Biochemistry Flashcards
Define the Cori cycle
Glycogen => glucose => lactate in muscle Lactate travels to liver Lactate => glucose in liver Glucose goes back to muscle => glycogen
Which vitamin is niacin?
B3
What are the 3 ketone bodies?
Beta-hydroxybutyrate Acetone Acetoacetate
How many ATP are produced for each NADH?
2.5
What does VItC deficiency cause?
Survy
What is the major determinant of glycogen glucose conversion?
Insulin: glucagon ratio
What is the cutoff for waist circumference for greatly increased risk of metabolic complications for females?
>= 88
What happens to leptin in obesity?
There is a decreased sensitivity to leptin, but increased amounts of leptin
Which cells secrete CCK?
I cells of the small intestine
In what part of the cell does beta oxidation occur?
MItochondria
How many H+ are put into the intermembrane space for each NADH molecule?
10
How many H+ are put into the intermembrane space for each FADH2 molecule?
6
Which vitamin is riboflavin?
B2
What is the key sign for VitB2 deficiency?
Magenta tongue
What are the 4 Ds of pellagra?
Photosensitive dermatitis. Diarrhoea. Dementia. Death
What is the range for BMI to be obese?
>30
What is the cutoff for waist circumference for increased risk of metabolic complications for males?
>= 94cm
Where does vitamin K come from?
It is produced by gut flora
Where do we get intrinsic factor from?
It is synthesised by parietal cells of the stomach
Deficiency of which vitamin will cause xerophthalmia?
VitA
Why is VitC often given with iron supplements?
VitC reduces Fe3+ to Fe2+, which is better absorbed
How do RBCs produce most of their energy?
Anaerobic glycolysis
Which cells release insulin?
Beta cells of the islets of Langerhans of the pancreas
What is the advantage of chylomicrons from the gut travelling through lymphatics to reach blood?
It bypasses the liver
Where and in which order is VitD hydroxylated?
Skin => liver => kidney
What is transported into cells with glucose via GLUT-4 transporters?
Potassium
What disease will deficiency of niacin cause?
Pellagra
What is the most abundant mineral in the human body?
Calcium
What are the 3 defining features of a vitamin?
Organic compound Not made by the body Essential biochemical funcitons
Where is ghreline released?
Stomach
Which organs have glucose-6-phostphatase?
Liver and kidney
Which vitamin is pyridoxine?
B6
What happens when muscles release excessive calcium and become an uncontrolled ATPase?
Malignant hyperthermia
What inhibits carnitine acyl transferase 1?
Malonyl CoA
What happens to insulin levels in starvation?
Decrease
What causes Wilson’s disease?
Excess copper
What is the classic triad of symptoms for diabetes?
Polydipsia, polyphagia polyuria
What happens to glucose in the liver when glycogen stores are saturated?
Glucose is converted to fatty acids
What do muscles use for fuel with bursts of heave activity eg 50m sprint?
Phosphocreatine
Which vitamin is thiamine?
B1
What is the significance of glycogen being insoluble?
Exerts little osmotic effect
How many phases of insulin release are there after a meal?
2
Name 3 consequences of calcium deficiency
Rickets. osteoporosis and poor blood clotting
Which organelle is an endosymbiotic bacteria?
Mitochondria
In disease of which organelle do we often see ragged red fibers?
Mitochondria
Which enzyme allows the liver to export glucose to the blood?
Glucose-6-phosphatase
How long will glycogen reserves last in the fasting state with relative inactivity?
12 hours
Which enzyme converts glycogen => glucose-1-phosphate
Glycogen phosphorylase
What is a typical daily dietary energy requirement for an adult?
10 MJ
How much protein do we make and break down every day?
300g
What is the range for BMI to be underweight?
Where is ammonia processed into urea?
Liver
What does excessive iron cause?
Haemochromatosis
What is at the core of glycogen?
Glycogenin
The levels of which hormone increase just befor a meal?
Ghrelin
Which monosaccharide(s) are aldoses?
Glucose and galactose
What are the side effects of orlistat?
Explosive diarrhoea. Steatorrhea
Release of which hormone is stimulated by hyperglycaemia?
Insulin
In what part of the cell does glycolysis occur?
Cytosol
What is another name for dextrose?
Glucose
What are the two major families of sugars?
Aldose and ketose
Which monosaccharide(s) are ketoses?
Fructose
What will happen if there are too many free fatty acids in the blood that are not bound to albumin?
Arrhythmia
Release of which hormone is stimulated by hypoglycaemia?
Glucagon
How many molecules of ATP are yielded from aerobic metabolism of 1 glucose molecule?
30 or 32
What is the range for BMI to be morbidly obese?
>40
What diseases will insufficient thiamin cause?
Beriberi and Wernicke’s Encephalopathy
Which glucose transporter does insulin upregulate?
GLUT-4
Which fuel source is premium during starvation?
Fat
Which hormone does ghrelin antagonise?
Leptin
Why can’t humans digest cellulose?
Don’t have an enzyme to break the beta 1,4 bonds
Where in the cell does ketone acid synthesis occur?
Mitochondria
What mediates the effects of ghrelin?
Neuropeptide Y
Which vitamin is a cofactor in collagen synthesis?
VitC
What part of triacyglycerols can be used to make glucose?
Glycerol
Which pathway is VitK important for?
Coagulation cascade
What is a biochemical role of thiamine?
It is a co-factor for pyruvate decarboxylase (pyruvate => Acetyl CoA)
Glucose is all ___ ____ _____ .
