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Flashcards in Biochemistry Deck (38):
1

Amino acid with the smallest side chain

Glycine

2

Amino acid with the largest side chain

Tryptophan

3

Essential amino acids

Valine, Leucine, Isoleucine, Threonine, Methionine, Phenylalanine, Tryptophan, Arginine, Lysine, Histidine

4

Amino acid involved in the transfer of methyl group as S-adenosylmethionine

Methionine (also a precursor of homocysteine)

5

Branched amino acids

Valine, Leucine, Isoleucine (metabolites accumulate in MSUD due to deficiency in alpha ketoacid dehydrogenase)

6

Amino acid precursor of cathecholamines

Phenylalanine, Tyrosine

7

Amino acid that is the major carrier of nitrogen from peripheral tissues to the liver

Glutamine

8

Amino acid precursor of GABA and glutathione

Glutamate

9

Amino acids that are excitatory neurotransmitter

Aspartate and glutamate

10

Amino acid precursor of histamine

Histidine

11

Amino acid precursor of nitric oxide

Arginine

12

Amino acids with basic side chain (positively charged)

Arginine, Histidine, Lysine

13

Difference between hemoglobin and myoglobin

Hemoglobin
- 4 polypeptides
- Sigmoidal O2 dissociation curve
- Cooperativity
- O2 transport

Myoglobin
- 1 polypeptide
- Hyperbolic O2 dissociation curve
- Saturation
- O2 storage

14

Bohr Effect versus Haldane Effect

Bohr Effect - release of oxygen from hemoglobin when pH is low or when PCO2 is high

Haldane Effect - increased affinity of hemoglobin for CO2 when less O2 is bound to it

15

Factors that will shift the Oxygen Dissociation Curve to the right

Shift to right = decrease affinity = increase PO2
- Increase in temperature
- Increase in hydrogen atom (decrease in pH)
- Increase in CO2
- Increase in 2,3 BPG

Shift to the left = increase affinity = decrease PO2

16

Form of hemoglobin bound to carbon monoxide

Carboxyhemoglobin
- Hb "cherry pink" in color

CO 200x greater affinity for Hb than O2

Treatment: 100% O2 therapy

17

Oxidized form of hemoglobin (Fe3+) that does not bind O2 as readily

Methemoglobin
- Increased affinity for cyanide
- Chocolate cyanosis

Treatment: Methylene blue

If with cyanide poisoning, treatment is nitrite as it converts hemoglobin to methemoglobin which has higher affinity for cyanide

18

Mutations in Hereditary Spherocytosis

Ankyrin (most common), Spectrin, Band 41, and Band 3

Membrane skeletal protein abnormality that presents as anemia, splenomegaly, jaundice, and diagnosed using osmotic fragility test (increased fragility to hypotonic solution)

19

Type of hemoglobin in Sickle Cell disease

Hemoglobin S

Point mutation in genes coding for B chain replacing valine for glutamate

Hemoglobin S is prone to polymerization at low O2 tension leading to distortion

20

Hemoglobin S versus Hemoglobin C

Hemoglobin S - valine is substituted for glutamate
Hemoglobin C - lysine is substituted for glutamate

21

Alpha Thalassemia versus Beta Thalassemia

Alpha Thalassemia
- Inadequate synthesis of alpha chains
- Symptoms present at birth (since Hemoglobin F is composed of alpha chains)

Beta Thalassemia
- Inadequate synthesis of beta chains
- Symptoms appear later (8 months onward) since Hemoglobin F is present at birth
- Beta Thalassemia Minor - increased HbA2
- Beta Thalassemia Major - increased HbF

22

Type of collagen found in the basement membrane or basal lamina

Type IV

Type I - BONE, skin, tendon
Type II - CARTILAGE, vitreous bod, nucleus pulposus
Type III - RETICULIN (skin, blood vessels, granulation tissue)
Type IV - BASEMENT MEMBRANE
Type VII - beneath stratified squamous epithelium

23

Defective collagen in Ehlers-Danlos Syndrome

Type III

- Hyperextensibility of the skin
- Increased joint mobility
- Abnormal tissue fragility (fragile blood vessels, increased risk for aneurysms)

24

Defective collagen in Osteogenesis Imperfecta

Type I

- Autosomal dominant disease with abnormal Collagen Type I
- Multiple fractures
- Blue sclerae
- Hearing loss
- Dental imperfections

25

Defective collagen in Alport Syndrome

Type IV

- Hereditary Nephritis
- Hematuria
- Ocular lesions
- Hearing loss

26

Defective collagen in Epidermolysis Bullosa

Type VII

27

Scurvy

Vitamin C deficiency leading to decrease in cross-linking of collagen fibers

- Sore spongy gums
- Loose teeth
- Poor wound healing
- Petechiae

28

Menkes Disease

Copper deficiency which is required in LYSYL OXIDASE which catalyzes the formation of covalent cross-links in collagen fibers

29

Difference between Collagen and Elastin

Collagen
- Rich in glycine and proline
- Contains hydroxyproline or hydroxylysine

Elastin
- Rich in proline and lysine
- Does not contain hydroxyproline or hydroxylysine

30

Defective gene in Marfan Syndrome

Fibrillin gene

- Autosomal dominant connective tissue disorder
- Tall and thin
- Arachnodactyly
- Aortic dilatation and dissection
- Ectopia lentis

31

Action of Alpha-1 Antityrpsin

Inhibits proteolytic enzymes from hydrolyzing and destroying proteins

Alpha-1 Antitrypsin Deficiency
- Elastase destroys the alveolar walls leading to emphysema

32

Examples of substrate level phosphorylation

1,3 BPG --> 3 Phosphoglycerate (Glycolysis)
Phosphoenol pyruvate --> Pyruvate (Glycolysis)
Succinyl CoA --> Succinate (TCA)

33

How is ATP produced?

Substrate level phosphorylation
Citric acid cycle
Oxidative phosphorylation

34

Components of the Electron Transport Chain

Complex I - Reduced nicotinamide adenine dinucleotide dehydrogenase
Complex II - Succinate dehydrogenase ubiquinone oxidoreductase
Complex III - Ubiquinonecytochrome C oxidoreductas
Complex IV - Cytochrome C oxidoreductase
Complex V - Muscle phorphorylase

35

Complex IV inhibitor

CYANIDE, CO, Sodium azide, HYDROGEN SULFIDE

Complex I - Barbiturates, Piericidin, Amytal, Rotenone
Complex II - Malonate, Carboxin, TTFA
Complex III - Antimycin A, Dimercaprol

36

Mechanism of action of Uncouplers

Increases permeability of the inner mitochondrial membrane to protons (without establishing proton gradient and without ATP production)
- Increased O2 consumption
- Decreased NADH/NAD and FADH/FAD ratio
- Decreased ATP synthesis
- eg ASPIRIN, 2,4 DINITROPHENOL

37

ATP Synthase inhibitor

Oligomycin

38

Inhibits transport of ADP into and ATP out of the mitochondria

Atractyloside