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Deslyn, AHS class 3D. And this is my biology blog!



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Thursday, January 25, 2007

Question One:
1. A picture with explanation of the different parts
2. Description of the analogy.



Nucleolus:
- Spherical shape
- Visible when cell is not dividing
- Contains RNA for protein manufacture

Ribosomes:
- Each cell contains thousands
- Miniature 'protein factories'
- Composes 25% of cell's mass
- Stationary type: embedded in rough endoplasmic reticulum
- Mobile type: injects proteins directly into cytoplasm

Rough Endoplasmic reticulum:
- Tubular network fused to nuclear membrane
- Goes through cytoplasm onto cell membrane
- Stores, separates, and serves as cell's transport system
- Ribosomes embedded in surface

Golgi apparatus:
- Protein 'packaging plant'
- A membrane structure found near nucleus
- Composed of numerous layers forming a sac

Plasma membrane:
- Outer membrane of cell that controls cellular traffic
- Contains proteins (left, gray) that span through the membrane and allow passage of materials

Lysosome:
- Digestive 'plant' for proteins, lipids, and carbohydrates
- Transports undigested material to cell membrane for removal
- Vary in shape depending on process being carried out
- Cell breaks down if lysosome explodes

Mitochondria:
- Second largest organelle with unique genetic structure
- Double-layered outer membrane with inner folds called cristae
- Energy-producing chemical reactions take place on cristae
- Controls level of water and other materials in cell
- Recycles and decomposes proteins, fats, and carbohydrates, and forms urea

A cell is just like a factory, the nucleus acting as the one in charge of everything happening in it. The nucleolus in the nucleus is the key to manufacturing the proteins in the cell. The ribosomes are like the people who make the proteins, working in a particular place, the rough endoplasmic reticulum. They are then brought to lysosomes whereby they are digested. The golgi apparatus is the place where the proteins are then packed and work their way through other materials in the plasma membrane, out of the factory, the cell. Finally, the mitochondrion recycles or decomposes these proteins.




Question Two:
C. If animal cells were to have cell walls, what might happen?
Answer: The cell wall is the outermost covering of a cell, it provides protection for the object as well as an outer structure. The cell wall provides plant cells with a protective covering and keeps the plant rigid, so it can stand up even under pressure from wind, rain, or even snow. This wall is made of cellulose and is also with fibers of other molecules of carbohydrates. It is also due to the lack of a rigid cell wall, that animal cells appear to be circular and they do not have a fixed shape. If there was cell wall present in animal cells, the animal cells will become stiff and rigid, and all would have a fixed shape. Also, if the cell wall was present in the animal cells, then the animal would then be unable to move about freely anymore, and become stationary like a plant.

&6:09 AM

This is my biology blog!
This is my biology blog!
This is my biology blog!
This is my biology blog!
This is my biology blog!

&3:33 AM