Term
|
Definition
| the number of times larger an image appears, compared with the size of the object |
|
|
Term
| what type of magnification do microscopes produce? |
|
Definition
|
|
Term
|
Definition
| the smallest distance between 2 points on a specimen that can still be distinguished by the microscope |
|
|
Term
| what does a higher resolution do to an image? |
|
Definition
|
|
Term
| define an optical/light microscope |
|
Definition
| a microscope that uses lenses to focus a beam of light |
|
|
Term
| Explain how an optical microscope works |
|
Definition
1. Place specimen in slide 2. Clip to
stage 3. Place the lowest power objective
lens over the slide by using the nose
piece 4. Adjust coarse focus knob while
looking into eyepiece 5. Adjust iris
diaphragm for optimum light 6. Twist
nose piece to a higher magnification 7.
Look down ocular tube & focus with fine
focus knob 8. Repeat |
|
|
Term
| Name 10 key components of an optical microscope |
|
Definition
Slide, clips, stage, nose
piece, objective lens,
coarse focus knob,
eyepiece, fine focus
knob, iris diaphragm,
ocular tube |
|
|
Term
| Name 2 things specimens have to be |
|
Definition
|
|
Term
| what does staining provide? |
|
Definition
|
|
Term
| what type of slide do living organisms need? |
|
Definition
|
|
Term
| name 4 advantages of light microscopes |
|
Definition
| 1. Cheap 2. Easy to use 3. Portable 4. Can study dead and living organisms |
|
|
Term
| what is the maximum magnification of a light microscope? |
|
Definition
|
|
Term
| what is the maximum resolution of a light microscope? |
|
Definition
| 200nn / 0.2 micrometers because they use visible light |
|
|
Term
| name 2 disadvantages of light microscopes |
|
Definition
| 1. low magnification 2. low resolution |
|
|
Term
| what is the equation for working out total magnification? |
|
Definition
Total magnification
= mag power of objective lens x
mag power of eyepiece lens |
|
|
Term
|
Definition
| a photo image seen by a light microscope |
|
|
Term
| Name the 2 types of electron microscope |
|
Definition
| 1. laser scanning electron microscope 2. transmission electron microscope |
|
|
Term
| what is the wavelength of an electron? |
|
Definition
|
|
Term
| how do electron microscopes work? |
|
Definition
The beam of fast
electrons are fired
from a cathode and
then focused onto a
photographic plate |
|
|
Term
| what condition do electron microscopes have to be in? Why? |
|
Definition
| vacuum - prevents electrons hitting particles |
|
|
Term
| in a transmission electron, how are specimens stained? |
|
Definition
They are
chemically fixed by
being dehydrated
and stained by
metallic salts |
|
|
Term
| how do transmission electron microscopes work? |
|
Definition
Some electrons
from the beam
pass through and
are focused on a
photographic plate |
|
|
Term
| what is the magnification of a transmission electron microscope? |
|
Definition
|
|
Term
| what is the resolution of a transmission electron microscope? |
|
Definition
|
|
Term
| what type of image does a transmission microscope produce? |
|
Definition
| a 2D black and white electron microscope |
|
|
Term
| what is the maximum magnification of a scanning electron microscope? |
|
Definition
|
|
Term
| how do scanning electron microscopes work? |
|
Definition
| the beam of electrons causes secondary electrons to bounce off the specimen's surface and be focused on to a screen |
|
|
Term
| what sort of image do scanning electron microscopes form? |
|
Definition
| a 3D black and white electron micrograph |
|
|
Term
| how are specimens stained in a scanning electron microscope? |
|
Definition
| with a fine film of metal and placed in a vacuum |
|
|
Term
| name 5 disadvantages of electron microscopes |
|
Definition
| 1. large = not portable 2. expensive 3. have to be trained to use one 4. specimens have to be dead 5. metallic salt stains are hazardous |
|
|
Term
| how do laser scanning microscopes work? |
|
Definition
| they use laser light to scan an object point by point and assemble, by PC, the pixel info into one image on a PC screen |
|
|
Term
| name 2 features of the images of a laser scanning microscope? |
|
Definition
| high resolution and high contrast |
|
|
Term
| name one special feature of a laser scanning microscope? what does this allow it to do? |
