What are the maximum magnification & resolutions of both a light and electron microscope?
light (up to X1500 and low resolution); and electron (up to X500 000 and high resolution).
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What is resolution?
Resolution is how well small, close objects can be seen separately. High resolution produces detailed images of cells (ultrastructure).
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Why do some specimens require preparation before being viewed under a microscope?
Specimens need preparation to make structures visible. Light microscopes need stains (e.g. acetic orcein for DNA). Electron microscopes need lead salts to scatter electrons and produce images. The pictures produced are called micrographs.
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What is the equation for finding the magnification factor?
The magnification of a micrograph is the observed size/actual size. (AIM)
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What do most cells consist of?
Organelles; nucleus, nucleolus (makes ribosomes), mitochondria (make ATP for cellular energy), lysosomes (contain lytic enzymes), chloroplasts (plant cells only), centrioles (animal cells only, aid cell division), cilia and flagella (beat to produc
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What are the organelles involved in protein synthesis and their role?
Ribosomes make proteins, rough endoplasmic reticulum transports the protein to Golgi apparatus which packages and secretes it out of the cell.
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What are the main differences between Eukaryotes and Prokaryotes?
Eukaryotic cells have a true nucleus and membrane-bound organelles. Prokaryotes have naked DNA and small organelles with no membranes around them.
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What is the 'fluid mosaic model'?
The fluid mosaic is a phospholipid bilayer with scattered proteins.
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What is the role of a cell surface membrane?
The cell surface membrane is for transport (partially permeable) and recognition/signalling (e.g. receptor molecules for hormones).
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What are the differences between active and passive transport?
Passive transport (diffusion/facilitated diffusion) does not use energy, while active transport does and is against a concentration gradient.
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Definition of osmosis.
Osmosis is diffusion (net movement) of water from high water potential to low across a cell membrane.
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What is edo/exocytosis?
Endocytosis is bulk movement of fluid/particles into a cell. Exocytosis is movement to the outside of the cell.
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Describe the cell cycle.
The life cycle of a dividing cell is the cell cycle. It mostly involves copying and checking genetic information. The final small part involves mitosis which forms two new cells. Cells can continue a cell cycle or they differentiate.
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What are the main stages of mitosis?
The main stages of mitosis are: Prophase (chromosomes thicken, become visible); Metaphase (chromosomes line up on the equator); Anaphase (chromatids separate); and Telophase (each set of chromatids forms a new nucleus).
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What is the relationship between the new cell and the parent cell?
New cells produced in mitosis are genetically identical (same chromosome combinations) to each other and the parent cell. Cells formed by meiosis are not genetically identical.
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Give some examples of a stem cell that becomes specialised.
Some mitosis (e.g. bone marrow) produces stem cells. These can differentiate into many different cell types (e.g. red blood cells, neutrophils). They are specialised for their function (e.g. epithelial or guard cells).
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How are cells, tissues and organs linked?
Cells are organised into tissues (e.g. squamous or ciliated epithelium; xylem/phloem) which are organised into organ systems.
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Other cards in this set
Card 2
Front
What is resolution?
Back
Resolution is how well small, close objects can be seen separately. High resolution produces detailed images of cells (ultrastructure).
Card 3
Front
Why do some specimens require preparation before being viewed under a microscope?
Back
Card 4
Front
What is the equation for finding the magnification factor?
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