specialised cells Flashcards
what are erythrocytes (red blood cells)
have a flattened biconcave shape increasing sa:v
in mammals these cells do not have nuclei or many other organelles
which increases the space available for haemoglobin so more oxygen can be transported
also flexible so that they are able to squeeze through narrow capillaries
what are neutrophiles (type of white blood cells)
have a multi-lobed nucleus which makes it easier for them to squeeze through small gaps to get to the site of infections
the granular cytoplasm contains many lysosomes that contain enzymes to attack pathogens
what are sperm cells
male gametes
their function is to deliver genetic info to the female gamete
sperm have a tail/flagellum so they are capable of movement and contain many mitochondria to supply energy to swim to the egg
acrosome on the head contains digestive enzymes allowing the sperm to penetrate
what are palisade cells
present in the mesophyll
contain chloroplasts to absorb large amounts of light for photosynthesis
have thin cell walls increasing the diffusion of co2
large vacuole to maintain turgor pressure
chloroplasts can move within the chloroplasts
what are root hair cells
present at the surfaces of the roots near the growing tips, have long extensions called root hairs
which increase surface area of the cell
maximises the uptake of the water from the soil
what are guard cells
guard cells opening is called stomata
which are necesseary for co2 to enter plants for photosynthesis
when guard cells lose water, they become less swollen and change shape and stoma closes to prevent further water loss
cell wall of a guard cell is thicker one one side so cell doesn’t change shape as its volume changes
what are squamous epithelium
very thin due to the squat or flat cells as its one cell thick
present when rapid diffusion across a surface is essential
forms the lining of the lungs rapid diffusion of oxygen
what are ciliated epithelium cells
cells have hair like structures called cilia
lines the trachea causing mucus to be swept away from lungs
goblet cells are also present releasing mucus to trap unwanted particles in the air
what are cartilage
connective tissue found in the outer ear nose and end of bones
contains fibres , of elastin and collagen
flexible
prevents the ends of bones from rubbing together and causing damage
muscle?
tissue that needs to be shorten to contract
skeletal muscles, myofibrills which contain contractile proteins
what are epidermis
single layer of packed cells
covered by a waxy waterproof cuticle to reduce water loss
what are xylem tissue
vascular tissue responsible for transport of water and minerals throughout plants
have elongated dead cells
these walls are strengthened with lignin providing structure
what are phloem tissue
vascular tissue in plants transports organic nutrients from leaves and stems
it is composed of sieve tube cells separated by perforated walls called sieve plates
