Cell Presentation Full

8/3/2019 Cell Presentation Full

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The Cell


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Cell Parts Cell Membrane, Cell Wall, Cytoplasm Protein Production - Nucleus,

Nucleolus, Endoplasmic Reticulum,Ribosomes, Golgi Bodies, Lysosomes

Energy- Mitochondrion, Chloroplasts(Energy- Mitochondrion, Chloroplasts)

Miscellaneous - Microtubules,Microfilaments, Plastids


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Cell Membrane It also connects the the endoplasmic

reticulum, and the nuclear membrane. Inthe image below we have colored themembrane to highlight its composition. Theyellow represents the phospholipids. Thepurple represents the membrane proteins


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Cell Membrane The Cell membrane performs

a number of critical functionsfor the cell. It regulates all thatenters and leaves the cell; inmulticellular organisms itallows self recognition. Inorder to understand the

function of the cell membraneyou must understand itsstructure .

phospholipids


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Cell Membrane

Close-up

Here we see a cross section of the cellmembrane you should notice twodifferent structures: The phospholipids are the round yellow structures withthe blue tails , the proteins are thelumpy structures that are scatteredaround among the phospholipids.


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This is a simple representationof a phospholipid. the yellow

structure represents theHYDROPHILLICor water lovingsection of the phospholipid. The

blue tails that come off of thesphere represent theHYDROPHOBICor waterfearing end of the Phospholipid.Below is a structural model of aphospholipid that explains whatthese terms mean.


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Cell Wall Cell walls arethe rigidstructure foundsurroundingplant cells.They providesupport for theplant


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Cytoplasm

The term cytoplasm refers toeverything between the cellmembrane and the nuclear

envelope. It consists of primarily ofwater. It also contains variousorganelles as well as salts,

dissolved gasses and nutrients .


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Cytoplasm

Protein Producing Organelles:Endoplasmic Reticulum,Ribosomes, Golgi Apparatus,Lysosomes

Energy Producing Organelles -Mitochondrion, Chloroplasts

Specialty Structures -centrioles,vacuoles, cell walls, cilia,flagella, plastids


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NUCLEUS-nuclear envelope

The nuclear envelope is a doublemembrane. Is has 4 phospholipid

layers. It is also has large poresthrough which materials pass backand forth.


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Nucleus

The headquarters of the cell. It is a largedark spot in EUKARYOTIC cells. It

controls all cell activity. Close up youwill see that the nuclear membrane hasmany pores. The nuclear membrane iscontinuous with the E.R.


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The thick ropy strandsare the CHROMATIN .

The large solid spot isthe NUCLEOLUS . Thenucleolus is a knot of

chromatin. Itmanufacturesribosomes.

With the outer membrane removed it ismuch easier to see the contents of thenucleus.


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Chromatin

Within the nucleus are found chromatinand a structure called the nucleolus.Chromatin is DNA in its active form. Itconsists of DNA looped around histoneproteins. The nucleolus is a knot ofchromatin. It is the nucleolus that

manufactures ribosomes .


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Endoplasmic Reticulum

Smooth, noribosomes

rough, hasribosomes


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Smooth E.R.

The endoplasmic reticulum is a series of doublemembranes that loop back and forth betweenthe cell membrane and the nucleus.

These membranes fill the cytoplasm but youcannot see them because they are verytransparent. There are two distinct types ofE.R.: The rough E.R. has ribosomes and is thesite of protein synthesis; the smooth E.R. hasno ribosomes


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The endoplasmicreticulum is a series of

double membranes thatloop back and forthbetween the cell

membrane and thenucleus. Thesemembranes fill the

cytoplasm but youcannot see thembecause they are very

transparent.

R.E.R .


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Ribosome The ribosomes

are the organ-elleswhichmanufactureproteins. They aremade of twoseparate parts.These structuresare both made ofribosomal RNA.


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GOLGI BODY


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Golgi Apparatus The golgi body isresponsible for

packaging proteinsfor the cell. Once theproteins areproduced by the

rough E.R. they passinto the sack- likecisternae that are themain part of the golgibody .These proteins are then squeezed off into the littleblebs which drift off into the cytoplasm.


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LysosomeLysosomes are calledsuicide sacks. They areproduced by the golgibody. They consist of asingle membrane

surrounding powerfuldigestive enzymes.From this screen you

can cut the lysosomeand move it around.


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Lysosomes With the outer

membraneremoved it is mucheasier to see thecontents of thelysosome. Thoselumpy brownstructures aredigestive enzymes.


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"suicide sacks They dissolve

bacteria and otherforeign bodies.Under someconditions thelysosomes in a cellwill break open anda cell will self

destruct in aprocess calledautolysis (giving riseto the name "suicidesacks" .


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VacuoleVacuoles are large empty

appearing areas foundin the cytoplasm. Theyare usually found in plant

cells where they storewaste. As a plant cellages they get larger. In

mature cells they occupymost of the cytoplasm.


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CENTRIOLE ENLARGED


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MicrofilamentThese are hair like

extensions off of the cellmembrane. Cilia tend to besmall and numerous andflagella tend to be large&few. They beat back andforth rhythmically. Inunicellular organisms their

job is locomotion. In largemulticell organisms theirrole is to move fluid pastthe cell. Notice the 9+2arrangement of themicrotubles.


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Microtubule Centrioles are found

only in animal cells.

They function in celldivision. Zoom in andnotice the 9 groups of 3 arrangement of the

protein fibers.


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The MITOCHONDRION isthe powerhouse of the cell. It is thesite of respiration. It has a doublemembrane. From this view you cansee very little >>>>>>>>>>

Th b i


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The outer membrane is cut toget a better look. With theouter membrane removed itis much easier to see thecontents of themitochondrion. The white

folded structure is the innermembrane. Most ofAEROBIC RESPIRATION

occurs along thismembrane. Get a really good look by cutting the inner membrane . >>>next slide>>>>>


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The inner membranes is ruffled. It has

a very large surface area. These ruffles arecalled cristae. Mitochondria have theirown DNA and manufacture some their

own proteins. It is thought that themitochondrion evolved from symbioticbacteria that took up residence insidethe first eukaryotic cells.


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INSIDE THE INNER

MITOCHONDRION

Pl tid l


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Plastids Plastids are large

organelles found on plantsand some protists but not in

animals or fungi. They caneasily be seem through alight microscope. The otherclass of plastid are calledleucoplasts (colorlessplastids);

they usually store food molecules. Included inthis group are amyloplasts or starch plastidsshown here in potato root cell.


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PLASTIDS- Chloroplast

Chloroplastsrepresent one

group of plastids calledchromoplasts

(coloredplastids).

Th hl l t i th it


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With the outer membrane removed it is mucheasier to see the contents of the chloroplast. Thestacks of disk-like structures are called theGRANA. The membranes connecting them arethe THYLAKOID MEMBRANES.

The chloroplast is the siteof photosynthesis. Itconsists of a doublemembrane. Cut the outermembrane to get a betterlook inside.


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Grana and Thylakoid

Membranes The membranes

that you see here

are the site ofphotosynthesis. Itis here that theenergy harnessing

process ofphotosynthesisoccurs.

Dissolve the Remaining

membrane and zoom into get a better look.

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