How to register and join MyElimu CLICK HERE

Post Reply 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Giltwizy Offline
Youth 4 Change

Posts: 2
Likes Given: 1
Likes Received: 1 in 1 posts
Joined: Mar 2014
Reputation: 0
Friend:  Add as Friend

Points: 0.00 points
Post: #1

 [size=18pt]I. Cells Contain Organic Molecules[size=14pt]A. Most Common Elements[size=14pt]1. Most common elements in living things are carbon, hydrogen, nitrogen, and oxygen.[size=14pt]2. These four elements constitute about 95% of your body weight.[size=14pt]3. Chemistry of carbon allows the formation of an enormous variety of organic molecules.  [Image: c12.gif][size=14pt]4. Organic molecules have carbon and hydrogen; determine structure and function of living things.[size=14pt]5. Inorganic molecules do not contain carbon and hydrogen together; inorganic molecules (e.g., NaCl) can play important roles in living things.  [Image: naclspfil.GIF][size=14pt]B. Small Molecules Have Functional Groups[size=14pt]1. Carbon has four electrons in outer shell; bonds with up to four other atoms (usually H, O, N, or another C).  [Image: bondtypes.jpg][size=14pt]2. Ability of carbon to bond to itself makes possible carbon chains and rings; these structures serve as the backbones of organic molecules.[size=14pt]3. Functional groups are clusters of atoms with characteristic structure and functions.[size=14pt]a. Polar molecules (with +/- charges) are attracted to water molecules and are hydrophilic.  [Image: watermolsmall2.jpg][size=14pt]b. Nonpolar molecules are repelled by water and do not dissolve in water; are hydrophobic.[size=14pt]c. Hydrocarbon is hydrophobic except when it has an attached ionized functional group such as carboxyl (acid) ( [Image: bioche1.jpg]COOH); then molecule is hydrophilic.  [Image: mol1.GIF][size=14pt]d. Cells are 70-90% water; degree organic molecules interact with water affects their function.  [Image: watermolsmall3.jpg][size=14pt]4. Isomers are molecules with identical molecular formulas but differ in arrangement of their atoms #000000 solid;margin:15px;width:95%;">
\\"[Image: \\"[Image:
  [size=14pt]C. Large Organic Molecules Have Monomers[size=14pt]1. Each small organic molecule can be a unit of a large organic molecule called a macromolecule.[size=14pt]2. Small organic molecules (e.g., monosaccharides, glycerol and fatty acid, amino acids, and nucleotides) that can serve as monomers, the subunits of polymers.[size=14pt]3. Polymers are the large macromolecules composed of three to millions of monomer subunits.[size=14pt]4. Four classes of macromolecules (polysaccharides or carbohydrates, triglycerides or lipids, polypeptides or proteins, & nucleic acids such as DNA & RNA) provide great diversity.[size=14pt]D. Condensation Is the Reverse of Hydration[size=14pt]1. Macromolecules build by different bonding of different monomers; mechanism of joining and breaking these bonds is condensation and hydrolysis.[size=14pt]2. Cellular enzymes carry out condensation and hydrolysis of polymers.[size=14pt]3. Condensation involves a dehydration synthesis because a water is removed (dehydration) and a bond is made (synthesis).[size=14pt]a. When two monomers join, a hydroxyl ( [Image: bioche1.jpg]OH) group is removed from one monomer and a hydrogen is removed from the other.[size=14pt]b. This produces the water given off during a condensation reaction.  [Image: dhsprot5.jpg][size=14pt]4. Hydrolysis (hydration) reactions break down polymers in reverse of condensation; a hydroxyl
[Image: bioche2.jpg]OH) group from water attaches to one monomer and hydrogen ( [Image: bioche1.jpg]H) attaches to the other.

