Molecular Biology 1-2

Molecular Biology 1-2

put together by: Linda Fahlberg-Stojanovska

Disclaimer: I put these together for my kid for his smartphone.

However, I found most images had very small type and increased the font size. I am posting it because another teacher might find this useful.

The sources are given. If I have used anything illegally, write me and I will take it off.

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• Cell Structure - Eukaryotes

• Cell Parts - Eukaryotes

• Bacteria

– Gram Positive / Negative

• Viruses

Contents

Eukaryote Cell

http://www.biologycorner.com/bio1/cell.html3

Eukaryote

http://www.enchantedlearning.com/subjects/animals/cell/

4

Eukaryote

http://www.enchantedlearning.com/subjects/plants/cell/

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Endoplasmic Reticulum (ER)

http://endoplasmicreticulum.net/

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Golgi apparatus (GA)

• Like a post office - it packages and labels items and then sends to different parts of the cell.

• It primarily modifies proteins from the rough ER

• transport of lipids

• creation of lysosomes

• creation of polysacharides

• Modify, sort, and store macromolecules for cell secretion (exocytosis) In glandular (secretion) cells > 100 GA.

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http://www.biology4kids.com/files/cell_er.html


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http://creationrevolution.com/2010/11/golgi-apparatus-steel-industry-of-the-simple-cell-%E2%80%93-part-6/

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Mitochondria- animalsMitochondria = organelles that produce energy ATP

• Both plants and animals have mitochondria, but plants produce ATP in their chloroplasts.

• signaling,

• cellular differentiation,

• control of cell cycle; cell growth and death,

• Mitochondria have a double membrane

• Outer is relatively smooth; Inner is very convoluted

• The membrane proteins are part of cellular respiration and the synthesis of compounds, they are

energy dense with ATP adenosintriphosphate).

Chloroplast - plant

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http://en.wikipedia.org/wiki/Mitochondrion

Mitochondria- animals Chloroplast - plant

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Chloroplast - plant Mitrochondria – animal

Chloroplasts are organelles • found in plant cells • conduct photosynthesis , that is the chemical

process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight.

• capture light energy to conserve free energy in the form of ATP.

• are green because they contain the chlorophyll pigment.

• are members of a class of organelles known as plastids.

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Chloroplast - plant Mitrochondria – animal

http://www.tutorvista.com/biology/chloroplasts

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Lysosome - animal• Lysosomes are organelles

• They contain acid hydrolase enzymes.hydrolase is a digestive enzyme that catalyzes the hydrolysis of a chemical bond (breaks down polymers).

• Lysosomes break down waste materials and cellular debris.

Vacuoles – plant

• Lysosomes also digest food particles, and engulfed viruses or bacteria.

• The membrane around a lysosome allows the digestive enzymes to work at the 4.5 pH they require.

http://www.biology4kids.com/files/cell_lysosome.html

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Phagocytosis Lysosome digesting food

http://apbio-werle.wikispaces.com/Cell+and+Cell+Transport+%28Ch+6-7%29

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Lysosome - animal

Vacuoles - plant Lysosomes – animals

http://www.biologycorner.com/APbiology/cellular/notes_cells2.html

• Their main function is as a space-filler in the cell but they also perform digestive functions similar to lysosomes.

Vacuole

• Vacuoles are large, liquid-filled organelles found only in plant cells, occupying up to 90% of a cell's volume and have a single membrane.

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Plasma membrane = Cell membrane

• The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment.

• Cell membrane is semi-permeable (selectively permeable) to ions and organic molecules and controls the movement of substances in and out of cells.

• It consists of the lipid bilayer with embedded proteins.

• Cell membranes serve as the attachment surface for the cell wall, glycocalyx, and intracellular cytoskeleton.

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Plasma membrane = Cell membrane

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Cytoskeleton

• The cytoskeleton (CSK) is a cellular "skeleton" made out of protein. It is within a cell's cytoplasm.

• Eukaryotic cells contain 3 main kinds of cytoskeletal filaments:

– microfilaments,

– intermediate filaments

– microtubules.

http://www.sparknotes.com/biology/cellstructure/intracellularcomponents/section1.rhtml

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Bacteria Cell Prokaryote

http://en.wikipedia.org/wiki/Bacterial_cell_structure

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Bacteria

• Bacteria are divided into two major groups:

Gram-negative and Gram-positive

• Gram-negative bacteria

– Inner membrane

– Thin layer of peptidoglycan in periplasmic space

– Outer membrane = lipopolysaccharide + protein

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Bacteria

• Bacteria are divided into two major groups: Gram-negative and Gram-positive

• Bacteria come in 4 basic shapes:

– Baccilli (rod )

– Cocci (spherical)

– Spirilli (spiral)

– Vibrios (comma)

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Bacteria - Shapes

24http://www.biotopics.co.uk/microbes/bacter.html

Bacteria – Gram Staining

• Gram-negative bacteria

– Inner membrane

– Thin layer of peptidoglycan in periplasmic space

– Outer membrane = lipopolysaccharide + protein

• Gram-positive bacteria

– Inner membrane

– Thick layer of peptidoglycan called 'wall' (causes staining)

– No outer membrane (usually)

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26http://www.biologie.uni-hamburg.de/b-online/library/micro229/terry/images/micro/gramposneg.gif


• Steps in Gram Staining

– heat fix a smear of bacterial culture

– apply a primary stain of crystal violet

– add Gram’s iodine solution to bind crystal violet in the cell

– rapid decolorization with alcohol or acetone

Gram-positive cells are stained deep purple.

– counterstain with safranin

Gram-negative cells are stained red.

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28http://pathmicro.med.sc.edu/fox/culture.htm


• Reagents of Gram Staining

– Crystal violet (primary stain)

– Gram's Iodine solution(mordant that fixes crystal violet to cell wall)

– Decolorizer (e.g. ethanol)

– Safranin (secondary stain)

– Water (preferably in a squirt bottle)

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• How Gram Staining Works– 2. Gram's iodine solution (iodine and potassium iodide) is

added to form a complex between the crystal violet and iodine. This complex is a larger molecule than the original crystal violet stain and iodine and is insoluble in water.

– 3. decolorizer dehydrates the peptidoglycan layer, shrinking and tightening it. The large crystal violet-iodine complex is trapped in the thick peptidoglycan layer of Gram positive bacteria and stained.

– Conversely, the thin peptidoglycan layer of Gram negative cells cannot hold the crystal violet-iodine complex and the color (stain) is washed out and lost.

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Virus particles (virions) •genetic material (DNA or RNA segment)•capsid (protein coat that protects these genes) •envelope (of lipids) (some virions)

Flu virus

Virus

31http://www.synapses.co.uk/science/fluvirus.html

http://www.abc.net.au/health/library/stories/2004/07/08/1831345.htm

Virus - Bacteriophage

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• The Capsid – Head. It is

protein coat around nucleic acid. Capsid is divided into subunits called capsomeres.

• The Body - Rod shaped

structure has retractible sheath around a central hollow core.

• The Tails – At end of core is

spiked plate with 6 tail fibers which help anchor the virus to its host.

http://www.armageddononline.org/viruses.html

Education

Molecular Biology 1-2