Flashcards in Organisation and specialisation of cells Deck (19):
What are differentiated cells?
-Cells are specialised to carry out a specific function.
What is the organisation of a multicellular organism?
How are erythrocytes specialised?
-Red blood cells have flattened biconcave shape which increases SA:V, essential for transporting blood.
-No nuclei or organelles so increased space for haemoglobin.
-Flexible so can squeeze through narrow capillaries.
How are neutrophils specialised?
-White blood cells have multi-lobed nucleus which makes it easier to squeeze through small gaps to get to infection site.
-Granular cytoplasm contains lysosomes that contain enzyme to attack pathogens.
How are sperm cells specialised?
-Have tail or flagellum to help with movement.
-Contain mitochondria to supply energy to swim.
-Acrosome on head contain digestive enzymes to digest ovum.
How are palisade cells specialised?
-Chloroplasts for photosynthesis.
-Rectangular shaped so can be closely packed together.
-Thin cell walls which increase rate of CO2 diffusion.
-Large permanent vacuole to maintain turgor pressure
How are root hair cells specialised?
-Long extensions which increase SA which maximises uptake of water and minerals from soil.
How are guard cells specialised?
-Become less swollen when lose water so they close to prevent water loss.
-Cell wall is thicker on one side so doesn't change shape symmetrically when loses volume.
What is a tissue?
-Collection of differentiated cells.
What are the types of tissues?
-Nervous tissue; transmission of electrical impulses.
-Epithelial tissue; cover body surfaces.
-Muscle tissue; contract.
-Connective tissue; gold tissues together.
-Epidermis tissue; cover plant surfaces.
-Vascular tissue; transport water and nutrients.
How is squamous epithelium specialised?
-Very thin due to flat cells and only one cell thick.
-Rapid diffusion across a surface.
How is ciliated epithelium specialised?
-Cilia move in rhythmic manner.
-Goblet cells also present which release mucus, and cilia sweep away mucus.
How is cartilage specialised?
-Found in ear, nose, between bones.
-Prevents ends of bones from rubbing due to containing fibres of elastin and collagen.
How is muscle specialised?
-Skeletal muscle fibres contain myofibrils which contain contractile proteins.
How is the epidermis specialised?
-Single layer of closely packed cells.
-Covered by waxy cuticle to reduce water loss.
-Stomata present to let oxygen and carbon dioxide in and out.
How is the xylem tissue specialised?
-Transport of water and minerals
-Composed of elongated dead cells which are strengthened by lignin which provide structural support for plants.
How is the phloem tissue specialised?
-Transport of nutrients.
-Composed of sieve tube cells and separated by sieve plates.
What is an organ?
-Collection of tissues.
-E.g. heart or leaf.