Metabolism COPY COPY

Question 1

List the measures of metabolism

Answer 1

Oxygen Uptake, Carbon Dioxide Production, Heat Generation

Question 2

Describe what happens across metabolism normally after a meal, in terms of hormonal and enzymatic control

Answer 2

Laz’s notes pg 104 where i decided to underline

Question 3

Exemplify the importance of mtDNA , and the importance of the mother when it come to the exemplified importance

Answer 3

“Despite its diminutive size, the importance of mtDNA is highlighted by the fact that mutations within mtDNA are frequent cause of human genetic disease.

The inheritance of mtDNA is via the ovum , meaning that mtDNA mutations are transmitted to all maternal offspring. ”

Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 4

Describe the precess of endocytosis ,including details of the possible fates of endocytosed material

Answer 4

pg 85(Fate of endocytosed material)

Fate of Endocytosed Material

• The first place endocytosed material goes in the early endosome - the sorting compartment. From here, there are three things that could happen:
  
  1. Recycling - the material could be recycled and sent back to the plasma membrane. E.g. Transferrin receptor (the main mechanism for taking up iron) is recycled back to the plasma membrane.
  2. Degradation - see below

Transcytosis - material can be carried to the basolateral membrane

Question 5

Why does FADH2 pump lead to one less proton being oump in the respiratory chain

Answer 5

[pg 82 below ATP synthase diagram]

“Succinate dehydrogenase is an integral membrane protein that is firmly attached to the inner surface of the inner mitochondrial membrane. There, it can communicate directly with ubiquinone.

“Succinate dehydrogenase is an integral membrane protein that is firmly attached to the inner surface of the inner mitochondrial membrane. There, it can communicate directly with ubiquinone. ”

Question 6

Describe the difference in function between LDL and HDL and where pathologies may occur

Answer 6

pg 93 ibook (paragraph 3)

Question 7

“Perform calculations to calculate the theoretical maximum yield of ATP per glucose molecule due to the krebs cycle during aerobic respiration. ”

Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Answer 7

“The majority of the energy that derives from the metabolism of food is generated when the reduced coenzymes are re-oxidised by the respiratory chain in the mitochondrial inner membrane in a process known as oxidative phosphorylation (lecture 5).

The Krebs cycle only operates under aerobic conditions, as the NAD+ and FAD needed are only re-generated via the transfer of electrons to O2 during oxidative phosphorylation.

ibook pg 75 :Re-oxidation of the reduced co-factors NADH and FADH2 by the process of oxidative phosphorylation yields the following:
Three ATP molecules are formed by the re-oxidation of each NADH molecule.

Two ATP molecules are formed by the re-oxidation of each FADH2 molecule.

Therefore, from the Krebs Cycle:
​
1 X acetyl CoA gives 3 x NADH plus 1 x FADH2 + 1x GTP = 12 ATP
”

Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 8

For the muscle , brain and nervous system, adipose tissue , heart and liver identify:

proportion of body weight

any relevent informattion on how it uses ATP

a description where relevant on its use of fats and vcarbohydrates

Answer 8

pg 96 Laz’s notes (General Metabolic Features of some specialised tissues:)

Question 9

Describe the changes iacross metabolism after a meal and after prolonged fasting,include a descrption of hormones involved in this also

Answer 9

pg 106 Laz’s notes

Question 10

Where is cholesterol mainly found, and what is its functions there

Answer 10

“More than 90% of the body’s cholesterol (shown below) is found in cell membranes where it can increases or decreases membrane stiffness, depending on temperature and nature of membrane (see Cells Lecture 1).”

Question 11

Describe the different types of endocytosis

Answer 11

pg 85 Laz’s notes (ENdocytosis)

• Receptor-mediated endocytosis - substances bind to specific receptors and begins to form a vesicle which has a protein coat around it.
• Pinocytosis - fluid drinking - the cell extends it’s membrane and takes in some extracellular fluid.
• Macropinocytosis/Phagocytosis - can take up large particles such as bacteria.

Question 12

Suggest how mitochondrial respiration may be examined experimentally.

