Biochemistry- Protein Structure And Hemoglobin

Front 1

What level of protein structure has maximally extended structures with phi and psi angles defined as zero?

Back 1

Primary

Front 2

What type of protein structure has intra chain H-bonding?

Back 2

Secondary

Front 3

What are the three types of secondary protein structures?

Back 3

Helical (alpha-helix)
Beta (maximally extended primary sequence)
Random Chain( interactions between R groups)

Front 4

Helical and Beta secondary structures are due to the H-bonding between atoms in what bond?

Back 4

peptide bond

Front 5

How are Beta-barrels formed?

Back 5

When Beta-sheets roll on themselves (super secondary structure)

Front 6

What is a super secondary structure?

Back 6

The result of localized folding of secondary structures that are due to interactions of multiple secondary domains.

Front 7

What are two common super secondary structures?

Back 7

Helix loop Helix (transcription factors)
and Beta-barrel

Front 8

What is the difference between super secondary structures and tertiary structures?

Back 8

Super secondary structures have localized folding domains that may have structural or functional significance in that area. Tertiary structures occur when the whole protein is affected by folding.

Front 9

What are the two types of Tertiary Protein structures?

Back 9

Globular and Fibrous

Front 10

What are the differences between Globular and Fibrous tertiary protein structures?

Back 10

Globular: functional (enzymes)
variety of different kinds of secondary structures

Fibrous: structural
one dominating kind of secondary structure

Front 11

What forces are involved in maintaining a Tertiary structure?

Back 11

1.Hydrogen bonds
2. van der Waals forces(repulsion forces of like chargers, weakest alone but can build up)
3. Hydrophobic interactions (repelled by water, pushed into interior of structure)
4.electrostatic forces (salt bridges formed by charged groups on the structure)

Front 12

What protein structure is only found in multisubunit proteins?

Back 12

Quaternary structure

Front 13

What is a quaternary protein structure?

Back 13

The overall orientation of the polypeptides as a consequence of those polypeptides interacting with one another.

Front 14

Primary function of myoglobin?

Back 14

To store oxygen in muscles for release in periods of oxygen deprivation (short rapid bursts, muscle twitching)

Front 15

Primary function of hemoglobin?

Back 15

Carry oxygen from lungs to tissue and to bring CO2 from tissue to lungs.

Front 16

What is the difference in subunits between hemoglobin and myoglobin?

Back 16

Hemoglobin has 4 subunits so it can carry 4 moles of oxygen.
Myoglobin has one subunit so it can only carry 1 mole of oxygen.

Front 17

What are the hemoglobin subunits composed of?

Back 17

2 alpha and 2 beta subunits, all 4 have an iron complex to heme.

Front 18

Oxygen binds to what to form Heme B?

Back 18

Oxygen binds to the iron portion of protoporphyrin IX.

Front 19

What are the four primary regulators of oxygen binding to hemoglobin and what kind are they all? Why are they important?

Back 19

Negative regulators.
1. CO2
2. 2,3-BPG
3. H+
4. Cl-
Important in releasing oxygen to the surrounding tissues

Front 20

Poor binding of oxygen to hemoglobin is know as what kind of state?

Back 20

T-state or tense state which means hemoglobin has a reduced affinity for oxygen

Front 21

Oxyhemoglobin tetramers are in a high binding state known as?

Back 21

R-state (relaxed state) where they have an increased affinity for oxygen

Front 22

What affect does CO2, 2,3-BPG, H+, and CL- have on hemoglobin?

Back 22

They increase the proportion of T state

Front 23

How is the R-state effected as oxygen is binded to each subunit of hemoglobin?

Back 23

R state of the overall hemoglobin will increase as each subunit binds oxygen.

Front 24

HbF stands for what?

Back 24

Fetal hemoglobin

Front 25

Why does fetal hemoglobin have a higher affinity for oxygen than adult hemoglobin?

Back 25

It has to compete for oxygen with adult hemoglobin in maternal blood so has to have higher affinity since it is the only way for the fetus to receive oxygen.

Front 26

How is CO2 bound to hemoglobin when transported from the tissues to the lungs?

Back 26

Transported by a covalent attachemnt to amide nitrogens forming carbamino-Hb.

Front 27

What happens to the CO2 on hemoglobin once it reaches the lungs?

Back 27

The high partial pressure of O2 favors the R-state which leads to the release of the CO2.

Front 28

What is the Bohr effect?

Back 28

Increases in hydrogen ion concentration decrease the amount of oxygen bound to hemoglobin at any oxygen concentration.

Front 29

Tissues have a decreased pH due to?

Back 29

formation of bicarbonate by RBCs

Front 30

A decrease in pH levels in tissues will lead to?

