August 30, 2017

Biology: Fungi

Most fungi are eukaryotes, use spores to reproduce, and are heterotrophs.

Most fungi feed by absorbing food through their hyphae. The hyphae produce and discharge digestive chemicals into a food source, which is broken down into small substances that are absorbed by the hyphae.

Fungi produce spores in fruiting bodies. Most fungi reproduce both asexually and sexually.

Fungi are decomposers that recycle Earth's chemicals.

Hypha - One of many branching, threadlike tubes that make up the body of a fungus.
Budding - A form of asexual reproduction in which a new organism grows out of the body of a parent.
Fruiting body - The reproductive hypha of a fungus.
Lichen - The combination of a fungus and either an alga or an autotrophic bacterium that live together in a mutualistic relationship.

Classification of Fungi

Threadlike Fungi - This group contains about 600 different species of molds, including many common bread molds. These fungi produce spores in their threadlike hyphae.
Source: Emaze
Sac Fungi - This group contains over 30000 diverse species of fungi, including yeast, morels, truffles, and some fungi that cause plant diseases, such as Dutch elm disease. They are called sac fungi because they produce spores in structures that look like sacks. 

Source: Toronto Wildlife
Club Fungi - This group includes about 25000 species of mushrooms, bracket fungi, plant parasites, and puffballs. Club fungi produce spores in structures that look like clubs.

Source: Wikispace
Imperfect Fungi - The 25000 species in this group include this Penicillium, the source of an important antibiotic. The fungi in this group are not known to reproduce sexually.

Source: Wikispace

August 29, 2017

Biology: Algal Blooms

Red tides occur when a population of algae increases quickly in ocean waters. Some algae can produce toxins that poison animals.

Nutrients in a lake or pond build up over time, causing an increase in the amount of algae. An accelerated rate of eutrophication can lead to the deaths of many organisms in the lake or pond.

Algal bloom - The rapid growth of population of algae.
Source: Wikipedia

Red tide - An algal bloom that occurs in salt water.
Source: Wikipedia
Eutrophication - The buildup over time of nutrients in freshwater lakes and ponds that leads to an increase in the growth of algae.
Source: BBC

August 24, 2017

Biology: Viruses


A virus is a small, nonliving particle that invades and then reproduces inside a living cell. Viruses are nonliving because viruses are not cells. Viruses also cannot make food, take in food, or produce wastes. Viruses can only multiply when they are inside a living cell.

A host is a living thing that provides a source of energy for a virus or an organism. Organisms that live on or in a host and cause harm to the host are called parasites. Almost all viruses act like parasites because they destroy the cells in which they multiply.


Structure of Viruses

All viruses have two basic parts: an outer coat that protects the virus and an inner core made of genetic material. A virus's genetic material. A virus's genetic material contains the instructions for making new viruses.
The coat of a virus plays an important role during the invasion of a host cell. This coat is made of proteins. Each virus contains unique proteins in its coat. The shape of the proteins allows the virus's coat to attach to, or lock onto, certain cells in the host.

How Viruses Multiply

After a virus attaches to a cell, it enters the cell. Once inside, a virus's genetic material takes over the cell's functions. The genetic material directs the cell to produce the virus's proteins and genetic material. These proteins and genetic material are then assembled.

Active Viruses

After entering a cell the virus's genetic material takes over the cell's functions, and the cell quickly begins to produce the virus's proteins and genetic material these parts assemble into new viruses. When it is full of new viruses the host cell bursts open and releases the new viruses.

Hidden Viruses

Virus's genetic material becomes part of the cell's genetic material. The virus's genetic material may stay in this inactive state for a long time.

August 16, 2017

Biology: Protists

Animal-like protists, or protozoans, include sarcodines, ciliates, zooflagellates, and sporozoans. Like animals, these protists are heterotrophs. Most protozoans move by using pseudopods, cilia or flagella.

Funguslike protists include water molds, downy mildews, and slime molds. Like fungi, these protists are heterotrophs, have cell walls, and use spores to reproduce.

Plantlike protists, or algae, include euglenoids, dinoflagellates, diatoms, green algae, red algae, and brown algae. Like plants, these organisms are autotrophs.

Image result for protist

- An animal-like protist.

Pseudopod - A "false foot" or temporary bulge of the cell membrane used for feeding and movement in some protozoans.

Contractile vacuole - The cell structure that collects extra water from the cytoplasm and then expels it from the cell.

Cilia - The hairlike projections on the outside of cells that move in a wavelike manner.

Symbiosis - A close relationship between two organisms in which at least one of the organisms benefits.

Mutualism - A type of symbiosis in which both partners benefit from living together.

Spore - A tiny cell that is able to grow into a new organism.

Algae - A plantlike protist.

Pigment - A colored chemical compound that absorbs light, producing color.