Spongy Mesophyll Layer: Loosely packed cells, which are covered with a thin film of water, allows diffusion of gases. These have large air spaces.
B5 and B6
Nutrition can be defined as the:
-Taking in of nutrients, which contain raw materials, or energy which are absorbed and assimilated and then can be used for growth and repair.
Food Tests
Starch: Iodine solution (Positive test: Black/blue)
Reducing Sugar: Benedicts Solution (Positive test: orange/red)
Protein: Biuret Test (purple/violet)
Fats: Ethanol (white emulsion)
Enzymes: The substrate fits into a special part of the enzyme called the active site. If the enzyme no longer works, we say its denatured.
Some enzymes are…
-Amylase: In the saliva, breaks down starch into sugar.
-Protease: Made in the pancreas, it breaks down protein into amino acids using the enzyme pepsin.
-Lipase: Made in the pancreas, it breaks down fat.
B7 Transport in Plants
How the xylem works
- Water enters the root hairs.
- Water moves to the xylem vessels in the center of the root.
- Water moves in the xylem vessels. These vessels are in vascular bundles near the outside of the stem.
- Water moves through the xylem vessels in vascular bundles in the leaves.
- Water evaporates inside the leaf, and diffuses into the air through the stomata on the underside of the leaf.
The Phloem
Organic compounds are transported in the phloem. This movement is called translocation.
B8 Transport in Humans
The Heart: Pumps blood around the body.
There are 4 main compartments in the heart.
Blood flows into the right atrium through the vena cava. The blood is then pumped into the right ventricle. Tricuspid valves divide the right atrium and right ventricle to prevent backflow of blood.
Then the blood flows through the pulmonary artery into the lungs. After the blood as has oxidized it goes through the pulmonary vein and into the left atrium. The blood then flows into the left ventricle and finally exits the heart through the aorta.
Artery: Thick, elastic walls so that it does not burst. Small lumen (where the blood flows through)
Arteries carry oxygenated blood to the organs.
Vein: Thin walls, valves to prevent backflow of blood. Large Lumen.
Veins carry deoxygenated blood to the heart.
Capillary: Single cell walls
Red Blood Cells
Red blood cells are small so that it can easily fit into capillaries. They are biconcave so that there is a larger surface area. They don’t have a nucleus so that there is more room for cytoplasm. Cytoplasm contains hemoglobin and hemoglobin carries oxygen around the body.
White Blood cells
White blood cells are larger and have a large nucleus. They are transparent. Their function is to defend the body against infects by bacteria and viruses.
There are 2 types of white blood cells.
Phagocytes: Phagocytes engulf foreign material.
Lymphocytes: These make antibodies, which attack and destroy bacteria and viruses. Antibodies are proteins, which are secreted by the lymphocytes.
All cells have antigen or recognition markers on their surface that will stimulate a specific lymphocyte to produce antibodies that will inactivate or destroy the foreign cell.
Platelets
Platelets are tiny fragments of cells found in the blood. Their function is to help blood to clot by clumping together at the site of a wound.
Plasma
This is the liquid part of the blood. It is a solution of materials, which are being transported such as glucose, amino acids, minerals, urea, carbon dioxide, and hormones and also heat.
P9 Respiration
Anaerobic and Aerobic Respiration
Aerobic Respiration
This is the release of energy in cells by the breakdown of food substances in the presence of oxygen.
Aerobic respiration releases a relatively large amount of energy from food. Some of this energy is lost as heat, but the body for uses the rest for:
-Keeping warm
-Muscles
-Growing and repairing cells.
Anaerobic Respiration:
This is the release of a relatively small amount of energy by the breakdown of food substances in the ABSENCE of oxygen. Some of the energy remains in the end products.
A byproduct of anaerobic respiration is Lactic Acid. Lactic acid makes the muscles feel cramped and therefore only allow us to exercise for a short period of time. The lactic acid diffuses into the blood and is then broken down in the liver. You breathe faster after exercise because your liver needs the extra oxygen to break down the lactic acid. This is called paying off your OXYGEN DEBT.
The Human Breathing System
Trachea-Bronchus-Bronchiole-Alveoli.
The Alveoli
Alveoli are adapted for gas exchange, some of the features that would suggest this are…
-The have a large surface area
-The walls of the alveoli ate thin
-They are moist (to dissolve oxygen)
In Alveolus In Blood
High Oxygen Concentration Oxygen Low Concentration
Low carbon dioxide concentration Carbon Dioxide high concentration
Other Additional Information
Protein is a long chain of amino acids
Starch is a long chain of glucose molecules
