ILA1 Sickle cell Flashcards

1
Q

What are characteristics of sickle cell anaemia?

A

Low RBC count
Episodes of pain
Repeated infections

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2
Q

When do signs and symptoms of SCA usually begin?

A

Childhood

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3
Q

How does SCA lead to shortness of breath and fatigue?

A

Sickle RBC break down prematurely, which leads to anaemia and so fatigue

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4
Q

How does SCA cause jaundice?

A

Rapid breakdown of RBC and heamoglobin

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5
Q

How does SCA cause the painful episodes (vaso-occlusive crisis)?

A

When sickled RBC (stiff and inflexible) get stuck in small blood vessels, which deprives tissues of oxygenated blood. Can lead to organ damage

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6
Q

Where has the highest rates if SCA?

A

Africa, Mediterranean, Central America and Carribean

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7
Q

Mutation in which gene causes sickled Hb?

A

HBB gene

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8
Q

What are the sub-units of normal Hb?

A

2 alpha and 2 beta globin chains

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9
Q

How is sickle RBC different to normal?

A

HbS units replace both beta chains

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10
Q

What is the change in amino acid sequence in HbS?

A

Glutamic acid replaced by valine at position 6

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11
Q

What causes the sickle shape?

A

Abnormal Hb stick together leading to long rigid molecules

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12
Q

What is Hbc and HbE

A

Replacing of one beta subunit.
HbC is caused by lysine replacing glutamic acid at position 6
HbE by lysine replacing glutamic acid at position 26

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13
Q

What is beta thalassemia?

A

Lack of beta subchains

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14
Q

What is the difference between SC disease and SC anaemia?

A

SCD is a group of collected conditions, the most common being SCA

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15
Q

What is the inheritance pattern shown by SCA?

A

Autosomal recessive, both beta subunits need to have the mutation

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16
Q

What is a single nucleotide polymorphism (SNP)?

A

Most common type of genetic variation. Occur once in every 300 nucleotides. It is a variation in a single nucleotide at a specific position.

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17
Q

What is the SNP that causes SCA?

A

CTC to CAC causing glutamic acid to valine

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18
Q

How does sickling reduce affinity for oxygen?

A

It causes a change in shape which makes it harder for the oxygen to bind

19
Q

What are potential complications of SCA in pregnancy?

A
Anaemia could worsen
Pain worsen (keep heat pads to reduce vasoconstriction and so pain)
20
Q

What direction does polymerase read?

A

Reads 3’-5’ meaning template is produced in 5’-3’

21
Q

Why does replacement of glutamic acid with valine lead to change in shape?

A

Glu is hydrophilic and val is hydrophobic. In deox HbS valine associates with another hydrophobic area on another molecule causing long mols and change in shape

22
Q

Mitosis: Chromosomes are moving towards opposite poles of the cell and there are no nuclear membranes. Which phase?

A

Anaphase

23
Q

What is the last stage of mitosis?

A

Cytokinesis

24
Q

What are the microtubules that chromosomes attach to in mitosis made out of?

A

Tubulin

25
Q

What stain turns granules in mast cells purple?

A

Toludine blue

26
Q

Brown pigment in liver cells. Possible haemochromatosis. What stain turns iron containing pigments blue?

A

Perl’s stain

27
Q

Pedigree: male to male, every gen. what type?

A

Autosomal dominant

28
Q

Which substance splits two DNA strands apart during DNA replication?

A

Helicase

29
Q

A gene sequence is coded in?

A

SINGLE STRAND DNA

30
Q

A promotor sequence is coded in

A

Single strand DNA

31
Q

What do specific amino acids bind to?

A

tRNA

32
Q

The transcriptome of a whole cell is composed of?

A

mRNA

33
Q

Alternative splicing of codon regions producing different products of a gene occurs in?

A

mRNA

34
Q

A protein composed of two or more peptide chains held together by non-covalent cross links has what structure?

A

Quaternary

35
Q

In the cytoplasm the structure that is created by covalent bonds is (Proteins)?

A

Primary

36
Q

Alpha helixes and beta sheets are examples of what structure of protein?

A

Secondary

37
Q

Which of these cells kill bacteria using respiratory burst?

A

Neutrophil

38
Q

Dihydrogen oxide is also known as…?

A

Water

39
Q

Which enzyme catalyses 1,3 bisphosphoglycerate to 3-phosphoglycerate?

A

PHOSPHOGLYCERATE KINASE

40
Q

The average 70kg man has a store of approximately 350g of what energy source?

A

Glycogen

41
Q

How are steroid hormones transported in the blood?

A

Bound to plasma proteins

42
Q

How does HbS cause sickling?

A

In hypoxia the abnormal HbS crystallises and the mutated valines join to normal valine

43
Q

How does capillary occlusion occur in SCA?

A

Sickle cells bind to and activate endothelial cells causing inflammation