Multicellular Organisms Flashcards
What do cells form?
Tissues
What are the four main types of tissue?
- Epithelium
- Connective tissues
- nervous tissue
- muscle tissue
Gas exchange definition
The process by which oxygen is gained (entering the body) and carbon dioxide (leaving the body) is removed from the body occurring across gas exchange surfaces by diffusion.
Gas exchange membranes are most efficient when they are?
- thin
- moist
- good blood supply (in animals)
- large surface area
- large difference in concentration across the membrane
Explain gas exchange in animals?
Animals need oxygen and get rid of carbon dioxide. Animals have adapted to perform gas exchange more efficiently
What are the different ways gases can be exchanged with an external environment of water?
Across the body surface, across external gill or across internal gill
What animal has exchange across the whole body surface in an aquatic environment?
Jellyfish
What aquatic animal has exchange across external gills?
Axolotl
What aquatic animal has exchange across internal gills?
Fish
What was can gas exchange occur in an external environment of air?
Exchange at the end of fine tubes through out the body and exchange across internal lungs
What is an animal that has gas exchange at the end of fine tubes through out the body? and How?
Insects. And they do this by breathing in through their spiracles (small holes in abdomen). Then the air enters the spiracle allowing oxygen to travel along a network of tubes called trachea to reach the cells in the insects body.
What is an organism that has gas exchange internal lungs? Explain how this process occurs.
Frog. Gas exchange occurs when the frog gulls in air. Then the pressure of the air inside the mouth cavity increases, air moves from the mouth cavity (high pressure) to the lungs (low pressure)
Draw the lungs and label.
Refer to book for drawing.
What is the difference between small animals and large animals in terms of gas exchange?
In small animals the SA:vol ratio is large enough for diffusion across the general body surface HOWEVER in larger animals the SA:vol ratio is small, diffusion across the body surface is insufficient and therefore their bodies have developed specialised respiratory systems.
Where does gas exchange occur in complex plants?
In the leaves, stems and roots
What is an example of a complex plant?
Flowering plant (rose)
Draw and label a cross section of a leaf.
Refer to book for drawing
What is the function of the cuticle in the leaf?
It is a waxy compound on the very outer surface of the upper epidermis and may reduce water loss by evaporation.
What is the function of the upper epidermis in the leaf?
Protects against water loss by the cuticle or by epidermal hairs which trap moisture and reflect light. Protects against invasion of pathogens so that the most inner leaf is sterile.
What is the function of palisade mesophyll?
Major site of photosynthesis. Many chloroplasts for light absorption and photosynthesis.
Wha is the function of xylem?
Transports water and miner to the leaves.
What is the function of phloem?
Transports sugars (sucrose)
What is the function of the spongy mesophyll in the leaf?
Irregular shaped cells that fit loosely together to leave large air spaces which permit diffusion of gases through leaves.
What is the function of lower epidermis in the leaves?
Protects from pathogens and water loss
What is the function of guard cells?
Uneven thickening of cellulose wall permits opening and closing of the stomata pore as turgidity changes.
What is the function of the stomata pore?
Can be opened (to allow diffusion of O2 and CO2 down a concentration gradient) or closed (to limit water losses by evaporation when in a drier atmosphere)
What is the function of stomata in leaves?
- Allow exchange of CO2 and O2 between the inside of the leaf and the surrounding atmosphere
- Closes to prevent the escape of water vapour from the leaf (transpiration)
What happens to the guard cells when water is drawn in?
Water is drawn in through osmosis. Class expand and their turgidity is increased, this expansion is not uniform, resulting in the guard cells drawing apart and the stomp opening.
How does bark on a tree allow for gas exchange to occur?
Bark is the barrier for gas exchange and parts in the bark called lenticels open and allow for exchange of gases with cells of the stem beneath the bark
How does gas exchange occur in the root?
- oxygen from the air spaces I. The soil can diffuse into the root hair cells or epidermal cells an enter the roots
- carbon dioxide can diffuse out of the root
Draw a cross section of a root
Refer to book
What are the three characteristics of girls (fish gas exchange network)
- thin filaments with a large surface area
- dense capillary network
- rich blood supply to transport carbon dioxide to and oxygen away from the gills.
How does gas exchange occur in fish?
Water goes in through the mouth and pumped across the gills out the operculum in a bony fish or gill flaps in cartiliginous fish. Oxygen goes into the blood and the water with goes out of fish.
What makes lungs efficient form of gas exchange for animals?
- huge internal surface area
- reduced water loss because it’s inside he body
- efficient circulatory system for transport
Draw a labelled diagram of the alveoli during gas exchange
Refer to book
What are the similarities between lungs and gills?
- large moist surface area
- dense capillary network
What are the differences between lungs and gills?
Lungs:
- air passage kept open with cartilage
- air pushes in and then back out in opposite direction
Gills:
- not self supporting as they are buoyed up by water
- single flow because of not enough energy
Are all organisms able to transport in the same way?
No because some organisms are small enough to use simple diffusion to transport wastes and nutrients. But larger multicellular organism have more complicated transport systems.
How does transport occur in very small and flattened animals in a high moisture region?
Environment circulates materials past cells and organism can create a current that brings materials past it’s body e.g paramecium through diffusion because of large SA:vol ratio
What do flattened animals lack?
No heart, ni blood vessels and no blood
How does small organisms transport?
- one or more muscular hearts pump body fluids to maintain circulation
- fluids move slowly at low pressure
- blood like fluid is pumped by the heart into large spaces bathing the cells in order to supply the, with nutrients
How does transport occur in large animals?
Fluids are circulated within a network of blood vessels. Blood carries the nutrients gases and waste products. Pumped by heart with pressure.
How many chambered hearts does a large animal have?
2,3 or 4
What is closed circulation?
When blood is enclosed in the heart and blood vessels
What is blood made of?
Plasma and cells (red, white and platelets)
What is the function of red blood cells?
Oxygen transport
What is the function of white blood cells?
Fighting pathogens/infection
What is the function of platelets
Prevent blood clots