2.1 cell structure Flashcards
describe the roles if the cytoskeleton
- moves cilia and flagella
- provides support for the cell
- changes the shape of the cell
what is the nucleus?
- the part of the cell that contains the genetic information
- it is surrounded by a double membrane called the nuclear envelope
what is the function of the smooth endoplasmic reticulum?
- responsibe for lipid and carbohydrate synthesis
what is the function of the rough endoplasmic reticulum?
- contains ribosomes for protein synthesis
- helps to transport molecules from one area of the cell to another.
What is the nucleolus?
the inner part of the nucleus that is responsible for making ribosomes.
What are lysosomes?
specialised vesicles that contain hydrolitic enzymes for breaking down cell organelles
what are cilia and flagella?
- part of the cytoskeleton, they help with cell movement.
what is the cytoskeleton made from?
- micro filaments
- micro tubules
- intermediate fibres
what is the cell wall?
- a freely permeable defense mechanism for pathogens.
what is the function of the golgi apparatus?
- modifies and packages proteins
- produces lysosomes
what is the vacuole?
a fluid filled sack found in plant cells, it helps to maintain their turgor
what are ribosomes?
the site of protein synthesis
what are mitochondria?
the site of aerobic respiration
what is the structure of mitochondria?
a membrane that forms cristae, with an inner fluid matrix
what are chloroplasts?
the site of photosynthesis
what is the structure of chloroplasts?
a double membrane with a fluid called stroma
how does a transmission electron microscope work?
electromagnets are used to focus a beam of electrons through the specimen
what is the resolution of a TEM?
0.05-2nm
what is the magnification of a TEM?
X 1 000 000
How does a scanning electron microscope work?
a beam of electrons is scanned across the specimen which knocks electrons off of the specimens. They the gather in a cathode ray tube to form an image.
what is the resolution of a SEM?
5-50nm
What is the magnification of a SEM?
X 500 000
what are some advantages of electron microscopes?
- higher resolution and magnification than light microscopes
- SEM produces a 3D image
- produces detailed images
what are some disadvantages of electron microscopes?
- very expensive
- must be trained to use
- black and white image
- complex staining required
- image may contain artefacts
- specimen must be dead and in a vacuum
what is an eyepiece graticule?
a measuring device found within the eyepiece of a microscope
what is a stage micrometer?
a precise measuring device used alongside the eyepiece graticule to calibrate a microscope
what is resolution?
the ability to distinguish clearly between two spearate points
what are photomicrographs?
the image produced by a light microscope
what are electron micrographs?
the image production by an electron microscope
what is magnification?
the number of times large an image appears
what is the magnification calculation?
image size = actual size X magnification
what is the resolution of a light microscope?
200nm
what is the magnification of a light microscope?
X 1500