Back 30

1.an increase in H+ which leads to
2. nitrogen groups on the hemoglobin becoming charged
3. which changes the conformation from more R to more T
4. which pushes the oxygen off and into the tissues.

Front 31

In the Bohr effect what can the H+ ions interact with and ionize?

Back 31

N-terminal amino acid groups of alpha chains and imidazole groups(nitrogen) of Histanine in alpha and beta chains

Front 32

What is the chloride shift?

Back 32

When bicarbonate is released from the RBC a huge charge differential is made since it has a (-) charge. Cl- counters this movement by entering the RBC thus a shift of negative charges is made.

Front 33

What is a hemoglobinopathy?

Back 33

What happens if hemoglobin doesn't work properly.

Front 34

What kind of hemoglobin genes are there?

Back 34

alpha and beta globin gene clusters

Front 35

What is the direction of the globin gene cluster developmental pattern of expression?

Back 35

5' -> 3'

Front 36

What is the major site of hemoglobin in a fetus and as an adult?

Back 36

In the fetus it is the liver and spleen and after birth the bone marrow takes over.

Front 37

HbA2 is a measure of what?

Back 37

fetal hemoglobin found in adult blood.

Front 38

What can be helpful in separating different types of hemoglobin genes in blood?

Back 38

hemoglobin electrophoresis

Front 39

What does HbA1c measure and what is it useful in diagnosing?

Back 39

Measures how much glucose is in the blood and is useful in diagnosing diabetes type II

Front 40

What types of mutations are there in Hemoglobin genes?

Back 40

Qualitative and Quantitative

Front 41

What is an example of a qualitative abnormality in a globin gene?

Back 41

Sickle cell anemia

Front 42

What is another name for a quantitative abnormality of a globin gene and what are the 2 classes?

Back 42

Thalassemias
alpha-thalassemia (loss or reduction of alpha-hemoglobin gene)
beta-thalassemia (loss or reduction of beta-hemoglobin gene)

Front 43

Both Hemoglobin S and Hemoglobin C mutations occur at which codon?

Back 43

Codon 6 on the adult beta-globin gene.

Front 44

What causes genes to stick together and form the sickle shape in Hemoglobin S mutations?

Back 44

The glutamic acid is changed to a valine which changes a hydrophilic gene to a hydrophobic gene. The valines interact with one another and stick together.

Front 45

What causes the sickle cells to lysis?

Back 45

The sickle shape causes the membrane to weaken and distort which will cause the RBCs to lysis which causes the hemolytic anemia part of sickle cell anemia.

Front 46

What happens in the Hemoglobin C mutation?

Back 46

Glutamic acid is changed to lysine (+ to - charge) but both are hydrophilic so no major change in cell shape. Relatively benign mutation.

Front 47

What type of disorder is sickle cell anemia?

Back 47

autosomal recessive disorder

Front 48

What is special about sickle cell anemia in regards to genotype and phenotype?

Back 48

It has a recessive genotype, but a dominant phenotype. Meaning that a heterozygous individual can still manifest sickle cell disorder.

Front 49

What are symptoms of sickle cell anemia (6 items)?

Back 49

1.hemolytic anemia (low hematocrit)
2. hyperbilirubinemia resulting in jaundice and icterus (brain damage due to build up of bilirubin in brain)
3. reticulocytosis (increased immature RBCs)
4. vaso-occlusive crisis due to hypoxic injury in tissues
5. increased susceptibility to infection (bone marrow isn't functioning properly, leukopenia)
6. chronic hypoxia leads to impaired growth and development and organ damage

Front 50

The genes for various hemaglobinopathies have survived because it gives a somewhat immunity to what other disease and why?

Back 50

malaria, since it travels and survives on the RBC. In individuals with various hemaglobinopathies the RBC is often weak and damaged so this gives malaria less of a chance to thrive and allows the host to time survive and reproduce and pass on their genes.

Front 51

Thalassemias are what type of hemoglobinopathy?

Back 51

Quantitative

Front 52

What is HbH disease?

Back 52

An alpha-thalassemia/ an absence of 3 of 4 alpha subunits which leads to beta-tetramers.

Front 53

What is Hb Bart'?

Back 53

an alpha-thalassemia in which no alpha subunits are present and leads to hydrops fetalis and neonatal death

Front 54

An absence of both beta-subunits of hemoglobin leads to what?

Back 54

It is a beta-thalassemia and leads to alpha tetramers which are very unstable and RBCs destroyed in sleep and bone marrow.

Front 55

HbA1c is what?

Back 55

glycosylated hemoglobin

Front 56

How long is the life-cycle of a RBC?

Back 56

120 days

Front 57

What is your HbA1c levels used in diagnosing?

Back 57

Type 2 diabetes

Front 58

What is the normal percentage for HbA1c?

Back 58

less than 7%