|
Definition
| they have DEPTH SELECTIVITY = can focus on structures at different depths within a specimen = can clearly observe whole living species, as well as cells |
|
|
Term
| give an example of how laser scanning microscopes are used in the medical profession |
|
Definition
| to observe fungal filaments within the cornea of the eye of a patient with fungal corneal infection |
|
|
Term
| as well as the medical profession, how else are laser scanning microscopes used? |
|
Definition
|
|
Term
| Name 3 things you can see with an optical microscope |
|
Definition
| 1. Living organisms, such as Paramecium & Amoeba 2. Human blood & cheek cells 3. thin sections of animals, plants & fungal tissue e.g. bone, muscle, leaf |
|
|
Term
| Name a colourless specimen |
|
Definition
|
|
Term
| Name 3 ways you can see unstained specimens |
|
Definition
| 1.Use light interference, rather than light absorption 2. use a dark background 3. stain it |
|
|
Term
|
Definition
| a coloured chemical that binds to molecules in or on the specimen, making it easy to see |
|
|
Term
|
Definition
|
|
Term
| define differential staining |
|
Definition
| stains that bind to specific cell structures, staining each structure differently so the structures can be easily identified with a single preparation |
|
|
Term
| how does acetic orecin work? |
|
Definition
| binds to DNA & stains chromosomes red |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| how does iodine in potassium iodide solution work? |
|
Definition
| stains cellulose in plant cell walls yellow & stains starch blue/black |
|
|
Term
| explain how specimens are prepared |
|
Definition
| 1. dehydrate specimen 2. embed in wax (prevents distortion in slicing) 3. thinly slice specimen to make specimens 4. stain and mount with special chemicals for preservation |
|
|
Term
| what is the equation for magnification? |
|
Definition
| magnification (M) = photomicrograph (I) / actual image size (A) |
|
|
Term
| how do you convert from mm to micrometers? |
|
Definition
|
|
Term
| how would you work out the actual length of a photomicrograph from just knowing its magnification? |
|
Definition
| 1. measure the widest length of the photomicrograph 2. convert to micrometers 3. divide by magnification |
|
|
Term
| explain how you would draw a slide |
|
Definition
| 1. use a prepared slide such as a transverse section through a dicot leaf 2. set up and focus 3. draw with a sharp pencil 4. use a title 5. indicate scale 6. make a low-power plan of specimen (do not draw individual cells or shade) 7. label 8. draw a high-power plan (draw cells) and label |
|
|
Term
| define an eyepiece graticule |
|
Definition
| a measuring device that is placed in the eyepiece of a microscope and acts as a ruler when you view an object under the microscope |
|
|
Term
| how is the eyepiece graticule 'put onto' the specimen? |
|
Definition
| it is superimposed and the dimensions of the specimen can be measured in eyepiece units |
|
|
Term
| why does an eyepiece graticule have to be calibrated for each different objective lens? |
|
Definition
| because when a slide is magnified it doesn't actually increase in size so the eyepiece scale has to be calibrated |
|
|
Term
| what is used to calibrate an eyepiece graticule? |
|
Definition
|
|
Term
|
Definition
| a small scale measuring device that is placed on a microscope stage and used to calibrate the value of eyepiece divisions at different magnifications |
|
|
Term
| explain how you would use a stage graticule to calibrate the eyepiece graticule if the ruler of the stage graticule is 1000 micrometers long and divided into 100 divisions, and the total magnification is x40 |
|
Definition
| 1. insert eyepiece graticule into x10 eyepiece of microscope 2. put stage graticule on stage & bring it to focus up to a total magnification of x40 3. align eyepiece graticule and stage graticule 4. the stage graticule corresponds to 40 eyepiece divisions 5. so each eyepiece division = 1000/40 = 25 micrometers |
|
|
Term
| name 4 types of organism whose cells are eukaryotic |
|
Definition
| animals, plants, fungi, protocists |
|
|
Term
| name 8 features eukaryotic cells have |
|
Definition
| 1. nucleus with nuclear envelope and chromosomes 2. nucleolus containing RNA 3. cytoplasm 4. cytoskeleton 5. plasma membrane 6. membrane-bound organelles 7. small vesicles 8. ribosomes |
|
|
Term
|
Definition
| small structures within cells, each of which carries out a specific function |
|
|
Term
| how do we know the structure of organelles? |
|
Definition
|
|
Term
| how do we know the function of organelles? |
|
Definition
|
|
Term
| does the nucleus have a single or double membrane? |
|
Definition
|
|
Term
| what is the name of the nucleus' double membrane? |
|
Definition
|
|
Term
| name a feature of the nuclear envelope, and explain what this allows it to do |
|
Definition
| it has pores = allows larger substances (e.g. mRNA) out and others in (e.g. steroid hormones) |
|
|
Term
| the inner and outer membranes of the nuclear envelope can fuse. what does this allow? |
|
Definition
| ribosomes and dissolved substances to pass through |
|
|
Term
| how many micrometers is the nucleus? |
|
Definition
|
|
Term
| what type of microscope can see a nucleus? |
|
Definition
|
|
Term
| what does the nucleus contain? |
|
Definition
|
|
Term
| does the nucleolus have a membrane? |
|
Definition
|
|
Term
| what does the nucleolus contain? |
|
Definition
|
|
Term
| what is the function of the nucleolus? |
|
Definition
|
|
Term
| besides the nucleolus, what else the nucleus contain? |
|
Definition
|
|
Term
|
Definition
| the genetic material, consisting of DNA wound around histone proteins |
|
|
Term
| when a cell divides, chromatin coils to form what? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| define the rough endoplasmic reticulum |
|
Definition
| a network of membranes containing fluid filled sacs called cisternae |
|
|
Term
| what is the function of the cisternae |
|
Definition
| to form channels for transporting substances from one area of a cell to another |
|
|
Term
| what is the rough ER coated with? |
|
Definition
|
|
Term
| what is the function of the ribosomes? |
|
Definition
| to assemble amino acids into proteins |
|
|
Term
| where do the proteins that the ribosomes make go to? |
|
Definition
| they pass through the membranes into the cisternae to be transported to the golgi apparatus for modifying and packaging |
|
|
Term
| what is the only structural difference between the rough ER and the smooth ER |
|
Definition
| the smooth ER does not have ribosomes coated on it |
|
|
Term
| what does the smooth ER contain? |
|
Definition
| enzymes that catalyse reaction involved with metabolism (e.g. synthesis of cholesterol, lipids & steroid hormones) |
|
|
Term
| name 3 things the smooth ER is involved with in terms of lipids |
|
Definition
| absorption, synthesis and transport |
|
|
Term
| define the Golgi apparatus |
|
Definition
| a stack of membrane-bound flattened sacs |
|
|
Term
| what bring materials to and from the golgi apparatus? |
|
Definition
|
|
Term
| name the 2 main functions of the golgi |
|
Definition
| modification and packaging of proteins |
|
|
Term
| give 3 examples of how a golgi modifies |
|
Definition
| 1. adds sugar molecules to make glycoproteins 2. adds lipid molecules to make lipoproteins 3. folds proteins into 3D shape |
|
|
Term
| the golgi packages proteins into vesicles which are pinched off. name 2 places the vesicle will take the protein |
|
Definition
| 1. to be stored in the cell 2. moved to plasm membrane for either incorporation into plasma membrane of exportation outside cell |
|
|
Term
| name 3 shapes mitochondria can be |
|
Definition
| 1. spherical 2. rod-shaped 3. branched |
|
|
Term
| how many micrometers long are mitochondria? |
|
Definition
|
|
Term
| are mitochondria single or double bounded? |
|
Definition
|
|
Term
| what is between the inner and outer membranes of the mitochondria? |
|
Definition
|
|
Term
| what is the inner membrane folded into? what is it coated in? what does this increase? |
|
Definition
| folded into CRISTAE, coated in electron carriers and enzymes, increases SA |
|
|
Term
| what is the centre of the mitochondria called? |
|
Definition
|
|
Term
| what is the function of the mitochondria? |
|
Definition
| to produce ATP during aerobic respiration |
|
|
Term
| what do mitochondria do in terms of replication? |
|
Definition
|
|
Term
| where are mitochondria abundant? |
|
Definition
| in cells where there is a lot of metabolic activity e.g. liver cells |
