Topics in BiologySkeleton and Type of Skeletal Materials Bones and Types of Bone Bones and Type of Bone part 2 Red Blood Cells and Hemoglobin Tropical Rainforest and Savanna with their characteristics Desert and Swamp Forest with their characteristics Autotrophic mode of Nutrition Amazing facts in Biology Characteristics of Protists Characteristics of Reptiles
Academic Questions in Biology
Chemical digestion of carbohydrate (cooked starch) begins in the _____.
ANSWER is Mouth
The digestion of carbohydrate (cooked starch) begins in the mouth through an enzyme called salivary amylase (formerly called ptyalin) found in the saliva. This enzyme breaks down the starch present in carbohydrates into maltose. Maltose is a disaccharide. Please read on sugars and disaccharide here.
Note: With regards to digestion, chemical digestion is emphasized. We also have mechanical digestion which involves the grinding action of the teeth.
When we reflect on some of the necessities of life, oxygen (O2) will definitely rank among the top. Although oxygen makes up about 21% of the atmosphere, it is still enough to make planet earth livable for its different inhabitant. Please read on the composition of the atmosphere here.
In humans, without the red blood cell and hemoglobin, atmospheric oxygen will be considered a waste because the various bodily cells, tissues and organs will not be able to utilize it for respiration.
Note: Breathing and respiration is NOT the same thing.
Breathing is simply when one inhales and exhales air. Oxygen is inhaled while Carbon(IV)oxide is exhaled.
Respiration is the use of oxygen to break down food in order to generate energy in the form of ATP (ATP stands for Adenosine Tri Phosphate).
In order to make our explanation a little bit simpler, we will look at some of the facts pertaining the red blood cells and hemoglobin.
1. The red blood cell can also be referred to as an erythrocyte.
2. The red blood cells are one of the solid components of the blood; the others being white blood cells and platelets.
Note: Blood is actually a mixture of liquid (plasma) and solid (cells). This is why a blood could be dried and grounded to form a blood meal.
3. An average human being produces up to 2.5 million red blood cells per second.
4. The blood is ordinarily light or pale yellow in color. It is the red blood cells that give it its red coloration.
5. The red blood cell has the shape of a biconcave disc with a thickness of 2.5 micrometers at its edges and less than 1 micrometer at its center.
Image of Red Blood Cells. Credit: The Franklin Institute
6. The red blood cell is very flexible and as a result, it can squeeze through blood capillaries by altering its shape without destroying itself.
Note: Capillaries are very tiny and microscopic blood vessels that operate at the cellular level. (Think of a blood vessel as a pipe that carries blood within our body system. The other blood vessels are the arteries and veins). Read on arterial disorders here.
7. A mature red blood cell has NO nucleus. Instead, it contains hemoglobin within.
8. Some scientists are of the opinion that if the matured red blood cells had a nucleus, the nucleus would be damaged when the red blood cells attempt to pass through the blood capillaries. This damaged nucleus will result in the sudden death of the red blood cell.
9. Red blood cell has no DNA, RNA, mitochondria or any other organelle found in most cells. For this reason, it does not require energy to carry out its functions since the mitochondria (power house of the cell) is absent.
10. In the early weeks of embryonic life, the red blood cells are produced in the yolk sac. They contain nucleus at this time.
11. During the 3rd to 8th months of pregnancy, the red blood cell is produced mainly in the liver. The spleen and lymph nodes also produces some red blood cell during this period.
12. During the last month of pregnancy and after birth, the red blood cells are produced exclusively in the bone marrow.
13. After age 20, the long bones of the human body stop producing red blood cells. Examples of long bones are humerus (bone of the arm) and femur (bone of the thigh). The red blood cells are now produced in the membranous bones. Examples of membranous bones are the vertebrae, sternum and ribs. Please read on bones of the human body here.
14. The major function of the red blood cell is to transport hemoglobin. This implies that the hemoglobin is present inside the red blood cell.
15. It is the hemoglobin in the red blood cell that binds with oxygen to form oxyhemoglobin.
Note: The red blood cell has other functions too. For instance, they initiate the transport of CO2. This is made possible because they contain an enzyme called carbonic anhydrase which catalyzes the reversible reaction between carbon(IV)oxide (CO2) and water (H2O) to form carbonic acid (H2CO3). It is in this form that CO2 is transported back to the lungs for expiration.
16. The red blood cells can bind more strongly to carbon(II)oxide or carbon monoxide (CO) than the rate at which oxygen binds to hemoglobin. This is why death is very rapid in carbon monoxide poisoning.
17. Red blood cells are red when hemoglobin in it is combined with oxygen to form oxyhemoglobin. They become blue after the oxygen has been delivered to the body cells.
18. An average man has 5,200,000 red blood cells per cubic millimeter of blood.
19. An average woman has 4,700,000 red blood cells per cubic millimeter of blood.
20. Erythropoietin is a hormone that stimulates the production of red blood cells. This hormone is produced in the kidneys and an increase in its production is trigged during hypoxia.
Note: Think of hypoxia as when there is very little amount of oxygen in the blood; and as a result, the body tissues lack oxygen too.
21. Iron is very vital in the formation of hemoglobin. This is why it is always present in blood capsules and often recommended for blood building.
22. The red blood cells have an average lifespan of 120 days after which they are destroyed by the liver and spleen respectively.
23. Anemia results when there is little or no hemoglobin in the blood. Anemia will also occur when there are too few red blood cells in the blood.
24. Polycythemia is the presence of too many or excessive red blood cells in the blood. This condition is seen in people that live in high altitude.
Note: The higher the altitude, the lower the oxygen present in the atmosphere.
25. Polycythemia Vera (also called Erythremia) is when there are excessive red blood cells in the blood as a result of genetic aberration.
Amazing facts in Biology
An adult human being is composed of about 60% water. In fact, a newly born baby is composed of about 80% of water. This will drop to 65% after a year and finally to about 60% as the child ages
Without saliva, food can never be enjoyed. Food becomes tasteless since saliva is needed to dissolve the chemicals present in food onto the tongue’s taste buds.
Saliva also contains an enzyme called salivary amylase or "ptyalin" which helps to digest cooked starch to maltose. Maltose is a double sugar or disaccharide. Please read on sugars here
NOTABLE POINTS IN Biology
The gas used in the manufacture of food by plants is Carbon dioxide or Carbon(IV)oxide or CO2.
Plants manufacture food through a process called photosynthesis. Please read on photosynthesis here
Note: Plants are the only orgnisms that take away CO2 from the atmosphere
In the Biological organization of life, it is said that cells form tissues, tissues form organs and organs form systems. There are 12 systems in the human body; these are: