3.17: Obtaining Oxygen

Ferns and other plants provide their own oxygen from photosynthesis and take it in through stomata.

Generally, you probably think of plants as oxygen producers. You breathe oxygen in, and plants release it. Your release carbon dioxide, and plants take it in. The perfect cycle. But, that's not the whole story. Like all other cells, plant cells need ATP to function. So, to break down their self-made sugars, they need oxygen as all other organisms do. Plants obtain oxygen in two ways: They use the oxygen they produce during photosynthesis. They import oxygen from the atmosphere through stomata, small openings on the undersides of their leaves. Stomata have cells around them called guard cells that have the ability to open and close. When open, gases enter and leave

Insects obtain oxygen through spiracles, which are small abdominal holes.

Grasshoppers, flies, and other insects do not breathe through their mouths. Oxygen is obtained through small holes in the sides of their abdomens called spiracles. Spiracles lead into tracheal tubes called tracheae that branch out into smaller tubes called tracheoles. From there, oxygen diffuses into body cells.

Some species of prokaryotes are anaerobic, or capable of living without oxygen.

Botulism is a serious pathogenic disease that leads to paralysis of the muscles. Clostridium botulinum, the bacterium responsible for botulism, is a kind of prokaryote that can live without oxygen. Anaerobic bacteria are adapted to live in places where oxygen is not available. To some anaerobes, oxygen is poisonous and can kill them. To others, such as this species, oxygen is benign.

Many other animals inhale oxygen through internal lungs.

Many more complex organisms, including all amphibians, reptiles, birds, and mammals, have evolved an internal system for obtaining oxygen through an internal organ called the lung. This spongy structure is involved in the delivery of oxygen to cells.

Fish absorb dissolved oxygen from water through gills.

Oxygen gas (O2), like that you breathe, is dissolved in water—it is a mixture. Fish absorb the dissolved oxygen through gills. Gills are often described like fans or feathers, and they extract dissolved oxygen gas from the surrounding water as it passes over them.

Which statement best summarizes the reason living things depend on oxygen?

Oxygen is used during cellular respiration.

Which statement is true about oxygen in plants?

Plants both produce and use oxygen for photosynthesis and cellular respiration, respectively.

Most plants and animals respire aerobically.

The energy required by all animals and plants to live and grow is provided by the chemical process called aerobic respiration. Most plants and animals breathe oxygen, which is then combined with glucose to form carbon dioxide and water and release energy.

Living things depend on oxygen for cellular respiration. Mechanisms of obtaining oxygen vary among groups of organisms.

The mechanisms to obtain oxygen vary, depending on the complexity of the organism: - diffusion: prokaryotes and simple organisms, such as the flatworm - pore entry: plants and insects - absorption by gills: fish - inhalation through lungs: reptiles, birds, and mammals Nearly every living thing depends on oxygen to live, because it is used during cellular respiration to produce ATP, the energy that cells use for all functions.

Living things depend on a consistent source of oxygen for cellular respiration. Their survival depends on it.

The more energy, the more an organism can do. Oxygen, along with glucose, is an important part of producing energy. Just as a great job or a winning stock makes money, oxygen is one component necessary to make energy.Usable energy, stored in ATP, must be generated constantly by each and every cell. ATP fuels all cellular functions, and without it a cell dies. The manner in which living things obtain oxygen varies quite a bit.

Single-cell organisms obtain oxygen by diffusion.

Your body contains more bacterial cells than it does human cells.Do bacteria take in oxygen? Yes, most of them do, and they do it for the same reason you do—to produce ATP via cellular respiration. How does a single cell take in oxygen? Well, the only possible way is through diffusion. Since bacteria have no tissues or organs, the only way is through the cell membrane. Like bacteria, single-cell organisms such as the amoebas at right also take in oxygen by diffusion across their cell membranes.

Which term best relates to the mechanism that flatworms use to obtain oxygen?

diffusion

Flatworms also obtain oxygen by diffusion.

As strange as it seems, flatworms, and many other similar organisms, do not take oxygen in through their mouths. Like bacteria, flatworms take in oxygen by diffusion. Oxygen gas (O2) that is dissolved in water—not the oxygen in H2O—enters through cell membranes of the surface cells and diffuses through the rest of the body. That oxygen is used up in cellular respiration to produce ATP.