped
Prokaryotes: Bacteria
Size of Organisms
ProkaryoticAlways unicellular
uni = one
SUPER SMALLEukaryotic
Mostly multicellular (more than one cell)
Range from cell size (microscopic) to the size of a sequoia tree (83 m=272 ft)
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
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
What are the functions of the viral structures?
Tail – protein shaft that contracts to inject viral genetic information into host cell
Viral Structure - Bacteriophage
Membranous envelope – lipids that attach and fuse to host cells membrane
Viral Structure – Other Types
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
Viruses vs. Cellular Life
• Viruses need a host to reproduce– Goal: create more copies of their genetic material
• Two methods– Lytic Cycle– Lysogenic Cycle
How do viruses reproduce?
• 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
• 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 CycleAttachment
Entry
ReproductionInsertion
Separation
Viral Reproduction – Lysogenic Cycle
Lytic Cycle• New viruses
made• Cellular host dies
Lysogenic Cycle• Genome copies
made• Cellular host lives
Viral Reproduction
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)
Common Viral Infections
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 organelles?
An organelle is a “mini organ” inside a eukaryotic cell that
carries out a specific function.
Cell MembraneLipid bilayer that surrounds the cell
Embedded proteins control what materials enter and leave the cell.
Cell WallSupport, strength, and protection
Found outside plasma membrane;
made out of cellulose
Plant Cell Wall
Bacteria Cell Wall
ChloroplastsContains chlorophyll
Site of photosynthesis reactions
6H2O + 6CO2 C6H12O6 + 6O2
sunlight
MitochondriaProduces ATP (energy) for the cell
during cellular respiration
C6H12O6 + 6O2 6H2O + 6CO2 + ATP
Composed of inner and outer membrane
Endoplasmic ReticulumMembranous stacks with rough and
smooth sections
Participates in protein synthesis and membrane synthesis
LysosomesContains enzymes that break
down cell wastes and foods
Recycle old cell parts
Lysosomes contain digestive enzymes