Answer 12

pg 83 ibook

Question 13

Name the different types of Lipoproteins, and describe how they are recognised by different cells

Answer 13

pg 91 from (LIPOPROTEINS ARE CATEGORISED ACCORDING TO THEIR DENSITY:) to (Lipoprotein Lipase) Laz’s notes

Question 14

Describe the controllers of the glucose metabolism pathway

Answer 14

Laz’s notes pg 101 AD

The pathway is controlled by:

• Product of the reaction or pathways (the product could be an activator or inhibitor of the enzyme)
• External signalling molecules relaying information from other pathways
• Hormones

Question 15

Describe the three principle stages of the synthesis of cholesterol from acetyl CoA and describe where rhey occur

Answer 15

pg 85 (Cholesterol biosynthesis - the numbered bulltet point part) Laz’s notes

The biosynthesis of cholesterol can be split into three main parts:

1. Synthesis of isopentyl pyrophosphate, an activated isoprene unit which serves as a key building block (occurs in cytoplasm).
2. Condensation of six molecules of isopentyl pyrophosphate to form squalene (occurs in cytoplasm).
3. Cyclisation and demethylation of squalene by monooxygenases to give cholesterol (occurs in ER).

Question 16

Describe how proteins forl in general and what can interfer with this and how

Answer 16

• (pg 43 (Folding of Proteins))
• Proteins generally fold into the single conformation of lowest energy
• Chaperones may be involved to make sure that folding occurs in the most energetically favourable way
• By breaking bonds that hold the protein together, we can denature the protein into the original flexible polypeptide
• Common Denaturants used in the lab:
  
  • Urea (breaks hydrogen bonds)
  • 2-mercaptoethanol (breaks disulphide bonds)( (

Question 17

`Explain diseases that can occur as result of problems with post translational modification and quality control in the ER

Answer 17

pg 81 (Cystic Fibrosis Transmembrane-Conductance Regulator (CFTR))

Cystic Fibrosis Transmembrane-Conductance Regulator (CFTR)

• CFTR is an ABC transporter-class chloride channel in epithelial cell plasma membranes.
• Mutations of the CFTR gene affects the functioning of the chloride channels in the membrane which causes Cystic Fibrosis.
• The most common mutation (ΔF508) results from DELETION of three nucleotides, which causes the loss of phenylalanine (Phe) at the 508th position on the protein.
• As a result, the CFTR does not fold properly and is degraded in the ER.
• Small molecule corrector 407882 binds to the cytoplasmic domain of ΔF508 CFTR and enhances its movement to the cell surface, restoring function.

Question 18

Provide a summary of glycolysis and the processes that could ensue s under different conditions in metabolism

Answer 18

pg 97 laz’s notes(Summary of Glycolysis:), which continues a little on pg 98

Question 19

How is metabolism affected by diabetes across the body

Answer 19

Laz’s notes pg 103(How metabolism is affected)

Question 20

What is special about proline as an amino acid

Answer 20

• When proline is joined to a polypeptide chain - the NH group of the amino acid is LOST
• This prevents the side chain from hydrogen bonding with C=O groups of another residue within the helix
• This distorts the helical conformation
• Puts a kink into it

pg 43 (LAz)

Question 22

(1)Give an overview of endocytosis

Answer 22

pg 79 Laz’s notes : Endocytosis Overview:

Endocytosis Overview:

• Material recognised at plasma membrane is brought in via endocytic pathway
• First pathway is the Early Endosome (involved in recycling) - material from early endosome can recycle back to the plasma membrane and keep going round and round.
• Or it can be sorted into another compartment called the Late Endosome.
• If the material is destined for destruction it will be taken to the lysosome to be broken down.