[size=18pt]II. Carbohydrates[size=14pt]A. Monosaccharides, Disaccharides, and Polysaccharides[size=14pt]1. Monosaccharides are simple sugars with a carbon backbone of three to seven carbon atoms.  [Image: hexoses.jpg][size=14pt]a. Best known sugars have six carbons (hexoses).  [Image: glucose1.jpg][size=14pt]1) Glucose and fructose isomers have same formula (C6H12O6) but differ in structure.[size=14pt]2) Glucose is commonly found in blood of animals; is immediate energy source to cells.[size=14pt]3) Fructose is commonly found in fruit.[size=14pt]4) Shape of molecules is very important in determining how they interact with one another.[size=14pt]2. Ribose and deoxyribose are five-carbon sugars (pentoses); contribute to the backbones of RNA and DNA, respectively.[size=14pt]3. Disaccharides contain two monosaccharides joined by condensation.[size=14pt]a. Sucrose is composed of glucose and fructose and is transported within plants.[Image: VLObject-800-021205011213.gif][size=14pt][size=14pt]b. Lactose is composed of galactose and glucose and is found in milk.[size=14pt]c. Maltose is two glucose molecules; forms in digestive tract of humans during starch digestion.  [Image: maltose.gif] #000000 solid;margin:15px;width:95%;">[th]
 [size=14pt]B. Polysaccharides Are Varied in Structure and Function[size=14pt]1. Polysaccharides are chains of glucose molecules or modified glucose molecules [size=14pt]a. Starch is straight chain of glucose molecules with few side branches.  [Image: starch_yellow2.gif][size=14pt]b. Glycogen is highly branched polymer of glucose with many side branches; called "animal starch," it is storage carbohydrate in the liver of animals.  [Image: glycogen_yellow.gif][size=14pt]c. Cellulose is glucose bonded to form microfibrils; primary constituent of plant cell walls.  [Image: cellulose.gif][size=14pt]d. Chitin is polymer of glucose with amino acid attached to each; it is primary constituent of crabs and related animals like lobsters and insects.[size=18pt]III. Lipids[size=18pt][size=14pt]A. Lipids[size=14pt]1. Lipids are varied in structure.[size=14pt]2. Many are insoluble in water because they lack polar groups.[size=14pt]B. Fats and Oils Are Similar[size=14pt]1. Each fatty acid is a long hydrocarbon chain with a carboxyl (acid) group at one end.[size=14pt]a. Because the carboxyl group is a polar group, fatty acids are soluble in water.[size=14pt]b. Most fatty acids in cells contain 16 to 18 carbon atoms per molecule.  [Image: hcfattyacid.gif][size=14pt]c. Saturated fatty acids have no double bonds between their carbon atoms. (C-C-C-)[size=14pt]d. Unsaturated fatty acids have double bonds in the carbon chain.(C-C-C-C=C-C-)  [Image: satunsatfa.gif][size=14pt]e. Saturated animal fats are associated with circulatory disorders; plant oils can be substituted for animal fats in the diet.[size=14pt]2. Glycerol is a water-soluble compound with three hydroxyl groups.[size=14pt]3. Triglycerides are glycerol joined to three fatty acids by condensation  [Image: Lipid1.GIF][size=14pt]4. Fats are triglycerides containing saturated fatty acids (e.g., butter is solid at room temperature).[size=14pt]5. Oils are triglycerides with unsaturated fatty acids (e.g., corn oil is liquid at room temperature).[size=14pt]6. Fats function in long-term energy storage in organisms; store six times the energy as glycogen.[size=14pt]C. Waxes Are Nonpolar Also[size=14pt]1. Waxes are a long-chain fatty acid bonded to a long-chain alcohol.[size=14pt]a. Solid at room temperature; have a high melting point; are waterproof and resist degradation.[size=14pt]b. Form protective covering that retards water loss in plants; maintain animal skin and fur.[size=14pt]D. Phospholipids Have a Polar Group[size=14pt]1. Phospholipids are like neutral fats except one fatty acid is replaced by phosphate group or a group with both phosphate and nitrogen  [Image: lecithin.jpg][size=14pt]  2.Phosphate group is the polar head: hydrocarbon chain becomes nonpolar tails[size=14pt]3. Phospholipids arrange themselves in a double layer in water, so the polar heads face outward toward water molecules and nonpolar tails face toward each other away from water molecules.  [Image: membrane.jpg][size=14pt]4. This property enables them to form an interface or separation between two solutions (e.g., the interior and exterior of a cell); the plasma membrane is a phospholipid bilayer.  [Image: phosolipid.jpg][size=14pt]E. Steroids Have Carbon Rings[size=14pt]1. Steroids differ from neutral fats; steroids have a backbone of four fused carbon rings; vary according to attached functional groups.[size=14pt]2. Cholesterol is a precursor of other steroids, including aldosterone and sex hormones.  [Image: Cholesterol.GIF][size=14pt]3. Testosterone is the male sex hormone.[size=14pt]4. Functions vary due primarily to different attached functional groups.IV. Proteins[size=18pt][size=14pt]A. Amino Acids  [Image: aamodel.gif][size=14pt]1. Amino acids are the monomers that condense to form proteins, which are very large molecules with structural and metabolic functions.  [Image: glycine.gif][size=14pt] 2. Structural proteins include keratin, which makes up hair and nails, and collagen fibers, which support many organs.[size=14pt]3. Myosin and actin proteins make up the bulk of muscle.[size=14pt]4. Enzymes are proteins that act as organic catalysts to speed chemical reactions within cells.  [Image: lockandkeyenzymes6.jpg] [size=14pt]5. Insulin protein is a hormone that regulates glucose content of blood.[size=14pt]6. Hemoglobin transports oxygen in blood.[size=14pt]7. Proteins embedded in the plasma membrane have varied enzymatic and transport functions.[size=14pt]B. Peptide Bonds Join Amino Acids[size=14pt]1. All amino acids contain a carboxyl (acid) group ( [Image: bioche1.jpg]COOH) and an amino group ( [Image: bioche1.jpg]NH2).[size=14pt]2. Both ionize at normal body pH to produce [Image: bioche1.jpg]COO- and [Image: bioche3.jpg]NH+; thus, amino acids are hydrophilic.[size=14pt]3. Peptide bond is a covalent bond between amino acids in a peptide; results from condensation reaction.[size=14pt]a. Atoms of a peptide bond share electrons unevenly (oxygen is more electronegative than nitrogen).[size=14pt]b. Polarity of the peptide bond permits hydrogen bonding between parts of a polypeptide.  [Image: 01ta.gif][size=14pt]4. Amino acids differ in nature of R group, ranging from single hydrogen to complicated ring compounds.[size=14pt]a. R group of amino acid cysteine ends with a sulfhydryl ( [Image: bioche1.jpg]SH) that serves to connect one chain of amino acids to another by a disulfide bond ( [Image: bioche1.jpg][Image: bioche4.jpg]S).[size=14pt]b. There are 20 different amino acids commonly found in cells.[size=14pt]5. A peptide is two or more amino acids joined together.[size=14pt]a. Polypeptides are chains of many amino acids joined by peptide bonds.[size=14pt]b. Protein may contain more than one polypeptide chain; it can have large numbers of amino acids.[size=14pt]C. Proteins Can Be Denatured[size=14pt]1. Both temperature and pH can change polypeptide shape.[size=14pt]a. Examples: heating egg white causes albumin to congeal; adding acid to milk causes curdling. When such proteins lose their normal configuration, the protein is denatured.[size=14pt]b. Once a protein loses its normal shape, it cannot perform its usual function.[size=14pt]2. The sequence of amino acids, therefore, forecasts the protein's final shape.[size=14pt]D. Proteins Have Levels of Structure[size=14pt]1. Final 3-D shape of a protein determines function of the protein in the organism.[size=14pt]a. Primary structure is sequence of amino acids joined by peptide bonds.[size=14pt]1) Frederick Sanger determined first protein sequence, with hormone insulin, in 1953.[size=14pt]a) First broke insulin into fragments and determined amino acid sequence of fragments.[size=14pt]b) Then determined sequence of the fragments themselves.[size=14pt]c) Required ten years research; modern automated sequencers analyze sequences in hours.[size=14pt]2) Since amino acids differ by R group, proteins differ by a particular sequence of the R groups.[size=14pt]b. Secondary structure results when a polypeptide takes a particular shape.[size=14pt]1) The [Image: bioche5.jpg](alpha) helix was the first pattern discovered by Linus Pauling and Robert Corey.[size=14pt]a) In peptide bonds, oxygen is partially negative, hydrogen is partially positive.[size=14pt]b) Allows hydrogen bonding between the C [Image: bioche6.jpg]O of one amino acid and the N [Image: bioche7.jpg]H of another.[size=14pt]c) Hydrogen bonding between every fourth amino acid holds spiral shape of a helix.[size=14pt]d) [Image: bioche5.jpg]helices covalently bonded by disulfide (S [Image: bioche1.jpg]S) linkages between two cysteine amino acids.[size=14pt]2) The [Image: bioche8.jpg]sheet was the second pattern discovered.[size=14pt]a) Pleated [Image: bioche8.jpg]sheet polypeptides turn back upon themselves; hydrogen bonding occurs between extended lengths.[size=14pt]b) [Image: bioche9.jpg]keratin includes keratin of feathers, hooves, claws, beaks, scales, and horns; silk also is protein with [Image: bioche8.jpg]sheet secondary structure.[size=14pt]3. Tertiary structure results when proteins of secondary structure are folded, due to various interactions between the R groups of their constituent amino acids[size=14pt]4. Quaternary structure results when two or more polypeptides combine.