chapter 1, unit 2. cell theory and imaging technology.

Question 1

what did Hans and Zacharias Janssen contribute to microscopy?

Answer 1

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

Question 2

what was the magnification of Hans and Zacharias Janssen’s microscope?

Answer 2

it was 20x.

Question 3

what did Robert hook contribute to microscopy?

Answer 3

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”.

Question 4

what is a compact microscope?

Answer 4

one containing 2 or more lenses.

Question 5

what did antoni van leeuwenhoek contribute to microscopy?

Answer 5

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.

Question 6

francesco redi experiment in 1668.
what was it intended to provide evidence against? and how were they conducted?

Answer 6

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.

Question 7

louis Pasteur’s experiments in 1864:
what did they prove? how was it conducted?

Answer 7

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.

Question 8

what did robert brown contribute to cell theory?

Answer 8

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.

Question 9

what did m.j Schleiden contribute to cell theory? (1838)

Answer 9

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.

Question 10

what did Schleiden and Schwann propose about plants and animals? ( 1838)

Answer 10

All plants and animals are composed of cells and the cell is the most basic unit of life.

Question 11

what did rudolph virchow (1859) state?

Answer 11

stated that all cells arise only from pre-existing life/ cells/

Question 12

what does cell theory state?

Answer 12

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.

Question 13

what are viruses composed of?

Answer 13

viruses are composed of genetic material and a protein coat. `

Question 14

define magnification

Answer 14

increasing the size of an image produced.

Question 15

define contrast

Answer 15

ability to distinguish between structures of a cell.

Question 16

define resolution

Answer 16

ability to distinguish between two parts close together.

Question 17

how can you improve contrast?

Answer 17

you can use stains which usually kill the cells or you can manipulate the light source.

Question 18

what is the closet two parts can be that the human eye can still distinguish between?

Answer 18

0.1mm or larger.

Question 19

limit of resolution of a standard light microscope

Answer 19

0.0000006 mm or larger. anything more and the light blurs.

Question 20

when was confocal microscope developed?

Answer 20

in the 1980s.

Question 21

describe a confocal microscope.

Answer 21

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.

Question 22

what protein is used in a confocal microscope?

Answer 22

specimens are coated in a fluorescent green to produce images. this protein glows green under ultraviolet light.

Question 23

who developed the first electron microscope and when?

Answer 23

james hillier and albert prebus did. they developed it in the 1930s.

Question 24

what is a body tube on a microscope

Answer 24

the body tube is the tube attached to the eye piece.

Question 25

what is the arm of a microscope

Answer 25

the arm is the part attached from where all the lenses are to the stage. it looks like a neck

Question 26

what is the stage of a microscope?

Answer 26

the stage is the part you place the specimen on.

Question 27

what is the revolving nose piece of a microscope?

Answer 27

it is the part that all of the objective lenses are connected to. it rotates.

Question 28

what is the condenser/ diaphragm on a microscope?

Answer 28

the part below the stage that directs the light onto the specimen.

Question 29

what is the base on a microscope?

Answer 29

the part at the very bottom.

Question 30

where is the course adjustment knob on a microscope?

Answer 30

it is slightly above the fine adjustment knob. is it likely larger.

Question 31

where is the fine adjustment knob on a microscope?

Answer 31

below the course adjustment knob. it is smaller.

Question 32

where is the iris diaphragm on a microscope?

Answer 32

below but still connected to the stage condenser.

Question 33

where is the stage condenser?

Answer 33

above but still connected to the iris diaphragm and stage.

Question 34

define gene mapping

Answer 34

the study of the molecular structure of DNA and map the genomes of various species.

Question 35

cell communication

Answer 35

scientists can observe molecules involved in communication between cells using green fluorescent protein technology. e.g hormones, neurotransmitters.

Question 36

define prokaryotic cells

Answer 36

cells without nuclei (e.g bacteria)

Question 37

define eukaryotic cells

Answer 37

cells with nuclei and more complex organelles.

Question 38

what elements are found in cells?

Answer 38

carbon, hydrogen, oxygen, and nitrogen.

Question 39

what role do carbohydrates play in the cell. give examples of carbohydrates.

Answer 39

they supply energy to the cells. e.g sugar, starch, cellulose,

Question 40

what role do lipids play in cells? provide examples of lipids.

Answer 40

they serve as structural components of cell membranes, function as energy storehouses, and function as important signaling molecules. e.g fats and oils.

Question 41

what role do proteins have in cells? give examples of proteins.

Answer 41

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

Question 42

what role do nucleic acids have in cells? give examples

Answer 42

carry genetic information which is read in cells to make the RNA and proteins by which living things function.. e.g DNA and
RNA

Question 43

what role does the cell membrane serve in the cell?

Answer 43

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.

Question 44

what role does the nucleus serve in the cell?

Answer 44

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.

Question 45

what role does the cytoplasm serve in the cell?

Answer 45

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.

Question 46

define cell wall and where it is found.

Answer 46

found in plants, some bacteria, protists, and fungi. it is a rigid frame around the cell that provides strength and support.

Question 47

define chloroplasts and where they are found.

Answer 47

they are the site of photosynthesis. they are found in plants, some protists, and fungi.

Question 48

what is the chemical formula of photosynthesis?

Answer 48

co2+ h2O + light energy = c6H12O6+O2

Question 49

what role do centrioles serve and where are they found?

Answer 49

they are involved in cell division. they are only found in animal cells.

Question 50

what role to vascuoles and vesicles have in the cell?

Answer 50

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.

Question 51

are vascuoles found in plant or animal cells?

Answer 51

they are found in plant cells.

Question 52

are vesicles found in plant or animal cells?

Answer 52

they are found in animal cells.

Question 53

what role do lysosomes play?

Answer 53

they are sacs in the cell that contain strong chemicals which break down and recycle meterials.

Question 54

what role do ribosomes play in the cell?

Answer 54

they are granules which can be attached to the endoplasmic reticulum or floating in the cytoplasm. they are the site of protein synthesis.

Question 55

what role do endoplasmic reticulum play?.

Answer 55

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.

Question 56

what role does golgi apparatus play?

Answer 56

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.

Question 57

what role does the mitochondria play in the cell?

Answer 57

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.