General Biology 1 - Cell Membrane and Cell structure.pptx

A cell’s membrane is a phospholipid bilayer. These molecules look like a tadpole. It has a head end facing the inside and outside of the cell, and tail end facing each other.

It is made up of two layers that are composed of phospholipid bilayer.The bilayer id formed by arrangement of phospholipids in a manner that their head regions ( which are hydrophilic) face external environment as well as the internal cytosolic environment.
The (hydrophobic) tails of these phospholipids face each other. Forces underlying thr formation of this bilayer are electrostatic, van del Waals, non-covalent interactions, and hydrogen bonds.
This unusual arrangement of hydrophilic and hydrophobic layers doesn’t allow nucleic acids, amino acid, proteins, carbohydrates, and ions to pass through the bilayer.

1. Structure and Function of Cell Membrane

2. Structure It is a very thin and flexible skin covering the cell. 2. It is the outermost layer in animal cell and second innermost layer in plant cells. It lies near to cell wall in plant cells. 3. It is the living membrane. 4. Semipermeable due to presence of fine pores .

3. Structure It is made up of two layers that are composed of phospholipid bilayer.The bilayer id formed by arrangement of phospholipids in a manner that their head regions ( which are hydrophilic) face external environment as well as the internal cytosolic environment.

4. Structure The (hydrophobic) tails of these phospholipids face each other. Forces underlying thr formation of this bilayer are electrostatic, van del Waals, non-covalent interactions, and hydrogen bonds.

5. Structure This unusual arrangement of hydrophilic and hydrophobic layers doesn’t allow nucleic acids, amino acid, proteins, carbohydrates, and ions to pass through the bilayer.

6. Function It protect the cell. To be the barrier keeping the constituents of the cell in and unwanted substances out. To be a gate allowing transport into the cell of essential nutrients and movement from a cell of waste products.

7. Phospholipids make up the cell membrane. Each phospholipid consists of a phosphate head linked to 2 fatty acid chains. The head is hydrophilic and interacts with water. The tails are hydrophobic and hate water. Phospholipids create two layers to make the cell’s double membrane.

8. Parts of the cell membrane

9. Phospholipid bilayer is a double layer made up of phospholipid molecules. These molecules are like a tadpole. It has a head and a tail. The phospholipid head is a hydrophilic (water-loving) because they interact with water outside and inside the cell. The phospholipid tail is a hydrophobic (water-repelling) that is made up of fatty acids, they hate and repel water.

10. Integral Membrane Protein are the proteins of the cell membrane which are completely embedded in the bilayer of phospholipids and have hydrophilic and hydrophobic regions. The region touching the hydrophobic tails are ought to be hydrophobic region whereas the region of the protein exposed to the watery environment are the hydrophilic regions.

11. Their main function is to allow the polar and big molecules to pass across the membrane which are restricted by the phospholipid bilayer. They act as the gate for making the transportation either active or passive easier. All transmembrane protein or the protein involve in transportation of molecules are Integral Membrane Protein but not all Integral Membrane Protein are transmembrane protein.

12. Integral Membrane Proteins are the following:

13. Channel Proteins/ Transport Proteins Channel Proteins are integral proteins that are a transmembrane protein.

14. These molecules move to an area of high concentration to an area with lower concentration. Some channel proteins are always open. It is called non-gated channel protein. It is needed whenever the balance of water and ions must be assisted by the constant passage of water and ions into or out of the cell. Another type of channel protein is the one that opens and shut which is called gated channel protein.

15. It remains closed until it receives a special chemical or electrical signal to open. Channel proteins on the surface of nerve cells reacts to electrical signals created by the flooding of ions through the membrane next to them. As they open, ions spill through and continue the electrical disturbance. This passes a s signal very quickly through the body. Some channel proteins have also a 1- or 2-way process.

16. Marker Proteins/ Glycoproteins/ Cell Recognition Protein Marker proteins are integral membrane protein but not a transmembrane protein. They have carbohydrates in them that extend across the cell membrane and serve to identify the cell. The immune system uses these proteins to identify friendly cells from foreign cell invaders.

17. They serve as a nametag which is unique as fingerprints. These proteins play a very important role especially in organ transplant. If the marker proteins on a transplanted organ are different from those of the original marker proteins of organ, the body will reject the organ and trait it as a foreign invader which will then be attacked by the white blood cells to protect the body.

18. Receptor Proteins There are two types of receptor protein, Membrane receptors associated with signaling are all integral membrane proteins that can transmit signals through the lipid bilayer, while other receptors are known to be peripheral membrane protein.

19. Peripheral Membrane Protein Peripheral proteins are only located in the inner or outer surface of the phospholipid bilayer like floating iceberg. Receptor Proteins are peripheral membrane protein.

