b2.3 - cell specialisation Flashcards
diploid cells
containing 2 set of chromosomes (2n)
morula
solid ball of cells (16-32) formed from divisions of zygote
blastocyst
cluster of dividing cells formed by the fertilised egg
- hollow ball of cells
trophoblast
- outer layer of blastocyst
- cells will become the placenta
inner cell mass (ICM)
- cells within the blastocyst that will become the embryo
This difference in gene expression is what determines the type of cell that is formed
yuh
morphogen
form-giving molecules secreted by cells in early embryo
enterocyte cells
- found on surface of villi, in intestines, absorbs nutrients
increasing surface area in digestive system
- villi on surface of small intestine, enterocytes are found on the surface of villi, each have 600 microvilli
increasing surface area in kidney
- proximal convoluted tubule has microvilli to absorb substances
squamous type 1 pneumocytes
- thin cells in the lungs responsible for gas exchange
- reduces diffusion distances
- make up 95% of the alveolar surface
type 2 pneumocytes
5% of the alveolar surface but outnumber the type I cells. They are cuboidal in shape, with the tip of the cell protruding into the alveolar space
- surface surfactant into alveolar space
types of muscles (3)
- cardiac (cardiomyocytes)
- skeletal
- smooth
cardiomyocytes
- 150 micrometres
- single nucleus
- many mitochondria
- branced fibres
how are cardiomyocytes connected to each other
- branced fibres connects to neighboring cardiomyocytes by gap junctions & intercalated discs
- 3D
skeletal muscles
- in bundles surrounded by connective tissues
- can be up to 12 cm
- unbranched
- many nuclei
- contain myofibrils (made of actin and myosin)
largest human cell
egg cell
list functions of proteins (provide examples)
transport (hemoglobin in oxygen transport)
contractile (actin and myosin in muscles)
defense (antibodies in immune)
hormonal (insulin to regulate blood sugars)
reasons for cell division in living organisms
- growth and development
- repair and regeneration
- reproduction
- maintain SA:V
- genetic stability