Question 23

Describe the cause and consequences of Familial Hypercholesterolaemia, and describe different sevgerities of this and under which circumstances one may get such severities

Answer 23

pg 92 writing bit Laz’s notes

Question 24

Describe the features of the different classes of Familial Hypercholesterolaemia(kind of extra)

Answer 24

table on pg 93 Laz’s notes

Question 25

pg 78 ibook quiz

Question 26

Decribe the post-translational modification of proteins that occurs in the golgi apparatus, and give an example of this (include detials of the golgi apparatus structure in your answer)

Answer 26

pg 82 Laz's notes

Question 27

“ Draw a cross sectional representation of a mitochondrion, identifying its component parts. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Answer 27

pg 79

Question 28

“Summarise the glycerol phosphate shuttle and the malate-aspartate shuttle, in particular stating why these mechanisms are required. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Answer 28

pg 76( right), pg 77(left), met 4 slide 28-31

Question 29

Describe the process of gluconeogenesis

Answer 29

pg 98 Laz's notes

Question 30

WHich molecule is this

Answer 30

HDL

Question 31

Explain the genral mechanism of storage of cholesterol in cholesterol transport , including descriptions of structure

Answer 31

pg 92 ibook(Lipid Transport)

Question 32

Define metabolism

Answer 32

The sum of all processes in the body.

Question 33

Recall how proteins are synthsised initially

Answer 33

pg 96 ibook(Free and membrane bound ribosomes )

Question 34

Recall the different metabolic functions in different tissues

Answer 34

pg 103 ibook and pg 104 NB

Question 36

Descrinbe the structure of the golgi appratus and its function, include details of how it functions in an overviewexcytosis

Answer 36

pg 79(Vesicular transport complexity) Laz's notes **Vesicular Transport Complexity** * The Golgi Apparatus is responsible for packaging and sending the proteins from the ER. * The Golgi Apparatus has three sections: **cis**, **medial** and **trans** * The **cis** Golgi network is **closest to the ER**. * Exocytosis Overview: * Endoplasmic Reticulum --\> Cis Golgi network * Cis Golgi Network --\> Medial Golgi Apparatus --\> Trans Golgi Network * Trans Golgi Network --\> Cell Surface via different types of secretory vesicle

Question 37

Describe all the post-translational modification that a lysosymal enzyme goes through as it moves through the golgi Apparatus, and how it is funall sorted.

Answer 37

pg 84 **Laz's notes** * Specific example of how carbohydrates are important in certain types of sorting events - Lysosomal Enzymes. * These enzymes are involved in degrading proteins and lipids and they are destined to go to the **lysosome**. * **Lysosomal hydrolase precursors** are recognised in the **cis Golgi network**. * The carbohydrates on the Lysosomal hydrolase precursor are modified by the **addition of a phosphate** **onto the carbohydrate, which acts as a TAG**. * **The phosphorylation of mannose is catalysed by** **PHOSPHOTRANSFERASE****.** (using ATP as the phosphate donor) * Now the lysosomal enzymes are tagged with a **phosphorylated sugar** - a very specific tag. * When they reach the **trans Golgi network**, the phosphorylated sugar is detected by a very specific receptor - **Manose-6-Phosphate receptor** - which leads to the enzymes being packaged into specific vesicles. * The specific vesicles have **targeting signals** on the outside which are specific to the **lysosome** but the vesicles travel first to the **late endosome**. * The late endosome contains a **proton pump**, which **pumps protons** from the cytoplasm **into the late endosome** so **THE LUMEN OF THE LATE ENDOSOME IS RELATIVELY ACIDIC**. * In the **acidic environment** the M6P receptor releases the phosphorylated lysosomal hydrolases. * Once released, the **phosphate is removed** by a **phosphohydrolase** - SO IT CAN NO LONGER GO BACK TO THE GOLGI BECAUSE IT DOES NOT HAVE IT'S PHOSPHATE. * Because of this mechanism, you get an **accumulation of lysosomal hydrolases in the late endosome**. * **THE LATE ENDOSOME MATURES TO FORM A LYSOSOME.** The M6P receptors are **recycled** back to the trans Golgi network

Question 38

Where does the malate aspartate shuttle primarily take place as oppose to glycerol-phosphate

Answer 38

met 4 slide 27 Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 39

“Recall two examples of the use of NADPH in reductive biosynthesis.” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Answer 39

“biosynthesis of RNA and cholesterol, allowing electron transport in catabolism to be kept separate to that of anabolism. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 40

