chapter 1, unit 2. cell theory and imaging technology. Flashcards
what did Hans and Zacharias Janssen contribute to microscopy?
they invented the first compound microscope in 1595. it was a 2 lens system consisting of an ocular lens and an objective lens. it was the first compound light microscope. it had a magnification of 20x
what was the magnification of Hans and Zacharias Janssen’s microscope?
it was 20x.
what did Robert hook contribute to microscopy?
in 1665 he creatd a 3 lens system consisting of an ocular lens, a field lens, and an objective lens. he observed cork at about 30x magnification and noted tiny chambers which he called “ cells”.
what is a compact microscope?
one containing 2 or more lenses.
what did antoni van leeuwenhoek contribute to microscopy?
he developed a single lense microscope that could magnify up to 250x. he observed living cells such as bacteria, unicellular protozoa, and sperm. he called them animalcules.
francesco redi experiment in 1668.
what was it intended to provide evidence against? and how were they conducted?
the experiment was meant to provide evidence against spontaneous generation. the experiment involved a jar with meat in it. to show that flies do not appear, they must be allowed in.
louis Pasteur’s experiments in 1864:
what did they prove? how was it conducted?
these proved the theory of biogenesis. he conducted this experiment by putting broth in a flask and boiling it, one of the flasks did not have access to oxygen while the other did.
what did robert brown contribute to cell theory?
in 1833 he used a single lens microscope to observe the nuclei in orchid cells and recognized that this cell structure must have been important to the cell function.
what did m.j Schleiden contribute to cell theory? (1838)
he observed that all plants are composed of cells containing a nucleus. he proposed that the nucleus was responsible for the development of the remainder of the cell. discussed his findings with his friend, Theodore schwann. schwann found similar structures in cells.
what did Schleiden and Schwann propose about plants and animals? ( 1838)
All plants and animals are composed of cells and the cell is the most basic unit of life.
what did rudolph virchow (1859) state?
stated that all cells arise only from pre-existing life/ cells/
what does cell theory state?
1) all living things are made up of one or more cells and the materials produced by these cells.
2) all life functions take place in cells. making them the most basic unit of life.
3)all cells are produced through preexisting cells through the process of cell division.
what are viruses composed of?
viruses are composed of genetic material and a protein coat. `
define magnification
increasing the size of an image produced.
define contrast
ability to distinguish between structures of a cell.
define resolution
ability to distinguish between two parts close together.
how can you improve contrast?
you can use stains which usually kill the cells or you can manipulate the light source.
what is the closet two parts can be that the human eye can still distinguish between?
0.1mm or larger.
limit of resolution of a standard light microscope
0.0000006 mm or larger. anything more and the light blurs.
when was confocal microscope developed?
in the 1980s.
describe a confocal microscope.
1) a laser concentrates light onto a specimen.
2) the reflection is passed through a tiny opening called the confocal pinhole and reaches an electronic detector that converts the light into an image.
3)only the light returning from a specific place reaches the pinhole
4) a section is developed in high resolution
5) multiple parts are added together to create a high resolution image.
what protein is used in a confocal microscope?
specimens are coated in a fluorescent green to produce images. this protein glows green under ultraviolet light.
who developed the first electron microscope and when?
james hillier and albert prebus did. they developed it in the 1930s.
what is a body tube on a microscope
the body tube is the tube attached to the eye piece.
what is the arm of a microscope
the arm is the part attached from where all the lenses are to the stage. it looks like a neck
what is the stage of a microscope?
the stage is the part you place the specimen on.
what is the revolving nose piece of a microscope?
it is the part that all of the objective lenses are connected to. it rotates.
what is the condenser/ diaphragm on a microscope?
the part below the stage that directs the light onto the specimen.
what is the base on a microscope?
the part at the very bottom.
where is the course adjustment knob on a microscope?
it is slightly above the fine adjustment knob. is it likely larger.
where is the fine adjustment knob on a microscope?
below the course adjustment knob. it is smaller.
where is the iris diaphragm on a microscope?
below but still connected to the stage condenser.
where is the stage condenser?
above but still connected to the iris diaphragm and stage.
define gene mapping
the study of the molecular structure of DNA and map the genomes of various species.
cell communication
scientists can observe molecules involved in communication between cells using green fluorescent protein technology. e.g hormones, neurotransmitters.
define prokaryotic cells
cells without nuclei (e.g bacteria)
define eukaryotic cells
cells with nuclei and more complex organelles.
what elements are found in cells?
carbon, hydrogen, oxygen, and nitrogen.
what role do carbohydrates play in the cell. give examples of carbohydrates.
they supply energy to the cells. e.g sugar, starch, cellulose,
what role do lipids play in cells? provide examples of lipids.
they serve as structural components of cell membranes, function as energy storehouses, and function as important signaling molecules. e.g fats and oils.
what role do proteins have in cells? give examples of proteins.
Proteins are responsible for nearly every task of cellular life, including cell shape and inner organization, product manufacture and waste cleanup, and routine maintenance. Proteins also receive signals from outside the cell and mobilize an intracellular responses. e.g muscles, hormones, dna
what role do nucleic acids have in cells? give examples
carry genetic information which is read in cells to make the RNA and proteins by which living things function.. e.g DNA and
RNA
what role does the cell membrane serve in the cell?
it serves as a protective barrier for the cell. it allows the transport of needed materials into the cell and waste materials out. it allows for cell communication and the recognition of molecules.
what role does the nucleus serve in the cell?
it contains DNA - the genetic material of the cell that directs all cellular activities. it is surrounded by the nuclear envelope, which has pores to allow the transport of materials into and out of the nucleus.
what role does the cytoplasm serve in the cell?
it is a gel-like substance inside of the cell membrane. it contains the nutrients required to carry on the life processes. the organelles are suspended in the cytoplasm. it allows for cytoplasmic streaming- movement of organelles and molecules within the cell.
define cell wall and where it is found.
found in plants, some bacteria, protists, and fungi. it is a rigid frame around the cell that provides strength and support.
define chloroplasts and where they are found.
they are the site of photosynthesis. they are found in plants, some protists, and fungi.
what is the chemical formula of photosynthesis?
co2+ h2O + light energy = c6H12O6+O2
what role do centrioles serve and where are they found?
they are involved in cell division. they are only found in animal cells.
what role to vascuoles and vesicles have in the cell?
they are bound by the membrane. they are the sites for the storage of nutrients, products of secretion, fats, and water. plant cells have large vascuoles and animal cellshave small vesicles.
are vascuoles found in plant or animal cells?
they are found in plant cells.
are vesicles found in plant or animal cells?
they are found in animal cells.
what role do lysosomes play?
they are sacs in the cell that contain strong chemicals which break down and recycle meterials.
what role do ribosomes play in the cell?
they are granules which can be attached to the endoplasmic reticulum or floating in the cytoplasm. they are the site of protein synthesis.
what role do endoplasmic reticulum play?.
A series of tubes extending from the nuclear envelope surrounding the nucleus. rough endoplasmic reticulum is associated with protein synthesis. smooth endoplasmic reticulum is associated with lipid production.
what role does golgi apparatus play?
flat, disc like sacs involved in modifying and packaging substances to be transported from the endoplasmic reticulum for use in the cell or out of the cell.
what role does the mitochondria play in the cell?
the site of cellular respiration where chemical energy in sugar is converted into ATP energy that the cell can use for growth , transport, repair, and movement.