20. How cell membrane allows substances to pass through?

21. Essential and continuous parts of the life of a cell are the taking in of nutrients and the expelling of wastes. All of these must pass through the cell membrane. Transport may occur by diffusion and osmosis across the membrane. It can also occur when a vesicle attaches to the cell membrane from the inside and then opens to form a pocket, expelling its contents to the outside.

22. This may be called exocytosis. The cell membrane may also envelope something on the outside and surround it, taking it into the cell. This may be called endocytosis or phagocytosis. There are also processes where molecules move across a membrane from a region of low concentration to a region of high concentration, and this requires a source of energy to "pump" the molecules uphill in concentration. Such processes are called active transport.

23. Chloroplast

24. Cells are the basic unit of structure and function of all life forms. It is made up of several structures or organelles that perform a unique function that facilitates life. The fundamental parts of the cell are the nucleus, cytoplasm and the cell membrane.

25. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION CYTOPLASM Gel-like substance enclosed within the cell membrane, which is made up of water, proteins, lipids, nucleic acids, inorganic salts, etc. It provides structure to cell, support and suspend organelles and cellular molecules CELL STRUCTURE AND FUNCTION

26. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION CELL MEMBRANE Two-layered structure of lipids and proteins It is made up of a phospholipid bilayer. Phospholipids are lipid molecules made up of a phosphate group head and two fatty acid tails. Importantly, the properties of phospholipid molecules allow them to spontaneously form a double-layered membrane. It is selectively permeable which means it only allows entry of materials needed by the cell and eliminates those which are not. CELL STRUCTURE AND FUNCTION

27. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION NUCLEUS Membrane-bound organelle that contains genetic material (DNA). Regulates or control all cell activities. The site for DNA replication, and transcription but not translation. CELL STRUCTURE AND FUNCTION

28. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION GOLGI APPARATUS Composed of stacks of flattened structures that contain numerous vesicles containing secretory granules These organelles help in processing and packaging the Macromolecules like proteins and lipids that are synthesized by the cell and hence act as the‘post office’ of the cell. CELL STRUCTURE AND FUNCTION

29. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION ROUGH ENDOPLASMIC RETICULUM A continuous membrane system that forms a series of flattened sacs Within the cytoplasm. Contains Ribosomes. Transports proteins and other materials CELL STRUCTURE AND FUNCTION

30. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION SMOOTH ENDOPLASMIC RETICULUM Meshwork of fine tubular membrane vesicles, part of a continuous membrane organelle in the cytoplasm of eukaryotic cells Does not have ribosomes attached to it, synthesize lipids CELL STRUCTURE AND FUNCTION

31. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION CENTRIOLE An organelle inside animal cells that are made of microtubules Only found in animal cells, Aid in Cell division, it organizes things that help in cell division CELL STRUCTURE AND FUNCTION

32. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION NUCLEOLUS This structure is made up of proteins and ribonucleic acids (RNA) Helps in protein synthesis and production of the ribosome in the cells CELL STRUCTURE AND FUNCTION

33. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION MITOCHONDRION They are made of two membranes. The outer membrane covers the organelle and contains it like a skin. The inner membrane folds over many times and creates layered structures called cristae. Helps in protein synthesis and production of the ribosome in the cells CELL STRUCTURE AND FUNCTION

34. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION LYSOSOME Membrane-bound cellorganelle that contains digestive enzymes “Suicide Sacks”. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. They clean out all unnecessary materials inside the cell. CELL STRUCTURE AND FUNCTION

35. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION RIBOSOMES They are composed of special proteins and nucleic acids Site for mRNA translation. This is where proteins are made from the mRNA coming from the nucleus. CELL STRUCTURE AND FUNCTION

36. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION VACUOLES It is a sphere filled with fluid and molecules inside a cell, are membrane- bound sacs within the cytoplasm. They store nutrients, water and food and increase cell size during growth. CELL STRUCTURE AND FUNCTION

37. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION CHLOROPLAST Filled with saclike chlorophyll which is the green pigment used in photosynthesis Found only in plant cell, Site of photosynthesis (food-making process of plants) CELL STRUCTURE AND FUNCTION

38. CELL ORGANELLE STRUCTURE FUNCTION ILLUSTRATION CELL WALL It can be tough, flexible, and sometimes rigid. Composed of the polysaccharides cellulose, hemicelluloses and pectin. Can only be seen in plant cell. It gives shape and protection to the cell. CELL STRUCTURE AND FUNCTION

39. An organelle is like the internal organ of a cell. It is a membrane bound structure found within a cell. The organelles are structures that has their specific function to facilitate life processes of the cell .

40. The mitochondrion, Golgi apparatus, endoplasmic reticulum, vacuole, ribosome and lysosome are common to both plants and animal cells. Centrioles are only found in animal cells while cell wall and chloroplast are only found in plant cells.

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