Describe the role of cytochrome oxidase

Answer 40

pg 67 (Cytrochrome oxidase) Laz's notes) ## Footnote **Cytochrome Oxidase** Cytochrome Oxidase is the last membrane complex in the electron transport chain. It initially receives **2 electrons** from cytochrome C in the first cycle of the electron transport chain, and then the cycle repeats so that cytochrome oxidase has **4 electrons** in total. Cytochrome oxidase passes the electrons to **Oxygen** to generate **water**. Furthermore, **4 protons** are pumped into the intermembrane space, thus enhancing the proton gradient. 4e- + 4H+ + O₂ --------------\> 2H₂O Oxygen is the ideal terminal electron acceptor because it has a **high affinity for electrons**, proving a driving force for oxidative phosphorylation.

Question 41

Describe how fats are transported in the body, adnd taken up by tissues to be used.

Answer 41

pg 91 (Lipoproteins) Laz's notes

Question 42

Describe how ketone bodies are formed in metabolism(this requires some other deeper understqanding which i did not have)

Answer 42

pg 75 Laz's notes(**Ketone Body Formation)** **KEY POINT: Acetyl CoA formed from b****-oxidation can only enter the TCA cycle if****b****-oxidation and carbohydrate metabolism are balanced****. This is because OXALOACETATE is needed for entry of Acetyl CoA into the TCA cycle.** If fat breakdown predominates (e.g. when fasting/starving), **acetyl CoA forms:** * **Acetoacetate** * **D-3-hydroxybutyrate** * **Acetone** * **These are known as KETONE BODIES.** *

Question 44

Describe the formation of squalene from isopently pyrophosphate

Answer 44

pg 87 Laz's notes

Question 45

Provide a summary of glycolysis and what ensues under different conditions in metabolism

Question 46

“Summarise the processes by which the amino acid alanine is converted into acetyl-CoA.” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 47

he synthesis of bile acids and steroid hormones from cholesterol

Answer 47

pg 89 Laz's notes

Question 48

Decsribe how bile salts function

Answer 48

1st section on Laz's notes pg 90

Question 49

summarise the synthesis of cholesterol from acetyl-CoA(long shit)

Answer 49

Laz's notes pg 85-88

Question 50

Describe possible feeatures of a glucose metabolism step that metabolic control ussually takes place at

Answer 50

pg 101 Laz's notes AD

Question 51

Describe structural feature s thta allow acetyl CoA to donate acetyl to other molecules

Answer 51

Met 4 slide 7

Question 52

Label the following molecule

Answer 52

pg 90 Laz's notes

Question 53

DIffertiate between type q and type 2 diabetes

Answer 53

* Type I - cannot make insulin * Type II - reduced responsiveness to insulin

Question 54

Describe the function of GLP 1

Answer 54

Laz's notes pg 104

Question 55

metabolism quiz on pg 94 ibook

Question 56

What is the role of the thioester linkage in acetyl CoA

Answer 56

pg 75 laz's notes (Process of beta oxidation)

Question 57

“Explain how ATP synthase is able to generate and utilise ATP respectively, with reference to its structure.” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Answer 57

pg 29 ABS" notes

Question 58

Using change in free energy describe how the two relevant coenzymes in the respiratory chain can bee responsible for several phosphanhydride bonds(for deeper understanding try and understand why the mnumbers shown do not work out)

Answer 58

pg 81 ibook left side up till (_Chemiosmotic Model of Oxidative Phosphorylation_)

Question 59

“Explain the proposed evolutionary origins of mitochondria. and outline the evidence for them Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Answer 59

pg 80 ibook left side

Question 60

Calaculate the ATP yield of palmitate

Answer 60

pg 75(**Net ATP Production of Palmitate b-oxidation compared to aerobic respiration:) to page 76 (Fatty acid biosynthesis) Laz's note**

Question 61

summarise the pathways for the synthesis of fatty acids with respect to the substrates and products, coenzymes used, carrier molecules and their cellular locations

Answer 61

pg 76(**Fatty Acid Biosynthesis - Lipogenesis) to 77 Laz's notes**

Question 62

Name and exemplify the three types of intracellular transport

Answer 62

**(pg 78Types of Intracellular Transport) Laz's notes** 1. **Gated Transport** - e.g. nuclear import 2. **Trans-membrane Transport** - e.g. import of newly synthesised proteins into ER 3. **Vesicular Transport** - e.g. inter-organellar transport

