Cell structure Flashcards
What is magnification?
Magnification is how much bigger an image appears compared with the original object. Magnification produced by microscopes is LINEAR
What is resolution?
Resolution is the ability of an optical instrument to see or produce an image that shows fine detail
How do you calculate total magnification?
Total magnification = eye piece magnification x objective lens magnification
How do you calculate image size? What is the equation triangle?
Image = Actual size x magnification
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What is a optical microscopes resolution and magnification?
Optical microscopes = x1500 and resolution of 200nm (cant distinguish objects closer than this)
What are the advantages and disadvantages of optical microscopes?
Optical microscopes advantages:
Cheap, easy to use, portable, can study whole live specimens
Disadvantages:
Low resolution and magnification
What is the resolution of electron microscopes?
Electron microscopes have a wavelength of 0.004nm
Discuss transmission electron microscopes
Transmission electron microscopes chemically fix their specimens (dehydrate and stain). Electrons [ass through the specimen. They have a magnification of 2-50 million times
What image to transmission electron microscopes produce?
Transmission electron microscopes produce a 2D black and white image called an electron micrograph
What type of image does a scanning electron microscope produce?
Scanning electron microscopes produce a black and white 3D image
How do scanning ekecetron microscopes work?
Scanning electron microscopes use electrons that bounce off the specimen after it has been fixed and covered in a film of metal. This occurs in a vacuum.
How do laser scnanning microsopes work and whatvare their advantages?
laser scanning microscopes (confocal) scan the objects point by point. The advantages are:
High resolution and contrast image, theyhave depth electivity and so can study whole live specimens
How would you study a live specimen?
Studying a live specimen:
- School light microscope and adjust the iris diaphragm to reduce illumination of specimen.
- use light interference and a dark background to observe them
How do you prepare a slide?
Preparing slides:
- dehydrate
- embed in wax
- slice sections
What are 5 stains and what do they show?
Stains:
- Methyline blue - general
- acetic orsein- DNA stained red
- Eosin- stains cytoplasm pink
- sudan red- stains lipids
- iodine- cell walls yellow and starch blue
What is the scale used for microscopes?
The scale used is logarithmic meaning it goes up in steps where there is a 10 fold increase
what organisms are eukaryotic?
Animal cells, plant cells, fungi cells and protoctista are all examples of eukaryotic cells
What are some similarities between animals and plant cells?
Similarities between animal and plant:
Nucleus, nucleolus, ribosomes, mitochondria, endoplasmic reticulum Golgi, plasma membrane, vesicles
Where are some differences between animal and plant cells?
Differences between animal and plant:
- Plants have vacuole
- plants have chloroplasts
- plants have amyloplasts containing starch
- plants have a cell wall
What is the structures and functions of nucleus?
Nucleus:
- nuclear envelope with pores, chromatin, nucleolus
- stores genetic information, provides instructions for protein synthesis
What is the definition of chromatin?
Chromatin- DNA packaged with histone proteins
What is the structure and functions of Rough ER
Rough ER:
- Cisternae provide large surface area for ribosomes
- ribosomes for protein synthesis
What is the structure and functions of smooth ER
Smooth ER:
- cisternae
- lipid metabolism, synthesis of cholesterol steroid hormones lipids and phospholipids and absorption and transport of lipids
What is Golgi structure and function?
Golgi:
- Near vesicles , membrane bound flattened sacs
- protein modification (adding sugars or lipids), folding of proteins and packaging into vesicles for storage or movement
