CH 12 Eukaryotes

Algae

eukaryotic photoautotrophic organisms that have sexual reproductive structures in which every cell becomes a gamete.

• Found in aquatic habitats

• Most have cell walls made of cellulose

• Contain chlorophyll and are photosynthetic

Chlorophyta

Green pigmented division of algae that have chlorophyll a and b, store sugar and starch as food reserves, and have rRNA sequences similar to plants

• The progenitors of plants

Rhodophyta

Red algae, generally containing the pigment Phycoerythrin, the storage molecule floridean starh, and cell walls of agar or carrageenan

Phaeophyta

Brown algae with walls composed of cellulose and alginic acid, a thickening agent

Chrysophyta

golden algae, yellow-green algae, and diatoms

Water Molds

• They have tubular cristae in their mitochondria.

• They have cell walls of cellulose instead of chitin.

• Their spores have two flagella—one whiplike and one “hairy.”

• They have true diploid bodies rather than haploid bodies.

Look like fungi, but have cells walls made of cellulose and have flagella

Parasite

An organisms living at the expense of another organism (the host)

• Roundworms, tapeworms, hookworms, flukes

• Parasitology = study of parasites (including protozoa, helminths, and arthropods)

Parasitic Helminths and Vectors

Parasites cause damage, but do not want to destroy their host

• Parasites can cause

  • Nutritional deprivation

  • Direct trauma or obstruction

  • Inflammation

Ectoparasites

Live on the surface of host

• ticks and lice

Endoparasites

Live within the host

• worms and protozoa

Obligate parasites

Must spend some part of their life cycle on the host

Facultative Parasites

Free-living, but can attach to a host

Permanent Parasites

Remain in or on a host

• tapeworm

Temporary Parasite

Feed on a host & then leaves

• biting insects

Mechanical Vectors

Parasite does not go through any part of its life cycle during transit

• ex. flies that carry parasite eggs, bacteria, or viruses from feces to food

Biological Vectors

Parasite goes through part of its life cycle in host

• ex. Anopheles malaria mosquito is both a host and biological vector

Arachnids

Adults have four pairs of legs

• 2 body regions

  • cephalothorax

  • abdomen

    • Ticks

    • Mites

    • Spiders

Ticks

Most important arachnid vectors

• Cause lyme disease, rocky mountain disease, spotted fever, and babesiosis

Mites

Transmit rickettsial diseases

Arthropod Vectors

Adults have 3 pairs of legs and 3 body regions

• fleas

• lice

• flies

• mosquito

• true bugs

African Sleeping Sickness

Trypansoma are spread by the bite of tsetse flies

Lesmaniasis

Caused by leishmania, flagellated protozoan carried by dogs and small rodents

• Transmitted by infected female sand flies

• Involves large painless skin ulcers to form around bite wound

Mosquitos

Carry the deadliest diseases

• Malaria parasite (Plasmodium) carried by anopheles mosquito