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The CellThe Cell
The The fundamental fundamental unit of life for unit of life for plants & plants & animals.animals.
http://library.thinkquest.org/3564/gallery.html
How do we observe cells?How do we observe cells?• Light microscopes–Compound• Up to 1,500x magnification–Dissecting • Up to 30x magnification
• Electron microscopes–Scanning• Up to 10,000x magnification–Transmission• Over 200,000x magnification
How big are cells?How big are cells?
Many different sizes
Average sized cell is 50 micrometers
◦~ 500 cells per inch
A fruit tree leaf may have 50 million
cells
A mature fruit tree may have 15
trillion cells!!
Prokaryotic vs. Eukaryotic Prokaryotic vs. Eukaryotic cellscellsProkaryotic cells
◦ Cells without a nucleus pro = before karyon = nucleus
◦ Very simple organisms such as bacteria
Eukaryotic cells◦ Cells that have a
nucleus eu = well or good karyon = nucleus
◦ Found inside all plants & animas
Animal & Plant CellsAnimal & Plant Cells
Animal & plant cells are Animal & plant cells are both eukaryotic and have both eukaryotic and have many of the same many of the same structures.structures.
http://www.science-art.com/image.asp?id=1319&search=1&pagename=Animal_and_Plant_Cell
http://biology.about.com/library/weekly/aa031600b.htm
PROKARYOTIC CELLS VS. EUKARYOTIC (ANIMAL & PLANT) CELLS
StructureProkaryotic Cell
Typical Animal Eukaryotic Cell
Typical Plant Eukaryotic Cell
Cell Wall Yes No YesCentrioles No Yes No
ChromosonesOne long DNA strand
Many Many
Cilia or Flagella
Yes, simple Yes, complex Some present
Endoplasmic Reticulum
NoYes (some exceptions)
Yes (some exceptions)
Golgi Complex
No Yes Yes
Lysosomes No Common NoMitochondria No Yes YesNucleus No Yes YesPeroxisomes No Common CommonPlasma Membrane
Yes Yes Yes
Ribosomes YesYes
Yes
The Plant CellThe Plant Cell The components of a typical plant
cell:– Cell wall– Protoplast
Plasma Membrane– Cytoplasm
Plastids Chromoplasts Chloroplasts
Endoplasmic Reticulum Mitrochondrion Vacuole
–Nucleus Nuclear Membrane Chromosomes Ribosomes DNA
Plant Cell WallPlant Cell Wall
http://trc.ucdavis.edu/biosci10v/bis10v/week2/2webimages/figure-04-27-photo.jpg
http://www.daviddarling.info/encyclopedia/C/cellwall.html
• Freely permeable membrane– Water & nutrients
• Protects internal structures (organelles)
• Provides rigidity and/or flexibility
Plasma membranePlasma membrane
1st membrane inside cell wall
Lipid bi-layer surrounding the cytoplasm
Highly selective permeability–Controls what comes in
and out of cell Extremely thin–12,500 membranes
stacked = thickness of 1 piece of paper
CytoplasmCytoplasm
Viscous, jelly-like fluid composed of proteins
Occupies most of the volume of the cell
Includes all cellular parts (organelles) inside the plasma membrane, not including the nucleus
http://sun.menloschool.org/~cweaver/cells/c/cytoplasm/
Cytoplasm - PlastidsCytoplasm - Plastids
Responsible for photosynthesis, starch storage, and synthesis of molecules
Give color to plantsChloroplasts
◦Photosynthesis, green in color
Chromoplasts◦Yellow, red, or orange in
colorhttp://nowai.files.wordpress.com/2006/08/autumn_tree_1920.jpg
Plant Cell with ChloroplastPlant Cell with Chloroplast
Cytoplasm – Endoplasmic Reticulum Cytoplasm – Endoplasmic Reticulum (ER)(ER)
Network of tubular membranes connected to the nucleus.
