Kingdom Protista Mostly unicellular Mostly unicellular Workbook pages 58-9

Homeostasis Maintaining an optimal balance of conditions Homeo – similar Stasis – standing still

Osmoregulation water Fresh water hypotonic to cell

Contractile Vacuoles Surrounded by canals, which absorb water by osmosis and pump it into the contractile vacuole. Surrounded by canals, which absorb water by osmosis and pump it into the contractile vacuole. Special type of vacuole!!!!! Special type of vacuole!!!!! Active transport – uses ATP Why? Water is pumped out against concentration gradient

Contractile Vacuoles through a pore which opens and closes. Exocytosis – vacuole contracts to pump water through a pore which opens and closes. Inside cell Outside cell

Contractile Vacuoles Can also release water into the cell if needed

deo-transport.htm#Paramecium_- _Contractile_Vacuoles

Flagella Usually 1 or 2 Usually 1 or 2 long, whip-like structures lash back & forth long, whip-like structures lash back & forth complex cellular projections complex cellular projections

Cilia Numerous and short Numerous and short Motile or Sensory Motile or Sensory Rapid synchronised oar-like movement Rapid synchronised oar-like movement v=QGAm6hMysTA

Eyespot (stigma) photoreceptive organelle photoreceptive organelle senses light direction and intensity senses light direction and intensity simplest and most common "eyes“ in nature simplest and most common "eyes“ in nature Signals the flagella to change direction Signals the flagella to change direction organism swims towards/away from the light (phototaxis) to optimise photosynthesis organism swims towards/away from the light (phototaxis) to optimise photosynthesis

red eyespot of Euglena

All protozoa digest their food in stomach- like compartments called vacuoles. Some protists are also autotrophic and contain chlorophyll for photosynthesis Energy 99-world-of-the-protozoa-feeding-styles-of- the-protozoa-video.htmhttp://videos.howstuffworks.com/hsw/ world-of-the-protozoa-feeding-styles-of- the-protozoa-video.htm (4.5 min) transport.htm#Paramecium_- _Endocytosis_http:// transport.htm#Paramecium_- _Endocytosis_ (very short, Paramecium)

Reproduction (1min) world-of-the-protozoa-reproduction-of- protozoa-video.htmhttp://videos.howstuffworks.com/hsw/ world-of-the-protozoa-reproduction-of- protozoa-video.htm (2 min)

Reproduction – Binary Fission All prokaryotes, most protozoa, and some cell organelles. All prokaryotes, most protozoa, and some cell organelles. Asexual Asexual DNA replication and cytokinesis DNA replication and cytokinesis 2 offspring genetically identical to parent. 2 offspring genetically identical to parent.

Reproduction – Sexual Slower and uses more energy Slower and uses more energy Requires 2 parents Requires 2 parents Usually under environmental stress Usually under environmental stress Meiosis  gametes  genetic variation Meiosis  gametes  genetic variation More common in: ciliates ciliates parasitic protists parasitic protists

 Homeostasis (25 min) Clickview