Question 63

Describe how sorting occurs at the trans golgi network

Answer 63

pg 83 Laz's notes (Sorting at the trans golgi network) **Sorting at the Trans Golgi Network (Exocytosis)** * Proteins have gone through the Golgi Apparatus and had their carbohydrates processed. * RECAP: **Two Most Common Routes: Constitutive Secretory Pathway + Regulated Secretory Pathway** * Constitutive Secretory Pathway - continually going out towards the plasma membrane in an **unregulated** manner. * Regulated Secretory Pathway - for materials that have to be secreted in a **regulated** manner e.g. neurotransmitter. Proteins, such as neurotransmitter, will be sorted into a specific secretory vesicle and the vesicle is **stored in the cytoplasm** until its release is **triggered** by a **SIGNAL** e.g. hormone. * When the signal molecule (e.g. hormone) binds to the **cell surface receptor** it triggers an **intracellular signalling pathways** that causes the **release of the stored secretory proteins**.

Question 64

Describe the functions of four different hormones that tak epart in the hormonal control of metabolism

Answer 64

pg 102 Laz's notes * **Insulin** - secreted when glucose levels rise - stimulates uptake and use of glucose and storage of glycogen and fat * **Glucagon** - secreted when glucose levels fall - stimulates gluconeogenesis and the breakdown of glycogen and fat * **Adrenaline** - strong and fast metabolic effects to **mobilise glucose** for 'fight or flight' * **Glucocorticoids** - steroid hormones that increase synthesis of metabolic enzymes concerned with **glucose availability**.

Question 65

Describe how cholesterol is made from squalene

Answer 65

pg 88 Laz's notes

Question 66

Summarise the process by which amino acids lead to products that can enter the TCA cycle

Answer 66

Met 4 slide 24-26

Question 67

Describe the size of mtDNA and its abundance in the cell

Answer 67

“Human mitochondrial DNA (mtDNA) existing as a 16,569 bp circular genome, encoding just 37 genes. However, unlike nuclear DNA, several copies of the mitochondrial genome can be found within a single cell. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 68

What is the role of glucagon in diabetes

Answer 68

**Diabetes is not just a result of a decreased sensitivity to insulin or insulin deficiency but it's also a defect in terms of glucagon secretion.** **Glucagon in Type 2 Diabetes** * Important protection against hypoglycaemia. * Major Site of Action - LIVER - glucagon stimulates gluconeogenesis and glycogenolysis.

Question 69

Summarise the electron transport chain in mitochondria with reference to the functions of coenzyme Q (ubiquinone) and cytochrome c.

Answer 69

pg 81 . ibook right side Each unit in the chain has a HIGHER AFFINITY for electrons than the previous unit, allowing them to flow in a logical order. pg 68 Laz's notes(Redox reactions **Redox Reactions** Electron transfer reactions involving a **reduced substrate** and an **oxidised substrate**..A substrate that can exist in both oxidised and reduced states is known as a **redox couple** e.g. NAD+/NADH, FAD/FADH₂.The ability of a redox couple to accept or donate electrons is known as the **reduction potential** or **redox potential**. **Standard Redox Potentials** **NEGATIVE** **redox potential = tendency to** **DONATE** **POSITIVE** **redox potential = tendency to** **ACCEPT** Each successive membrane complex or carrier has a **more positive redox potential** than the previous component of the ETC. This means that the transfer of electrons from one complex to the next is **energetically favourable**. As they progress along the chain, the electrons **lose energy**.

