Patterns In Nature 1 Flashcards
State cell theory and describe evidence for its support
- All living matter is made up of one or more cells
- Shwann and Schleiden both agreed that plants and animals were made of cells. Schleiden stated that cells are the basic structures of all living things
- Durochet earlier stated that all plants and animals are made of cells
- the chemical reactions of a living organism take place within cells
- the invention of the electron microscope allowed scientists to see the internal structures of cells
- all cells are formed from pre-existing cells and these cells contain hereditary information
- Virchov proposed this earlier and Pasteur proved it with his swan-neck experiment
- Brown saw the nucleus in plant and animal cells for the first time.
Outline the historical development of cell theory.
1665- Robert Hooke uses the term cell for the first time while studying the surface of a cork and other plant materials
1675- Anton van Leeuwenhoek discovers unicellular organisms - “animacules” (bacteria)
1824- Rene Dutrochet states that all plants and animals are made up of cells
1831- Robert Brown reports of a nucleus in both animal and plant cells
1838- Matthias Scheiden concludes that plants are made of cells
1839- Theodore Schwann suggests that all animal cells are composed of one or more cells as well and the cell is the basic unit of that the structure of all living things
1858-Rudolph Virchov proposes that all cells arise of pre-existing cells, giving competition to the “spontaneous generation” theory
1862- Louis Pasteur disproves spontaneous generation with his swan-neck flask experiment
1930’s to twentieth century- electron microscope is invented by Ernst Ruska in 1933
Discuss the significance of technological advance to developments in cell theory.
The invention of the electron microscope allowed scientists for the first time to view the internal structures of a cell. Prior to this, scientists relied on other means to discover and compose the cell theory.
The cell theory would have never risen without the invention of the light microscope, which allowed Hooke to describe and use the term “cell” for the first time.
Without the rising of new technology, the microscope’s magnification would have never improved, and a closer and more accurate look at cells would have never been developed.
Identify cell organelles seen with current light and electron microscopes
Light ‘scope: cell wall, cell membrane, nucleus, chloroplast, vacuole, cytoplasm; (in non-school LM) nuclear membrane, Golgi body, mitochondria, nucleolus. (staining required)
Electron ‘scope: all structures of a light ‘scope plus endoplasmic reticulum, ribosomes, lyosomes centrosome and cytoskeleton. (staining required)
Describe the parts of a nucleus and its function.
- Control centre of the cell
- Contains chromosomes
- RNA (a messenger chemical) is exits via the porous double nuclear membrane
Nucleolus
- a dense granula region inside the nucleus
- it is responsible for the creation of ribosomes
Other parts:
- Nuclear pore (holes in the nuclear membrane)
- Nuclear sap
- Chromatin
Describe the parts of the mitochondria and its function.
- responsible for respiration - ATP
- double membrane increases surface area
Parts:
- Outer membrane
- Inner membrane
- Matrix (horizontal lines inside?)
- Crista (outer layer of the matrix)
- Particles adhering to the crista
Describe the parts of a chloroplast and its function.
- contains the green pigment chlorophyll
- responsible for photosynthesis
- light energy is trapped in the chlorophyll in the thylakoid membranes
Other parts:
- double membrane
- stroma (inside of a chlorophyll filled with stacks of thylakoids which are collectively called grana)
- lamella (streaks within the chloroplast, collectively known as a granum)
- starch grain
Describe the parts of the Endoplasmic Reticulum and its function.
- connects the cell membrane with the nuclear membrane
- involves the transport of materials
- rough ER is connected the nucleus and has ribosomes attached to it, unlike smooth ER.
Ribosomes: where the synthesis of protein occurs which involves the linking of amino acids in the correct sequence. Can be floating free or attached to ER. It has a small and large sub-unit.
Describe the parts of a Golgi body and its function.
- responsible for the packaging, storing and secreting of complex molecules e.g. saliva and sweat.
- flattened sacks shaped like a disc
Other parts:
- lyosome: bubbles from the Golgi body. These contain enzymes that dissolve substances/ invaders/ old particles in a cell and assist white blood cells.
- convex forming face
- vesicles (buds off from Golgi body)
