Level of organisation and Cell structure

What are the levels of organisation in organisms?

What are the levels of organisation in organisms?

What are the cell structures and their functions in both plants and animals?

CELL STRUCTURE	DESCRIPTION
NUCLEUS	Membrane-bound organelle that contains genetic material
CYTOPLASM	Material that fills cell to facilitate chemical reactions and hold organelles in place
CELL MEMBRANE	Phospholipid bilayer that controls the movement of substances into and out of cell
CELL WALL	External to cell membrane that protects and maintains the shape of cell (prevents cell from bursting)
MITOCHONDRIA	Membrane-bound organelle that carries out cellular respiration
CHLOROPLAST	Plastids in plants that carry out photosynthesis
RIBOSOME	Site of protein synthesis
VACUOLE	Storage organelle in plants to store Water and dissolved substances

What are the similarities and differences between plant and animal cells?

PLANT CELL	ANIMAL CELL
Multicellular organism
Nucleus
Mitochondria
Cytoplasm
Cell membrane
Fixed shape	No fixed shape
Large vacuole	Little or no vacuole
Cell wall	No cell wall
Stores carbohydrates as Starch	Stores carbohydrates as Glycogen
Contains Chloroplasts to conduct photosynthesis	Does not contain Chloroplasts (cannot conduct photosynthesis)

What is the importance of cell differentiation in the development of specialised cells?

CELL DIFFERENTIATION: Process involving the development of newly formed cells into more specialised and distinct cells as they mature

CELL DIFFERENTIATION

Diagram showing the production of Specialised Cells via Differentiation

IMPORTANCE OF CELL DIFFERENTIATION: All specialised cells and organs constructed from them have developed as a result of cell differentiation Undifferentiated cells receive signals which stimulates the expression of genes for cell to undergo change in metabolism and shape, enabling them to carry out specialised functions - forming a specialised cell Therefore, this allows organism to develop cells necessary to grow and develop as specialised cells can undertake specific functions For example, stem cells can differentiate into nerve cells to carry electrical impulses, hence allowing muscle movement

What are the advantages and disadvantages of using stem cells in medicine?

STEM CELLS: Unspecialised cells that has two key qualities:

• Self-renewal: capable of continuous division and replication

• Potency: capacity to differentiate into specialised cell type

STEM CELLS IN MEDICINE

Picture showing the use of Stem Cell Therapy to form Tissue

EXPLANATION: Cell types that are not capable of self-renewal are non-stem cells (e.g tissues) As these tissues cannot be regenerated or replaced, stem cells are a viable therapeutic option when these tissues are damaged

ADVANTAGES AND DISADVANTAGES:

ADVANTAGE	DISADVANTAGE
Medical benefits in therapeutic cloning to heal diseases and chronic illnesses	Ethical issues surrounding the use of embryonic stem cells involving the destruction of human embryos
Potential in discovering treatments and cures for diseases such as Parkinson's disease and cancer	Uncertainties regarding long-term effects
Ability to test potential drugs and medicine without the use of animals or human simulation	Rejection by the patient's body as certain stem cells are obtained from embryos instead of their own cells
Reduced risk of rejection as patient's own cells can be used	Difficulty in controlling differentiation of pre-specialised cells into desired cell