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
Describe the structure of a red blood cell?
Circular concave disc shape with no nucleus. Only contains heamoglobin. To carry oxygen.
What is the function of arteries?
Carry oxygenated blood vessels away from the heart
Describe the build of the artery and why it must be like this?
Thick and elastic muscular walls to pump blood at high pressure around the body
What are the function of arterioles?
Smaller arteries leading into capillary beds
What is the function of veins?
Carry deoxygenated blood toward the heart.
Why do veins contain valves in their walls?
To direct blood flow because they are only pumped at low pressure
Describe the build of veins
Walls are thin and contain less muscle because blood is pumped at low pressure.
What is the function of venules?
Venules are smaller veins leading out of capillary beds
Draw and label the structure of the artery, vein and capillary.
Refer to book for drawing
What is the build capillaries?
The are one cell thick
Describe transport in the capillaries
- Oxygen, nutrients and minerals are go from blood to cell.
- carbon dioxide, water wastes move from cells into capillaries
What type of circulation does the human heart have?
Double circulation
Explain double circulation in the human heart
The right side of the heart pumps blood to the lungs.
The blood then returns to the left side of the heart and is then pumped around the rest of the body.
Draw structure of capillaries
Refer to book for diagram
Draw a heart and label
Refer to book
What is the function of the atria?
Top chamber which receives blood from the lungs (left side) or body (right side)
What is the function of the ventricle
Bottom chamber which receives blood from the atria above it, pushes blood out of the heart under high pressure.
Why is the left ventricle wall thicker than the right wall?
The left is thicker because it pumps the blood further around the body
What is the function of the heart?
Direct the blood flow to flow in one direction only
Describe the way in which blood pumps through the heart?
Refer to book
How many chambered hearts do fish have?
2
Describe the flow of blood in a fish?
- Deoxygenated blood enters the atrium and then passes directly into the ventricle
- ventricle pumps blood to the gills
- in the gills carbon dioxide diffuses Out and oxygen diffuses in
What does single circulation mean?
It means that the blood travels through the heart only once in each cycle.
Draw and label a fish heart.
Refer to book for diagram
Does a fish have single circulation or double circulation?
Single
How many chambers do amphibians have in their hearts?
Three
Describe the circulation of blood in amphibians.
Amphibians have double circulation.
- blood is pumped to the lungs via the ventricle
- blood is oxygenated and returns to the heart via the left atrium
- blood travels to the ventricle and then is pumped to the body to supply cells with nutrients and oxygen
- blood returns to the heart and enters the right atrium
Draw and label an amphibian heart
Refer to the diagram
What is the function of the lymphatic system?
- transport fluids back to the blood
- drains excess fluids from tissues
- removes debris from cells of body
- transports fat from digestive system
Describe blood flow in capillaries
- The blood flow slows to allow nutrients and gases to move out and into the cells
- carbon dioxide diffuse out of the cells and back into the capillaries
Describe transport in aquatic small plants
- Movement of water circulates materials past the body of these plants/algae
- diffusion of substances in/out of the body as in algae etc
Describe transport in large plants in aquatic habitat
If flattened = diffusion
Complex = internal support system of xylem and phloem
Describe transport in small living plants (terrestrial)
-diffusion
Describe transport in large terrestrial plants
Have xylem and phloem to transport materials
What makes up the vascular bundle
Xylem + phloem + cambium
Describe Transport of water in a plant
- Water in to the leaf through xylem
- Evaporates through stomata
- Water molecules leave the stomata and more is drawn up to replace it (transpiration)
- Phloem takes away sugars made by the leaf to supply other parts of the plant
Function of the xylem in stems
Carries water and minerals upwards from the roots
Function of the phloem in stems
Carries mainly sucrose down from the leaves
Function of the cambium in stems
Forms new xylem and phloem and strengthens stem
What is the function of the cortex and pith in stems
Packing cells that store food
Function of the epidermis in stems
Protective skin of the stem
Draw root cross section
Refer to book
Draw stem cross section
Refer to book
How is xylem formed
From the Mott remains of dead cells that join together when the end walls of the cell wither away
What causes the transpiration stream?
- Water from soil pushed up
2. Leaf cells lose water so must replenish therefore it is continuous
What are the factors affecting transpiration and why?
Light-opens stomata
Heat-causes water to evaporate from the stomata
Wind-can increase evaporation of water from stomata
Humidity-allows water to evaporate from stomata quickly
What is the phloem made of?
Parenchyma cells, sieve tube cells and companion cells
Draw and label the difference in structure of the Salem and the phloem
Refer to book
What is translocation
Transport of sugars and amino acids which are needed by the plant
What does translocation require?
Energy
Describe the process of translocation
- photosynthetic cells manufacture sugars as glucose
- glucose is converted to sucrose
- sucrose is transported by the phloem to where it is needed or to be stored
Differences between xylem and phloem?
Refer to table in book
Digestion definition
The chemical and mechanical breakdown of food into small molecules to be absorbed into the body
Mechanical digestion definition. Give example
Large pieces of food being broken down into small pieces of food e.g chewing and grinding
Chemical digestion definition give example
Enzymes break down complex food substances into simple sub units such as glucose amino acids, fatty acids and glycerol
Which nutrients do not need breaking down to enter cells?
Water, vitamins and minerals because they are small
Describe the process of digestion in human body
- Ingestion of food
- Mechanical, digestion of food (physical)
- Chemical, digestion of food (involves enzymes)
- Movement of food along the alimentary canal
- Absorption of digested food and water into lymph and blood
- Elimination of material that is not absorbed
What is the alimentary canal?
Continuous tube running from the mouth to the anus
What does the digestive system include?
Esophagus, stomach, small intestine, large intestine
What enzymes breaks down carbohydrates?
Amylase
What enzyme breaks down protein
Protease
What enzymes breaks down lipids
Lipase
Describe the digestion that occurs in the mouth
Mechanical: chewing on food break down food into smaller particles
Chemical: salivary glands secrete saliva which contains mucus and salivary Amylase
What do you call food that has been chewed up and formed into a lump?
A bolus
How does swallowing occur
Tongue moves upwards and backwards to push the bolus into the back of the mouth, the pharynx
What does the pharynx lead to?
The oesophagus
What is peristalsis?
Muscular contraction that pushes food along
Describe the digestion in the stomach?
Mechanical: muscular contraction finds food
Chemical: gastric juice secreted by the gastric gland, protein digested by gastric protease
Describe digestion in the duodenum
Mechanical: broken down by bile
Chemical: breaks down by pancreatic amylase, protease and lipase
Describe digestion in the small intestine?
Chemical: intestinal amylase, protease and lipase
Where is bile produced
In the liver
Where is bile stored and secreted
In the gall bladder
