Planet Earth and Its Environment A 5000-million year Journey

Part of the Patterns in Nature ModuleBiology in Focus, Preliminary CourseGlenda Childrawi and Stephanie HollisPatterns in NatureTopic 6: Chemicals in CellsDOT PointIdentify the major groups of substances found in living cells and their uses in cell activitiesfaculty.clintoncc.suny.edu

Chemicals in cellsStudies of the ultrastructure of cells reveal a variety of organelles in the cytoplasm that function together so that a cell can carry out life processes.

Our studies will now proceed to a chemical level, the chemicals that make up these cell organelles.cellular-immunity.blogspot.com

Chemicals in cellsThe chemical substances found in cells fit into two main groups: organic substances and inorganic substances.

The term organic should not get mixed up with modern day use of the term organic meaning a product of a farming method that avoids the use of pesticides, artificial fertilisers and herbicides.bms.brookes.ac.uk

Inorganic CompoundsThese are part of the inanimate (nonliving) world. These substances do not contain the element carbon combined with hydrogen and do not have long chains. Examples include:Mineral salts (calcium salts, sodium chloride and phosphorus)WaterSome gases (carbon dioxide and oxygen) CO contains carbon but it has no hydrogen so is inorganic

answers.comInorganic CompoundsMany inorganic substances are required for very specific purposes. For example, calcium is important for bone function and iron is an important component of haemoglobin (the oxygen carrier in red blood cells).

oxygenpf.com.au

Inorganic CompoundsSome mineral ions are enzyme cofactors (they must be present for a particular enzyme function). For example, phosphorus and nitrogen are essential for plant growth and water is a major component of living tissue which must be present for life to exist.

animal-world.com

Organic CompoundsChemical substances that are synthesised by living things and contain atoms of carbon and hydrogen. Carbon atoms bond very strongly with other carbon atoms and form long chains.

These chains are the basis of the large organic molecules made by cells.homepages.ius.edu

Organic CompoundsMost organic compounds are very large molecules termed macromolecules or polymers which include:Carbohydrates (sugars and starch)Lipids (fats and oils)ProteinsNucleic acid (DNA and RNA)Vitamins

answers.comCarbohydratesCarbohydrates are the most common organic compounds in nature. Carbohydrates consist of carbon, hydrogen and oxygen atoms. These include:Monosaccharides Disaccharides Polysachharides

See Handout Pgs 101-102 of Textvisionlearning.com

CarbohydratesMonosaccharides Are the simple sugars that are the building blocks for the more complex carbohydrates. The most common is glucose which is the main product of photosynthesis and is the molecule most commonly used as an energy source in plants and animals.

Sugar glucose: CHOclick4biology.infoCarbohydratesDisaccharides consist of two joined monosaccharaides. These include maltose, lactose and surcose. When carbohydrates are transported from the leaves to other parts of the plant, it is usually in the form of surcose.

worldofmolecules.com

CarbohydratesPolysaccharides Large molecules in which hundreds to thousands of monosaccharides are linked together. Some are used for the storage of energy, others are used for structural purposes.

For example, starch consists of many joined glucose molecules and is used in plants as a storage molecule which can be broken down when energy is needed.

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Carbohydrates Polysaccharides Glycogen is a form of energy stored as granules in the cytoplasm of animal cells.

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Lipids Lipids are also made of carbon, hydrogen and oxygen atoms but they are more energy efficient storage molecules than carbohydrates.

Lipids are organic compounds that have an oily, greasy or waxy consistency. They are relatively insoluble in water.

Lipids Most lipids are made of a glycerol molecule to which fatty acids attach. Triglycerides have three fatty acids attached to each glycerol.

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Lipids Lipids may be fats (solid at room temperature eg: butter) or oils (liquid at room temperature, eg: olive oil). Most fats are animal products and oils are plant products.

Lipids Uses of lipids:Lipids form an extremely important structural part of all membranes in cellsLipids are important biological fuels, storing large quantities of energy for both plant and animal cells.Some lipids are essential structural parts of hormones (chemical messengers produced by cells).

Proteins Proteins are large complex macromolecules and they are the second most abundant chemical in cells. They too are made of carbon, hydrogen, oxygen and often sulfur atoms.

en.wikipedia.org

ProteinsProteins are made up of one or more long chains of nitrogen-containing amino acids. These are the building blocks. There are only 20 amino acids, but their arrangement provides a huge variety of proteins.

DNA determines the actual sequence of amino acids in any protein.

umass.eduProteinsEach chain of amino acids is called a polypeptide which are held together by chemical bonds called peptide bonds.

One or more polypeptide can be twisted together into a particular shape which results in the overall structure of a protein.

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ProteinsProteins form structural components in cells and tissues. Together with water, they form the basic structure of protoplasm (the cytoskeleton) in cells and form parts of tissue such as bone, hair and nails.

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ProteinsProteins are also an important structural part of cell membranes. Together with lipids, they regulate the passage of substances across the cell membrane.

(These proteins are like the bouncers at the door)

library.thinkquest.org

Nucleic AcidNucleic Acids contain carbon, hydrogen and oxygen but also contain nitrogen and phosphorus.

All nucleic acids are made up of simple repeating units (monomers) called nucleotides linked together to form single chains of RNA or double strands of DNA.

chem4kids.com

Nucleic AcidEach nucleotide is made up of a simple sugar (R ribose or D deoxyribose), a phosphate and a nitrogenous base. It is the sequence of bases which differs, providing the genetic code for a cell.

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Nucleic AcidDNA (deoxyribonucleic acid) stores the information that controls the cell thereby the whole organism. Its responsible for transmitting inherited information from one cell to another.

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Nucleic AcidRNA (ribonucleic acid) is found in small amounts in the nucleus and in larger amounts in the cytoplasm. There are three types: one, the messenger which is involved in passing on information that is stored in DNA. The other types assist the message to be translated into proteins (Youll learn more about this in the HSC)

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HomeworkAnswer the following questions in your notebook. Be prepared to discuss next lesson. How do organic and inorganic compounds differ? Identify an example of each.Carbohydrates and lipids contain carbon, hydrogen and oxygen. How do they differ?

Complete 2.1 Prelim Dot Point text pg 29