the origin of cells
Cells can only be formed by division of pre-existing cells
note: this is proved by Louis Pasteur in his experiment, that is the only way cells are formed. This division is called mitosis
The first cells must have arisen from inorganic material.
note: This is proved by Miller Urey in his experiments
The origin of eukaryotic cells can be explained by the endosymbiotic theory
note: where two prokaryotic cells form one eukaryotic
note: this is proved by Louis Pasteur in his experiment, that is the only way cells are formed. This division is called mitosis
The first cells must have arisen from inorganic material.
note: This is proved by Miller Urey in his experiments
The origin of eukaryotic cells can be explained by the endosymbiotic theory
note: where two prokaryotic cells form one eukaryotic
the cell theory
- Living organisms are composed of cells.
- Cells are the smallest unit of life.
- Cells come from pre-existing cells.
The cell theory exceptions/limitations are the muscles and Fungal hyphae because they are multi-nucleated, and the Giant algae.
source: Biology class.
louis pasteur
• He made a nutrient broth by boiling water containing yeast and sugar, which had a swan-necked flask when he remove it he could see the microorganism that he could never have seen with the swan neck on. He proved that cells only come from
pre-existing cells.
pre-existing cells.
source: biology class
recipe for the origin of life
1)The synthesis of simple organic molecules (amino acids) from inorganic molecules (water, carbon dioxide, ammonia)
2)The assembly of these molecules into polymers (e.g. polypeptides from amino acids)
3)Formation of polymers that can self-replicate to allow for inheritance of characteristics
4)Development of membranes with internal chemistry different from their surroundings
2)The assembly of these molecules into polymers (e.g. polypeptides from amino acids)
3)Formation of polymers that can self-replicate to allow for inheritance of characteristics
4)Development of membranes with internal chemistry different from their surroundings
how do life began?
Miller's experiment showed that organic compounds such as amino acids, which are essential to cellular life, could be made easily under the conditions that scientists believed to be present on the early earth.
note: Miller showed that by making reactions with some chemicals you can imitate the conditions where live come from, that was in the first years of the earth. Prove that live arrive in the early earth.
note: Miller showed that by making reactions with some chemicals you can imitate the conditions where live come from, that was in the first years of the earth. Prove that live arrive in the early earth.
source: http://people.chem.duke.edu/~jds/cruise_chem/Exobiology/miller.html
endosymbiotic theory
Theory that chloroplasts and mitochondria were once free living prokaryotes that were engulfed by larger prokaryotes and survived to evolve into modern organelles. It explains their origin and their double membranes. This concept postulates that chloroplasts and mitochondria are the result of years of evolution initiated by the endocytosis of bacteria and blue-green algae. According to this theory, blue green algae and bacteria were not digested; they became symbiotic instead.
note: Evidence for this theory is that the chloroplast and mitochondria has double membrane, their own DNA and ribosomes.
note: Evidence for this theory is that the chloroplast and mitochondria has double membrane, their own DNA and ribosomes.
source: http://biology.kenyon.edu/HHMI/Biol113/the%20endosymbiotic%20theory.htm
the cells carry out all functions necessary for life
Metabolism: chemical reactions inside the cell, including cell respiration to release energy
Sensitivity: perceiving and responding to changes in the environment
Homeostasis: controlling conditions inside the cell
Growth: an irreversible, increasing in size
Reproduction: producing offspring
Nutrition: obtaining food
note: All this functions are tied together to produce the functioning living unit
source: Biology class.