CELLS
Cell theory
1. All living things are made up of cells
2. Cells are the smallest unit of life
3. All cells come from pre-existing cells
Exceptions to the cell theory (Atypical examples)
1. Striated muscle tissue: Multinucleated, very large
2. Aseptate fungal hyphae: Large, multinucleated
3. Giant algae: Very lage, uninucleated
Functions of life
- MR. H GREN
● Metabolism: Sum of all enzyme catalysed reactions
● Reproduction: Division
● Homeostasis: Maintaining internal environmental conditions
● Growth: Enlargement based on consumption
● Response: To external environment
● Excretion: Removal of metabolic waste
● Nutrition: Synthesis of organic molecules or absorption of organic
matter
Surface area : Volume
★ Rate of metabolic reactions depends on the volume
★ Rate of excretion/absorption depends on the surface area
● Small cells = big SA:V = more efficient because every unit of volume
that needs nutrients or produces waste has more surface area
membrane
● Big cells = small SA:V = less efficient because every unit of volume
has less surface area membrane
- Big cells have slow rate of substance absorption and excretion
due to larger diffusion pathway and concentration gradient
, Differentiation
● It is the expression of some genes but not others in order to carry out
a specific function
● All cells of an organism contain the entire genetic information but only
express some genes
- Gene expression = differentiation
Reproduction
Occurs in order to….
1. Replace damaged or dead cells
2. Growth
● Reproduced cells go through the process of differentiation to produce
different cell types (with different functions)
Stem cells
● Initially unspecialized cells that can divide and differentiate into
different types to carry out different functions
Types of stem cells
1. Tultipotent: can differentiate into ANY cell type
2. Pluripotent: can differentiate into MANY cell types
3. Multipotent: can differentiate into a FEW CLOSELY RELATED cell
types
4. Unipotent: Can differentiate only into ASSOCIATED cell type
Magnification
Cell theory
1. All living things are made up of cells
2. Cells are the smallest unit of life
3. All cells come from pre-existing cells
Exceptions to the cell theory (Atypical examples)
1. Striated muscle tissue: Multinucleated, very large
2. Aseptate fungal hyphae: Large, multinucleated
3. Giant algae: Very lage, uninucleated
Functions of life
- MR. H GREN
● Metabolism: Sum of all enzyme catalysed reactions
● Reproduction: Division
● Homeostasis: Maintaining internal environmental conditions
● Growth: Enlargement based on consumption
● Response: To external environment
● Excretion: Removal of metabolic waste
● Nutrition: Synthesis of organic molecules or absorption of organic
matter
Surface area : Volume
★ Rate of metabolic reactions depends on the volume
★ Rate of excretion/absorption depends on the surface area
● Small cells = big SA:V = more efficient because every unit of volume
that needs nutrients or produces waste has more surface area
membrane
● Big cells = small SA:V = less efficient because every unit of volume
has less surface area membrane
- Big cells have slow rate of substance absorption and excretion
due to larger diffusion pathway and concentration gradient
, Differentiation
● It is the expression of some genes but not others in order to carry out
a specific function
● All cells of an organism contain the entire genetic information but only
express some genes
- Gene expression = differentiation
Reproduction
Occurs in order to….
1. Replace damaged or dead cells
2. Growth
● Reproduced cells go through the process of differentiation to produce
different cell types (with different functions)
Stem cells
● Initially unspecialized cells that can divide and differentiate into
different types to carry out different functions
Types of stem cells
1. Tultipotent: can differentiate into ANY cell type
2. Pluripotent: can differentiate into MANY cell types
3. Multipotent: can differentiate into a FEW CLOSELY RELATED cell
types
4. Unipotent: Can differentiate only into ASSOCIATED cell type
Magnification