Question 70

Met 5 quizzes, pg 84 ibook

Question 71

Recall the posible deivations of fats , and the processes that follow digestion up till their storage

Answer 71

i(book pg 85 2nd paragraoh & pg 86 left side line 1-3)“ Fats are derived from three primary sources, namely the diet, de novo synthesis by the liver and release from storage depots in adipocytes. Lipid digestion by the action of lingual gastric and pancreatic lipase results in the formation of Monoacylglycerol (MAG), diacylglycerol (DAG) and free FAs. During digestion, bile salts are released from the gall bladder and help to solublize fatty acids molecules, forming micelles which include other molecules such as cholesterol, lysophosphatidic and fat-soluble vitamins e.g. A, D, E and K. Fatty acids from the micelles are absorbed by enterocytes lining the brush border of the small . intestine and TAGs are resynthesized under the control of several enzymes prior to incorporation into chylomicrons (CM) and transportation (covered in lecture 7). ”

Question 72

Describe Regulation of hormone secretion in pancreatic b cells

Answer 72

Laz's notes pg 103(Regulation of hormone secretion in pancreatic b cells)

Question 73

Give an illustration of the degradatio pathways with your own example

Answer 73

pg 85 Laz's notes (**lustration of Degradation Pathway:** EXAMPLE - LDLs)

Question 74

Explain th e difference between NADP and NAD and its advantage

Answer 74

“NADP+ is a relative of NAD+, differing only by a phosphate group attached to one of the ribose rings. The phosphate group does not participate in electron transfer, but gives it a slightly different conformation, meaning that it will bind to different enzymes than NAD+. NADP+ takes part in anabolic reactions, whereas NAD+ takes place in catabolic reaction” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 75

Describe the **Regulation of glucagon secretion in pancreatic** **a** **cells:**

Answer 75

Laz's notes pg 105 (**Regulation of glucagon secretion in pancreatic** **a** **cells:)**

Question 76

What is the genreal effect on metabolism of defective insulin signalling

Answer 76

* The general effect on metabolism of defective insulin signalling is that your metabolic status is controlled **'*as if you were starving***'. Without the insulin signalling, your body doesn't know that you have fuel.

Question 77

Summarise protein and fat metabolism in the body,

Answer 77

pg 99 Laz's notes

Question 78

Describe the secretory or exocytotic pathway

Answer 78

pg 80(**The Secretory or Exocytic Pathway)** Laz's notes

Question 79

“Explain the Krebs or TCA (tricarboxylic acid) cycle with particular reference to the steps involved in the oxidation of acetyl Co-A and the formation of NADH and FADH2 and the cellular location of these reactions. ”

Answer 79

pg 75 ibook

Question 80

What are the orignins of cholesterol

Answer 80

“Although some is taken up in the diet, the majority of the body’s cholesterol is synthesized by the liver from the molecule acetyl-CoA. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 81

Met 6 quiz on pg 89

Question 82

Describe a cause of a lack of bile salts and the possible consequences of this lack

Answer 82

pg 86 line 3 up till beta-oxidation “If bile salts are lacking (e.g. obstruction of the bile duct by a gallstone) then fat may pass through the gut undigested resulting in steatorrhea (fatty stool). Steatorrhea is also a major side effect of Orlistat/lipstatin usage, which prescribed as an obesity treatment and is an inhibitor of gastric and pancreatic lipases. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 83

explain how inborn errors of fatty acid metabolism may cause disease, and how thus diseases are managed

Answer 83

pg 88 left side(Disorders of Fatty acid Metabolism) to 89 ibook

Question 84

summarise the pathways for the metabolism of fatty acids with respect to the substrates and products, coenzymes used, carrier molecules and their cellular locations

Answer 84

firstly, for information on the first enzyme in the cycle: (pg 88 ibook ,left side(Disorders of fatty acid metabolism) then read from pg 86 (β-oxidation ) to pg 87, ibook, script for info on first enzyme : “A family of 5 different Acyl-CoA-dehydrogenases catalyze the initial step in each cycle of fatty acid β-oxidation within the mitochondria matrix: Each Acyl-CoA-dehydrogenase can bind a fatty acid chain of varying lengths: 3-hydroxyacyl-coenzyme A dehydrogenase Short-chain acyl-coenzyme A dehydrogenase Medium-chain acyl-coenzyme A dehydrogenase Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase Very long-chain acyl-coenzyme A dehydrogenase ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 85

