In this essay, we want to express; Cell Functions and Processes unit the discuss chemical reactions and molecular functions which underlie important chemical processes such energy production and storage, cell respiration, and intracellular interactions. Topics include:
Osmosis is the diffusion of water molecules across a semi-permeable membrane from an area of high concentration to an area of low concentration. In cells, osmosis occurs across the cellular membrane to keep a cell from becoming flaccid (not enough water) or turgid (too much water).
Cellular Energy Production:
There are several types of cellular energy production. Plants produce energy from light through a process known as photosynthesis. Eukaryotic cells use their mitochondria to generate ATP through a process called cell respiration. Respiration that uses oxygen is called aerobic respiration while oxygen-less respiration is called anaerobic respiration.
Cell transport is movement of materials across cell membranes. Cell transport includes passive and active transport. Passive transport does not require energy whereas active transport requires energy to proceed. Passive transport proceeds through diffusion, facilitated diffusion and osmosis.
In order for biological processes to proceed, organisms need to maintain standard internal balances. They do so through systems of negative feedback called homeostasis which ensure that all things happen in moderation. The processes and controls involved in homeostasis vary from organism to organism, but often involve hormonal signals.
Anaerobic respiration is the process of producing cellular energy without oxygen. Anaerobic respiration is a relatively fast reaction and produces 2 ATP, which is far fewer than aerobic respiration. Anaerobic respiration happens in the cytoplasm where glycolysis releases energy from glucose and fermentation recycles NADH back to NAD+.
Aerobic respiration is the process of producing cellular energy involving oxygen. Cells break down food in the mitochondria in a long, multistep process that produces roughly 36 ATP. The first step in is glycolysis, the second is the citric acid cycle and the third is the electron transport system.
Cell diffusion is a type of passive cell transport. In diffusion, molecules move from areas of high concentration to areas of low concentration in order to decrease the concentration gradient. Diffusion from areas of low concentration to areas of high concentration is not energetically favorable.
Photosynthesis is a process found in plant cells which converts light energy into chemical energy in the form of sugars that the plant can store and use at any time. Photosynthesis takes place in the chloroplasts, an organelle only found in plant cells, and consists of two parts: the light dependent reaction, which converts light energy into ATP, and the Calvin cycle, which converts ATP into glucose.
The Calvin cycle is the second step of photosynthesis which converts ATP into glucose for storage. It is also called the “light independent reaction” or the “dark reaction” because unlike the light dependent reaction, light plays no role in the reaction. The Calvin cycle takes place in the stroma, the semi-liquid fluid inside chloroplasts.
The citric acid cycle, also known as the Krebs cycle, is involved in cell respiration and produces NADH and FADH2 for the electron transport chain. The Krebs cycle also produces two ATP, but much more ATP is produced later, in the electron transport chain, so that is not its main purpose.
light dependent reaction:
The light dependent reaction is the first step of photosynthesis which converts light energy into ATP. The light dependent reaction takes place inside the chloroplasts along the thylakoid membrane.
Electron transport system:
The electron transport system is the stage in cellular respiration in which oxidative phosphorylation occurs and the bulk of the ATP is produced. The electron transport system creates an electron gradient inside the mitochondria along the inner membrane so that when protons re-enter the matrix through the ATP synthase, their potential energy is converted into chemical energy in the form of ATP.
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