|
|
Term
| how big are chloroplasts, in micrometers? |
|
Definition
|
|
Term
| where are chloroplasts only found? |
|
Definition
| plant cells and some protocists |
|
|
Term
| where are chloroplasts most abundant in plants? |
|
Definition
| in the palisade mesophyll later |
|
|
Term
| are chloroplasts single or double membrane bound? |
|
Definition
|
|
Term
| what does the inner membrane contain? |
|
Definition
| membrane sacs called thylakoids |
|
|
Term
| what do thylakoids contain? |
|
Definition
|
|
Term
| what is a stack of thylakoids called? |
|
Definition
|
|
Term
| what is the fluid-filled matrix in the middle called? |
|
Definition
|
|
Term
| what are the joins between the grana called? |
|
Definition
|
|
Term
| what is the space between the inner and outer membranes called? |
|
Definition
| intermembrane compartment |
|
|
Term
| what do chloroplasts contain? |
|
Definition
| loops of DNA and starch grains |
|
|
Term
| what is the function of the chloroplasts? |
|
Definition
| photosynthesis - light energy is trapped by chlorophyll in granum to make ATP, water is split to supply hydrogen bonds which reduces CO2 using energy from ATP to make carbohydrates in the stroma |
|
|
Term
| what is the single membrane of a vacuole called? |
|
Definition
|
|
Term
| what does the vacuole contain? |
|
Definition
|
|
Term
| in plant cells vacuoles are large and permanent. in animal cells they are... |
|
Definition
|
|
Term
| explain the function of a vacuole |
|
Definition
| when it is full it pushes against cell wall = makes cell turgid = stability & support |
|
|
Term
|
Definition
| spherical sacs formed by the Golgi apparatus |
|
|
Term
| do lysosomes have a single or double membrane? |
|
Definition
|
|
Term
| what do lysosomes contain? what does its contents do? |
|
Definition
| hydrolytic enzymes - hydrolyse and digest |
|
|
Term
| what is the function of the lysosomes? |
|
Definition
| to separate hydrolytic enzymes from rest of cell |
|
|
Term
| where are lysosomes abundant? |
|
Definition
| phagocytic cells, such as neutrophils and macrophages |
|
|
Term
| what is the role of lysosomes in phagocytic cells? |
|
Definition
| digest foreign matter engulfed by the phagocytic cell by fusing to phagosome surrounding the foreign matter |
|
|
Term
|
Definition
| hairs which protrude from the cell and rhythmically beat to move mucus, dust and dirt |
|
|
Term
| what are cilia formed from? |
|
Definition
|
|
Term
| what do cilia contain? and in what formation? |
|
Definition
| microtubules in a 9+2 arrangement |
|
|
Term
| what does one cilia act as? what does this allow? |
|
Definition
| it acts as an antenna as it contains receptors. this allows cells to detect signals about its immediate environment |
|
|
Term
|
Definition
| a protrusion from the cell which allows movement |
|
|
Term
| what does undulipodia contain? |
|
Definition
|
|
Term
| what is the only human cell with an undulipodia? |
|
Definition
| a spermatozoon cell = allows movement |
|
|
Term
| name 4 organelles without membranes |
|
Definition
| 1. ribosomes 2. centrioles 3. cytoskeleton 4. cell wall |
|
|
Term
| what is the diameter of a ribosome in nanometers? |
|
Definition
|
|
Term
| what are ribosomes made of? |
|
Definition
|
|
Term
| what fits between the small and large subunits of a ribosome? |
|
Definition
| mRNA for protein synthesis |
|
|
Term
| name 2 places ribosomes are found |
|
Definition
| 1. free in the cytoplasm for the assembly of proteins that will be used in the cell 2. bound to the rough ER for protein synthesis |
|
|
Term
| what are centrioles made of? |
|
Definition
| 2 bundles of microtubules at right angles to each other |
|
|
Term
| what are microtubules made of? |
|
Definition
|
|
Term
| how are the microtubules arranged in a centriole? |
|
Definition
| They are arranged to from a cylinder |
|
|
Term
| how do centrioles form cilia or undulipodia? |
|
Definition
| 1. before a cell divides, the spindle, made of threads of tubulin, forms from the centriole 2. chromosomes attach to the middle of the spindle and motor proteins walk along the tubulin thread pulling the chromosomes to opposite ends of the cell 3. the centrioles multiply & line up below the cell surface membrane 3. the microtubules sprout outwards from each centriole = cilium/undulipodium |
