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AS BIOLOGYThe ultrastructure of the cell
LEARNING OBJECTIVES
By the end of this section you should be able to:-
Recognise the following organelles from a diagram of theeukaryotic animal and plant cell (rough and smooth endoplasmicreticulum, Golgi apparatus,mitochondria, ribosomes, lysosomes,chloroplasts, plasma (cell surface) membrane, nuclear envelope, centrioles,
nucleus, nucleolus and cilia).
Outline the functions of the following structures:-rough andsmooth endoplasmic reticulum, Golgi apparatus, mitochondria, ribosomes,
lysosomes, chloroplasts, plasma (cell surface) membrane, nuclearenvelope, centrioles, nucleus, nucleolus and cilia.
8/3/2019 As Biology Cell Project Part 1
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The Eukaryotic Cell
The BeginningsRobert Hooke was the first person to observe cells in 1665.He looked at thin slices of cork under a very simple microscope.The cork appeared as little boxes which he called cells.In 1883 MathiasSchleiden and Theodor Schwann proposed that all
plants and animals were composed of cells which were the basicbuilding blocks of life.In 1855 Rudolf Virchow stated that new cells arise from thedivision of pre-existing cells and that chemical reactions needed forlife occurred inside the cell.All this work led to the formation of the cell theory(click to
complete exercise on cell theory)
For more information click on link belowhttp://fig.cox.miami.edu/~cmallery/150/unity/cell.text.htm
http://celltheorymatchlink1.htm/http://fig.cox.miami.edu/~cmallery/150/unity/cell.text.htmhttp://fig.cox.miami.edu/~cmallery/150/unity/cell.text.htmhttp://celltheorymatchlink1.htm/8/3/2019 As Biology Cell Project Part 1
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Eukaryotic Animal Cell
Eukaryotic means true nucleus Eukaryotic cells have a nucleus which contains the
DNA. Eukaryotic animal cells are surrounded by a cell
membrane. Inside is the jelly like substance called cytoplasm. Contained in the cytoplasm is the nucleus and other
organelles(copy the glossary file into your area and continue to add words and meanings) The other cell organelles include the endoplasmic
reticulum,(rough & smooth) mitochondria, Golgiapparatus, ribosomes, lysosomes, centrioles, cilia,nucleolus.
http://cell%20glossary%20link2.xls/http://cell%20glossary%20link2.xls/8/3/2019 As Biology Cell Project Part 1
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Endoplasmic Reticulum
STRUCTURE
Complex system of sheet likedouble membranes continuouswith the nuclear membrane
Fluid filled spaces/sacs
between the membranescalled CISTERNAEwhichallow materials to betransported through cell
Two types of ER
smooth has no ribosomesattached (RER)
rough has ribosomesattached (SER)
FUNCTION
Forms an extensive transportsystem
Site of protein synthesis(Rough ER)
Site of lipid, steroid andcarbohydrate synthesis(smooth ER)
Stores and transports thesematerials
SEE DIAGRAM
http://www.botany.uwc.ac.za/SCI_ED/grade10/cells/er.htmhttp://www.botany.uwc.ac.za/SCI_ED/grade10/cells/er.htm8/3/2019 As Biology Cell Project Part 1
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MitochondriaSTRUCTURE
Relatively large organelle Rod/sausage shaped 1um
5um Have a double membrane
The outer controls the entry &exit of materials
Inner has many folds calledcristae Surface of each crista is covered
with stalked particles where ATPis made
Mitochondria are filled with a jellylike matrix
The matrix contains proteins,lipids, ribosomes and loops ofDNA
Mitochondria can replicatethemselves when the cell divides
FUNCTION
Site of aerobic respiration (Krebscycle & oxidative phosphorylation)
Responsible for the production ofenergy rich ATP molecules
The numbers of mitochondriareflect the metabolic activity of thecell so large numbers are foundin muscle and liver cells
SEE DIAGRAM
http://www.jdaross.mcmail.com/mitochon.htmhttp://www.jdaross.mcmail.com/mitochon.htm8/3/2019 As Biology Cell Project Part 1
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Golgi apparatus
STRUCTURE
Formed from small pieces ofrough ER which form smallvesicles which join to make aGolgi body
Chemicals made in the ERcollect in the Golgi body wherethey are modified
Small vesicles can then bepinched off the Golgi bodycarrying new chemicals awaywhich are secreted when the
vesicle reaches the cellmembrane
Some of the vesicles becomelysosomes
FUNCTION
Assembling glycoproteins(such as mucin) by combiningcarbohydrate and protein
Transporting and storing lipids
Formation of lysosomes Producing digestive enzymes Secretes carbohydrates which
are used in the formation ofplant cell walls and in insectcuticles
SEE DIAGRAM
What have you learnt?
Click here to walk the plank
http://www.cs.utexas.edu/users/s2s/latest/cell1/src/tutorial/golgi.htmlhttp://walkplank2link3.html/http://walkplank2link3.html/http://www.cs.utexas.edu/users/s2s/latest/cell1/src/tutorial/golgi.html8/3/2019 As Biology Cell Project Part 1
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Ribosomes
STRUCTURE
Small dense structures foundin huge numbers.
Can be attached to the roughER of floating in the cytoplasm.
