Cellular Biology 1 Flashcards
What is the cell theory
A set of principles developed over time via multiple investigations. The discovery of the cell was made through the invention of the microscope between 1665-1838.
Cell Theory
There are 3 major parts of the cell theory:
All organisms are made of cells.
All existing cells are produced by other living cells.
The cell is the most basic unit of life.
Limiting factor of cell
Cell size is limited.
As cell size increases, it takes longer for materials to diffuse from the cell membrane to the interior of the cell
Surface area-to-volume ratio:
as a cell increases in size, the volume increases 10x faster than the surface area
Microscopes
Microscopes are required to visualize cells.
Light microscopes can resolve structures that are 200nm apart. (What is a nanometer?)
10,000,000 nm = 1 cm
Electron microscopes can resolve structures that are 0.2nm apart.
Contributors to the cell theory
Robert Hooke
Anton van Leeuwenhoek
Matthias Schleiden
Theodor Schwann
Rudolf Virchow
Robert Hooke
First scientist to use a microscope to see cellular structure. Came up with “cell” term from looking at cork.
- English Scientist
- Used the compound microscope to observe cork
- Hooke observed that cork is composed of small, hollow compartments
- The parts prompted Hooke to think of small rooms (cells) in a monastery, so he gave them the same names :CELLS
- Investigated cork through experimenting with the compound microscope and came up with the name cells
Anton van Leeuwenhoek
Helped create more power lens (270x) and discovered other living cells such as bacteria and protozoa
- Dutch Tradesmen
- Study new approaches for creating lenses to observe cloth
- Leeuwenhoek’s microscope was more powerful than Hooke’s compound microscope
- From investigating and experimenting with his microscope, Leeuwenhoek became one of the first scientists to refer to living cells when he observed an abundant number of single-celled organisms, which he called animalcules (plant & animals), swimming in a drop of pond water
Matthias schleiden
- German Scientist
- Fascinated with plant cells, Schleiden used the compound microscope and studied plant cells.
- From investigating and experimenting with plants, projected plant parts are made of cells!
- Discussed what he observed with his dear friend, German scientist Theodor Schwann.
Theodor Schwann
- German Scientist
- Studied plant & animal cells, and was intrigued by the similarities between the two.
- From investigating and experimenting with plant & animal cells, Schwann was able to determine that all animals are made of cells!
- Schwann published the 1st statement of the cell theory: all living things are made of cells and cell products!
Rudolf Virchow
Based on his investigations and experiments, he stated that all cells come from preexisting cells, which is the 2nd part of the cell theory: all existing cells are produced by other living cells!
Robert Hooke was the first person to see cells.
T
Bacteria cells have a cell membrane.
T
The Cell Theory was developed by a single scientist.
F
Plant cells have cytoplasm.
T
Cells taken from fungi do not have DNA.
F
Cells can only come from pre-existing cells.
T
It only took five years to develop the Cell Theory.
F
What is a prokaryotic cell?
Same bacteria have a tail-like structure called a flagella, that helps it to move
A capsule surrounds tome bacteria and helps them avoid the body’s immune system
Simple cells
Bacteria
These cells do not have a nucleus, their DNA is circular and floats in the cytoplasm
Pro = before; karyon = nucleus
Relatively small 5 - 10 um
Lack membrane-bound organelles
Earliest cell type
Characteristics of a Prokaryotic cell
No membrane bound organelles
DNA not enclosed in membrane bound nucleus
–> DNA is localized in a nucleoid region
Genome is one circular chromosomes
DNA is not associated with histones
Cell wall made of peptidoglycan
Divide by binary fission
Generally: Smaller & less complex than eukaryotic cells
What are archaeas?
Prokaryotes
Relatively small 5 - 10 um
lack membrane-bound organelles
Usually live in extreme environments (thermophiles, halophiles)
What is an eukaryotic cell?
Cells found in plants, animals, protists, and fungi.
The cell is composed of 4 main parts:
1. Cell membrane
2. Cytoplasm
3. Nucleus - “control center” of cell, DNA
4. Organelles - small structures that carry out specific functions (“little organs”)
Characteristics of an eukaryotic cell
Eukaryotic cells have a nucleus
Have many membrane-bound organelles (mitochondria, vacuole, endoplasmic reticulum, ribosomes, lysosomes, plastids in plants)
DNA contained in “linear chromosomes”
Cytoplasm present
Outer boundary is cell membrane except in plant cells - well made of cellulose
Cell membrane inside wall (plants)
Some have flagella/cilia for movement
Larger, more complex
Examples: protozoans, algae, fungi, plants, animals
the comparison traits between bacteria, archaea and eukaryotes (1)
Bacteria
Cell type: Prokaryotic
Cell Wall: Made of peptidoglycan
Sensitivity to antibiotics :Yes
First amino acid during protein synthesis: Formylmethionine
DNA: Mostly circular chromosome and plasmids
Histones: No
Organelles: No
Ribosomes: 70S
the comparison traits between bacteria, archaea and eukaryotes (2)
Archea
Cell type: Prokaryotic
Cell Wall: Does not contain peptidoglycan
Sensitivity to antibiotics : No
First amino acid during protein synthesis: Methionine
DNA: Circular chromosome and plasmids
Histones: Yes
Organelles: No
Ribosomes: 70S
