denaturation proteins Flashcards
(26 cards)
What are proteins composed of?
Proteins are polymers of amino acids.
What is the primary structure of a protein?
The sequence of amino acids.
What defines the secondary and tertiary structures of proteins?
The protein’s folded state.
What is the native conformation of a protein?
The state in which the protein is most active and functional.
What forces hold proteins in their native conformations?
- Hydrogen bonds
- Ionic interactions
- Disulfide bridges
- Hydrophobic interactions
What is denaturation?
Changing the conformation of a protein by disrupting its forces, resulting in a loss of protein activity.
What happens to a protein’s solubility during denaturation?
It changes and frequently results in the formation of a solid in the solution.
What are denaturing agents?
Reagents or conditions that can cause denaturation, such as heat, pH changes, alcohol, and heavy metal salts.
How does heat act as a denaturing agent?
It supplies kinetic energy, causing atoms to vibrate and disrupting weak forces like hydrogen bonds.
What is the effect of extremes of pH on proteins?
They can change the charges on amino acid R-groups, disrupting ionic bonds.
How does ethanol function as a denaturing agent?
It forms hydrogen bonds with protein molecules, disrupting their hydrogen bonding.
Why is a 70% alcohol solution preferred for disinfecting?
It penetrates bacterial cell walls effectively, unlike a 95% solution which coagulates proteins at the surface.
What is the effect of heavy metal salts on proteins?
They form strong bonds with disulfide groups, disrupting disulfide bridges and causing precipitation.
Why are substances high in protein used as antidotes for heavy metal poisoning?
They combine with metal ions to form insoluble solids.
What is the purpose of this lab?
To examine four different ways of denaturing protein.
What are the four methods of denaturing protein in this lab?
- Effect of heat on albumin
- Effect of pH changes on albumin
- Effects of 95% ethanol on albumin
- Effects of lead(II) nitrate or silver nitrate on albumin
What happens to egg albumin when heated above 60 °C?
Bonds in the protein molecules break and reform, causing denaturation.
What is coagulation in the context of protein denaturation?
The process where uncoiled proteins interact to form a solid mass.
What is the procedure for preparing a stock albumen solution?
Add the white of one egg to 100 mL of distilled water and stir until in solution.
What is the control setup in the experiment?
Let the albumen solution stand at room temperature, measure temperature, and determine pH.
What are the effects of adding 1M HCl to albumin?
It alters the pH, potentially leading to denaturation.
What are the expected observations when lemon juice is added to milk?
Changes in color, texture, etc.
What is the main question regarding the results from milk casein?
Was the milk casein denatured?
True or False: All groups obtained the same results with the milk casein.
False.
