02 Components of the Cell and its Internal Working
Molecules of Life [TB Order]¶
Animals store excess glucose in the form of Glycogen.
Cellulose can't be digested by humans, and only ruminating animals like cows can do so through the help of the microorganisims in their intestines which help them break them down. Although we can't digest it, it is good for us as the lining of our intestines secrete mucus which allows food to pass freely.
A pound of fat contains more than the twice the amount of energy as compared to a pound of carb. The downside is it's very hard to get rid of them as they are stored deep in our adipose tissues which swell or shrink as we deposit or withdraw fat from them.
Unsaturated fatty acids are those which have fewer than the max number of hydrogen atoms. They appear bent. For a fat to be saturated all 3 components need to be straight.
Sometimes a food manufacturer wants to use vegetable oil but wants the end product to be solid, in that case adds hydrogen, this process is called hydrogenation. Unfortunately, hydrogenation also leads to trans fat which are very detrimental to our health. Some fats like omega 3 are very healthy for us, these are found in foods like nuts and salmons.
Cholesterol is a base steroid on top of which other hormones like testosterone is made. Anabolic steroids mimic testosterone, these are given to treat diseases like cancer and AIDS, but athletes abuse this and the use of this has dangerous side effects such as depression, liver damage, violent behavior.
Changing one element's sequence in proteins can be very detrimental as it affects the proteins ability to function. Eg. Substitution of one amino acid in hemoglobin incorrectly results in sickle cell disease, an inherited blood disorder.
High Fever are dangerous for this very reason as with the inc in temp, the proteins tend to lose their shape.
Linking of Ribonucleic Acid can be represented as:¶
| Base-1 | Base-2 |
|---|---|
| Adenosine | Guanine |
| Cytosine | Thymine / Uracil |
Difference between RNA and DNA:¶
| Category | DNA | RNA |
|---|---|---|
| Full name | Deoxyribonucleic acid | Ribonucleic acid |
| Sugar | Deoxyribose | Ribose |
| Bases | Adenine (A), Guanine (G), Cytosine (G), Thymine (T) | Adenine (A), Guanine (G), Cytosine (C), Uracil (U) |
| Structure | Double-stranded helix | Single-stranded helix |
| Function | Stores genetic information | Transfers genetic information and assists in protein synthesis |
Termninology in this module:¶
| Term | Equivalent |
|---|---|
| Starch | Amylose |
| Indigestible fibres | Cellulose |
| Animal starch | Glycogen |
A Tour of the Cell [TB Order]¶
Plasma Membrane: - Made of Phospholipids which comprise of phospholipid bilayer, one for hydrophilic head and other for hydrophobic tail. - Inside the bilayer, it mostly comprises of proteins which regulates what goes in and out. It can freely move and is called Fluid Mossaic.
Superbug : Ruptures the plasma membrane, causing a staph infection. Mostly occurs in schools, hospitals and gyms.
Animal cells lack cell wall, but compensate w the help of an extracellular matrix (protein collagen).
Nucleus : - It is separated from the cytoplasm by a double membrane called the nuclear envelope. It has holes. - Long DNA molecules and associated proteins from fibres called chromatin are present, each chromatin fibre has one chromosome.
Ribosomes : - Some case the proteins made by ribosomes are made in nucleus and are transported to the cytoplasm through the pores of the nuclear envelope, in other cases they are in the cytoplasm itself, making proteins that remain fluid within the cell, sometimes even connected to the ER. - Cells that make a lot of proteins have a lot of ribosomes.
Endoplasmic Reticulum: - Rough ER : To make more plasma membrane, it can budd off. Cells that secrete a lot of protein such as your salivary glands, which secrete enzymes in your mouth are rich in rough ER. - Smooth ER: Repro hormones are rich in smooth ER. They help in detoxification, example liver cells as well. This eventually strengthen's the body's tolerance to that drug, therefore requiring more dosage to have the same effect.
Golgi Apparatus : Is the ship port of the cell.
Lysomes: Safe area for animale cells to digest large proteins, nucleic acids .etc. without decomposing itself. It can also engulf organelles within the cell, essentially recycling it. Heriditary disorders occur as a result of lysome storage disease.
Vacuoles : Can pump out or accept water based on need. Central Vacuole comprises of more than half the volume of a mature plant cell. Some cells of flowering plants, in their vacuoles may have pigments present in them to attract pollinating insects. Other plants store toxic elements in their vacuoles to protect themselves against plant eating animals.
Plants have both chloroplasts and mitochondria but animals only have mitochondria.
Cytoskeleton shape is maintained using microtubules.
Movement in Cells: - Cilia : Short hair liked strucutres that are many in number and move back and forth in a coordinated fashion. Eg - Cilia in windpipe that are responsible to sweep mucus in the respiratory system get damages due to smoking leading to respiratory complications in smokers. - Flagella : They are singular, whip - like structures that help in movement os sperms during fertilization. The problems with flagella often times lead to infertility problems. - Pilli : Helps in attachment to surfaces.