Cells and Transport

Eukaryotes and Prokaryotes

• eukaryotes have a nucleus and other cell bound organelles
• prokaryotes do not have a nucleus or mitochondria. Instead, they have a plasma-ring of DNA
• eukaryotes are much bigger
• eukaryotes are animals, plants, algae (protoctista), fungi
• prokaryotes are bacteria

Animal and Plant Organelles

• nucleus - contains genetic material and controls activities of cell
• cell membrane - controls substances that go in and out. Holds cell and protects
• cytoplasm - jelly like substance where chemical reactions occur
• mitochondria - provides energy (ATP) 
• ribosomes - provides and makes proteins
• vesicles - take things in or releases

Extra Plant Organelles

• cell wall - keeps structure of cell and supports/protects
• chloroplasts - contains green pigment (chlorophyll) to absorb light energy (photosynthesis)
• vacuole - stores water and minerals to keep cell firm (contains cell sap)

Specialist Cells

• systems supply the cell's needs and remove waste products
• they keep internal environement surrounding cell constant
• specialist cells are adapted to a particular function
• tissues are groups of specialist cells
• tissues fold together to make an organ
• a system is different organs working together

Examples of specialised cells are root hair cell, palisade cell, nerve cell, fat cells, sperm cell.

Cell Differentiation

Differentiation is the process of a cell changing from one cell type to another, for example, becoming from a less specialised cell type to a more specialised cell type

• an undifferentiated cell is one which is not specialised (yet)
• a differentiatied cell is one which has become specialised

Stem Cells

Stem cells are a class of undifferentiated cells that are able to differentiate into specialised cell types

Embryonic Stem Cells

• embryonic stem cells can turn into any specialised cell. They can be harvested from donated embryos formed by invitro fertilisation (IVF)
• an embryonic stem cell is removed from an embryo and cultured to give a mass of undifferentiated stem cells.
• Then they can be cultured to develop new differentiated tissues or organs

Adult Stem Cells

• adult stem cells are found in the blood and bone marrow. They can become many specialised cells (but not as many as embryonic). 
• adult stem cells are removed from tissue in blood and bone marrow and cultured to give a mass of them
• then they are further cultured to develop new tissue or organs or they are injected back inside patient to produce new tissue where needed.

Microscopy

• resolution is how…