Cell Strucure Flashcards
Everything from microscopes to cellular organelles, you gotta know it all inside out!
dont mention magnification here….
What is Resolution in microscopy?
This is the ability to distinguish between 2 separate points, clearly
NOT THE SAME AS MAGNIFIATION, Do not get confused…
What is Magnification in microscopy?
The number of times larger an image appears, as compared to the size of the real object.
Think Formula triangle……
Equation for Magnification
Magnification = Image Size / Real Size
Using IMA Formula triangle for easy use!
What techniques are used to see unstained and live specimens?
- Light interference (rather than light absorption. It eliminate halos and extra light. )
- Dark background
What is a Logarithimic Scale?
think of powers….
- This is a scale is used to represent data that spans a wide range of values, making it easier to visualise and compare.
- Instead of increasing linearly, a logarithmic scale increases by orders of magnitude. This means each step on the scale represents a multiplication of the previous value, often by a factor of 10
usefull to compare exponetially growing / increasing relative values…
Give the main features of Laser Scanning Confocal Microscope
give the mag, resolution, images and use
- Uses a laser to create an image, pixel per pixel onto a digital screen, with high contrast
- MAGNIFICATION: x2000 and more
- RESOLTION: Greater than Opticals
- Image?»_space; Sharp, 3D, coloured image with depth selectivity
- Used mostly by med professionals
Depth Selectivity: Ability to focus on different depths of an organism
you should know what this stands for
Give the features of a TEM.
give the give the mag, resolution, images and use
- Uses a beam of electrons, in a VACCUM!
- MAGNIFICATION: X2,000,000
- RESOLUTION: 0.2nm
- Image?»_space; 2D, black and white thinly sliced images, detecting electrons passing through specimen
- Specimen must be dehydrated, stained with metal salts, always!
Electrons passing through specimen = can see internal cell structures!!
you should know what this stands for
Give the features of a SEM.
give the give the mag, resolution, images and use
- Similar to a TEM, uses a beam of electrons in a vaccum!
- MAGNIFICATION: x200,00
- RESOLUTION: 10nm
- Image?»_space; 3D images, black and white, with a DEAD specimen, with metallic stain
- Computers normally add false colouring
metallic stains: may pose a toxic hazard to the users,
What is the structure of the smooth endoplasmic reticulum (SER)?
System of membranes with cisternae
No ribosomes
What is the function of the Smooth Endoplasmic Reticulum?
- Contains enzymes to catalyse cellular reactions.
- Undergoes lipid-synthesis and lipd transporation (within cell)
What is the structure of the Rough Endoplasmic Reticulum?
- System of folded membranes, close to the nucleus, containing fluid-filled cavities called cisternae that are continuous with the nuclear membrane.
- Coated with ribosomes
What is the function of the Rough Endoplasmic Reticulum?
- Provides a large surface area for ribossomes (enhancing amino acid assembly)
- Cisterae provides a channel to transport molecules in from nucleus.
What is the structure of the Nucleus?
- A large organelle surrounded by a nuclear envelope, containing many nuclear pores, holding cell’s genetic information (DNA)
nuclear envelope = double membrane
What is the function of the Nucleus?
- Controls the cell activities (controlling DNA Transcription)
- Chromatin - DNA Complexfound in chromosomes
What is the structure of the Golgi Apparatus?
- Collection of fluid fillled, membrane bound flattened sacs. Secretory vesicles can be pinched off to bring materials to and from (via edges)
What is the function of the Golgi Appuratus?
- Carries out lipid-synthesis
- Makes new lysosomes!
What is the structure of mitochondria?
- Spherical, rod shaped or branched.
- Surrounded by double membranes (inner and outer) with fluid filled space in between -> inner membrane folded into cristae
- Fluid filled matrix
What is the function of the mitochondria?
- Carries out aerobic respiration, where ATP is produced
- Mostly found in energy intensive regions e.g muscle cells
What is the structure of Cilia/Undilipodia?
