Exam 1 Chapter 23 Protists Flashcards
Protists
- Eukaryotes that do not fit in Animalia, Plantae, or Fungi
- usually very small
- usually reproduce asexually unless in stress conditions
- paraphyletic + polyphyletic group
Eukaryotes vs Prokaryotes
Eukaryotes have cytoskeleton + compartmentalization (membrane bound nucleus and organelles).
Eukaryotes vs Prokaryotes
Eukaryotes have cytoskeleton + compartmentalization (membrane bound nucleus and organelles).
phagotrophic
ingest particle food
osmotrophic
ingest soluble food
protistan nutrition
phototrophs, heterotrophs, mixotrophs.
phagotrophs, osmotrophs
protistan mechanisms
slimy or hard protective coverings toxins sharp projectiles bioluminescence spines
protistan structures
- cyst
- flagella
- pseudopodia
- cilia
protistan cysts
may arise from sexual or asexual reproduction.
facilitate spread of pathogen from on host to another
consumption may lead to human health problems
multicellularity
from single cells to colonies to true multicellularity
arisen multiple times
fosters specialization
few innovations have had as great an influence on the history of life
diplomonads
unicellular move with flagella 2 nuclei Giardia (CAUSES DIARRHEA) Lack mitochondria but have some mitochondrial genes in DNA
Euglenozoa
Among the earliest eukaryotes to possess mitochondria
1/3 have chloroplasts and are autotrophic
may become heterotrophic in dark
others lack chloroplast and are heterotrophic
all have a flexible pellicle
no sexual reproduction
Kinetoplastids
2nd major group in Euglenozoa
Unique, single mitochondrion
DNA maxicircles and minicircles
Trypanosomes cause human diseases
African sleeping sickness – tsetse fly
Leishmaniasis – sand fly – cause severe lesions
Chagas disease – skin contact with urine or blood of infected wild animal. Heart affected by parasite and increases in size.
Dinoflagellates
Photosynthetic, unicellular with flagella
Live in aquatic environments
Some are luminescent
Do not appear to be directly related to any other phylum
Major Cause of “Red tide” which are “blooms” that kill – fish, birds, and marine mammals may die from toxins
Apicomplexans
Spore-forming animal parasites
Apical complex is a unique arrangement of organelles at one end of the cell which enables the cell to invade its host.
Plasmodium causes malaria. Symptoms include chills and fever usually in late afternoon.
Complex life cycle – sexual, asexual, different hosts.
Eradication focused on eliminating mosquito vector, drug development, vaccines.
ciliates
Feature large numbers of cilia arranged in longitudinal rows or spirals around the cell
Pellicle – tough but flexible outer covering
2 types of nuclei
Micronucleus – without will reproduce asexually
Macronucleus – essential for function
Have two types of vacuoles
Food vacuoles – digestion of food
Contractile vacuoles – regulation of water balance
Brown algae
Conspicuous seaweeds of northern regions Life cycle involves alternation of generations Sporophyte – multicellular and diploid Gametophyte – multicellular and haploid Not plants but protists.
diatoms
Photosynthetic, unicellular organisms
Unique double shells made of silica
choanoflagellates
filter bacterial food from the water through the collars on the cells; structure similar to one on sponges
Propulsion by a single posterior flagellum
Consider: Choanoflagellates are the group of protists with similarities to sponges and other animals, including humans.
foraminiferans
resemble tiny snails; have shells called tests composed of organic materials reinforced with grains of inorganic matter; their tests help make up many limestone deposits including the White Cliffs of Dover
amoebae
move by pseudopodia extension
Green Algae
Only once in evolution these algae gave rise to all land plants. Have 2 monophyletic groups: Chlorophyta and charophytes. Diverged from land plants over 1BYA. Can be single cell, multicellular or colonial.
The parasite that is responsible for causing malaria is called
Plasmodium
The classic symptoms of malaria are:
headaches and nausea
