Lesson 4:
All cells are surrounded by a plasma membrane, which separates the cell from its environment. Some cells, such as plant cells, have an additional cell wall to provide structure and support. The cell membrane is comprised of a 50:50 mix of proteins and lipids, fit together in a mosaic. The proteins serve various functions: some of the proteins have pores, through which substances can flow into and out of the cell; some serve as receptors that identify and attach to a specific molecule, such as a hormone or nutrient that is important for cell function. Some are identity markers, such as the ABO blood types. Some are enzymes. Some are receptors that change the function of the cell, such as opening or closing channels, Some are anchors that hold fibers within the cell to keep its shape. The plasma membrane is a complex structure, not just a film around the cell.
Inside the cell are the organelles:
Deep inside the cell is the nucleus, or in the case of bacteria, the nucleoid. This is where the DNA and corresponding RNA (which is similar to a mirror copy of the DNA) resides and is reproduced.
Next to the nucleus are the ribosomes. The proteins that are used inside the cell are created in the ribosomes. It takes about 50 proteins to make a ribosome, and ribosomes are the factories for making proteins.
All cells but bacterial cells have an endoplasmic reticulum. This is where proteins are created for use outside of the cell or for the cell membrane. It also provides the surface area needed for chemical reactions within the cell. It transports products from one part of the cell to another, adds sugars to proteins, creates fatty acids, phospholipids, and steroids. Enzymes are chemicals that break bonds in molecules to break the molecule apart or attach them in different ways. Enzymes in the endoplasmic reticulum also can detoxify chemicals such as alcohol, pesticides, and carcinogens (cancer-causing chemicals).
In the Golgi apparatus, proteins are repackaged, modified, and excreted out of the cell. It's like the shipping department.
There are also Lysosomes within the cell, which are membrane-enclosed vesicles of enzymes needed for recycling materials or digesting bacteria. Amazingly, their membranes are impermeable to their own enzymes, to keep them from digesting themselves.
Mitochondria are the metabolism of the cell. They are surrounded by a double membrane: a smooth outer layer, and an inner layer with a series of folds. This increases the surface area for chemical reactions involved in producing energy for the cell. Mitochondria are self replicating. If the cell needs more energy, the mitochondria divide and reproduce themselves by the DNA that is part of the mitochondrial structure.
Finally, there is the cytoskeleton. This is a network of filaments (proteins) that produce movement of the cell and movement of the organelles and chemicals within the cell.
All cells but bacterial cells have these components. Bacterial cells have only the nucleoid, which is less defined than the nucleus of other types of cells and ribosomes. They usually only have one chromosome (double strand of DNA) instead of multiple pairs of chromosomes. One might conclude that the simple bacterial cell developed into the more complex cells via evolution, but there is no progression in the record. There is either the bacterial cell structure (prokaryotic) or the other (eukaryotic). The other organelles are all or nothing. No cell has only some of them.
For life to move beyond the single bacterial cell to any other organism, all of the other structures must be in place for the organism to survive. There is no organelle that could be removed and have the organism survive.
Science has yet to create a gene for even one new protein, create DNA or RNA in a lab.
• So, given the complexity of DNA and cell structure, what makes more sense: purposeful design by our creator, or random chance? • Can you think of any way that DNA or cells in general, could have evolved?
Many scientists understand that this complexity is an insurmountable barrier to their evolutionary belief system. Since they recognize that life could not have evolved on earth, even if given infinite time and chance, they turn to “panspermia” – the idea that life on earth was transported from other planets. They do this hoping that somehow conditions somewhere else could have allowed life to evolve, under some unknown and unseen circumstances.
• Does this help support their evolutionary beliefs? No, this just kicks the ball down the road.
The Bible clearly tells us how life came to be. Our efforts to find alternative origin theories do not stand up to scrutiny. It takes more faith not to believe the Bible than it does to believe!
All cells are surrounded by a plasma membrane, which separates the cell from its environment. Some cells, such as plant cells, have an additional cell wall to provide structure and support. The cell membrane is comprised of a 50:50 mix of proteins and lipids, fit together in a mosaic. The proteins serve various functions: some of the proteins have pores, through which substances can flow into and out of the cell; some serve as receptors that identify and attach to a specific molecule, such as a hormone or nutrient that is important for cell function. Some are identity markers, such as the ABO blood types. Some are enzymes. Some are receptors that change the function of the cell, such as opening or closing channels, Some are anchors that hold fibers within the cell to keep its shape. The plasma membrane is a complex structure, not just a film around the cell.
Inside the cell are the organelles:
Deep inside the cell is the nucleus, or in the case of bacteria, the nucleoid. This is where the DNA and corresponding RNA (which is similar to a mirror copy of the DNA) resides and is reproduced.
Next to the nucleus are the ribosomes. The proteins that are used inside the cell are created in the ribosomes. It takes about 50 proteins to make a ribosome, and ribosomes are the factories for making proteins.
All cells but bacterial cells have an endoplasmic reticulum. This is where proteins are created for use outside of the cell or for the cell membrane. It also provides the surface area needed for chemical reactions within the cell. It transports products from one part of the cell to another, adds sugars to proteins, creates fatty acids, phospholipids, and steroids. Enzymes are chemicals that break bonds in molecules to break the molecule apart or attach them in different ways. Enzymes in the endoplasmic reticulum also can detoxify chemicals such as alcohol, pesticides, and carcinogens (cancer-causing chemicals).
In the Golgi apparatus, proteins are repackaged, modified, and excreted out of the cell. It's like the shipping department.
There are also Lysosomes within the cell, which are membrane-enclosed vesicles of enzymes needed for recycling materials or digesting bacteria. Amazingly, their membranes are impermeable to their own enzymes, to keep them from digesting themselves.
Mitochondria are the metabolism of the cell. They are surrounded by a double membrane: a smooth outer layer, and an inner layer with a series of folds. This increases the surface area for chemical reactions involved in producing energy for the cell. Mitochondria are self replicating. If the cell needs more energy, the mitochondria divide and reproduce themselves by the DNA that is part of the mitochondrial structure.
Finally, there is the cytoskeleton. This is a network of filaments (proteins) that produce movement of the cell and movement of the organelles and chemicals within the cell.
All cells but bacterial cells have these components. Bacterial cells have only the nucleoid, which is less defined than the nucleus of other types of cells and ribosomes. They usually only have one chromosome (double strand of DNA) instead of multiple pairs of chromosomes. One might conclude that the simple bacterial cell developed into the more complex cells via evolution, but there is no progression in the record. There is either the bacterial cell structure (prokaryotic) or the other (eukaryotic). The other organelles are all or nothing. No cell has only some of them.
For life to move beyond the single bacterial cell to any other organism, all of the other structures must be in place for the organism to survive. There is no organelle that could be removed and have the organism survive.
Science has yet to create a gene for even one new protein, create DNA or RNA in a lab.
• So, given the complexity of DNA and cell structure, what makes more sense: purposeful design by our creator, or random chance? • Can you think of any way that DNA or cells in general, could have evolved?
Many scientists understand that this complexity is an insurmountable barrier to their evolutionary belief system. Since they recognize that life could not have evolved on earth, even if given infinite time and chance, they turn to “panspermia” – the idea that life on earth was transported from other planets. They do this hoping that somehow conditions somewhere else could have allowed life to evolve, under some unknown and unseen circumstances.
• Does this help support their evolutionary beliefs? No, this just kicks the ball down the road.
The Bible clearly tells us how life came to be. Our efforts to find alternative origin theories do not stand up to scrutiny. It takes more faith not to believe the Bible than it does to believe!
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