Proteins

This molecule is...

Which of the following statements are true about proteins? Check all that apply.

[blank_start]Amino acid[blank_end] sequence determines the [blank_start]primary[blank_end] structure of a protein. This is determined by the codons in DNA and m[blank_start]RNA[blank_end]. [blank_start]Secondary[blank_end] structure refers to one of two shapes that a polypeptide may take: beta-[blank_start]pleated sheet[blank_end] or alpha [blank_start]helix[blank_end]. This is determined by [blank_start]hydrogen[blank_end] bonding. [blank_start]Tertiary[blank_end] structure is the further folding of the polypeptide on itself. The polypeptide begins to form a more complex, unique, three-dimensional shape. Finally, [blank_start]quaternary[blank_end] structure - which does not apply to all proteins - is the interaction between several polypeptides to form a globular protein, one common example being [blank_start]haemoglobin[blank_end], responsible for carrying oxygen.

Label the types of bonds found in the tertiary structure of proteins.

[blank_start]Fibrous[blank_end] proteins tend to have structural roles, while [blank_start]globular[blank_end] proteins usually have [blank_start]functional[blank_end] roles.

Functional proteins are more soluble than structural proteins.

Fibrous proteins are more resistant to changes in pH and temperature than globular proteins.

Which of the following are structural proteins? Check all that apply.

[blank_start]Haemoglobin[blank_end] is a [blank_start]functional[blank_end], [blank_start]globular[blank_end] protein with a [blank_start]quaternary[blank_end] structure consisting of [blank_start]four[blank_end] polypeptide sub-units. It also has a [blank_start]prosthetic group[blank_end], which is essential to its purpose of carrying [blank_start]oxygen[blank_end] around the body.

Insulin contains only alpha helices.

The role of insulin is to regulate [blank_start]glucose[blank_end] concentration in the blood. It does this by binding to a [blank_start]specific[blank_end] target receptor, which triggers the [blank_start]uptake[blank_end] of [blank_start]glucose[blank_end] into cells and the metabolism of [blank_start]glucose[blank_end] in [blank_start]respiration[blank_end]. The overall effect is a [blank_start]decrease[blank_end] in blood [blank_start]glucose[blank_end] concentration.