Lab 7.

Question 1

What kind of proteins is haemoglobin?

Answer 1

A heme protein.

Question 2

What is the prosthetic group found within haemoglobin?

Answer 2

A heme group.

Question 3

What will the heme group of haemoglobin reversibly bind to?

Answer 3

Oxygen.

Question 4

What kind of cells is haemoglobin found in?

Answer 4

Exclusively in red blood cells (RBCs).

Question 5

What is the job of haemoglobin in RBC’s?

Answer 5

It transports oxygen from the lungs to the rest of the body.

Question 6

What structure does haemoglobin take up?

Answer 6

A tetramer. is made up of four subunits or two identical dimers (αβ)1 and (αβ)2 . Each subunit is composed of a polypeptide chain.

Question 7

How is the haemoglobin tetramer made up?

Answer 7

It is made up of four subunits or two identical dimers.

Question 8

What are the 4 subunits of haemoglobin?

Answer 8

2 alpha subunits.

2 beta subunits.

Question 9

What is each haemoglobin subunit composed of?

Answer 9

A polypeptide chain.

Question 10

What are the 2 conformations of haemoglobin?

Answer 10

The T conformation.

The R conformation.

Question 11

What is the T conformation of haemoglobin?

Answer 11

The form of haemoglobin that is not bound to oxygen.

Question 12

What is the R conformation of haemoglobin?

Answer 12

The form of haemoglobin that is bound to oxygen.

Question 13

What kind of bonds are found between the hb subunits whilst they are in the deoxygneated state?

Answer 13

Weak ionic and hydrogen bonds.

Question 14

What kind of bonds are found between the hb subunits whilst they are in the oxygneated state?

Answer 14

Some of the hydrogen bonds are broken so that it can weakly bind to oxygen.

Question 15

Where is the α-globin gene located in the genome?

Answer 15

On the short arm of chromosome 16.

Question 16

Where is the β-globin gene located in the genome?

Answer 16

On the short arm of chromosome 11.

Question 17

How many copies of the α-globin gene are located on chromosome 16?

Answer 17

2.

α-1 and α-2.

Question 18

How are the α and β-globin genes arranged on their respective chromosomes?

Answer 18

As 3 exons and 2 introns.

Question 19

What are haemoglobinopathies?

Answer 19

A group of genetic disorders.

Question 20

What causes haemoglobinopathies?

Answer 20

The production of an abnormal hemoglobin molecule.

Question 21

What are 4 examples of haemoglobinopathies?

Answer 21

Sickle cell anaemia (Hb S).

Haemoglobin C disease (Hb C).

Haemoglobin SC disease (Hb SC).

Thalassemia.

Question 22

What is thalassemia?

Answer 22

When a person synthesises low quantities of normal hemoglobin.

Question 23

What variant of haemoglobin do people with sickle cell have?

Answer 23

A variant called haemoglobin S or sickle haemoglobin.

Question 24

How many alleles for sickle cell must a person inherit in order for them to exhibit the trait?

Answer 24

2.

Question 25

What is the variant form of adult haemoglobin that leads to sickle cell?

Answer 25

Hemoglobin S (Hb S).

Question 26

What is the normal form of adult haemoglobin?

Answer 26

Haemoglobin A (Hb A).

Question 27

What kind of mutation leads to sickle cell disease?

Answer 27

A single nucleotide substitution (a point mutation).

Question 28

How does the SNP that leads to sickle cell change the amino acid sequence?

Answer 28

It replaces a glutamic acid with a valine.

Question 29

How does the SNP that cuases sickle cell change the triplet code?

Answer 29

It changes CAG to CTG.

Question 30

How does sickle cell affect the binding properties of haemoglobin?

Answer 30

It affects the binding ability of haemoglobin to oxygen.

Question 31

What kind of genetic disorder is sickle cell disease?

Answer 31

An autosomal Recessive Disorder.

Question 32

How do the individual properties of glutamic acid affect the side chains that they create?

Answer 32

Glutamic acid creates a polar side chain. Valine creates a nonpolar hydrophobic side chain.

Question 33

How do the nonpolar/hydrophobic properties of valine affect the shape of the deoxygenated form of haemoglobin?

Answer 33

It causes the polymers to stiffen and distort the RBC into a sickle shape.

Question 34

How does the distortion of polymers within a red blood cell affect the lifespan of red blood cells?

Answer 34

Sickle-shaped RBCs die prematurely and this leads to a shortage of RBCs.

Question 35

What condition is caused by a shortage of red blood cells?

Answer 35

Anaemia.

Question 36

How does the sickle shape of red blood cells affect small blood vessels?

Answer 36

Sickle shaped RBCs can block small blood vessels, this can lead to the death of nearby cells or organ damage.

Question 37

What are 8 common symptoms of sickle cell anaemia?

Answer 37

Tiredness. Anemia. Growth retardation. Infection. Chronic pain in any body part Ulcers. Renal dysfunction. Stroke.

Question 38

What is the worlds largest genetic disorder?

Answer 38

Sickle cell disease.

Question 39

What kind of people are mainly affected by sickle cell disorder?

Answer 39

People of African, Caribbean, Middle Eastern, Eastern Mediterranean and Asian origin.

Question 40

Who discovered sickle cell disease in 1910?

Answer 40

Dr. Herrick.

Question 41

What are 5 methods of managing sickle cell disease?

Answer 41

Prevent the deoxygenation of tissues. Keep hydrated. Avoid infection. Balanced diet. Regular medical check ups.

Question 42

What are 4 common treatments of sickle cell disease?

Answer 42

Medication. Transfusion. Bone marrow transplantation. Gene therapy.

Question 43

Why is the mobility of Hb S altered during agarose gel electrophoresis at an alkaline pH?

Answer 43

Becuase the HB-S is missing the negatively charged glutamate in the β-globin chain. This makes Hb S less negative than Hb A.

Question 44

What are 3 methods of detecting sickle cell anaemia via targeted mutation analysis?

Answer 44

ASO. RFLP. PCR.

Question 45

What are the 2 restriction endonucleases that are used to detect sickle cell via RFLP?

Answer 45

DdeI or Mst-II.

Question 46

What method can be used to detect sickle cell via prenatal diagnosis?

Answer 46

FISH.

Question 47

What 2 methods can be used to detect sickle cell via preimplantation genetic analysis?

Answer 47

PCR. FISH.

Question 48

Can DNA sequencing be used to detect sickle cell?

Answer 48

Yes.

Question 49

What is the basis of the RFLP test for sickle cell disease?

Answer 49

That restriction enzymes will recognise specific restriction sites within a DNA sequence.

Question 50

What are the normal 3 codons that specify amino acids 5, 6 and 7 in the β-globin gene?

Answer 50

CCT- GAG-GAG. Pro-Glu-Glu.

Question 51

What are the abnormal 3 codons that specify amino acids 5, 6 and 7 in the β-globin gene?

Answer 51

CCT-GTG-GAG. Pro-Val-Glu.

Question 52

What is the recognition site for the MST-II enzyme?

Answer 52

CCTNAGG.

Question 53

How does the mutated form of the β-globin gene affect the cleavage site for MST-II?

Answer 53

Mst-II cannot recognise the T that replaces the A in the new sequence.