Cell Structure and Microscopy Flashcards
What Structures are in a Eukaryotic Cell?
Cytoplasm, Nucleus, Ribosomes, Mitochondria, Plasma Membrane, Nucleolus, R.E.R, S.E.R, Golgi Apparatus, Lysosomes, Vacuole**
What Structures are only in Plant Cells?
Chloroplasts, Permanent Vacuole, Cell Wall (Cellulose)
What Organelle can you only find in an Animal Cell?
Centriole
What are the Structures of a Prokaryotic Cell?
Cytoplasm, Ribosomes, Plasma Membrane, Chloroplasts, Vacuole, Cell wall (Peptidoglycan), Nucleoid (DNA), Plasmids, Slime Capsule, Pili, Flagella
What are the cell sizes of a Prokaryotic and Eukaryotic?
Prokaryotic: 0.5-5um
Eukaryotic: 10-100um
What are the Ribosome’s realtive sizes?
Prokaryotes: 70S (approx 10-20nm)
Eukaryotes: 80S (approx 22nm)
What is the process of producing ATP in the Mitochondria called?
Oxidative Phosphorylation
What are the 4 different types of Slide called?
Dry Mount
Wet Mount
Smear Slide
Squash Slide
How is a Wet Mount prepared?
- Specimens are suspended in a liquid e.g. water or immersion oil.
- A cover slip is placed at an angle
Aquatic organisms and other living examples can be viewed.
What are the 4 Steps of preparing a slide and what happens at each step?
o Fixing- Chemicals used to preserve specimens in as near natural state as possible.
o Sectioning- Specimens dehydrated with alcohol then placed in a mold with wax to be cut with a knife (microtome)
o Staining- Treated with colors to see structures of a cell.
o Mounting- Specimens secured to slide and cover slip is used.
Definition of Magnification?
how much bigger the image is compared to the original object viewed with the naked eye
Definition of Resolution?
The ability to distinguish between two points on an image.
Features of a Compound Light Microscope
o Uses visible light to illuminate a thin section of a living sample
o Low resolution compared to electron
o Can see thin cross section of a living thing (slice)
Features of a Confocal Laser Scanning Microscope
o Can see thin slices of an intact sample - cell structures
o Low resolution compared to SEM
o Only see fluorescent objects and can cause artefacts
o Can see mitosis/movement of mitochondria
Advantages of Electron Microscopy
o Done with a beam of electrons with a wavelength of less than 1nm
o Gives higher detail of the cell ultrastructure
o Produces images of up to x500,000 magnification
Disadvantages of Electron Microscopy
o Very expensive to use and restore
o Have to be used in a controlled environment
o Specimens can be damaged due to the complex process
o Specimens must be dead
o Can be a problem with artefacts
Features of a Scanning Electron Microscope (SEM)
o Can see the surface of objects at high resolution o Resolution not as high as TEM o Specimens must be dead o Generated 3D image that can be colored o Lower limit of resolution than TEM o Magnification up to x100,000
Features of a Transmission Electron Microscope (TEM)
o A beam of electrons are transmitted through a specimen
o Resolving power of 0.5nm
o Can see thin cross section of an object
o Specimens must be dead
o Very high resolution - higher than SEM
o Magnification up to x500,000
How do prokaryotes reproduce?
Binary Fission
What 3 structures make up the Cytoskeleton?
Microtubles, Microfilaments, Intermediate Filaments
Roles of the Microtubles
o Globular tubulin proteins
o Form hollow tubes to form as scaffold
o Determine cell shape
o Act as pathways for vesicles and organelles
Roles of Microfilaments
o Composed of actin (protein)
o Provide contractile motion when they collide with myosin
o Involved with contraction during cytokinesis
o Support the cell
o Responsible for cell movement
Roles of Intermediate Filaments
o Entwined dimers of proteins
o Add mechanical strength
o Help maintain cell integrity
Overall role of the cytoskeleton
o Provide strength and support o Determine cell shape o Movement of organelles o Hold organelles in place o Make up centrioles and spindle fibers
Process of Protein Production
o DNA is copied (transcription), mRNA moves out of the nucleus to the ribosomes
o The ribosomes coordinate the assembly of proteins (translation) using the mRNA
o The mRNA is translated and the proteins enter the cis face of the Golgi body in a vesicle
o The proteins are processed and modified and packaged up to leave in a vesicle from the trans face
o The vesicles fuse to the plasma membrane and the proteins are released (exocytosis)
Features of Nucleolus
o Lives in Nucleus
o Not membrane bound
Produces rRNA and communicates by sending mRNA to the ribosom
Features of Rough Endoplasmic Reticulum
o Flattened membrane to transport and synthesize proteins
o Made rough due to ribosomes
o Packages proteins
Features of Nucleus
o Surrounded by nuclear envelope (double membrane)
o Contains nucleolus
o Stores DNA as chromatin and coordinates cells activities such as growth, protein synthesis and reproduction.
