A2.2.1-A2.2.3 Cell Introduction & microscopy skills

What did the evolution of multicellular organisms allow?

The evolution of multicellular organisms allowed cell specialization and cell replacement

What are the three parts of cell theory

1. All living things are composed of cells.

2. Cells are the basic units of all living things.

3. New cells are

produced from preexisting cells.

What does mitosis result in?m

Mitosis results in genetically identical diploid daughter cells

What does meiosis generate

Meiosis generates haploid gametes (sex cells)

Haploid meaning

one set of 23 chromosomes

Diploid meaning

two sets of chromosomes, one from each parent

Who disapproved the theory of spontaneous generation

Pasteur disproved the theory of spontaneous generation with his experiments

How do prokaryotes divide

Prokaryotes divide through binary fission

Life functions

-nutrition

-homeostasis

-excretion

-growth

-response to stimulus

-reproduction

Who developed cell theory

-Robert hook is responsible for coining the term "cell" after looking at cork sections under a microscope

-Antonie van leewenhoek is considered the father of microbiology and master lens maker bc the lens he made and discovered animalcules in water

During what years what spontaneous generation the idea

Through the 1700s and 1800s, until Louis Pasteur disproved the idea in 1864 with his nutrient broth experiment

How did Robert remak discover cell division

In studying chicken embryos Robert REMAK discovered cell division under a microscope

What do scanning electron microscopes deliver?

Scanning electron microscopes deliver high resolution, 3D surface images of structures

What do transmission electron microscopes show

Transmission electron microscopes give us a view of inside cells and organelles

Mm to um (micrometers)

x1000

Um (micrometers) to nm

X1000

Magnification formula

Magnification= measured length/ scale bar label

Actual Size Calculation

Actual size= measured length/ magnification

If you have a scale bar and want to find the actual size:

then calculate the (actual size) x what the scale bar represents

How to calculate how many times an image has been magnified

-convert ruler to match scale bar unit

-next, step #1/ scale bar label

If your answer isn't in whole numbers what should u do

Convert till it's in whole numbers

What is fluorescence

Florescence is absorbance of light and re-emission at a longer wavelength

Fluorescent microscopes

Fluorescent microscopes have been developed with intense single wavelength light sources such as high power LED's or lasers. Light re-emitted by a stained sample generates particularly bright images

What is immunofluorescence used for?

Immunofluorescence is a technique for determining the location of an antigen or antibody in tissues by reaction with an antibody (or antigen) labeled with a fluorescent dye

What is produced from immunofluorescent staining

Antibodies that bind to a specific chemical in a cell are produced, a fluorescent marker is linked to the antibodies

How can multicolored fluorescent images be produced

Multicolored fluorescent images can be produced using multiple types of antibodies with fluorescent markers of different colors

What is TEM

Transmission electron microscopy

Compare electron vs light microscopes

Electron microscopes have a MUCH higher resolution than light microscopes because they use a beam of electrons instead of light waves, better magnification have allowed for scientists to to investigate ultra structure BUT Cells must be dead

What is resolution

Resolution is the ability of a microscope to show two close objects separately in the image

How much greater is the magnification of electron vs light microscopes

Electron microscopes can magnify 1000 times greater

Surface of nuclear envelope.

Inner membrane, outer membrane, nuclear pore

What is the function of nuclear pores

Nuclear pores regulate the entry and exit of molecules from the nucleus

How is the nucleus shape maintained

Nucleus shape is maintained by the nuclear lamina, a protein net lining the inside of the nucleus

What is freeze fracture electron microscopy

Freeze fracture electron microscopy is a technique used to produce images of surfaces within cells

Describe freeze fracture electron mucriscopy

1.A sample is plunged into liquified propane @ -190•C so it rapidly freezes

2. A steel blade is then used to fracture the frozen sample. The texture goes through the weakest points of the cell

3. A vapor of platinum or carbon is fired onto the fractured surface at an angle of ~35• to form a coating and this creates a replica of the surface

What does Cyro-EM do

Cryo-EM reveals structures of protein that maintains cell membranes. Used for researching the structure of proteins

Describe Cyro-EM

1.A thin layer of protein solution is applied to a grid and then flash frozen with liquid ethane @ -183•C to create smooth vitreous (like glass) ice and prevent formation of water crystals

2. The grid is placed in an electron microscope, and detectors record patterns of electrons transmitted by individual protein molecules

3. Computer algorithms produce a 3D image of the protein mc