cell structure

  • Magnification & resolution
  • cell's organelles
  • Specialised cells
  • Eukaryotes and Prokaryotes
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  • Created by: mariam
  • Created on: 28-09-09 21:36

Resolution & magnification

RESOLUTION- degree to which the two objects are together they can be ditinguished apart

  • HIGHER the RESOLUTION the MORE detail can be viewed

MAGNIFICATION- Degree to which the size of the image is larger than the object itself

IMAGE SIZE = ACTUAL x MAGNIFICATION

MM------ X1000----Nm-------x1000--------nm

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Endoplasmic reticulum

ENDOPLASMIC RETICULUM

  • membrane bound sacs called cisternae
  • on outer nuclear membrane
  • ROUGH ER has ribosomes
  • SMOOTH ER doesnt have ribosomes

Function;

  • ROUGH ER transports proteins made from ribosomes
  • some proteins secreted from the cell others on cell surface membrane
  • SMOOTH ER makes lipids
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Nucleus

NUCLEUS

  • dark patches chromatin, nuclear pores, nucleolus, nuclear envelope

Function;

  • Genetic material
  • chromatin; has the instruction for making dna & protein
  • also controls some of the cells activites and cells divide chromatin condenses into visible .
  • Nucleolus; makes rna & ribosomes these pass into the cytoplasm and proteins assembled here
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Golgi apparatus

GOLGI APPARATUS

  • stack of membrane bound flattened stacks

Function;

  • it recieves the proteins from the er------ then gets modified
  • modified proteins get packages into VESICLES
  • vesicles either secreted or sent to the surface of the cell
  • PACKAGES substances mainly proteins and glycoproteins
  • Also makes LYSOSOME
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Mitrocondria

MITROCONDRIA

  • folded inner membrane called cristae
  • central part of mito is the matrix

Function;

  • site where ADENSOINE TRIPHOSPHATE (ATP) is produced for respiration
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Choloroplast

CHLOROPLAST

  • inner membrane with THYLAKOIDS - flattened membrane sacs
  • THYLAKOIDS called GRANUM and CHLOROPHYLL molecules present on THYLAKOIDS and in the intergranal membranes

Function;

  • Photosythesis - lights energy drive reactions of photosythesis from where CARBOHYDRATE molecules are made from CO2 AND H20
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Lysosome

LYSOSOME

  • round organelle surrounded by membranes

Function;

  • digestive enzymes
  • can be used to DIGEST INVADING CELLS or to DESTROY the CELL when it needs to be replaced
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Ribosomes

RIBOSOMES

  • very small organelle either floating free in the cytoplasm
  • Or attached to ROUGH ER

Function;

  • Site where PROTEINS are MADE
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Centrioles

Centrioles

  • small HOLLOW CYLINDERS containing a ring of microtubles seen in ANIMAL CELLS during cell divsion

Function;

  • invovled in the SEPERATION of CHROMOSOMES during cell division
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Cell Specialisation

TISSUE: A collection of cells often (although not always) the same type, which are specialised to perform a one or more particular functions.

ORGAN: A part of a the body which forms a structural and functional unit. It is comprimised of more than one type of tissue.

SYSTEM: Collection of organs with a particular function

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Specialised cells

Cells can become specialised to carry out a particular role this is known at DIFFERENTIATION.

Cell can differentiate through;

  • THE SHAPE OF THE CELL
  • THE NUMBER OF A PARTICULAR ORGANELLE
  • CONTENTS OF THE CELL
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Specialised cells

WHITE BLOOD CELLS

  • Neutrophils contain a large number of lysosome so they can break down the bacteria as its a digestive enzyme so it can injest the invading pathogen.
  • Large number of Lysosome are present so it will prominently have GOLGI APPARATUS's

----------------------------------------------------------------------------------------------------

SPERM CELLS

  • Acrosome contains LYSOSOME, MITO for movement, tail has a single UNDULIPODIUM
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Specialised cells

RED BLOOD CELL

  • HAEMOGLOBIN ( protein) present to carry oxygen
  • no nucleus so it can carry MORE OXYGEN
  • BI-CONCAVE shape for increased surface area to therefore carry more oxygen

----------------------------------------------------------------------------------------------------

BETA-CELLS OF THE PANCREAS

  • insulin secreted when the blood glucose levels are HIGH
  • prominent ROUGH ER as it makes protein and insulin made of protein
  • GOLGI APPARATUS prominent as it will package the insulin into the vesicle and secrete it into the blood.
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Specialised tissues

SQUAMOUS EPITHELIA

  • found in the LINING of BLOOD VESSELS inner surface of the heart alveoli of the lungs
  • cells are smooth, flat and thin fitting together like tiles on a floor, so reduces friction
  • THINNESS = RAPID GAS EXCHANGE

(http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Epithelia/images/ven100he.jpg)

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Specialised Tissues

CILIATED EPITHELIA

  • Found in the lining of bronchioles and the oviducts
  • CILLIA wave is present to allow a sychronised rhythem that would move mucus/eggs over the cells

(http://image.tutorvista.com/content/tissues-plants-animals/ciliated-pseudostratified-columnar-epithelium.jpeg) (http://www.gwc.maricopa.edu/class/bio201/histoprc/colm4_s.jpg)

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Prokaryotes

Prokaryotes

  • NO nucleus, mito, chloroplast, er, cytoskeleton

ALWAYS PRESENT;

  • NUCLEOID DNA referred to choromosomes
  • PLASMA MEMBRANE
  • CELL WALL made of cross linked peptidoglycan
  • RIBOSOME small 20nm

SOMETIMES PRESENT;

  • MESOSOME, CAPSULE, PLASMID, PILLI and FLAGELLUM
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Picture of an Prokaryote

(http://manhattan.schoolwires.com/1525108613210363/lib/1525108613210363/prokaryotic_cell_(bacteria).jpg)

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Eukaryote

Eukaryotes

PRESENT ALWAYS

  • NUCLEUS
  • MITO
  • RIBOSOMES large 30nm
  • CYTOSKELETON - made of microtubles and microfilaments
  • ER

SOMETIMES PRESENT

  • CHLOROPLAST (plant cells)
  • CELL WALL - (cellulose walls in plant cells)
  • CILLIA and FLAGELLA
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Picture of an Eukaryote

(http://evolution.berkeley.edu/evosite/lines/images/cells.gif)

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Cytoskeleton

CYTOSKELETON

  • All animals and plant cells have a netwrok of PROTEIN FILAMENTS called MICROFILAMENTS
  • Act as SKELETON helping to support the cell and to determine its shape
  • Together with microtubles the filaments make up the CYTOSKELETON.
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Centrioles

CENTRIOLES

  • CENTRIOLES found in ANIMAL CELLS
  • Centrioles organise to make tiny structures called MICROTUBULES which are made of the PROTEIN TUBULIN
  • present during the CELL DIVISION as MICROTUBULES form to make the SPINDLE
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