BIOL 240 Chapter Notes - Chapter 7: Antifreeze Protein, Meat Tenderness, Kamaboko

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magentaraven992

20 Oct 2022

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McGill University

Department

Biology

Course

BIOL 240

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The main color changes are due to myoglobin and the oxidation states of heme. Myoglobin is a heat-stable protein that can maintain its protein structure at 50 degrees celsius (pink) and then when it undergoes denaturation the color changes from pink to greyish-brown. This is also do to the changes in oxidation states of heme group: fe(iii) metmyoglobin, fe(ii) + o2 oxymyoglobin and fe(ii) + h2o deoxymyoglobin. The color of meat is sometimes used as an indication of the internal temperature but it is not considered reliable in terms of food safety. Since they are easy to hydrolyze that is why they are easy to digest than mammal proteins: sarcoplasmic fish proteins: are usually enzymes. In dark muscles there is a high concentration of haemoglobin and myoglobin (and other pigments) where as light muscles have less.

Related Questions

What is the percent sequence identity between hemoglobin (2HHB) and myoglobin (1A6M)?

	A.	93%
	B.	39.46%
	C.	25.17%
	D.	4.08%

QUESTION 2

Which of the following statements is consistent with the sequence similarity parameter?

	A.	The abundance of amino acids with similar properties that are arranged in the same order is equal to the abundance of identical amino acids.
	B.	These parameters are not related and cannot be compared.
	C.	The abundance of amino acids with similar properties that are arranged in the same order is less than the abundance of identical amino acids.
	D.	The abundance of amino acids with similar properties that are arranged in the same order is higher than the abundance of identical amino acids.

QUESTION 3

Which of the following statements is consistent with the similarity parameter and visualization of the aligned structures?

	A.	Hemoglobin and myoglobin do not have similar structures.
	B.	Hemoglobin and myoglobin have only moderately similar structures, as indicated by the large abundance of gray chains.
	C.	Hemoglobin and myoglobin have very similar structures.
	D.	Hemoglobin and myoglobin are perfectly aligned at every amino acid.

QUESTION 4

Hemoglobin (2HHB) is ___ amino acids shorter than myoglobin; the sequence alignment considers only ___ amino acids, and alignment results show that hemoglobin is missing a contiguous strand of ___ amino acids.

	A.	10; 141; 6
	B.	10; 141; 5
	C.	10; 147; 6
	D.	10; 147; 5

QUESTION 5

Which of the following statements best describes the evolutionary relationship between hemoglobin and myoglobin?

	A.	The low sequence identity indicates that hemoglobin and myoglobin are not related, as tertiary structure cannot be used to study protein evolution.
	B.	Both the high sequence identity and structural similarity suggest that hemoglobin and myoglobin are related.
	C.	The difference in sequence identity and similarity values suggests that hemoglobin and myoglobin are related.
	D.	The high structural similarity suggests that hemoglobin and myoglobin are related, while the low sequence identity suggests that the genes for each protein have diverged through mutation and deletion of several amino acids.

QUESTION 6

The comparison of sequences and tertiary structures in this exercise indicates that:

	A.	only similar amino acid sequences can provide the same tertiary structure.
	B.	different amino acid sequences can provide very similar tertiary structures.

QUESTION 7

The structures of deoxyhemoglobin and oxyhemoglobin are derived from the same source, have the same exact amino acid sequence and length, and differ only in the presence of noncovalently bound oxygen.

	A.	True
	B.	False

QUESTION 8

When using the Sequencing and Structure Alignment tool, the degree of the structural similarity is shown by the superimposition of the backbones. Accordingly, which of the following statement best describes the comparison of deoxyhemoglobin and oxyhemoglobin?

	A.	Only slight differences in the backbone traces occur throughout the aligned proteins.
	B.	The only differences in the backbone traces occur near the oxygen-binding sites.
	C.	The backbone traces of the proteins are drastically different.
	D.	The backbone traces of the proteins are identical.

QUESTION 9

The alignment of 2HHB and 1HHO shows that the binding of oxygen results in _______ in the protein.

	A.	minor conformational changes at sites proximal and distal to the oxygen-binding site
	B.	no conformational change
	C.	drastic conformational changes
	D.	minor conformational changes only within the oxygen-binding site

QUESTION 10

The alignment of 2HHB and 1HHO shows that the conformation of the Fe-heme group _____ upon oxygen binding.

	A.	changes
	B.	does not change

What is the structure and type of bond of:

Insulin

Collagen

Myoglobin

Hemoglobin

Which one decomposes during denaturalization?

1. The dominant motif found in hemoglobin and myoglobin is: a) twisted beta sheet b) beta barrel c) helix-loop-helix d) 7-TM 2. Myoglobin has how many polypeptide chains? A) 1 b) 2 c) 3 d) 4 3. Structurally and functionally, hemoglobin closely resembles a(n) a) transmembrane protein b) mucopolysaccharide c) bile salt d) allosteric enzyme 4. The oxygen binding site in hemoglobin and myoglobin is called: a) BPG b) heme c) proximal-His d) N-terminal carbamate 5. The proximal His residue in hemoglobin and myoglobin binds to which atom or molecule? A) CO2 b) O2 c) Fe d) BPG 6. The distal His residue in hemoglobin and myoglobin binds to which atom or molecule? A) CO2 b) O2 c) Fe d) BPG 7. BPG binds to: a) N-terminal carbamate b) proximal His c) heme group d) central cavity 8. Indirect activity of CO2 is a result of increased concentration of which chemical species? A) BPG b) H+ c) heme iron d) distal His 9. Direct activity of CO2 is a result of binding to which molecular feature? A) the heme group b) the N-terminal ends of the 4 polypeptide chains c) the central cavity d) the proximal His 10. The sigmoidal, cooperative binding curve commonly observed for hemoglobin is a result of: a) competition between CO2 and O2 for heme binding. B) competition between heme and distal His for O2 binding c) competition between BPG and CO2 for binding at the central cavity site d) T to R transition 11. Hemoglobin has a tendency to release its oxygen to the tissues because: a) in this region pH is high and O2 concentrations are low b) in this region both pH and O2 concentrations are low c) in this region both pH and O2 concentrations are high d) there is much BPG in this region 12. Which statement about fetal hemoglobin is not true? A) fetal hemoglobin has gamma chains instead of beta chains b) fetal hemoglobin binds BPG less strongly than maternal hemoglobin c) fetal hemoglobin binds oxygen less strongly than maternal hemoglobin d) fetal hemoglobin binds oxygen more strongly than maternal hemoglobin 13. Which process is most responsible for the sickling of cells seen in sickle cell disease? A) aggregation of the oxygenated R form of hemoglobin-S to form insoluble fibers b) aggregation of the deoxygenated T form of hemoglobin-S to form insoluble fibers c) Hemoglobin-S does not contain heme d) Hemoglobin-S contains a mutant form of heme which will not bind oxygen 14. A person with sickle-cell trait is very unlikely to catch which disease? A) malaria b) colon cancer c) avian flu d) whooping cough 15. A person with a genetic defect which results in the synthesis of an insufficient amount of the alpha chain of hemoglobin is said to have which disease? A) alpha thalassemia b) beta thalassemia c) pernicious anemia d) Crohnâs disease

BIOL 240 Chapter Notes - Chapter 7: Antifreeze Protein, Meat Tenderness, Kamaboko

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