1 / 19

Functions of Proteins

Functions of Proteins. By: Alec Hoover, Katie Klick, and Cory Yerger (14.1-14.4). Functions of Proteins. Structural support Animals have structural proteins. These are chief constituents in skin, bones, hair, and nails. Two important proteins are: Collagen and keratin Catalysis

nerys
Download Presentation

Functions of Proteins

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Functions of Proteins By: Alec Hoover, Katie Klick, and Cory Yerger (14.1-14.4)

  2. Functions of Proteins • Structural support • Animals have structural proteins. These are chief constituents in skin, bones, hair, and nails. • Two important proteins are: • Collagen and keratin • Catalysis • All reactions that take place in living organisms are catalyzed by proteins called enzymes • Without enzymes reactions would be slow and useless

  3. Continued… • Movement • Muscle are made up of protein molecules • Myosin and actin • Transport • Hemoglobin in the blood carries oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs • Move molecules across the cell brain

  4. Continued… • Hormones • Many hormones are protein • insulin, erythropoietin, human growth hormone • Protection • The body makes proteins called antibodies to counteract foreign proteins • This is one of the major mechanisms used by the body to fight off diseases • Fibrinogen is the protein used in blood clotting

  5. Continued… • Storage • Proteins store material • Example: casein in milk and ovalbumin in eggs store nutrients for newborn mammals and birds. • Ferritin: protein in the liver that stores iron. • Regulation • Control the expression of genes • Regulate the kind of proteins synthesized in a particular cell • Dictate when it is controlled

  6. Continued… • A typical cell contains about 9000 different proteins; the entire human body has 100,000 different proteins • Classified by two major types: • Fibrous proteins • Insoluble in water and used mainly for structural purposes • Globular proteins • More or less soluble in water and used mainly for nonstructural purposes • Click Link:

  7. Side Chains • Side chains are responsible for the characteristics and functions of amino acids • Some amino acids have charged side chains • EX: Glutamic Acid & Aspartic Acid

  8. Cysteine • Two identical cystine monomers make up cysteine • Unique because its side chain ( -SH) can form disulfide bridges with another cysteine

  9. Charged Amino Acids • When an amino acid has an additional carboxyl group it loses a proton and forms a corresponding carboxylate anion • EX: Glutamic Acid  Glutamate • Side chain is negatively charges at neutral pH • Histidine, Lysine, & Arginine have basic side chains • Lysine & Arginine have side chains that are positively charges at or near neutral pH

  10. Aromatic Rings • Phenylalanine, Tryptophan, & Tyrosine have aromatic rings in their side chains • Allow us to locate and measure proteins because the aromatic rings absorb strongly • Can be detected using a spectrophotometer • Key precursors to neurotransmitters (substances involved in the transmission of nerve impulses)

  11. Serotonin • Tryptophan is converted to serotonin, calming agent • Low levels of serotonin are associated with depression • High levels produce a hyper condition • Bipolar disorder can be managed by controlling levels of serotonin

  12. L-dopa • L-Dihydroxyphenylalanine = L-dopa • Low levels of L-dopa are involved in Parkinson’s disease • Tyrosine or phenylalanine supplements increase levels of dopamine because it passes into the brain quickly through brain-blood barrier

  13. Hormones • Tyrosine and Phenylalanine are transformed into norepinephrine and epinephrine, stimulants • Epinephrine is the “Flight or Fight” hormone • Causes the release of glucose and other nutrients into the blood • Stimulates brain function

  14. Side Effects • Tyrosine & Phenylalanine may have unexpected effects in some people • Some people get headaches from the phenylalanine in aspartame, artificial sweetener in diet soft drinks • Tyrosine gives some people a morning lift • Tryptophan helps you sleep at night • Milk proteins are an aid in inducing sleep

  15. What Are Amino Acids? • Contains amino and carboxyl groups. • Structure: (side chain)

  16. What Are Amino Acids? • Form chains that make up proteins • 20 common amino acids found in nature • Called alpha amino acids • Listed on page 303 in figure 14.1

  17. How do we categorize them? • Classified into four groups based off of their polarity. • Non-polar • Polar But Neutral • Acidic • Basic • Non-polar side chains are hydrophobic and the side chains of the rest are hydrophilic. • Side chains are responsible for determining both the structure and function of each protein molecules.

  18. What are Zwitterions? • Compounds with a positive charge on one atom and a negative charge on another are known as zwitterions.

  19. Zwitterions • Zwitter is a German word meaning “hybrid” • Amino acids are zwitterions in a water solution and in the solid state • As the pH is changed in the solution, the amount of positive and negative charges in the molecules change. • When the pH is at the level where the positive and negative charges are balanced, it is known as the isoelectric point.

More Related