Biology Chapter 4 Flashcards
first described a cell in 1665
Robert Hooke
He was the first to describe living cells; discovered bacteria, protists, bloods cells and sperm cells
Antoine van Leeuwenhoek
What are 3 things all cells share?
plasma membrane, nucleus, cytoplasm
Developed the 1st modern cell theory in 1838
Matthias Schleiden
What are the 3 principles of the modern cell theory?
- Cells are the smallest living things; they are the basic unit of organization in all organisms
- All organisms are composed of one or more cells, metabolism and heredity occur within these cells.
- cells arise only by the division of previously existing cells, basically this means the life only started once
Why are cells microscopic?
Cells are able to synthesize quicker when they are small through diffusion, and cells can easily communicate when they are small.
When expanding the radius of a cell, which component expands faster and greater?
Volume
These are the most primitive type of cells, lacking a membrane bound nucleus and membrane bound organelles
prokaryotes
Prokaryotic cell walls are made of this cross linked complexes of carbohydrates and proteins
peptidoglycans
True or False. Archaebacteria have peptidoglycans in their cell wall.
False
network of tubes and fibers that supports cell and anchors the organelles, a scaffolding for the cell
cytoskeleton
found in plant cells, made of cellulose thick impermeable walls
cell walls
The ___ stores DNA which directs all cell biochemistry and has the blueprints for making more cells.
Nucleus
In the center of the nucleus is the __, where there is a lot of synthesis of ribosomal RNA (rRNA)
Nucleolus
2 lipid bilayers surrounding the nucleus
nuclear envelope
The area where the 2 lipid bilayers in the nucleus fuse to form a small hole
nuclear pore
Describe the molecular channels in the nucleus.
There are only 2 kinds of molecules that are allowed passage to and from the nuclear pore.
1- proteins moving into the nucleus to be incorporated with nuclear structures
2- RNA and RNA proteins moving out of the nucleus into the cytoplasm
What is the shape of DNA in eukaryotic cells?
linear
What is the shape of DNA in prokaryotic cells?
ring
When DNA is found in linear structures in the cell
chromosome