cell structures

Created by

Sophie Barker

Cards (62)

resolution = the minimum distance between two objects in which they can still be viewed as separate.
Magnification = how many times larger the image is compared to the object
How to prepare a dry mount ? 
Thin slice of specimen and place cover slip over top
How to prepare a wet mount ? 
Water is added on top of specimen before cover slip is placed on at an angle to prevent air bubbles.
How to prepare a squash slide ? 
A wet mount which you apply force to coverslip to squash the slide
When would a squash slide be used ?
To view chromosomes in mitosis of a root tip
How to prepare a smear slide ? 
Place a drop of sample at one end and using the edge of slide smear sample across to create a thin, smooth even coat.
When would you use a smear slide ? 
To look at cells in a blood test
Eyepiece graticule = a scale on a glass disc which can be inserted inside a light microscope
How to calibrate an eyepiece graticule ?
line up stage micrometer and eyepiece graticule
count how many divisions on the eyepiece graticule fit into one division on stage micrometer scale
calulate what 1 division on the graticule is worth
What is the value of one division on a micrometer ? 
10 micrometres
what is the purpose of staining ? 
to allow differentiation between cell components
differential staining = many chemical stains being used to stain different parts of as cell in different colours
Name 2 positive stains ?
Crystal violet
Methylene blue
Name 2 negative stains ?
Congo red
Nigrosin
Why do negative stains only stain the background ? 
The cytosol repels them so the stains cannot enter the cell.
Why do electron microscopes have such high resolution ? 
Beams of electrons have a short wavelength
What is the main advantage to electron microscopes ? 
Can see small organelles
What are the disadvantages to electron microscopes ? 
only in black and white
specimen must be non-living
Must be in a vacuum
Name 3 key differences between transmission and scanning electron microscopes ? 
transmission creates 2D images, scanning creates 3D images
Transmission shows internal structures, scanning shows external structure
Transmission must have thin specimen, scanning it does not matter
Laser scanning confocal microscope = fluorescent microscope
How does a laser confocal microscope create its images ? 
The high light intensity illuminates the specimen stained with a fluorescent dye.
What are 3 benefits to laser confocal microscope ? 
high resolution image
depth selectivity
view sections of tiny structures
What are the 5 components of the nucleus ? 
nuclear envelope
nucleoplasm
nuclear pores
chromosomes
nucleolus
What is the function of the nucleus ? 
Site of ribosome synthesis
Contains DNA for each cell
Site of DNA replication and transcription
What is the function of nuclear pores ? 
Allow mRNA to pass out of nucleolus after transcription
What is the function of nucleolus ? 
Site of rRNA production and ribosome synthesis
Functions of flagella ? 
mobility
sensory organelle for chemical stimuli
Functions of cilia ?
Movement of substances
Sensory
What is centrioles made from ? 
Microtubules
What is a centrosome ? 
A pair of centrioles
Function of centrioles ? 
Spindle fibre formation and organisation of chromosomes in cell division
cytoskeleton = network of fibres found within the cytoplasm all over a cell
What is the function of cytoskeleton ? 
Cell/organelle movement
maintain shape
provides mechanical strength
Describe structure of smooth Endoplasmic reticulum ? 
folded membranes
Describe the structure of rough Endoplasmic reticulum ? 
Folded membrane studded with ribosomes
What is the function of smooth E.R? 
synthesis and storage of lipids/carbohydrates
What is the function of rough E.R ? 
Synthesis of proteins
Structure of the golgi apparatus ? 
Folded membrane, with a constant shape evolution due to vesicles binding and pinching off
Function of Golgi ? 
Storage, modification and packaging of proteins