Organisation and Specialisation of Cells Flashcards
Why are cells specialised?
To carry out different roles and functions
How are erythrocytes specialised? (3)
- Flattened biconcave shape (increased SA:V) - For transporting O2 around the body
- Do not contain nuclei or organelles - increases space for haemoglobin
- Flexible - fit through capillaries
How are neutrophils specialised? (2)
- Multi-lobed nucleus - easier to squeeze through small gaps to get to site of infection
- Contains many lysosomes - contain enzymes to attack pathogens
How are sperm cells specialised? (3)
- Have flagellum- capable of movement
- Many mitochondria - supply energy for movement
- Acrosome on head - contains digestive enzymes to digest protective layers around ovum and allow to penetrate
How are palisade cells specialised? (4)
- Chloroplasts - photosynthesis and can move to catch more sunlight
- Rectangular box shapes - can closely pack to form continuous layer
- Thin cell wall - increases rate of diffusion
- Large vacuole - maintain turgor pressure
How are root hair cells specialised? (1)
Root hairs - long extensions that increase SA:V - Maximise water uptake
How are guard cells specialised? (1)
Can lose water - during water loss, it can absorb more water and swell to close the stomata and reduce any further water loss
What are the four main categories of tissue in animals?
- Nervous tissue
- Epithelial tissue
- Muscle tissue
- connective tissue
How is squamous epithelium specialised? (2)
- One cell thick and very thin - increase rate of diffusion
- Found in lungs - diffusion of O2
How is ciliated epithelium specialised? (2)
- Cilia - moves in rhythmic manner to sweep away mucus
- Goblet cells - produce mucus to trap dust and pathogens
How is cartilage specialised? (5)
- Firm and flexible connective tissue
- Composed of chondrocyte cells
- Prevents the ends of bones from rubbing against each other and causing damage
- Made of elastin and collagen
- Many fish have cartilage instead of bones
How is muscle specialised? (2)
- Skeletal muscles contain myofibrils (contain contractile proteins)
- Many mitochondria - max respiration for energy
How is the epidermis specialised? (3)
- Covered by waxy layer - reduce water loss
- Stomata can open and close to control diffusion and water loss
- Thin - allow light to go through to palisade layer
How is xylem tissue specialised? (2)
- Lignin - waterproof and provides structural support
- Hollow - act as vessels
How is phloem tissue specialised? (2)
- Sieve tube cells - control the direction and flow of sugars
- Companion cells - carry out cell processes as it hasn’t got space or organelles to do it itself
