Gaseous Exchange in Coral and Tuna

Gaseous Exchange in Coral Polyps and Tuna

• Gaseous exchange is by diffusion in both organisms.
• Both organisms have a large surface area to volume ratio for gas exchange.
• Gases pass across a thin layer of cells.
• The diffusion path is short.
• Gases move from an area of high concentration to low concentration.
• Oxygen is absorbed and carbon dioxide is removed.
• Coral is sedentary, with a low oxygen demand, while tuna swims continuously, with a high oxygen demand.
• Coral has no specialized structures for gas exchange, while tuna has gills.
• Coral has tentacles to increase surface area for gas exchange.
• Tuna has numerous gill filaments/lamellae to increase surface area.
• Coral does not require a transport system, while tuna does to transport gases.
• Tuna uses ram ventilation to force water over gills.
• Coral polyps may create a current using tentacles.
• Tuna uses counter-current exchange for maintaining a concentration gradient.

Movement of Sodium Ions Across Cell Membranes

• Sodium ions are charged.
• Cannot pass through the lipid bilayer.
• Movement is by facilitated diffusion and active transport.
• Using channel proteins and carrier proteins.
• Proteins are specific.
• Facilitated diffusion occurs through channel proteins.
• No energy is required for facilitated diffusion.
• Movement is from high to low concentration.
• Channel proteins can open and close/are gated.
• Carrier proteins are used in active transport.
• Active transport moves ions against the concentration gradient.
• Energy in the form of ATP is required for active transport.
• Carrier proteins can change their shape.

Cell Membrane Processes

• Cells of marine organisms constantly move substances.
• Substances move between cells or are exchanged with the surrounding sea water.
• Three processes are discussed in the table: diffusion, facilitated diffusion, and active transport.
• Diffusion is a passive process where substances move from high to low concentration, used to move glucose.
• Facilitated diffusion is a passive process that uses channel proteins to move substances from high to low concentrations, where substances moves from high to low concentration.
• Active transport uses carrier proteins to move substances from low to high concentrations, and this requires energy.

Plant and Animal Cell Responses to Concentrated Sugar Solutions

• Water diffuses from an area of high water potential inside a cell to an area of lower potential, such as concentrated sugar solution.
• In plant cells, the cell membrane pulls away from the cell wall.
• In animal cells, the cell shrinks.

Grouper Ventilation

• Ventilation occurs when the mouth opens and the operculum closes.
• The volume of the buccal cavity increases due to muscle contraction.
• The pressure in the buccal cavity decreases, becoming lower than that in the sea water.
• Water flows into the mouth.
• This is an active process requiring energy from ATP.

Shark and Grouper Classification

• Sharks and groupers are in the same phylum (chordates).
• Both have a notochord, dorsal neural tube, pharyngeal slits, and a post-anal tail
• Sharks have a cartilaginous skeleton and gill slits; groupers have a bony skeleton and operculum.
• Groupers have a swim bladder; sharks use denticles.

Cell Structure and Function

• Mitochondria are the site of aerobic respiration.
• Rough endoplasmic reticulum (ER) transports proteins.
• Ribosomes synthesize proteins.

Mitochondria in Marine Fish Muscle

• Muscle cells of marine fish have many mitochondria.
• Mitochondria provide energy in the form of ATP for movement/swimming/muscle contraction.

Carrier Proteins in Cell Membranes

• Carrier proteins span the membrane and are intrinsic.
• Involved in passive and active transport.
• Contain hydrophilic channels for ions or polar molecules/charged substances.
• Carrier proteins have gates that open and close, controlling the movement of substances into/out of the cell.
• Carrier proteins can change shape to transport substances.