B2.3 Cell Specialisation

cell that can divide (by mitosis) an unlimited number of times

bone marrow(for rbcs, wbs, platelets) hair follicle

The ability of stem cells to differentiate into more specialised cell types

can differentiate into any type of cell found in an embryo and extra embryonic cells eg. zygote

larger than inactive white blood cells to allow space for rER and Golgi apparatus to allow protein (antibody) synthesis

decreases more difficult for an organism to gain enough oxygen and nutrients at its cell surface, as its requirements will increase faster than the available surface for diffusion

cut coloured agar into cubes of required dimensions calc sa, vol, and sa to v ratio of each cube place cubes into boiling tubes containing diffusion solution measure time taken for agar cubes to become colourless

function- carry oxygen from lungs to respiring cells they are FLATTENED and have a BICONCAVE shape to maximise surface area and minimise volume so oxygen can diffuse into it quickly in lungs and out

tiny tubes found in the outer region of the kidney which are responsible for the reabsorption of vital substances like glucose and mineral ions

have microvilli and invaginations

extremely thin alveolar cells which make up the majority of the alveolar epithelium

provide a short diffusion distance to maximise the rate of gas exchange capillary walls are also only one cell thick maximises the rate of diffusion

rounded cells that have many secretory vesicles which secrete a solution that coats the epithelium of the alveoli

pulmonary surfactant has hydrophobic tails and hydrophilic heads which form a monolayer

reduces surface tension, maintaining alveolar shape and preventing the alveoli sacs sticking together provides moisture so oxygen can dissolve before it diffuses into the blood Carbon dioxide diffuses from the moist surface before it is removed in exhalation

yes

into fibres which are surrounded by a single plasma membrane called the sarcolemma

an organised arrangement of CONTRACTILE PROTEINS in cytoplasm many nuclei sarcoplasmic reticulum mitochondria and myofibrils

bundles of actin and myosin filaments, which slide past each other during muscle contraction

many deep tube-like projections that fold in from its outer surface- T tubules they run close to SR

yes

via specialised branched connections called intercalated discs, which allows the contraction to spread more quickly across the chambers of the heart

has a haploid nucleus in streamlined head- fuse w ovum to form diploid zygote acrosome w digestive enzymes to enter ovum many mitochondria for movement a flagellum for movement

to provide the large quantity of ATP needed for continual contraction