Cell Theory + Specilisation

Processes of life

Metabolism, Growth, Reproduction, Response to Stimuli, Homeostasis, Nutrition, Excretion, Movement

Metabolism

the sum of all the chemical reactions that occur within an organism

Growth 

the development of an organism 

Reproduction 

the ability to produce an offspring 

Stimuli

as the environment changes, the organism adapts,

Homeostasis

maintenance of a constant internal environment

Nutrition 

the ability to acquire the energy and materials needed to maintain life 

Excretion

the ability to acquire the energy and materials needed to maintain life

Movement

the ability to move or change position

Cells 

smallest structures of life with all properties of life 

Three points of cell theory

all living organisms are composed of one or more cells

cell is the basic unit of structure and function in living organisms

all cells arise from pre-existing cells

Who was cell theory developed by? 

Robert Hooke, Theodore Schwann, Matthias Scheldem 

Exceptions to cell theory

Viruses — non cellular

Red blood cells - lack nucleus

Multinucleated muscle fibres - contain multiple nucleus

Define atypical cells

cells that deviate from typical structures or characteristics expected based on cell theory

Unicellular 

a single celled organism that carries out essential processes of life 

Multicellular

an organism composed of more than one cell that functions as a single unit,

Tissue

A group of similar cells working together to carry out a functionO

Organ 

structure composed of different types of tissues that work together to perform specific functions.

Organ System 

group of organs that cooperate to carry out a major bodily function.

Organism

The highest level of specialization is the complete living organism, which is composed of multiple interacting organ systems. 

Stem Cells

Unspecialised cells that can differentiate and become specialised

Fertilization

A sperm cell and an ovum fuse to make a zygote

Define Potency:

Stem cells have the ability to differentiate into specialized cell types depending on the signals they receive.

When does differentiation occur?

occurs when different cells express different genes 

> All the __________ cells of a multicellular organism contain the same ________ information 

> But cells in __________ tissues perform different __________ 

> Cells in different tissues have different ________

Therefore some genes are ____________ in some cells but not others. 

somatic genetic

different functions

forms

expressed

Totipotent

Cells can become any cell type ixcluding extra - embryonic cells

they may form a complete organism

Pluripotent 

can form all cell types in the organism not including extra - embryonic cells 

cannot form a complete organism 

Multipotent

can generate several related types of cells

Unipotent

only forms single cell type

usally form in the embryonic stage and exist in the functioning organism

How can unspecialised cells differentiate into stem cells?

Mitosis

Two types of stem cells

Embryonic Stem Cells

Adult Stem Cells

Cell Specialization

 allows cells to perform a particular function more efficiently. 

^>Cells create different ________ needed to carry out different _________ processes and form different __________, 

> Proteins are coded for by _______.  

proteins metabolic structures

genes

What causes differentiation?

Cells differentiate according to their position in the embryo, 

Messengers are released by group of cells called organisers. 

The surrounding cells develop into a particular type of cell

Differentiation during embryonic development: 

Position of the cell within the embryo determines how it differentiates

Signaling chemicals called morphgens affect gene expression and control the differentiation of the cell. 

How do morphogens control differentiation?

Having different effects dependent on their concentration

When do morphogens control differentiation?

Embryonic development — coordinate the formation of tissues and organs.