Ch 3 Cell Organelles and Transport

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Cell organelles

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Nucleus:contains DNA

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Nuclear envelope ­ double membranehas poresselectively permeablehas nucleoplasm inside

Nucleolusribosomes made here

ChromatinDNA + proteinchromosomes = coiled chromatin

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Cytoplasmsite of chemical reactionsincludes:

cytosol ­ clear fluid that suspends other things

organelles ­ structures that carry outspecific duties

inclusions ­ stored nutrients or cellproducts

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Cytoplasmic Organelles

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Mitochondriacristae ­ folds in inner

membranesite for cellular

respiration (makesATP)

muscle,liver cellshave hundreds

unfertilized egg­ only a few

http://giantshoulders.files.wordpress.com/2007/10/mitochondria.jpg

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Ribosomes

http://publications.nigms.nih.gov/insidethecell/images/ch2_ribosome_proteinbig.jpg

made of proteins

sites of protein synthesis

may or may not be attached to endoplasmicreticulum

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Endoplasmic Reticulum

http://micro.magnet.fsu.edu/cells/endoplasmicreticulum/images/endoplasmicreticulumfigure1.jpg

fluid filled canalscarries substances

(proteins) from one part of cellto another

rough ­ has ribosomes attached

smooth ­ no ribosomes

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Golgi apparatus

http://www.google.com/imgres?imgurl=http://kvhs.nbed.nb.ca/gallant/biology/golgi_apparatus.jpg

membranous sacs

modifies and packagesproteins in secretoryvessels

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Protein is made by ribosome on Rough ER and then packaged inside vesicle by Golgi apparatus

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Whole process

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Lysosomes

http://micro.magnet.fsu.edu/cells/lysosomes/lysosomes.html

"suicide sacs"contain digestive

enzymesabundant in white

blood cells

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Peroxisomes

contain oxidase enzymes

convert free radicals (reactive chemicals that have a unpaired electrons) to hydrogen peroxide, then catalase converts hydrogen peroxide to water

numerous in kidney and liver cells

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Cytoskeleton

(cytoskeleton is red in picture)http://en.wikipedia.org/wiki/Cytoskeleton

network of protein structures throughout cytoplasm

framework

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Centrioles

http://www.biocom.arizona.edu/graphics/images/projects/centriole.jpg

close to nucleus

form mitotic spindle duringcell division

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cilia

move substances along cell surface

ex. in respiratory passages

http://www.hhmi.org/images/bulletin/sept2005/cilia_detail.jpg

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flagellalong whip­like extension used for locomotion

http://content.answers.com/main/content/wp/en­commons/thumb/3/34/300px­Flagella.png

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Types of cells in human body

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Plasma membrane

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Plasma Membrane Structure

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Selectively permeablephospholipid bilayerintegral proteins

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hydrophobic area­ relatively impermeable hydrophilic areas ­ like to be near watercholesterol ­ stabilizes the membraneproteins ­ enz., binding sites, transportglycoproteins ­ cell­to­cell recognition, receptors, blood type

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Cell Junctions1. tight junctions ­ bind cells together, adjacent plasma membranes fuse together

2. Desomosomes ­ anchor cell, prevent cells from pulling

apart

3. gap junctions ­ allow communication (heart,

embryonic cells), chemical molecules

can pass through

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Membrane Transport

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Fluids involved in cells:a. intracellular fluid ­ fluid inside cell that contains small amounts of gases, nutrients, salts dissolved in water

b. interstitial fluid ­ fluid that bathes the exterior of the cells; contains nutrients, hormones, neurotransmitters, salts, and waste products

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Transport through plasma membrane:

I. Passive transport ­ when substances are transported across the membrane without energy involved

a. diffusion­ process where molecules spread themselves thoughout available space; due to kinetic energy ­ move down a concentration gradient ­ affected by size of molecule (small = fast) and temperature (warmer = faster)

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molecules diffuse through membrane if:a. small enough to passb. dissolve in fatty portion

1. simple diffusion ­unassisted diffusion of solutes through the membrane

Ex. fats, fat­soluble vitamins, oxygen, carbon dioxideosmosis = simple diffusion of water

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2. facilitated diffusion ­ process driven by concentration gradient, but molecules are too big and are lipid­insoluble; needs a protein carrier to help

ex. glucose

3. filtration­ process where water and solutes are forces through a membrane by hydrostatic pressure exerted by blood (in human body)

­uses a pressure gradient (higher to lower pressure)Ex. happens in kidneys ­ solutes from capillaries

to kidney tubules

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II. Active Transport­ process where a cell uses energy to move substances across membrane

needed if:­molecule is too large­molecules can't dissolve in hydrophobic area­molecules need to move against concentration

gradient

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a. solute pumping ­ requires a protein carrier that combine with substances that need to cross

Ex. amino acids, some sugars, most ionsEx. sodium­potassium pump

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b. bulk transport ­ process used when substances can't move any other way.

1. Exocytosis­ moves substances out of cellsmall membrane bound vesicle fuses with plasma membrane and expells contents outside cell

2. Endocytosis ­ moves substances into cella. phagocytosis ­ engulfing

Ex. white blood cellb. bulk phase endocytosis ­ pinocytosis ­

"cell drinking"Ex. fluid containing dissolved solutes

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What happens to cells when they are put in different types of solutions?

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Three types of solutions:1. isotonic ­ solution that contains same tonicity

(strength) as normal cellEx. Ringer's lactate solution (5% dextrose,

0.9% salt); same water and solute content as cells

­cause no change in cell

http://content.answers.com/main/content/wp/en­commons/thumb/b/b1/300px­Osmotic_pressure_on_blood_cells_diagram.svg.png

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2. hypertonic ­ solution that contains more solutes (dissolved substances) than inside the cell

­causes cells to shrink (crenate)Ex. hypertonic solutions given to edema

patients (edema = swelling)

http://content.answers.com/main/content/wp/en­commons/thumb/b/b1/300px­Osmotic_pressure_on_blood_cells_diagram.svg.png

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3. hypotonic ­ solution that contains fewer solutes than a cell

­causes cell to expand or burstEx. distilled water

Hypotonic solution given to a patient with dehydration

teas, colas, apple juice, sports drinks

http://content.answers.com/main/content/wp/en­commons/thumb/b/b1/300px­Osmotic_pressure_on_blood_cells_diagram.svg.png

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