Protein Structure/Digestion & Absorption Flashcards
These proteins are generally compact, soluble, and spherical to oblate or egg-shaped.
Globular proteins
These proteins are typically elongated and insolube.
Fibrous proteins
What are the four levels of structure in proteins?
Primary structure, secondary structure, tertiary structure, quaternary structure
It is the linear arrangement of amino acids present in the polypeptide chain.
Primary structure
In this structure, each protein has a distinctive number and sequence of amino acid residues.
Primary structure
This structure refers to highly regular local sub-structures.
Secondary structure
It is the extended conformation of polypeptide chains.
Secondary structure
What are the two most common examples of secondary structure?
Alpha-helix and beta-pleated sheets
This structure refers to three-dimensional structure of a single protein molecule.
Tertiary structure
It is the connectivity between two or more polypeptide chains.
Quaternary structure
True or False: In quaternary structure, polypeptide chains must be identical in their primary structure.
FALSE. Polypeptide chains may be identical or different in primary structure.
What type of structure is found in hemoglobin?
Quaternary structure
Hemoglobin has how many subunits?
4 subunits (2 subunits of beta-globin, 2 subunits of alpha-globin)
Proteins are bound together by ___, while carbohydrates are bound together by ___.
peptide bonds; glycosidic bonds
What element is essential to the formation of the 20 different amino acids?
Nitrogen
True or False: Protein digestion begins in the mouth.
FALSE. It begins in the stomach.
Digestion breaks down proteins into ____.
Amino acids
True or False: Digestion of both proteins and carbohydrates can occur in the stomach.
FALSE. Due to the high acidity levels of the stomach, enzymes like amylase are rendered non-functional, and no digestion of carbohydrates occurs.
It is secreted in the stomach’s gastric acid. It attacks protein molecules, separates them, and breaks them down into amino acids.
Hydrochloric acid
Enzymes function best at what pH level?
7.0 pH
They are enzymes which break down proteins.
Proteases
It is the only protease able to digest collagen.
Pepsin
After the stomach, digestion of proteins continues in the ___.
Duodenum
The pancreas helps the digestion process by secreting which two pancreatic protease enzymes?
Trypsin and chymotrypsin
True or False: Protein absorption rate is faster for animal origin food than vegetarian/plant origin food.
TRUE
How are nucleic acids connected to carbohydrates?
Nucleic acids such as RNA and DNA require the presence of pentoses ribose and deoxyribose.
How are nucleic acids related to proteins?
Proteins provide the nitrogenous bases for DNA and RNA.