- Small, hair like protrusions structures, made up of microtubles in a 9+2 formation structure
- Such microtubles allow the cilia to MOVE SUBSTANCES!
What is the function of Cilia?
normall and epithelial!
- Contains receptors that detects environmental changes for most cells
- Epithelial Cilia - beating and moving bands of mucus in the trachea
What is the function of Undilipodia?
Only found in one place in animals: the sperm
Allows the sperm to move via tail like movements
What is the structure of Lysosome?
Small, single-membraned round bag-shapes with no interial structure
What is the function of Lysosomes?
- Containing digestive hydrolyctic enzymes to digest unused organelles and invading pathogens
- Kept seperated from the cytoplasm
basically the cell’s dustbins…
What is the Nucleolus’ function?
- This will make ribossomes for RER for protiensynthesis, found in the nucleus
What is the function of ribossomes?
- Carries out proteinsynthesis, bound to the RER
What is the structure of centrioles?
- 2 bundles of microtubles perpendicular to one another, made of tubulin
What is the function of centrioles?
- Makes up the spindle fibres involved in cellular mitosis, formed perpendicular to each other
- Makes up inner structure of cilia and undilipodia
What is thefunction of chloroplast?
- Carries out photosynthesis, where the grana (plural of granum) traps light energy
- To produce glucose needed during plant respiriation (ATP)
What is the function of cell vacuole?
- This will provide cell stability and support, keeping cell rigid
- Supports with cell water potential
has a membrance called: Tonoplast!
What is the function of the cell wall?
- This will provide cell stabilty and rigid strength.
What are the features of an Optical Microscope?
give the mag, resolution, and uses
- Uses visible light and lenses to magnify object images
- RESOLUTION: 200nm
- MAGNIFICATION: x1,500
- Image»_space; Uses white light, specimen may be living / dead
State and explain the main different staining techniques
- Differential Stain: More than one type of dye used, to highlight contrast between different organnelles
- Simple Stain: One basic dye used to highlight contrast
State and explain the 5 different stains
Methyl Blue : All purpose staining (animal, plant, blood ect)
Acectic Orcien: Binds and Stains DNA, in the chromosomes, in the nucleus - DARK RED*
Sudan Red: Binds and stains lipids - *RED**
- Eosin Stain: Acidic Dye, staining cytoplasm - PINK
- Iodine Stain - Staining Cellulose/Starch Granules - BLUE
What are 4 main purposes of staining?
- To provide a higher contrast
- To allow internal structures to be more visible
- Some organelles to be more visible
- To allow a clearer image to occur
State the 5 conventions of Low-Powered Drawings
- Smooth, continous lines without shading
- NO INDIVIDUAL CELLS, ONLY COMMON TISSUE
- Drawn to proportion always
- Lables HORIZONTAL to drawing
- Include Title, Mag and scale bars
State the 5 conventions of High-Powered Drawings
- Smooth, continous lines without shading
- DRAW 15-20 LARGE INDIVIDUAL CELLS
- Drawn to proportion always
- Lables HORIZONTAL to drawing
- Include Title, Mag and scale bars
NOT EVEN SHADING FOR STAINS!!
What is an eyepiece graticule? What is a stage micrometer?
- Eyepiece graticule fitted into a microscope eyepiece, with 100 divisions and no scale = eyepiece units. It represents diff lengths at diff mags and so has to be calibrated for each objective lens.
- A microscopic ruler is etched onto a slide = stage micrometer/stage graticule. each tiny unit is 10 micrometres, and the whole ruler is 1mm.
- You line up the eyepiece graticule and stage micrometer as best as you can, see what equals what and then calculate what one eyepiece unit is worth
in micrometres. - Measure how many eyepiece units the specimen is in width/length, and x by the micrometre amount.
Define Transcription
The process of making mRNA from DNA strand
Define Translation
- Forming of protiens at ribossomes, through amino acid assembly with tRNA, always complamentary to the triplet codon, to mRNA.