Explaoin how warfarin works

Answer 85

* pg 43 (Post Translational modification of proteins) * The starting set of 20 amino acids can be modified to create novel amino acids, enhancing the capabilities of the protein. ![]() * The formation of g-carboxyglutamate residues within several proteins of the blood clotting cascade (e.g. factor IX) is critical for their normal function by increasing their calcium binding capacities. * **WARFARIN works by inhibiting the carboxylation reaction**

Question 86

Give the details of a step of glucose metabolsim where it 's control is dependent on enzyme activity

Answer 86

Laz's notes pg 101 AD

Question 87

Met 9 quiz pg 105 ibook

Question 88

Describe the medication that may be used to manage FH

Answer 88

pg 94

Question 89

Recall what happens in the ER for post translational modification and quality control

Answer 89

pg 80(**ER: Post-Translational Modifications and Quality Control)**

Question 90

Describe the location of the enzymes involved in the krebs cycle, and where they act

Answer 90

“The Krebs cycle enzymes are soluble proteins located in the mitochondrial matrix space, except for succinate dehydrogenase, which is an integral membrane protein that is firmly attached to the inner surface of the inner mitochondrial membrane. Here, it can communicate directly with components in the respiratory chain. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 91

# Define the chemiosmotic theory.

Answer 91

(pg 81 ibook )“Chemiosmotic Model of Oxidative Phosphorylation Oxidative Phosphorylation proceeds in two steps: 1) The translocation or movement of protons from within the matrix of the mitochondria. This is controlled by the electron transport or respiratory chain. 2) The pumped protons are allowed back into the mitochondria through a specific channel, which is coupled to an enzyme which can synthesise ATP (ATP synthase). See Alberts, Figure 14-2, page 455 for a nice analogy of the theory with a battery operated pump. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 92

Reccal compliations of diabetess

Answer 92

* COMPLICATIONS: * Hyperglycaemia - causing progressive tissue damage * Increase in plasma fatty acids and lipoproteins - possible cardiovascular complications * Increase in ketone bodies - possible acidosis * Hypoglycaemia - possible coma if insulin dosage is not correctly controlled

Question 93

Exaplin aerobic and anaerobic repiration during exercise, includean explaination of the hormones involved

Answer 93

pg 100 Laz's notes

Question 94

“Recall the chemical composition of unsaturated and saturated fatty acids. and describe their storage in mammals

Answer 94

pg 85 ibook “Fatty acids (FA) are composed of a hydrophobic carbon chain and a hydrophilic head group and can be saturated with hydrogens (saturated fatty acids) or unsaturated (with one or more double bonds). They are typically stored as triacylgycerol (TAG) species. Double bonds introduce kinks into the carbon chains of thee molecules and means that they pack less tightly together, and are generally liquid at room temperature. In contrast, saturated fatty acids pack tightly together and are generally solid at room temperature.” “In mammals, fatty acids are stored as tryglycerides in the cytoplasm of specialised cells known as adipocytes. ” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks. Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks.

Question 95

Describe the fucntions of glycocylation and explain compartment identity

Answer 95

pg 83 Laz's notes top parts **Functions of Glycosylation** * Folding * Protection (e.g. glycocalyx) * Receptors * Recognition (e.g. blood groups) **Compartment Identity** * All the different membrane-bound intracellular compartments have a distinct protein and lipid content. Proteins make sure that they get to the correct compartment by having: * Targeting/Sorting signals (e.g. lysosomes) * Retention signals * Retrieval signals

Question 96

met 3 quiz

Question 97

“Explain how ATP synthase is able to generate and utilise ATP respectively, with reference to its structure.” Excerpt From: Imperial College London. “MBBS Year 1 MCD Autumn 17/18.” iBooks. x

Answer 97

“2) The pumped protons are allowed back into the mitochondria through a specific channel, which is coupled to an enzyme which can synthesise ATP (ATP synthase). See Alberts, Figure 14-2, page 455 for a nice analogy of the theory with a battery operated pump. ” pg 81(chemiosmotic model of oxidative phophorylation)

Question 98

Describe the synthesis of isopentyl pyrophosphate and describe where it occurs

Answer 98

occurs in the cytoplasm, pg 85(**Biosynthesis of Cholesterol - Step by Step ) to pg 86 Laz's notes**