|
|
Term
| where are centrioles only found? |
|
Definition
| animal cells, with the exception of some unicellular green algae (e.g. chlamydomonas) |
|
|
Term
|
Definition
| a network of protein-structures within the cytoplasm |
|
|
Term
| name 4 elements of a cytoskeleton |
|
Definition
| microfilaments, microtubules, cytoskeletal motor proteins, intermediate filaments |
|
|
Term
| what shape are the microfilaments? |
|
Definition
|
|
Term
| what are the microfilaments make of? |
|
Definition
| subunits of the protein actin |
|
|
Term
| what is the diameter of each microfilament in nanometers? |
|
Definition
|
|
Term
| what shape are microubules? |
|
Definition
|
|
Term
| what are microfilaments made of? |
|
Definition
|
|
Term
| what are the cytoskeletal motor proteins? |
|
Definition
| molecular motors & also enzymes which have a site that binds to and allows hydrolysis of ATP as their energy source |
|
|
Term
| what is the function of the microfilaments? |
|
Definition
| support, mechanical strength, maintains shape, allows cell movement |
|
|
Term
| what are functions of the microtubules? |
|
Definition
| 1. shape and support 2. form a track along which motor proteins drag cells from one area of cell to another 3. form a spindle before cell divides = allows chromosome movement 4. make up cilia, undulipodia and centrioles |
|
|
Term
| name 2 functions of the intermediate filaments |
|
Definition
| 1. anchor nucleus within cytoplasm 2. extend between cells in some tissues = allows cell signalling = stabilises tissues |
|
|
Term
| what is the plant cell wall made of? |
|
Definition
| bundles of cellulose fibres (beta glucose) |
|
|
Term
| what are cells absent from? |
|
Definition
|
|
Term
| name 4 functions of plant cell walls |
|
Definition
| 1. strength & support 2. shape 3. support of whole plant 4. permeable = solution can get through |
|
|
Term
| what are fungi cell walls made of? |
|
Definition
|
|
Term
| explain how a protein is made and secreted |
|
Definition
| 1. the gene that has the coded instructions for a protein housed into the chromatin in the nucleus is TRANSCRIBED onto a length of RNA to form mRNA 2. Copies of the mRNA are made 3. mRNA passes out of pores in the nuclear envelope to the ribosomes 4. as the ribosome, the instructions are TRANSLATED to form molecules of the protein 5. the molecules pass into the cisternae of the rough ER and travel along 6. vesicles with the protein molecules inside are pinched off from the rough ER and pass via microtubules and motor proteins to the golgi apparatus 7. vesicles fuse with the golgi apparatus 8. golgi packages, processes and functionalises the protein molecules 9. packaged protein molecules are pinched off in vesicles from golgi and move towards plasma membrane 10. vesicles and plasma membrane fuse, releasing the protein to the outside of the cell |
|
|
Term
| what has prokaryotic cells? |
|
Definition
|
|
Term
| name 5 similarities between eukaryotic cells and prokaryotic cells |
|
Definition
| have 1. plasma membrane 2. cytoplasm 3. ribosomes 4. DNA 5. RNA |
|
|
Term
| what is different about prokaryotic cells compared to eukaryotic cells? Give 7 differences |
|
Definition
| 1. smaller (1-5 micrometers) 2. less developed cytoskeleton with no centrioles 3. no nucleus 4. no membrane-bound organelles 5. cell wall is made of peptidoglycan 6. smaller ribosomes 7. naked DNA - floats around |
|
|
Term
| name 4 things some prokaryotic cells have |
|
Definition
| 1. protective waxy capsule surrounding cell wall 2. plasmids 3. flagella 4. pili |
|
|
Term
| what do the flagella allow? |
|
Definition
|
|
Term
|
Definition
| bacteria to adhere to host cells or each other |
|
|
Term
| what 2 shapes can prokaryotic cells be? |
|
Definition
| 1. bacillus (rod) 2. coccus (sphere) |
|
|
Term
| how do prokaryotic cells divide? |
|
Definition
|
|
Term
|
Definition
| a type of division found in prokaryotic cells and organelles such as chloroplasts and mitochondria |
|
|
Term
| why can't prokaryotic cells carry out mitosis? |
|
Definition
| because they have no linear chromosomes |
|
|
Term
| what is the endosymbiont theory? |
|
Definition
| that eukaryotic cells evolved from prokaryotes 1.5-2 billion years ago |
|
|
