Eukaryotes and Their Cell Structure

Eukaryotes

• Two types of cells: eukaryotic and prokaryotic
• All living organisms are composed of either eukaryotic cells or prokaryotic cells
• Prokaryotic cells are smaller and simpler than eukaryotic cells
• Prokaryotic cells do not have a nucleus or organelles
• Eukaryotic cells are larger and more complex than prokaryotic cells
• Eukaryotic cells have a nucleus and organelles
• Prokaryotes reproduce asexually via binary fission
• Eukaryotes reproduce both asexually (mitosis) and sexually(meiosis)
• Prokaryotic cells are unicellular but Eukaryotic cells can be uni- or multicellular

Eukaryotic Cell Structure

• Nucleus: Contains the cell's genetic material (DNA) and controls cellular activities
• Mitochondria: Powerhouse of the cell, responsible for generating ATP through cellular respiration.
• Golgi Complex: Responsible for packaging and sorting proteins and lipids, and transporting them to other parts of the cell
• Rough Endoplasmic Reticulum (RER): Ribosomes are attached to the RER, it is the site of protein synthesis
• Chloroplast: Found in plant cells, responsible for photosynthesis
• Smooth Endoplasmic Reticulum (SER): Involved in lipid synthesis, detoxification, and calcium storage
• Lysosome: Contains hydrolytic enzymes for breaking down waste material and cellular debris
• Plasma Membrane: Regulates the movement of substances into and out of the cell, it is a selectively permeable membrane
• Flagella: Long, whip-like structures that help in cell motility

Eukaryotic Cell Division

• Mitosis: Asexual reproduction - produces two genetically identical daughter cells from one parent cell
• Meiosis: Produces four genetically unique daughter cells from one parent cell, each with half the number of chromosomes.
• Mitosis can occur in haploid or diploid cells
• Meiosis can only occur in diploid cells

Kingdoms and Domains

• Eukaryotic organisms are classified into four kingdoms: Protista, Fungi, Plantae, and Animalia
• Organisms are further classified into three domains: Bacteria, Archaea, and Eukarya

Protista

• Protists are a diverse group of eukaryotic organisms that are not animals, plants, or fungi
• Protozoa: Heterotrophic protists - include various groups like amoebas, alveolates, and apicomplexans

Amoeba

• Move using pseudopods (false feet)
• Two main types: lobed amoeba and filamentous amoeba

Pathogenic Amebas

• Entamoeba hystolytica: Cause amebic dysentery, transmitted through fecal-oral route
• Naegleria fowleria: Brain-eating amoeba, enters through the nasal cavity, crosses the blood-brain barrier, and causes amebic meningoencephalitis
• Acanthamoeba: Causes corneal infection, commonly associated with contaminated contact lenses

Apicomplexans

• Intracellular parasites
• Toxoplasma gondii: Can infect all nucleated cells, spread through cat feces, and potentially cause brain infections
• Trypanosoma cruzi: Causes Chagas disease, transmitted via kissing bugs
• Leishmania: Causes leishmaniasis, transmitted through sand flies, affecting skin and internal organs

Algae

• A diverse group of photosynthetic protists
• Some algae are very large, like the giant kelp
• Some algae are unicellular and many are edible

Fungi

• Multicellular organisms that produce fruiting bodies, called mushrooms
• Can be saprophytic, parasitic, or mutualistic
• Some fungi are unicellular, like yeast
• Fungi are heterotrophic and obtain nutrients by absorbing organic matter

Lichens and Mycorrhizae

• Lichens are a symbiotic relationship between a fungus and an alga
• Mycorrhizae are a symbiotic relationship between a fungus and a plant root
• Both lichens and mycorrhizae are important for nutrient cycling in the environment and ecosystem health

Diatoms

• Unicellular algae with silica cell walls
• Important primary producers in marine ecosystems
• The fossilized remains of diatoms make up diatomaceous earth, used as a pesticide
• Diatoms, alongside other algae, are capable of producing harmful algal blooms which can cause illness if consumed

Dinoflagellates

• Responsible for red tides, which can cause mass fish kills and shellfish poisoning
• Important primary producers in marine ecosystems
• Some dinoflagellates produce toxins that can bioaccumulate in shellfish, causing harm to humans if consumed

Importance of Protists and Fungi

• Protists and fungi play vital roles in ecosystems, including decomposing organic matter, producing oxygen, and serving as food sources for other organisms.
• Fungi are also important for food production, such as mushrooms and bread, and for medicine, such as antibiotics.

The future of protists and fungi

• Protist and fungal populations are threatened by various environmental factors like pollution, climate change, and habitat destruction, requiring sustainable solutions to protect their biodiversity.

This quiz covers the fundamental differences between eukaryotic and prokaryotic cells, including their structures and reproductive methods. Explore various components of eukaryotic cells like the nucleus, mitochondria, and Golgi complex. Test your knowledge on cellular biology with this engaging quiz.