Different membranes are built (synthesized) in ER
Proteins are put together
http://scienceblogs.com/transcript/2006/07/golgi_maturation.php
Cytoplasm - MitochondriaCytoplasm - Mitochondria
Powerhouse of the cellInvolved with respiration –
the use of stored energyContain genetic material
such as DNA and RNA
http://www.a3243g.com/image_mitochondria.asp
Cytoplasm - VacuoleCytoplasm - Vacuole
Cavity in the plant cellFilled with watery
solution of dissolved salts, pigments, sugars etc.
Maintains cell turgor (like a water ballon).
Storage reserve for H2O
Vacuole much larger in plant than animal cells.
Vacuole
Mitochondria
NucleusNucleus
Cell control centerProminent
organelle in the cytoplasm essential for development and reproduction
http://www.itg.uiuc.edu/technology/atlas/structures/nucleus_actin/
Nuclear membrane or Nuclear membrane or envelopeenveloperegulates movement
of material between nucleus and cytoplasm
http://en.wikipedia.org/wiki/Nuclear_pore
Nucleus - ChromosomesNucleus - ChromosomesSpecific, highly organized bodies
in the nucleus. Contain a singular piece of DNA, which contains many genes, regulatory elements, and other nucleotide sequences (ATCG).
http://cnx.org/content/m15083/latest/
Nucleus - RibosomesNucleus - Ribosomes
Assembled inside the nucleus
Once built, can exist in the cytoplasm, chloroplasts, and other organelles
Synthesize proteins
http://rna.ucsc.edu/rnacenter/ribosome.html
Nucleus - DNANucleus - DNA
Deoxyribonucleic Acid
Contain genetic information for all cellular function◦Reproduction◦Creating
different tissues (and organs)
http://www.csb.yale.edu/userguides/graphics/ribbons/help/dna_rgb.html
CELL DIVISION & THE CELL CYCLE
http://focus.hms.harvard.edu/2003/March21_2003/cell_biology.html
• I=Interphase• M=Mitosis;
INNER RING: • M=Mitosis• G1=Gap 1• G2=Gap 2• S=Synthesis
NOT IN RING: G0=Gap 0/Resting.
The duration of mitosis in relation to the other phases has been exaggerated in this diagram.
THE CELL CYCLETHE CELL CYCLE
Interphase
Interphase (I) includes:• G1 = Gap 1• S = Synthesis• G2 = Gap 2
THE CELL CYCLE
Prophase
Mitosis includes:• Prophase• Metaphase• Anaphase• Telophase
THE CELL CYCLE
Metaphase
THE CELL CYCLE
Mitosis includes:• Prophase• Metaphase• Anaphase• Telophase
Anaphase
THE CELL CYCLE
Mitosis includes:• Prophase• Metaphase• Anaphase• Telophase
Telophase
THE CELL CYCLE
Mitosis includes:• Prophase• Metaphase• Anaphase• Telophase
Prophase
Metaphase Anaphase
Telophase
Prophase
Metaphase Anaphase
Telophase
THE CELL CYCLE
Mitosis includes:• Prophase• Metaphase• Anaphase• Telophase
Cytokinesis
THE CELL CYCLE
ChromosomesChromosomesA chromosones is a piece of DNA
that has genetic material called genes.
http://forensicnews.blogspot.com/by team uab, lsw
ChromosomesChromosomesChromosones vary between
different organisms.DNA molecule inside
chromosome can be linear or circular
Linear DNA
Circular DNA
ChromosomesChromosomesChromosomes are not visible
during G0 phase and Interphase.Chromosomes form a dense
mass of genetic material inside a cell’s nucleus.
Chromosomes become visible under a microscope during mitosis.
ChromosomesChromosomes
Chromosomes take on characteristic “X” form during mitosis.
http://www.copernicusproject.ucr.edu/ssi/HSBiologyResources.htm
Chromosomes in humansChromosomes in humans
Humans are diploid◦Have 2 identical sets of
chromosomes in every cellGametes are reproductive
cells◦Sperm & egg◦Have 1 unique set of
chromosones per cell
Interphase Prophase Metaphase Anaphase Telophase
ONION ROOT TIP MITOSISONION ROOT TIP MITOSIS
http://biog-101-104.bio.cornell.edu/biog101_104/tutorials/cell_division/onion_review_fs.html