Biochem - Pharmacology and Patient Safety

Question 1

What are hormones

Answer 1

Chemical messengers that control and regulate biological functions

Question 2

What do hormones bind to in order to act

Answer 2

Spp receptors, either on the cell surface or within the target cell
Interaction w/ receptor triggers and coordinates the biological effect

Question 3

Types of hormone transport

Answer 3

Autocrine
Paracrine
Endocrine

Question 4

Autocrine transport

Answer 4

Local cell-cell diffusion

Act on neighbouring cells of the same type

Question 5

Paracrine transport

Answer 5

Local cell-tissue diffusion

Act of diff cells in the same tissue

Question 6

Endocrine transport

Answer 6

Distributed by blood

Act on distant target cells

Question 7

Types of hormones

Answer 7

Peptide
Amino-acid derived hormones
Steroid and sterol 
Lipid 
Gaseous

Question 8

Examples of peptide hormones

Answer 8

Adrenocorticotropic hormone (ACTH)
Antidiuretic hormone (ADH)
Calcitonin
Human chorionic gonadotrophin (hCG)
Thyroid-stimulating Hormones (TSH)
Thyrotropin-releasing hormone (TRH)

Question 9

Examples of Amino-acid hormones

Answer 9

Adrenaline
Dopamine
Melatonin
Serotonin

Question 10

Examples of steroid and sterol hormones

Answer 10

Aldosterone
Cortisol
Progesterone
Testosterone

Question 11

Examples of lipid hormone

Answer 11

Leukotrienes
Prostacyclin
Prostaglandins

Question 12

Examples of gaseous hormones

Answer 12

Nitric oxide

Question 13

Membrane bound receptors - ion channels

Answer 13

Hormone bind to receptor (ion channel), and this causes a conformational change
Allowing ions to move from extracellular site of cell to intracellular —> membrane depolarisation

Question 14

Membrane bound receptors - G protein coupled receptors

Answer 14

Conformational change when hormone binds and GDP is swapped for GTP on the alpha subunit of G protein
Alpha subunit dissociates and binds to another effector protein
After action of protein, the GTP then gets hydrolysed back into GDP, leading to the dissociation of the alpha subunit from the effector protein
The alpha subunit reassociates to the beta and gamma subunits of the G protein

Question 15

Examples of effector proteins for G protein

Answer 15

Ca channel open and allows Ca+ move into the cell leading to increase in intracellular mediators

Question 16

What else can the alpha-subunit of the G protein do after dissociation

Answer 16

Associate with adenylyl cyclase to activate the catalysation of ATP into cAMP
Associate w/ guanylyl cyclase for GTP for cGMP
Both activates protein kinases

Associate w/ phospholipase C

Question 17

What does phospholipase C do

Answer 17

Catalyse the conversion of PIP2 to IP3 and DAG, which regulate enzyme activity

Question 18

Membrane bound receptors - kinases

Answer 18

Binding of the hormone activates kinase to phosphorylate proteins using ATP

Question 19

Intracellular receptors

Answer 19

Hormones move into the cell and either binds to receptor and hormone-receptor complex moves into nucleus or
Hormone goes alone to bind receptor in nucleus to affect DNA transcription

Question 20

Endocrine glands

Answer 20

Hypothalamus 
Thymus 
Pancreas 
Ovaries 
Testicles 
Adrenal 
Parathyroids 
Pituitary

Question 21

Lipids

Answer 21

Collective name for all fats and fat-like substances

Question 22

Classes of lipids

Answer 22

Fatty acids 
Triglycerols (fats and oils)
Glycerophospholipids (membrane lipids)
Sphingolipids (membrane lipids)
Cholesterol

Question 23

Features of fatty acids

Answer 23

Long chain -COOH
Can be saturated or unsaturated
Most unsaturated fatty acids have cis configuration
Unbranched

Question 24

What are fatty acids precursors for

Answer 24

Infl mediators:

Prostaglandins, thromboxanes and leukotrienes

Question 25

What do leukotrienes cause

Answer 25

Constriction of bronchioles and smooth muscle in intestine and increases permeability of capillaries

Question 26

What do lipoproteins do

Answer 26

Transport triacylglycerols

Question 27

Where are triacylglycerols stored

Answer 27

Adipocytes

Question 28

Metabolism of triacylglycerols

Answer 28

Triacylglycerols are too big so are broken down into fatty acids by lipoprotein-lipase Fatty acids are taken up by adipocytes and converted to acyl-CoA Glucose enters and metabolised into glycerol-3-P, this joins to acyl-CoA to re-form a triacylglycerol

Question 29

What happens when triacylglycerol is needed

Answer 29

Hormone-sensitive lipase breaks it down into glycerol and fatty acids, the fatty acids travel in the blood as a fatty acid-albumin complex

Question 30

Structure of glycerophospholipids

Answer 30

Amphiphilic Hydrophobic fatty acid chains (2) Polar head group (phosphate and alcohol) Glycerol molecule in between

Question 31

Cleavage of glycerophospholipases

Answer 31

Cleaved by phospholipases of the pancreas

Question 32

Features of sphingolipids

Answer 32

Amphiphilic

Question 33

Structure of sphingomyelin

Answer 33

Hydrophobic fatty acid chain Sphingosine molecule Polar head group - phosphate and choline

Question 34

Structure of glycolipids

Answer 34

Hydrophobic fatty acid chain Sphingosine molecule Polar head group - sugar

Question 35

Structure of cholesterol

Answer 35

Weakly amphiilic Polar OH group Hydrophobic steroid ring system

Question 36

Metabolism of sphingolipids

Answer 36

Ceramides | This can react w/ palmitate to form fatty acids

Question 37

Structure of cholesterol

Answer 37

Hydrophobic steroid ring system

Question 38

Site of cholesterol synthesis

Answer 38

All cells | Liver and intestines major sites