[size=14pt]1) Hemoglobin is globular protein with a quaternary structure of four polypeptides.[size=14pt]2) Most enzymes have a quaternary structure.V. Nucleic Acids[size=14pt][size=14pt]A. Nucleotides[size=14pt]1. Nucleotides are a molecular complex of three types of molecules: a phosphate (phosphoric acid), a pentose sugar, and a nitrogen-containing base.  [Image: modnucleotide.jpg][size=14pt]2. Nucleotides have metabolic functions in cells.[size=14pt]a. Coenzymes are molecules, which facilitate enzymatic reactions.[size=14pt]b. ATP (adenosine triphosphate) is a nucleotide used to supply energy.[size=14pt]c. Nucleotides also serve as nucleic acid monomers.  [size=14pt]B. Nucleic Acids[size=14pt]1. Nucleic acids are huge polymers of nucleotides with very specific functions in cells.[size=14pt]2. DNA (deoxyribonucleic acid) is the nucleic acid whose nucleotide sequence stores the genetic code for its own replication and for the sequence of amino acids in proteins.  [Image: dnamolecule.jpg][size=14pt]3. RNA (ribonucleic acid) is a single-stranded nucleic acid that translates the genetic code of DNA into the amino acid sequence of proteins.[size=14pt]4. DNA and RNA differ in the following ways:[size=14pt]a. Nucleotides of DNA contain deoxyribose sugar; nucleotides of RNA contain ribose.  [Image: ribose.jpg][size=14pt]b. In RNA, the base uracil occurs instead of the base thymine, as in DNA.[size=14pt]c. DNA is double-stranded with complementary base pairing; RNA is single-stranded.[size=14pt]1) Complementary base pairing occurs where two strands of DNA are held together by hydrogen bonds between purine and pyrimidine bases[size=14pt]2) The number of purine bases always equals the number of pyrimidine bases; called Chargaff's rule[size=14pt]3) Adenine pairs with Thymine & guanine pairs with cytoseine on DNA[size=14pt]4) Guanine & adenine are purines; Cytosine & thymine are pyrimidines[size=14pt]d. Two strands of DNA twist to form a double; RNA generally does not form helices.[size=14pt]C. ATP (Adenosine Triphosphate)[size=14pt]1. ATP (adenosine triphosphate) is a nucleotide of adenosine composed of ribose and adenine.[size=14pt]2. Derives its name from three phosphates attached to the five-carbon portion of the molecule.[size=14pt]3. ATP is a high-energy molecule because the last two unstable phosphate bonds are easily broken.[size=14pt]4. Usually in cells, a terminal phosphate bond is hydrolyzed, leaving ADP (adenosine diphosphate).[size=14pt]5. ATP is used in cells to supply energy for energy-requiring processes (e.g., synthetic reactions); whenever a cell carries out an activity or builds molecules, it "spends" ATP.  [Image: atp.jpg] Summary of Biological Macromolecules:#000000 solid;margin:15px;width:95%;">[td]
  • Energy storage (4 Cal/gm)
  • Structure (cell walls, exoskeletons)
  • Energy storage (9 Cal/gm)
  • Cell membranes
  • Cell structure
  • Enzymes
  • Molecular motors (muscle, etc)
  • Membrane pumps & channels
  • Hormones & receptors
  • Immune system: antibodies
[/td][td] Nucleic Acids: DNA
(forms a double helix)
  • 4 Bases: A, C, G, T
  • Deoxyribose sugar
  • Phosphate
  • Subunits called nucleotides
  • Storage of hereditary information (genetic code)
[/td][td]Nucleic Acids (RNA)3 types:
  • m-RNA
  • t-RNA
  • r-RNA
(usually a single strand)[/td][td]
  • 4 Bases: A, C, G, U
  • Ribose sugar
  • Phosphate
  • Subunits called nucleotides
 [/td][td]Protein synthesis:
  • m-RNA: working copy of genetic code for a gene (transcription)
  • t-RNA & r-RNA: translation of the code
 Macromolecule Building Blocks Functions
 PolysaccharidesSugars (monosaccharides)
 Lipids (Triglycerides)Fatty acids, glycerol
 Lipids (Phospholipids)Fatty acids, glycerol, phosphate group
 ProteinsAmino acids (20 types)
03-08-2014 01:10 PM
Visit this user's website Find all posts by this user Like Post Quote this message in a reply
Marion Offline
Regular User

Posts: 1
Likes Given: 0
Likes Received: 0 in 0 posts
Joined: Aug 2015
Reputation: 0
Friend:  Add as Friend

Points: 0.00 points
Post: #2

wow! loved it تصویر: images/smilies/smile.gif
08-18-2015 12:27 PM
Find all posts by this user Like Post Quote this message in a reply
Post Reply 

You may also like these discussions:
Thread: Author Replies: Views: Last Post
  Chemistry joerinxy 1 663 08-04-2017 09:35 AM
Last Post: JacquelineMichael
Post Icon Biology Topics za O Level Form 1 - 2 MyElimu 3 39,534 04-22-2017 06:05 PM
Last Post: Damian
Post Icon O-level Biology Past Papers Free Judith Mwakalonge 0 4,375 06-16-2014 08:36 PM
Last Post: Judith Mwakalonge
Post Icon CYTOLOGY (ADVANCED BIOLOGY) Giltwizy 0 14,942 03-08-2014 12:52 PM
Last Post: Giltwizy

User(s) browsing this thread: 1 Guest(s)