Specialised Cells Flashcards
What are the levels of organisation in multicellular organisms?
Cells are differentiate to form specialised cells adapted for specific functions
What are organ systems in multicellular organisms?
Groups of organs performing complex functions
Example: circulatory, nervous, respiratory.
What are organs in multicellular organisms?
Two or more tissues working together for a specific function
Example: heart, kidney, leaf.
What are tissues in multicellular organisms?
Groups of similar cells carrying out a particular function
Example: epithelia, muscle, cartilage.
What are organs in multicellular organisms?
Two or more tissues working together for a specific function.
Example: heart, kidney, leaf.
What are the advantages of cell specialisation?
- Increases efficiency
- Adapted to perform their specific function
What are the disadvantages of cell specialisation?
- Cells are dependent on others for their survival
- Unable to carry out all essential life processes.
- Supporting specialised cells requires organisms to develop complex organ systems
How do all specialised/differentiated cells have different functions?
- All cells contain the same genes but only certain genes are expressed- switched on
- Only specific genes are switched on to make a specific protein
Example: Red blood cells (erythrocytes) switch on the gene for the protein haemoglobin.
Why don’t red blood cells divide when mature?
They have no nucleus
How are red blood cells specialised for their function?
- Function: to transport oxygen and carbon dioxide around the body
- Contain haemoglobin
- Bi-concave, flattened disc shape
- Have no nucleus to make more room for maximum haemoglobin and therefore oxygen
- Large surface area to volume ratio for efficient diffusion
- Short diffusion distance to the centre of the cell
- Really flexible so able to squeeze through narrow blood vessels
How are squamous epithelial cells adapted for their function?
- They line exchange surfaces- e.g. alveoli
- Thin and flattened to maximise diffusion of O₂/CO₂ by reducing diffusion distance
How are ciliated epithelial cells adapted for their function?
- Function: Line the upper respiratory tract
- Contain cilia
- Beat rhymically which moves mucus containing trapped particles- e.g., dust and pathogens -out of the lungs
- Have more mitochondria compared to squamous epithelial cells.
What are the three types of muscle?
Skeletal muscles:
- Function: Moves the skeleton under voluntary control
- Cells fused into striated myofibres
- Attached to bones by tendons/ligaments
Cardiac muscles:
- Cells branched and organised in striated fibres
- Found only in the heart
- Involuntary (autonomic) control
Smooth muscle:
- Individual cells
- Found in walls of internal organs- e.g. intestines - Involuntary (autonomic) control
- Sower speed than skeletal and cardiac muscle
Why do skeletal and cardiac muscles have striations?
Due to the fact that they have many myofibres
How are sperm cells specialised for their function?
- Function: To fertilise the egg
- Streamlined shape and tail to easily swim towards the egg
- Lots of mitochondria to release energy to power the tail for movement
- Contain enzymes in the acrosome to penetrate the egg cell’s jelly coat membrane
What is the function of phagocytes?
- To engulf and digest pathogens
- Most common are neutrophiles and macrophages
How are phagocytes adapted for their function?
- Large nucleus to synthesise proteins and enzymes
- Can change shape for phagocytosis
