Unit 2 : Multi-cellular Organisms - Transport Systems Flashcards
What is the surface area to volume ratio for unicellular organisms ?
Relatively large
What is the surface area to volume ratio for multi-cellular organisms ?
Relatively small
What is the relationship between surface area to volume ratio ?
Inverse relationship
What are the 2 vessels involved in plants internal transport system ?
Xylem Vessel & Phloem Vessel
What does the xylem vessel transport ?
Transport water and minerals from the soil to the leaves for photosynthesis.
How does water travel up the plant ?
Via osmosis
Describe the structure of the xylem vessel ?
Dead hollow tube with rings of tough woody lignin for support.
What does the phloem vessel transport ?
Carries dissolved food from the leaves, up and down the plant.
What structures are within the phloem vessel ?
Companion cells control the phloem unit and provide energy. Food is transported in the cytoplasm strands through the sieve plates from cell to cell.
What is transpiration ?
Transpiration is the evaporation of water from the leaves.
What is the main site of photosynthesis in a plant ?
Leaves
What is the function of the wax cuticle ?
Waxy outer waterproof covering that reduces water loss by evaporation.
What is the function of the upper epidermis ?
Transparent thin layer of cell with no chloroplasts that allows light energy to pass through.
What is the function of the palisade mesophyll ?
Cells that contain lots of chloroplasts and are closely packed together. Most photosynthesis takes place in these cells.
What is the function of the spongy mesophyll ?
Round cells that contain some chloroplasts but have air spaces between cells to allow carbon dioxide to circulate and reach palisade cells.
What is the function of the vascular bundle ?
Contains xylem and phloem which supply all parts of the plant with water and dissolved food that is produced.
What is the function of the stomata ?
Tiny pores that allow carbon dioxide and water vapour to diffuse in and out of the leaf.
What is the function of the guard cells ?
Cells with chloroplasts on the lower epidermis that control the opening and closing of the stomata.
What does the animal circulatory transport system consist of ?
Heart, blood vessels , blood
What is the function of the red blood cells being disc-shaped and flexible ?
The cell can travel easily through narrow blood vessels.
What is the function of the red blood cell having a large surface area to volume ratio ?
Oxygen is kept close to the surface and can be released quickly.
What is the function of red blood cells having no nucleus ?
There is more room for haemoglobin and so more oxygen can be carried.
What is the function of red blood cells containing haemoglobin ?
This carries the oxygen picked up in the lungs and released to the body’s cells
What is the function of red blood cells having a larger diameter than capillaries ?
The cell is forced to slow down so that gas exchange will definitely happen.
What are the 3 different types of blood vessels ?
Artery, vein, capillary.
What is the heart muscle called ?
Cardiac muscle
What happens each time the muscle contracts ?
The blood is pumped around the body.
What is the path taken by the blood around the body ?
Blood from around the body arrives at the right side of the heart via the VENA CAVA. The blood is DEOXYGENATED. The blood enters the right ATRIUM, and then passes into the right VENTRICLE. The blood is then pumped out of the heart via the PULMONARY ARTERY which leads to the lungs. In the lungs the blood picks up oxygen and becomes OXYGENATED. Blood then travels from the lungs via the PULMONARY VEIN and enters the left side of the heart. The blood enters the left ATRIUM, then passes into the left VENTRICLE. The blood is pumped out of the heart via the AORTA to be transported to the rest of the body.
Describe the artery ?
Has thick muscular walls. Has a narrow lumen. Carries blood away from the heart. Carries blood at a high pressure.
Describe the vein ?
Has thin muscular walls. Has a wide lumen. Carries blood towards the heart. Carries blood at a low pressure. Contains valves.
Describe the capillary ?
One cell thick. Carries blood to and from cells. Has thin permeable walls.
How does the heart muscle receive a supply of oxygen ?
Via coronary artery
What branches out from the aorta ?
coronary artery.
What would a blockage to the coronary artery cause ?
Deprivation of oxygen either partial or complete and may lead to a heart attack
What does the reduction in the size of the lumen cause ?
Increase in blood pressure.
What would a fatty deposit in the blood vessel cause ?
blood clot
How can you reduce the risk of heart disease ?
Regular exercise and diet low in salt and fat.
What is the direction of breathing ?
nose/mouth=trachea=bronchi=bronchioles=alveoli
What are the mammals organs for gas exchange ?
lungs
Describe features of the alveoli ? (4)
There are millions of them so they present a very large surface area. They have a very good blood supply as they are surrounded by many capillaries. Their surface lining is very moist. This means that the gases can dissolve before they diffuse.
They have a very thin lining to allow faster diffusion.
How are the lungs kept clean ?
The trachea and bronchi are lined with tiny hair-like cilia and cells that secrete sticky mucus. Rhythmic beating of the cilia sweeps mucus with trapped dirt and micro-organisms upwards and away from the lungs. As well as the nose which is lined with tiny hairs and mucus. Glandular cells create sticky mucus. It then passes into the oesophagus and then into the stomach where the bacteria are killed by the stomach acid.
What does smoking affect ?
The tar in cigarette smoke paralyzes and kills cilia, and changes mucus secretion . Smokers have to cough to remove the mucus from their lungs more easily.
What problems can smoking cause ?
lung cancer, emphysema, bronchitis, coronary heart disease and throat cancer are caused or aggravated by smoking.
What gas exchange happens at the lungs ?
Oxygen diffuses into the capillaries. Carbon dioxide diffuses into the alveoli.
What gas exchange happens at the cells ?
Oxygen diffuses into the cells. Carbon dioxide diffuses into the bloodstream.
What is the digestive system also known as ?
Alimentary canal
What is peristalsis ?
Food moves along the alimentary canal due to muscular contractions.
What is digestion ?
Digestion is the breakdown of large insoluble food molecules into small soluble molecules. This allows the food molecules to pass through the small intestine/gut wall into the rectum.
What is the mechanism of peristalsis ?
When the circular muscles contract behind the portion of food, the central hole of the tube becomes narrower and the food is pushed along. At the same time, the circular muscles in front of the food becomes relaxed allowing the central hole to enlarge and let the food slip along easily.
What is second part of the small intestine designed for ?
The absorption of digested food products.
What are the digested food products from carbohydrates ?
Glucose
What are the digested food products from proteins ?
Amino Acids
What are the digested food products from fats ?
Fatty acids & glycerol
What is the advantage of the villus having a large surface area ?
The larger the surface area the quicker the absorption.
What is the advantage of the villus having a thin cellular lining ?
End products are able to pass through quickly.
What is the advantage of the villus having a dense network of capillaries ?
Allows glucose and amino acids to be carried away to the liver.
What is the advantage of the villus having a lacteal ?
Collects end products of fat digestion and passes onto the lymphatic system.
