Multicellular Organisms Flashcards
(120 cards)
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