Question 1
The model we use to explain how the cell membrane works is called a fluid mosaic model. The Fluid mosaic model was created by S.J Singer and Garth Nicolson in 1972. Between the living machinery of the inner cell and the harsh conditions of the outside world, stands the cells plasma membrane. As crucial as this barrier is, its surprisingly flexible, push it and it will move, poke hard enough and it will break and begin to regroup. We first look at the molecule called phospholipids when thinking about the plasma membrane. Lipids usually have three fatty acid chains, however this molecule has two fatty acid chains. Instead of the third fatty acid chain, a phosphate group is added on. This phosphate group is what makes the phospholipids so special. It is polar and hydrophilic, whereas the rest of the molecule is non-polar and hydrophobic. The hydrophilic heads point outwards as it attracts water molecules, whereas as the hydrophobic tails point inwards due to its mutual attraction and water repulsion. Therefore creating the phospholipid bilayer, which is the basis of all cellular membranes. Throw in some cholesterol and some carbohydrates and you have the basic structure of a plasma membrane. From chemical analysis, we conclude that there are protein in the cell membrane. Using freeze-fracture imaging and scanning electron microscope, we are able to differentiate between the extracellular surface of the membrane and the inside lipid bilayer. Within these lipid molecules, we also find different proteins, which do various things for the cell. For instance, they receive signal from the world outside, and also transport nutrients and waste. So nature composes the membrane with a composition or mosaic of different lipids, carbo...
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...y is generated, that energy being ATP. It is a folded membrane inside a membrane. The mitochondria looks a lot like a bacteria, and thats because scientists think that they became parts of our cells through endosymbiotic theory. In other words, they became parts of the cell, they produce ATP for that cell and then they get a place to live. Evidence supporting this theory being the fact that the mitochondria produces its own DNA through binary fission. The lysosome has sometimes been coined as the suicide sac. Lysosomes has digestive enzymes inside it that is contained within a membrane. A lysosome could go next to a vesicle that has material that we want to break down and those digestive enzymes will go in there and break it down. Lysosomes gets its name from when it pops the digestive enzymes would go throughout the cell and would kill the cell, dissolve the cell.
16. Describe two evolutionary consequences if the process of crossing over in meiosis ceased to occur. If crossing over in meiosis ceased to occur there would be less genetic variations and no diversity among a species. This would essentially mean that a species would not be able to adapt to an issue that could arise in the future, meaning that its species could potentially become extinct due to climate change or other arising events.
plasma membranes, meaning animals and plants contain lipids. In this paper I will display and
They are very tiny compared to other cells in the body and are also flexible membranes therefore, they can squeeze through the capillaries to transport oxygen closer to the cells. It is primarily composed of phospholipid bilayers, cholesterol, proteins and carbohydrates. The structure of the cell membrane is known as fluid mosaic structure. This is because the ‘fluid’ represents that membrane can move freely around the ‘mosaic’. This describes the pattern produced by the scattered protein molecules found in the phospholipid bilayer.
If a cell was a restaurant the cell wall would be like the walls of the restaurant because the walls protect the restaurant from the outside and gives shape to the restaurant in the same way the cell wall protects,supports,and gives shape to the cell. The cell membrane would be like the doors of the restaurant because the doors allow people to go
Mitochondria are tiny organelles found in nearly all eukaryotic cells. They are rather large organelles ranging from 0.5µm to 10µm in length and 1µm in diameter. The mitochondria are the energy factories of the cell and are located in the cytoplasm. They are the sites of cellular respiration. The mitochondria are responsible for generating ATP from such organic fuels as simple sugars and fats in the process of cellular respiration. This doubled-membrane organelle has its own DNA and can reproduce by splitting itself.
The cell plasma membrane, a bilayer structure composed mainly of phospholipids, is characterized by its fluidity. Membrane fluidity, as well as being affected by lipid and protein composition and temperature (Purdy et al. 2005), is regulated by its cholesterol concentration (Harby 2001, McLaurin 2002). Cholesterol is a special type of lipid, known as a steroid, formed by a polar OH headgroup and a single hydrocarbon tail (Wikipedia 2005, Diwan 2005). Like its fellow membrane lipids, cholesterol arranges itself in the same direction; its polar head is lined up with the polar headgroups of the phospholipid molecules (Spurger 2002). The stiffening and decreasing permeability of the bilayer that results from including cholesterol occurs due to its placement; the short, rigid molecules fit neatly into the gaps between phospholipids left due to the bends in their hydrocarbon tails (Alberts et al. 2004). Increased fluidity of the bilayer is a result of these bends or kinks affecting how closely the phospholipids can pack together (Alberts et al. 2004). Consequently, adding cholesterol molecules into the gaps between them disrupts the close packing of the phospholipids, resulting in the decreased membrane fluidity (Yehuda et al. 2002).
its original shape and shape. Within the phospholipid bi-layer there are proteins, and these. proteins are made up of polypeptide chains which are joined together. by hydrogen, hydrophobic and peptide bonds. Once the temperature has increased above 40°C the molecules vibrate so energetically that these bonds break easily and therefore create holes within the cell wall.
