cell structure

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

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

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

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

MITROCONDRIA

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

Function;

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

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

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

RIBOSOMES

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

Function;

• Site where PROTEINS are MADE

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

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

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

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

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SPERM CELLS

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

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

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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.

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

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

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

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

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.

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