Are about 20 25 nm indiameter in eukaryotic cellsand slightly smaller inprokaryotic cells
(80s type prokaryotic)
(70s type eukaryotic) Made up from two sub units
FUNCTION
Synthesize proteins
Synthesize enzymes
SEE DIAGRAM
http://www.biology4kids.com/files/cell_ribos.htmlhttp://www.biology4kids.com/files/cell_ribos.html8/3/2019 As Biology Cell Project Part 1
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Lysosomes
STRUCTURE
Small vacuoles formed whensmall pieces of Golgi body arepinched off
Contain hydrolytic enzymes
which digest materials in thecell
SEE DIAGRAM
FUNCTION
Release enzymes whichdestroy worn out organelles
Digest material taken into thecell (eg white blood cells which
have engulfed a bacterium)phagocytosis
Release enzymes to theoutside of the cell which digestmaterial around the cell
exocytosis Completely break down cellsafter they have died autolysis
http://www.people.virginia.edu/~rjh9u/lysosome.htmlhttp://www.people.virginia.edu/~rjh9u/lysosome.html8/3/2019 As Biology Cell Project Part 1
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Plasma (cell surface) membrane
STRUCTURE
This is the boundary betweenthe cell cytoplasm & theenvironment
Is partially permeable
Made up 45% protein & 45%phospholipids with theremaining 10% cholesterol,glycoprotein & glyolipids
FUNCTION
Controls movement ofsubstances in & out of the cell
Forms a recognition site sothat the bodys immune system
can recognize its own cells Acts as a receptor site for the
attachment of specifichormones andneurotransmitters.
SEE DIAGRAM
http://library.thinkquest.org/C004535/cell_membranes.htmlhttp://library.thinkquest.org/C004535/cell_membranes.html8/3/2019 As Biology Cell Project Part 1
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Nucleus, Nucleolus &Nuclear envelope
STRUCTURE
Largest organelle in the cell (10umdiameter)
Surrounded by a nuclear membrane/ envelope
Double membrane outer iscontinuous with the ER
Nuclear pores in the membraneallow the passage of largemolecules in & out (egmessengerRNA)
Material inside the nucleus is callednucleoplasm this containschromatin which makes up the DNA
of the cell in non-dividing cells it isspread out and during cell division itcondenses to form thechromosomes
A spherical structure called thenucleolus is found in the nucleusthis makes ribosomal RNA and
assembles the ribosomes.
FUNCTION
Acts as the control centre of thecell through the production ofmRNA and protein synthesis
Retains the genetic material in the
cell in the form of DNA /chromosomes
Manufactures ribosomal RNA(rRNA) & ribosomes
Starts the process of cell division
SEE DIAGRAM
What have you learnt? Click here to complete the
crossword
http://cellbio.utmb.edu/cellbio/nucleus.htmhttp://cellcrosslinl4.htm/http://cellcrosslinl4.htm/http://cellcrosslinl4.htm/http://cellcrosslinl4.htm/http://cellbio.utmb.edu/cellbio/nucleus.htm8/3/2019 As Biology Cell Project Part 1
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Cilia
STRUCTURE
3-10 um in length, 0.2umin diameter
Made of rings of 9 pairs
of microtubules Have basal bodyembedded in cytoplasm
Rest extends from basalbody
Only a few types of cellpossess cilia On cells which have cilia
there are large numbers
FUNCTION
To move an entireorganism (eg inparamecium it propels itthrough the water)
To move material withinan organism ( eg cilia inthe lining of therespiratory tract)
SEE DIAGRAM
http://www.cytochemistry.net/Cell-biology/cilia.htmhttp://www.cytochemistry.net/Cell-biology/cilia.htm8/3/2019 As Biology Cell Project Part 1
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CENTRIOLES(not found in plant cells)
Two short bundles of hollow cylinders (microtubules)positioned at right angles to each other
Found just outside the nucleus in a clear area ofcytoplasm called the centrosome
Wall of each centriole is made of 9 triplets of tubesarranged at an angle
During cell division they migrate to opposite poles toproduce the spindle which helps to move thechromosomes during cell division
SEE DIAGRAM
http://www.cs.utexas.edu/users/s2s/latest/cell1/src/tutorial/centriole.htmlhttp://www.cs.utexas.edu/users/s2s/latest/cell1/src/tutorial/centriole.html8/3/2019 As Biology Cell Project Part 1
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Chloroplasts
Found inside photosynthetic tissues of plants (abundant in palisade
mesophyll cells of leaves) Flat discs 2-10 um in diameter & 1um thick Have a double membrane called the chloroplast envelope Inner membrane folded into a series of lamellae Membrane controls the entry & exit of substances Inside the membrane is a fluid stroma which contains the enzymes
involved in photostnthesis Small amounts of DNA and oil are found in the stroma In stroma is a network of flattened sacs called thylakoids Grana (granum = sing) are formed when many thylakoids are stacked
together (like a pile of coins) (thylakoids also called lamella) Chlorophyll molecules are attached to the thylakoids
Large starch grains are also present which act as a tempory store ofcharbohydrate made in photosynthesis SEE DIAGRAM Click here to label the eukaryotic animal cell
http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/chloro.htmhttp://eukaryotic%20cell2link5.xls/http://eukaryotic%20cell2link5.xls/http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/chloro.htm8/3/2019 As Biology Cell Project Part 1
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Click here to play cell organelles
catch phrase
http://as%20biology%20catch%20phraseliink6.ppt/http://as%20biology%20catch%20phraseliink6.ppt/