Biology literally means "the study of life". Biology is such a broad field, covering the minute workings of chemical machines inside our cells, to broad scale concepts of ecosystems and global climate change. Biologists study intimate details of the human brain, the composition of our genes, and even the functioning of our reproductive system. Biologists recently all but completed the deciphering of the human genome, the sequence of deoxyribonucleic acid (DNA) bases that may determine much of our innate capabilities and predispositions to certain forms of behavior and illnesses. DNA sequences have played major roles in criminal cases (O.J. Simpson, as well as the reversal of death penalties for many wrongfully convicted individuals), as well as the impeachment of President Clinton (the stain at least did not lie). We are bombarded with headlines about possible health risks from favorite foods (Chinese, Mexican, hamburgers, etc.) as well as the potential benefits of eating other foods such as cooked tomatoes. Informercials tout the benefits of metabolism-adjusting drugs for weight loss. Many Americans are turning to herbal remedies to ease arthritis pain, improve memory, as well as improve our moods. Can a biology book give you the answers to these questions? No, but it will enable you learn how to sift through the biases of investigators, the press, and others in a quest to critically evaluate the question. To be honest, five years after you are through with this class it is doubtful you would remember all the details of meatbolism. However, you will know where to look and maybe a little about the process of science that will allow you to make an informed decision. Will you be a scientist? Yes, in a way. You may not be formally trained as a science major, but you can think critically, solve problems, and have some idea about what science can and cannoit do. I hope you will be able to tell the shoe from the shinola.
The mitochondria produces food for the cell by converting energy the cell needs. The mitochondria and the nucleus are two organelles within a cell that have many of the same similarities. Both organelles are made of two membranes. These layers isolate within the organelle all things considered, yet have protein channels that permit things to go in and out. Both contain DNA material that conveys qualities that encode for proteins. Both have qualities that make ribosomes, the machines that read the guidelines in RNA to make
The mitochondria is an organelle which is generally an oval shape and is found inside the cytoplasm and is again apart of the eukaryotic cells. The main function of the mitochondria is to complete cellular respiration; in simple terms it acts like a digestive system to break down essential nutrients and to convert it into energy. This energy is usually found to in ATP which is a rich molecule taken from the energy stored in food. Furthermore, mitochondria stores calcium for signalling activities; such as heat, growth and death. They have two unique membranes and mitochondria isn’t found in human cells like the red blood cells yet liver and muscle cells are filled entirely with mitochondria.
Cell membranes are selectively permeable which can let things in and kick some out. The cell membrane is liquidly and is made out of different things like a mosaic. That’s how the cell membrane got its name fluid mosaic model. The fluid mosaic model of the cell membrane has a different mixture of phospholipids, cholesterol, and proteins. The carbohydrates are attached
Synoptic Biology Synoptic biology is the ability to select and apply general principles. unfamiliar situations/data to be used. Modules 5 and 8 will have questions that test your understanding of modules 1,2,3 and 4. This is called the synoptic assessment. The synoptic element of modules 5 and 8 is worth more marks than the actual module content.
There are many functions lipids have. One of the main functions lipids are structural components in the cell. Lipids make up approximately 50% of the mass of most cell membranes. The lipids that are found in the cell membrane are called phospholipid. Phospholipid are the predominant lipids of cell membrane. Phospholipids aggregate or self-assemble when mixed with water, but in a different manner than the soaps and detergents. Because of the two pendant alkyl chains in phospholipids and the unusual mixed charges in their head groups, micelle formation is unfavorable relative to a bilayer structure.
Plasma membrane is made up of two layers of phospholipids which are a class of lipids and has many proteins embedded in it. The proteins have a function of providing support and shape to a cell. There are three different proteins in cell membranes (see appendix 1). The plasma membrane also regulates the entry and exit of the cell, as many molecules cross the cell membrane by osmosis and Prokaryotes include several kinds of microorganisms, such as bacteria and cyanobacteria. Eukaryotes include microorganisms as fungi, protozoa, and simple algae.
membranes and are also a component of energy depositing molecules like the ATP and ADP.