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