Decribe Division Of Labour (proteinsynthesis)
`
- In cell nucleus, DNA is unzipped by DNA Polymerase, removing double helix shape
- mRNA takes complementary base copy from DNA, leaves via nuclear pore, to RER > cisternae > ribossome
- Ribossomes read the BASE SEQUENCE in TRIPLETS
- tRNA is brought here, where assembled complemantary
- TRIPLET CODON FORMED: Where tRNA Molecules each have amino acids > peptide bonds > POLYPEPTIDE
mRNA = Coding Strand
DNA = Template Strand
Decribe what happens to protiens after assembly in ribossomes!
- Transport VESICLE will transport the polypeptide chain to the Golgi Body
- At Body, this polypeptide will have its shape folded and modified, among others, into a SPECIFIED TERTAIRY STRUCTURE
- Secretory VESICLE will again transport modified molecule, FUSE WITH THE PLASMA MEMBRANE, and exits cell via EXOCYTOSIS!!!!
Outline 4 of Cytoskeleton’s Main functions
give an example for each…
- PROVIDES MECHANICAL STRENGTH - via mircotubles
- AIDS TRANSPORTATION IN CELLS - vesicles, chomosome
- ALLOWS CELL MOVEMENT - phagocytosis, endocytosis
- ANCHORS ORGANELLES IN PLACE - nucleus in cytoplasm
State the components of The Cytoskeleton!
- Rod-Like Microfilaments
- Cylindrical Microtubles
- Intermidiate Filaments
- Motor Protiens
2 to mention
Structure and function of Microfilaments
Material and Diameter
- Providing mechanical support, strength and shape
- Allowing for cell movements via contractions e.g. Phagocytosis
7nm Diameter, made of Actin!
2 to mention
Structre and function of Microtubles
Material and Diameter
- Trackway for Motor Protiens, moving substances around cell
- Spindle Fibres during Cell Division (chromosome movement)
20-30nm, made of Tubulin
2 to mention
Structre and function of Intermidiate Filaments
Material and Diameter
- Cell-Cell signalling system
- Anchors the Nucleus in cytoplasm
10nm, made of many protiens
Structre and function of Motor Protiens
Material…
- Vesicle Transportation
- Organelle Transportation
- Chromosome movements
KINESIN AND DYNESIN!
HOW TO PREPARE A LAB SLIDE IN 6 STEPS!
- Grossing - Trimming to appropiate size
- Tissue Fixations - Preserved in Formaldyhide + alcohol dehydtration
- Sectioning - Cutting down specimen ULTRA THIN
- Staining - Highlighting contrast of specimen
- Cover Slip - laid at an angle to prevent AIR BUBBLES, blocking view
State 4 similarities of Prokaryotes and Eukaryotes
- Both with ribossomes
- Both with Cytoskeleton
- Both with Cell wall
- Both with Centrioles
State the Cell wall materials of: Bacterium, Fungi and Plants
- Bacterium = Peptidoglycan
- Plant = Cellulose
- Fungi = Chitin
State 7 differences of Prokaryotes and Eukaryotes
- P: No membrane bound organelles of ANY SORT!! E: Contains these
- P: Smaller cells, E: Larger Cells
- P: 70s Ribossome, E: 80s Ribossome
- P: No definite nucleus, E: Contains Defintie Nucleus
- P: Has plasmids, E: No plasmids
- P: Binary Fission, E: Mitosis (due to nucleus presence)
- P: Simple cytoskeleton, E: Normal Cytoskeleton
Give 4 main bacterial-only features
- Mesosme: larger SA plane for chemical reactions in cytoplasm
- Capsule: Slime Layering that protects virus infectoins and hides antigens (from immune attack)
- Pili: Adheres to other cells and provides a medium of plasmid transfer
- Flagellum: Tail to swim and move
What 2 types of mounts can be done?
and explain ‘em..
- Usually done for Optical Microscope
Wet mount: adding a drop of water to the specimen before placiing coverslip- esp used for mobile organisms. Prevents distortion and flattens the sample. - Dry mount: no water, placing coverslip straight away - used for hairs, pollen etc.
