Levels of Organisation and Cell Structure Flashcards
What are the levels of organisation in order?
- Organelles
- Cells
- Tissues
- Organs
- Organ Systems
- Organisms
What are organelles?
A component within a cell that carries out a specific function
Examples include chloroplasts and mitochondria
What are cells?
Basic functional and structural units in a living organism
- They make up a whole unicellular organism
- Examples include palisade mesophyll cells and sperm cells
What are tissues?
A group of cells of similar structure working together to perform a particular function
Examples include xylem and muscle
What are organs?
Made from a group of different tissues working together to perform a particular function
Examples include the heart and a leaf
What are organ systems?
Made from a group of organs with related functions working together to perform bodily functions within the organism
Examples include the digestive system and the root system
Which organelles are in every eukaryotic organism?
- Nucleus
- Mitochondria
- Ribosomes
- Cytoplasm
- Cell Membrane
Which organelles do plant cells have which animals cell do not have?
- Chloroplasts (containing chlorophyll)
- Permanent vacuole
- Cell wall
What is the function of the nucleus?
It contains the genetic material of the cell which controls how the cell grows and works, like cell divison
What is the function of the cytoplasm?
- The gel like fluid is the site of most chemical reactions in the cell (like anaerobic respiration)
- Provides a platform for organelles, allowing them to function and protecting them
What is the function of the cell membrane?
- Holds the cell together
- Controls which substances enter and leave the cell as it is selectively permeable
What is the function of the cell wall?
Gives the cell extra support and defines its shape
What is the function of chloroplasts?
- They are the site of photosynthesis, providing food for plants
- Contains chloropyll, which absorb light energy
What is the function of the permanent vacuole?
- Helps support the shape of the cell
- Storage of water and other materials, like cell sap
What is the function of mitochondria?
- It is the site of aerobic respiration
- Cells needing more energy will have more mitochondria
What is the function of ribosomes?
They are the site of protein synthesis
What is a specialised cell?
A cell within an organism which has adapted to perform a specific function through developing a different strucure and composition of subcellular structures (differentiation)
- Each cell in an organism will have the same genetic information, but only some of it will be used
- Examples include a sperm cell or a root hair cell
What are undifferentiated cells called?
Stem cells
When does most differentiation happen in animals?
When they are an embyro, although adult stem cells do exist in places such as the bone marrow
When does differentiation happen in plants and where do the stem cells come from?
Throughout their whole life via meristem tissue
How can stem cells be used in medicine?
- To grow new tissue and repair broken organs
- It can treat autoimmune diseases like diabetes
Why must an embryo grown through therapeutic cloning be used?
So that the stem cells are not rejected by the patients body
What are the benefits of using stem cells in medicine?
- Can treat a variety of diseases like diabetes
- Embyros grown through therapeutic cloning will produce stem cells which will not be rejected, like it does for organs which are donated
What are the medical risks associated with stem cell treatment?
- A virus could be transmitted from the stem cell cultured in the lab to the patient
- The cultured stem cell could develop mutations and become cancerous
What are the ethical issues with stem cell treatment?
- There is no saying who owns the embyro and who has rights over it
- Is it right to clone (playing god)?
- Should an embryo be treated as a person or not and is it truly alive?
