Topic 2.1 Eukaryotic cells Flashcards
Define a tissue
a group of specialised cells carrying out a particular bodily function
Define an organ
a structure made up of several different types of tissues grouped together to carry out a particular function for the body
Define an organ system
a group of organs working together to carry out a particular functions in the body
What are epithelial tissues?
tissues that from the lining of surfaces inside and outside the body
What are the 4 main types of tissue in the body?
- epithelial tissue
- muscle tissue
- connective tissue
- nervous tissue
Which type of epithelial cells usually line blood vessel surfaces and the walls of alveoli and capillaries?
squamous epithelium
What is a light microscope?
a tool that uses a beam of light and optical lenses to magnify specimens up to 1500x life size
What is an electron microscope?
a tool that uses a beam of electrons and magnetic lenses to magnify specimens up to 500 000 x life size
Define magnification
a measure of how much bigger the image you see is than the real object
Define resolution
a measure of how close together 2 objects can be before they are seen as one
What is a transmission electron micrograph (TEM)?
micrographs produced by the electron microscope that gives 2D images like those from a light microscope, but magnified up to 500 000 X
What is a scanning electron micrograph (SEM)?
micrographs produced by the electron microscope that have a lower magnification than the TEMs, but produce a 3D image
Give the equation for total magnification
total magnification= magnification of objective lens x magnification of eyepiece lens
State the advantages of a light microscope
- can see living organisms or parts of them, useful as it allows you to compare prepared slides with living tissue
- relatively cheap so available in schools, unis, hospitals and industrial labs and research labs
- light and portable
State the disadvantages of a light microscope
- preservation and staining tissue can produce artefacts in the tissues being observed
- limited powers of resolution and magnification
State the advantages of an electron microscope
-huge powers of magnification + resolution
State the disadvantages of an electron microscope
- all specimens examined in a vacuum so can’t see living material
- specimens undergo treatment resulting in artefacts
- preparation is very skilled work
- extremely expensive
- large and has to be kept under constant temperature and pressure
Define organelles
sub-cellular bodies found in the cytoplasm of cells
Define eukaryotes
a group of organisms with cells that have genetic material contained in a membrane-bound nucleus and also contain a number of membrane-bound organelles such as mitochondria and choloroplasts
What are prokaryotes?
a group of organisms including bacteria that have few organelles and have no nucleus
What is the cell surface membrane?
the membrane that forms the outer boundary of the cytoplasm of a cell and controls the movement of substances into and out of the cell
What are vesicles?
membrane ‘bags’ that hold secretions made in cells