IB Biology Topic 2.4 Protein

Nitrogenous wastes are produced by mammals primarily during of which of the following processes?

Catabolism in proteins

Outline the impact of denaturing agents on protein function.

Denaturation of proteins involves the disruption and possible destruction of both the secondary and tertiary structure. There are several agents that can change the structure of a protein, thus disabling the protein to carry out its function. These agents include: temperature, and pH. The agent pH, can alter intermolecular interactions within the protein (R-groups), such as hydrogen bonds or interaction between the polar/acidic/basic R-group. Enzymes, a type of a protein, have a specific temperature and pH and the when introduced a new extreme environment. The enzyme can lose its function and metabolism will be affected. Temperature can alter the hydrogen bonds if the heat is extreme. As temp increases, it increases the change of enzymes to collide with their substrate.

Nine R groups are hydrophobic with between zero and nine carbon atoms. Which R group does NOT contain a ring structure.

Methionine

Essential amino acids are those

Only acquired from external food sources

Hemoglobin is an example of what structure of a protein

Quaternary Structure

The site of protein synthesis (where amino acids are assembled to make a polypeptide) occurs at in this organelle

Ribosome

Which structure of protein folding included beta sheet and alpha helixes

Secondary

Discuss the factors affecting the solubility of proteins in water.

Solubility is affected by the polar side groups found in the R groups of amino acid. A protein that has any polar side group will be MORE soluble than on the ones that doesn't. Small proteins are likely to be more soluble than large ones because they are able to fit between water molecules in a solution.

Proteins control body chemistry in all of the following ways EXCEPT

Specifying the amount of blood in the body

State 4 functions of proteins giving an example of each.

Structural- Collagen strengthens bones, skin and tendons. Movement- Myosin found in muscle fibers causes contraction of the muscle which results in movement. Transport- Haemoglobin transports oxygen from the lungs to other tissues in the body. Defense- Immunoglobulin acts as an antibody.

Outline the production of a dipeptide by a condensation reaction. Include the structure of a generalized dipeptide in your answer. (View index card)

Within a condensation reaction, two amino acids are joined as water is produced. A carboxyl group is one amino acid reacts with the amine functional group on the second amino acid to eliminate water. The carboxyl group donates the OH group and the Amine functional group donate the hydrogen. As water is released, a peptide bond is formed between the Nitrogen and Carbon of both amino acids.

A protein molecule is composed of 45 amino acids. How many molecules long was the DNA sequence that coded for the amino acids?

135

Protein consisting of four amino acids undergo hydrolysis. How many water molecules must be broken down and reattached to amino acids molecules during the breakdown of a polypeptide made up of 6 amino acids.

3 water molecules

Most genes in a person's DnA store the amino acids sequence of a polypeptide. They use the genetic code to do this. Three bases of the gene are needed to code each amino acid in the polypeptide. The DNA is transcribed into mRNA. Proline is a unique protein, and can be converted to hydroxyproline by the presence of vitamin C. All of the cones below code for proline EXCEPT

CAG

Compare and Contrast the structure and function of collagen and insulin.

Collagen and insulin have different structure. Collagen is classified as a fibrous protein, while insulin is classified as a globular protein. Unlike globular protein which are spherical in shape, fibrous protein are elongated strand-like structures and are usually present in the forms of rod and wires. This is specific and necessary of collagen's function, which is needed to give tensile strength. An important differentiating feature between these two molecules regarding their solubility in water: collagen is not solute, whereas insulin is soluble in water. Collagen protein structure relies heavily on strong hydrogen bonds, while insulin has comparably weaker hydrogen bonds holding the structure together. Collagen consist of usually primary and secondary structure, compared to insulin that often olds into tertiary and sometimes quaternary structure. In terms of function, globular proteins, such as insulin is responsible for many function where fibrous protein, such as collagen, are responsible for soley structure in an organisms.

Describe the structure of proteins.

The primary structure of a proteins is made up of 20 different amino acids that are linked by peptide bonds. Peptide bonds are formed by condensation reaction, which involves the removal of water. This removal of water happens as an OH from the carboxyl group joins with an H from the amino group. There are four levels to a protein structure. The primary structure is the order in which amino aids are linked together to form a protein. The secondary structure is held in place by many weak hydrogen bonds. There are two secondary structure; one is the alpha helix structure and the second is the beta sheet. The tertiary structure allows of the 3-D shaping, where the R group of the amino acid can be identified as hydrophobic or hydrophilic. Then the quaternary structure reflects to the interaction between multiple polypeptide chain.