Specialisation of cells Flashcards
What is the organisation of a multi cellular organism?
specialised cells -> tissues -> organs -> organ systems -> whole organism
What is a specialised cell?
a cells that is differentiated, specialised to carry out very specific functions
How is an erythrocyte specialised to perform its function?
flattened biconcave shape - increases SA:V ratio
essential to their role of transporting oxygen
in mammals, they don’t contain a nucleus or many other organelles - increases space for haemoglobin
flexible to squeeze through narrow capillaries
How is a neutrophils specialised to perform its function?
specialised WBC, plays an essential role in the immune system
multi-lobed nucleus - makes it easier for them to squeeze through small gaps to get to the site of infection
granular cytoplasm contains many lysosomes - contain enzymes used to attack pathogens
How is a sperm cell specialised to perform its function?
male gametes, their function is to deliver genetic information to the female gamete, the ovum
sperm have a flagellum, so they are capable of movement
contain many mitochondria to supply the energy needed for locomotion
the acrosome on the head of the sperm contains digestive enzymes which are released to digest the protective layers around the ovum and allow the sperm to penetrate
acrosome shaped for penetration
How are palisade cells specialised to perform their function?
present in the mesophyll, contain chloroplast to absorb large amounts of light for photosynthesis
the cells are rectangular box shape which can be closely packed to form a continuous layer
thin cells walls, increasing the rate of diffusion for CO2
large vacuole to maintain turgor pressure
chloroplasts can move within the cytoplasm to absorb more light
How are root hair cells specialised to perform their function?
present at the surface of roots near growing tips
have long extensions called root hair
increase the surface area of the cell
maximises uptake of water and mineral from the soil
thin cells wall to reduce diffusion distance
vacuole containing cell sap - solution of ions and sugars, lower water potential
How are guard cells specialised to perform their fucntion?
pairs of guard cells on the surfaces of leaves form small openings called stomata
these are necessary for carbon dioxide to enter plants for photosynthesis
when guard cells lose water they become less swollen, due to osmotic forces
they change shape and the stoma closes to prevent further water loss
the cell wall of a guard cell is thicker on one side so the cell does not change shape symmetrically as its volume changes
