1 Cells and Microscopes Flashcards
How are proteins made and secreted? - (from gene to leaving the cell)
- gene coded instructions
-instructions are transcribed into a length of mRNA and exits nucleus through nuclear pores
-goes to ribosomes, instructions are translated
-insulin molecules are assembled
-everything passed into the cisternae
-vesicles pinched off, pass via microtubules + motor proteins
-vesicles fuse to the Golgi Apparatus
-insulin protein molecules may be modified
-these are then processed and packaged
-vesicles are pinched off
-move to plasma membrane
-vesicles fuse to plasma membrane
-opens and released the molecules out of the cell.
Prokaryotic cells
-no nucleus
-diameter of cell is 0.1- 0.5 micrometers (um)
-lack cytoskeleton
-no membrane bound organelles
-cell wall is made of peptidoglycan
-divide by binary fission
-70s ribosomes
-bacteria cells
Eukaryotic cells
-10-100 micrometers (um)
-cell wall is made of cellulose
-divide by mitosis, meiosis
-80s ribosomes
-Yeast, amoebae, plant and animal cells
Chloroplasts
What are the fields called, what they are made of and the liquid found in chloroplasts?
fields- grana
grana is made of thylakoids
liquid- stroma
Mitochondria
what is the folded membrane called?
cristae
Flagellum
cell movement
pilli
-transfer genetic material
-hold to surfaces
Villi, microvillus
-very thin
-increase surface area
cytoskeleton
-support cell shape
-direct substances + organelles
What are the 3 types of fibers?
-Microfilaments
-intermediate filaments
-microtubules
Shape and diameter of microfilaments
-Thread-like
- 3-6 nm diameter
Shape and diameter of intermediate filaments
-rope like
- 10nm
shape and diameter of microtubules
-hollow
- 24nm
Electron micrograph
A photo of an image seen using an electron microscope
Magnification
The number of times larger an image appears compared with the size of the object
Organelles
Small structures within cells, each of which has a specific function
Photomicrograph
Photo of an image seen using an optical microscope
Resolution
The clarity of an image, the higher the resolution = the clearer the image
Total Magnification (calculation)
Magnifying power of the objective lens (times)
magnifying power of the eyepiece lens
Optical microscopes
- cheap (relatively)
-easy to use
-portable
-used in schools, colleges etc.
Laser scanning microscopes
how it works and how its seen
-laser light to scan an object point by point
-displayed on a computer screen
-depth selectivity
Electron microscope
both types (similarities)
-Great deal of skill to use
-training needed
-large and expensive
-beam of fast traveling electrons
-electrons get fired from a cathode
-focused by magnets onto a screen or photographic plate
Transmission electron microscopes
-specimen
-2D or 3D
-color or b+w
-electrons
-Specimen is dehydrated and stained
-electrons pass through
- 2D image
-Black and White image
Scanning electron microscope
-2D or 3D
-color or b+w
-electrons
-do not pass through, electrons ‘bounce off’
-3D image
- black and white image but false color can be added
Laser confocal microscopes
-specimen ( 2 info)
-2D or 3D
-Specimen is stained
-Sample living things
-3D image
Homogenisation
Grind/ break up material
Centrifugation order
(organelles)
-nucleus
-mitochondria, chloroplasts
-microsomes
-ribosomes
Eyepiece graticule
-the measuring device put in the eyepiece (the ruler viewed under the microscope, cannot easily remove it)
Stage graticule
-Scale put on stage
-Used to calibrate the value of the eyepiece divisions at different magnifications.
Order of small measurements (after cm)
milli -10-3 - mm
micro -10-6 - um
nano -10-9 - nm
pico -10-12 - pm
Flagella
-Long appendages which rotate by a ‘motor’ in the cell envelope
-to move the cell and create motility
Cell envelope
-Outermost layer of a bacterial cell
-protect, maintain shape
-Allow appropriate metabolism growth + division of the cell
Ribosomes
-protein synthesis
-large and small subunit
Genophore
-Long double strand of DNA usually in one large circle
-Includes most of the genetic material of the organism
Nucleoid
-Most of the bacterial DNA is found here
-not membrane bound
Capsule
This layer of polysaccharide protects the bacterial cell
-Serves as a barrier against phagocytes by white blood cells
Plasmid
-Small circular DNA fragments
-Contain code responsible for antibiotic resistance
Storage Granule
Nutrients and reserves may be stored in these cytoplasmic inclusions in the form of glycogen, lipids, polyphosphates or in some cases Sulphur or mitogen.
Pilli, Fimbriae
-Hollow hair like structures made of proteins allow bacteria to attach to other cells
-A specialized pili, the sex pilis, allow the transfer of plasmid DNA, from one bacterial cell to another.
Cell membrane
Controls movement of substances in and out of the cell
Smooth ER
-The ER is a continuation of the outer nuclear membrane and its varied function suggests the complexity of the eukaryotic cell
-Synthesizes, stores and transports lipids and carbohydrates
Nucleus
-Enclosed in a double membrane
-Holds the DNA
Nucleolus
-Produces ribosomes
-stores genetic information
Rough ER
-Numerous ribosomes on its surface
-Ribosomes protein synthesis its collected by the ER for transport throughout the cell.
Golgi
-Membrane bound structure, with a single membrane
-Modifies proteins, sorts substances for secretion
-‘processes + packages’
Vacuole
-Membrane bound sack
-Plays a role in intracellular digestion and the release of cellular waste products
Peroxisomes
-Responsible for protecting the cell from its own production of toxic hydrogen peroxide
Mitochondrion
-Provides the energy the cell needs to move
-Respire to produce ATP
Lysomes
-Contain hydrolytic enzymes necessary for intracellular
-Secretes harmful enzymes out of the cell.
