Metabolism 3

Question 1

“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 1

“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 2

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

Answer 2

“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 3

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

Answer 3

[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 4

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

Answer 4

“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 5

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

Answer 5

pg 93 ibook (paragraph 3)

Question 6

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

Answer 6

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 7

List the measures of metabolism

Answer 7

Oxygen Uptake, Carbon Dioxide Production, Heat Generation

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

Answer 9

Laz’s notes pg 104 where i decided to underline

Question 10

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

Answer 10

pg 106 Laz’s notes