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Flashcards by megan.radcliffe16, updated more than 1 year ago
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Created by megan.radcliffe16
over 9 years ago
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| Question | Answer |
| What are the characteristics of a Transmission Electron Microscope? | 2D images - dead material Beam of electrons = black and white images- can be enhanced with colour. |
| What are the characteristics of a Scanning Electron Microscope? | Uses moving beam of electrons = 3D images shows surface detail excellent depth of field. |
| why are stains used with light microscopes? | 1. make structures more visible 2. enable small structures to be seen. |
| what are the different stains that can be used? | Light microscopes: 1. Methylene blue 2. Iodine Solution 3. Acetic Orcein TEMs: salts of heavy metals SEMs: layer of heavy metal |
| why are salts of heavy metals used in TEMs. | To deflect the beam of electrons |
| why is a layer of heavy metal used in SEMs? | To reflect the electrons |
| what does Methylene blue do to the cells? | Stains the nucleus dark blue and the cytoplasm pale blue |
| what does Iodine solution do to the cells? | Stains the plant cell walls orange/brown and starch grains purple. |
| what does Acetic Orcein do to the cells? | Stains the chromosomes red. |
| what does the modern cell theory state? | 1. All living organisms are composed of cells. 2. All new cells are derived form pre-existing cells. 3. Cells contain heredity information 4.metabolic reactions take place in cells |
| what is Metabolism? | The total of all chemical changes that take place in an cell/organism |
| What is Anabolism? | the metabolic process that builds up larger molecules from smaller ones. |
| what is catabolism? | the metabolic breakdown of complex molecules into simpler ones - resulting in the release of energy. |
| what is muticellular? | many cells working together |
| what is magniifcation? | the factor by which the image size is enlarged compared to the original object. |
| what is the calculation of magnification? | magnification= image size/ actual size |
| what is the calculation of magnification when using scale bars? | magnification= length of scale bar in micrometers/ length scale bar represents in micrometers |
| what is resolution? | 1. the degree of detail that can be seen 2. the ability to distinguish separately two small objects. |
| what are the two measurements that two points can be resolved? | 0.2 µm apart -light microscope 0,5 µm apart- electron microscope |
| why are light microscopes used more widely? | 1. cheaper 2. allows colour 3. required less expertise 4. can observe living matter |
| what is the ultra structure? | the detailed structure that is revealed with an electron microscope |
| what structures are seen in both animals and plants by a light microscope? | 1. nucleus 2. mitochondria 3. cytoplasm 4. cell surface memebrane |
| what structures are only seen in animal cells? | Vesicles |
| what structures are only seen in plant cells? | 1. cell wall 2. vacuole 3. chloroplast |
| what structures of the cells can only be seen by an electron microscope? | 1. rough ER 2. Smooth ER 3. Golgi 4. Cytoskeleton 5. Ribosomes 6. Plasmodesmata |
| what is the plasma membrane? | A partially permeable membrane that acts as a barrier between the inside and outside of the cell. It helps regulate the cells internal composition bu controlling the substances between the cell and its environment. |
| what is the nucleus? | contains the genetic information and controls all cellular activities. It is surrounded by the nuclear envelope - contains nuclear pores |
| why are the nuclear pore present on the nuclear envelope? | Allows movement of molecules into and out of the nucleus. |
| what is the cytoplasm? | It is a fluid where the chemical reactions of the metabolism take place. Where the enzymes, proteins and other substances produced and manufacture. |
| what are the three components that the cytoplasm is made up of? | 1. fluid 2. membrane systems 3. organelles |
| what is compartmentation? | It is the basis of cell organisation The division of labour.- allows cells to be split into compartments. |
| what does compartmentation do? | It ensures that different biochemical activities can take place in different places in ideal conditions. |
| what are the four advantages to compartmentation? | 1. potentially harmful substances/enzymes can be isolated- not able to damage the rest of the cell. 2. products of one reaction can bein close proximity- speed up rate of reactions. 3. surface area of membranes and number of enzymes is increased. 4. membranes can provide ion gradients. |
| what is the function of the nucleolus? | Synthesis of ribosomes. |
| what is chromatin? | Threadlike structures int eh cell nucleus. represent extended form of chromosomes during interphase. |
| what is the Endoplasmic Reticulum (ER)? | network of sac-like and tubular cavities formed from membrane. |
| what is the difference between Rough ER and Smooth ER? | Rough ER has ribosomes on the outer surface. Smooth ER has no ribosomes on outer surface. |
| what are the functions of Rough ER? | !. Protein synthesis 2. Transports proteins to other parts of cell. 3. Makes Golgi Apparatus |
| what are the functions of Smooth ER? | 1. Site of Lipid synthesis 2. Synthesises steriods |
| what is the Golgi Apparatus? | Stack of flattened membrane sacs |
| what are the functions of the Golgi? | 1. Forms lysosomes 2. Transports and modifies materials 3. Enzymes made in the rough ER are concentrated and packaged into vesicles |
| what are the characteristics of Mitochondria? | 1. outer membrane contains a folded inner membrane 2. important enzymes are attached to the inner membrane(large surface area) 3. Matrix present inside inner membrane 4. Contains DNA 5. Self- replicating |
| what are the functions of the Mitochondria? | 1. Aerobic respiration 2. ATP systhesis |
| what is the functions of ribosomes? | Site of protein synthesis |
| what are the sizes of ribosomes? | In Eukaryotic cells - 22nm In prokaryotic, mitochondria cells and chloroplasts -18nm |
| what are Lysosomes? | Simple spherical sacs bound by a single membrane containing hydrolytic enzymes. |
| what are the functions of Lysosomes? | 1. Autophagy ( digestion of worn out cells) 2. Digestions of material ingested by phagocytoysis 3. Secretion of Lysosomal enzymes 4. Autolysis- release of enzymes to destroy and break down cells. |
| what are the functions of chloroplasts? | Photosynthesis in plants - Grana- light reactions -Stroma- dark reactions |
| what are the characteristics of chloroplasts? | Contain DNA and are self replication contain own ribosomes- to carry out protein synthesis |
| what are Cillia and Flagella? | Hair like extensions. Long= Flagella Short= Cillia |
| What are the characteristics of the Cillia and Flagella? | 1. 3-4 µm long 2. covered with an extension of the plasma membrane. 3. Contains microtubules |
| what is the cytoskelaton made up of? | Actin microfilaments and microtubules |
| what are the functions of the cytoskeleton? | 1. provide mechanical strength to cells and holds them in shape. 2. Aids transport 3/ Enables cell movement |
| what is the difference between Eukaryotic cells and Prokaryotic cells? | Eukaryotic- larger and possess a nucleus and other membrane bound organelles in their cytoplasm. Prokaryotic- first forms of life. DNA not enclosed by nuclear membrane. Do not possess any membrane bound organelles. |
| what do Eukaryotic and Prokaryotic cells have in common? | 1. Both are single celled 2. Have cytoplasmic structure 3. Use flagella for cell movement 4. Have Ribosomes 5. Have cell wall and cytoplasm |
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