6.2 - Unicellular Organisms Flashcards
What are unicellular organisms often called?
Unicellular organisms are often called micro-organisms.
What are some unicellular organisms (from the 5 groups)?
Unicellular organisms include bacteria and some protists and fungi.
How do unicellular organisms obtain nutrients?
Most often, they must obtain nutrients by eating other organisms. Plant-like protists, and some types of bacteria, can make their own food through photosynthesis. The Euglena shown is a protist that has both plant and animal characteristics, which it uses for obtaining nutrients. Other micro-organisms, such as fungi and bacteria, interact with one another to obtain nutrients. Lichens are organisms that form from the interaction of a fungus with an algae.
Why do unicellular organisms need to move around to find food?
Many unicellular organisms live in bodies of water and must move around to find food.
In what environments are paramecia found (territorial or aquatic)?
Paramecia are unicellular organisms that are found in aquatic environments.
What do paramecia eat?
These animal-like protists feed on bacteria and algae.
What is the role of the cilia that paramecia are covered with?
Paramecia are covered with cilia that beat in unison, creating water currents that move the paramecium toward a food source. The oral groove of the paramecium also contains cilia that create currents that draw the food into a cavity. Once this cavity is filled, the food is enclosed in a vacuole where it is slowly digested. As the food vacuole travels through the cell, nutrients diffuse through the vacuole’s membrane into the cytoplasm. Any remaining waste materials are eliminated through an anal pore.
How do Amoeba obtain nutrients?
The amoeba is another animal-like protist that must move about to find food. The amoeba uses phagocytosis to feed on organisms. The pseudopods extend around the food material and form a food vacuole. The vacuole acts as a site of both storage and digestion. When the amoeba needs nutrients, chemicals are released into the vacuole to break down the stored food. The food particles are then able to diffuse into the cytoplasm of the cell. Once digestion is complete, wastes are released out of the cell by exocytosis.
What is the gas that most organisms need to live?
Most organisms need oxygen to live.
What allows organisms to obtain energy from food and what is the waste product?
The chemical reactions that allow organisms to obtain energy from food use oxygen and release carbon dioxide as a waste product. This means that there must be a steady exchange of oxygen and carbon dioxide into and out of the cell.
How does gas exchange occur in unicellular organisms?
In unicellular organisms, oxygen diffuses across the cell membrane into the cell. Carbon dioxide diffuses out of the cell once the concentration of carbon dioxide is higher inside the cell than it is outside of the cell.
Can organisms live without oxygen?
Some micro-organisms, including some bacteria and fungi, can survive without oxygen. Yeast is a unicellular fungus that can survive without oxygen. This characteristic makes yeast useful in many industries.
What are the 5 senses, and what are they used for?
Humans are able to detect changes in the environment using the five senses. They are: hearing, sight, smell, taste, and feeling.
Do unicellular have the 5 senses? If not, how do they respond to the environment?
No, unicellular organisms don’t have the 5 senses. They have to use other ways to sense their surroundings. Some bacteria can detect chemicals, such as sugar, in their environment and move toward them. Photosynthetic protists, like Euglena, can detect light using special sensors.
Are there any organisms that can’t respond to their environment?
All organisms are able to sense their environment in some way and respond to it.