Glucose is all D except 3
What is the order of B vitamins?
Thiamine. Riboflavin. Niacin. Pyridoxine. Cobalamin. The rich never park cars
Which vitamin is cobalamin?
B12
What would happen if you gave GLP-1 with food?
You would feel more full and eat less
What is the cutoff for waist circumference for increased risk of metabolic complications for females?
>= 80cm
What percentage of Australians are overweight or obese?
63%
How is VitB12 absorbed?
With intrinsic factor in the terminal ileum
Which two drugs are TGA approved for treatment of obesity?
Phentermine and orlistat
How is BMI calculated?
weight (kg) / height (m)^2
Why can’t the brain use fatty acids for energy?
FAs can’t cross BBB
What condition is caused by a diet that is severely deficient in energy and moderately deficient in protein?
Marasmus
How do fatty acids get into the mitochondria?
Carnitine acyl transferase
What effects may VitB12 deficiency have?
Dementia. Pernicious anaemia.
In starvation, what can fatty acids be turned into?
Ketones
What happens to sperm mitochondria at fertilisation?
They are discarded
What effect does adrenaline have on carbohydrate metabolism in the liver?
Causes catabolism of glycogen into glucose
Which nucleus of the hypothalamus does ghrelin stimulate?
Arcuate nucleus
How does phentermine treat obesity?
Sympathomimetic => supresses appetite
Which cells produce leptin?
Adipocytes
What is the preferred fuel for skeletal muscle?
Glucose
What is the cutoff for waist circumference for greatly increased risk of metabolic complications for males?
>= 102
Which vitamin will you run out of first if you stop eating?
Thiamine (VitB12)
Which protein causes uncoupling in brown fat?
Thermogenin
Which vitamin is niacin?
B3
What disease causes engorged lysosomes full of glycogen due to a deficiency of alpha 1,4 glucosidase?
Pompes diseases
What causes pellagra?
Insufficient VitB3 (niacin)
Which organs express GLUT4?
Muscle, adipose tissue and heart
How does orlistat treat obesity?
It is a lipase inhibitor => inhibits absorption of fat
What is created when electrons escape from the electron transport chain?
Reactive oxygen species
Why can’t fatty acids be converted into glucose?
Can’t convert acetyl CoA into pyruvate
What is starch?
A branched polymer of glucose found in many plants
What are the side effects of phentermine?
Increased HR and BP, anxiety, insomnia, dry mouth, headache
What does VitD deficiency cause in children?
Ricket’s
How many mitochondria are there per cell?
200-10,000
How much glucose does the brain need per day?
120g
How long will thiamine reserves last if you stop eating completely?
2 weeks
How much energy is there per mol of ATP?
30.5 kJ
How are fatty acids transported in the blood?
Bound to albumin
How does the retina produce most of its energy?
Anaerobic glycolysis
After several days of starvation, what is the main source of carbon backbone for gluconeogenesis?
Glycerol from TAGs
Where in the body can fatty acids be used for gluconeogenesis?
NOWHERE
What effects may folate deficiency have?
Spina bifida in pregnancy. Macrocytic anaemia.
What is the range for BMI to be normal?
18.5-25
How many molecules of ATP are yielded from anaerobic metabolism of 1 glucose molecule?
2
What is the range for BMI to be overweight?
25-30
What is the alanine cycle?
Nitrogen from protein catabolism in muscle is transferred to liver in the form of alanine. The ammonia is transferred to urea for excreted
How many ATPs are net produced by glycolysis?
2
How does CCK stimulate satiety/fullness?
Via the vagus nerve
How many ATP are produced for each FADH2?
1.5
Which hormone does adipocytes release to signal fat storage levels?
Leptin
Which two substances can activate hormone sensitive lipase?
Glucagon and adrenaline
Which organs express GLUT2?
Liver, pancreas and GIT
Which organ expresses glucokinase?
Liver
What does hyperuricaemia cause?
Gout
Which cells release glucagon?
Alpha cells of the islets of Langerhans of pancreas
How do we describe a fatty acid when there is a double bond at the third carbon from the end of the hydrocarbon chain?
Omega 3
How much energy is there per mol of NADH?
2200 kJ
Which prostaglandin does omega 3 fatty acids promote the formation of?
Prostacyclin
What causes beriberi disease?
Insufficient VitB1 (thiamine)
Which cells release somatostatin?
Delta cells of the of the islets of Langerhans of the pancreas
What condition is caused by a diet that is severely deficient in protein?
Kwashiorkor
What effect does leptin have on appetite?
Decreases
Which conditions can fibre prevent?
Diverticulosis and haemorrhoids
What effect does somatostatin have on alpha and beta cells of the pancreas?
Decreases release of their hormones
How many nitrogen atoms are there in urea?
2
In what part of the cell does the Krebs cycle occur?
Mitochondria
What are the main sources of carbon for gluconeogenesis in starvation?
Glycerol and proteins
Which cells express GLUT1?
All cells
Which peptide is released by cleavage of pro-insulin (apart from insulin)?
C-peptide
How does the body get rid of nitrogen?
In urea or ammonia
What is the principal sterol synthesized by animals?
Cholesterol
Which reaction does phenylalanine hydroxylase catalyse?
Phenylalanine -> tyrosine
What is the precursor for cholesterol synthesis in the liver?
Acetyl Co-A
In which organelle is squalene converted to cholesterol?
Endoplasmic reticulum
