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CELLS
Cell Theory
•All living things are composed of cells
•Cells are the smallest functional part
of a living organism
•All cells come from other cells
CELL TYPES
•Cells are either:
PROKARYOTIC
or
EUKARYOTIC
Prokaryotic cells
1. No nucleus or membrane bound organelles
•Nuclear region, contains one single DNA
molecule arranged in a circular chromosome
2. Structure:
• They have RIBOSOMES!!
•Cell membrane
• Cell wall (different than plants)
• Some have capsules outside wall
•Some have pilli or flagella
Eukaryotic cells
•Have NUCLEUS and membrane bound
organelles
•Plasma membrane
•Cytoplasm - everything between plasma
membrane and nucleus
Organelle
•
A minute (small) membrane bound structure within a
plant or animal cell that has a particular job or
function.
EUKARYOTIC CELLS
Nucleus
•
•
•
•
•
•
CONTROL CENTER for activities & reproduction
DNA & chromosomes housed here.
Has double membrane
Pores (holes or openings) to get messages in and out
Chromatin = DNA & Protein put together
Nucleolus - site of ribosome production
PLASMA MEMBRANE
•Made of phospholipid and protein bilayer.
•Cell boundary
•Regulates entering & exiting of materials
cytoskeleton
phospholipid
Channel
protein
Ribosomes
• Site of Protein Synthesis
Mitochondria
• Site of cellular respiration. Energy production
• Powerhouse. Numerous amounts in cells needing
lots of energy where a lot of work is done
(example: muscle cells)
Chloroplasts
• Site of photosynthesis where light energy is
converted to chemical energy.
• Contains the green pigment chlorophyll which
captures light.
• Found only in plants.
VACUOLE
• STORAGE for food and water
• PLANT VACUOLES are larger than
animal vacuoles
Some protista cell vacuoles pump water
out by contracting:
FIND 2 Contractile vacuoles
in this Paramecium?
Cell Walls
• Has Cellulose
• Nonliving
• Rigid
• Outer boundary
• Provides protection
and shape
Animal vs Plant Cell
•Animal cells
• Roundish
•Plant cells
• Rectangular
•Large permanent central vacuole
•Cellulose cell wall
•Chloroplasts
•(All other organelles are common to both)
HOW DO THE CHROMOSOMES OF
PROKARYOTIC CELLS DIFFER FROM THOSE OF
EUKARYOTIC CELLS?
•Except in the mitochondria and other organelles, eukaryotic
chromosomes are linear whereas prokaryotic chromosomes are
circular.
•Eukaryotes typically have many chromosomes, whereas prokaryotes
have only a single chromosome.
•Eukaryotic chromosomal DNA in the nucleus is wound on nucleosome
cores whereas prokaryotic DNA is “naked”—i.e., there are no
nucleosomes or other proteins on which the DNA is wound.
•Most eukaryotic cells are diploid, receiving a set of chromosomes
from each parent. Thus their chromosomes occur in homologous pairs,
each consisting of one chromosome from each parent bearing basically
the same genes in the same order. Prokaryotes are haploid; their
single circular chromosome is unpaired.
Time to
your wor
   
CELL SPECIALIZATION
• Different kinds of cells suited for a different
activity.
DIVISION OF LABOR
•Different cells divide their labor.
Each has a specific function and
supports each other.
Levels of Structure
•1. Cell
•2. Tissue
•3. Organ
•4. Organ system
•5. Organism
5. Organism
4. Organ System
3. Organ
2. Tissue
1. Cells
TISSUE
• Group of cells that are alike in structure and
activity in an organism.
EXAMPLES:
- muscles - motion
- bones – support
- nerves - coordination, perception and automatic
body functions
Can you name some other types of
tissue?
ORGAN
•Several tissues working as a unit
heart
•animal
brain
cell
stomach
stem
•plant
trunk
cell
leaf
CAN YOU LIST SOME MORE ANIMAL ORGANS?
ORGAN SYSTEM
Many organs involved in carrying out a function
•digestive
•nervous
•skeletal
•excretory
•respiratory
•endocrine
•circulatory
•muscular
•reproductive
•integumentary
ORGANISM
•Complete living thing
Cell
All 4 make up the
Tissue
organism
Organ
Organ system
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