Tag: carbohydrate metabolism

Quizzes (9) Questions (178)

Questions Related to carbohydrate metabolism

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

What is ATP?

  1. A hormone

  2. A protein

  3. An enzyme which brings about oxidation

  4. A molecule which contains high energy bond
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Adenosine triphosphate (ATP) is a nucleotide with three phosphates. The ATP is produced by the addition of phosphorous to nucleoside adenosine.
  • The first phosphate is attached by an ester bond. This bond is a normal covalent bond and not a high energy bond. 
  • The two-terminal phosphates are bonded by high energy acid anhydride bonds. 

Thus one molecule of ATP contains two high energy bonds.

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

ATP stands for which of the following?

  1. Adenosine phosphate

  2. Adenine triphosphate

  3. Adenosine diphosphate

  4. Adenosine triphosphate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chemically ATP is a nucleotide. In fact it is a higher order nucleotide because it contains not one but three phosphates. Compounds made up of (pentose) sugar and a nitrogenous base are called nucleosides. If the base is adenine, the nucleoside will be called adenosine. 

If one phosphate is attached to adenosine through an ester bond then the compound becomes a nucleotide and in this case it is called adenylic acid or adenosine monophosphate.
When second phosphorous is attached to the first phosphorous, through an acid anhydride bond, the nucleotide is called adenosine diphosphate. When third phosphorous is attached to the second phosphate through another acid anhydride bond, the nucleotide is called adenosine triphosphate or ATP.

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

$\sim P$ in ATP represents

  1. Two bonds with high energy

  2. Two moles of phosphorus

  3. Three atoms of high energy phosphate

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
ATP is known as energy currency of the cell and it is a nucleotide formed by the combination of adenine as a nitrogenous base, ribose sugar, and triphosphate. It is found in free cells which breaks to form energy by breaking it's high energy phosphate bonds. The high energy phosphate bonds break to form ADP and AMP. It is a hydrolysis reaction which occurs at extreme pH. It dephosphorylates to provide energy for metabolic function.
ATP has three phosphate out of which one is directly attached to the ribose with phosphate ester bond and it is low energy bond. The bond between two phosphate groups is a phosphoanhydride bond which is considered as high energy bond. So ATP has only two high energy bond phosphoanhydride bond.
So, the correct answer is option A.
Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

Conversion of ATP to ADP releases

  1. Energy

  2. Enzyme

  3. Hormone

  4. Electricity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Adenosine Triphosphate or ATP has stored energy in its bond with the third phosphate group. However when required, ATP loses its third phosphate group to release energy and gets converted back to ADP. The energy released is in the form of chemical energy that the cells can use.

So the answer is 'Energy'.

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

How many ATPs are required by $C _4$ plants in synthesis of one molecule of glucose

  1. 18 ATP

  2. 30 ATP

  3. 12 ATP

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Most of the plants that are adapted to dry tropical regions have the $C _{4}$ pathway. e.g. Sugarcane, Maize, Sorghum,etc. These plants are known as $C _{4}$ plants.For the formation of sugars, $C _{4}$ plants undergo $C _{4}$ cycle as well as $C _{3}$ cycle or Calvin cycle. In these plants double fixation of carbon dioxide occurs.

ATP consumed in $C _{4}$ plants:
$C _{4}$ cycle - 2 ATP per $CO _{2}$ fixed
$C _{3}$ cycle - 3 ATP per $CO _{2}$ fixed 
Total - 5 ATP per $CO _{2}$ fixed
Thus, to form one molecule of glucose or to fix 6 $CO _{2}$, 6 X 5 = 30 ATP are consumed.

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

One mole of glucose on metabolism, liberate how many kilo calories of energy ?

  1. 180

  2. 80

  3. 160

  4. 380
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

On complete combustion of glucose (1 mole) to CO$ _{2}$ & H$ _{2}$O, approx. 686 kcal of energy is released. When 1 g of glucose respires aerobically by ETS, Glycolysis and  Krebs cycle, around 38 ATP molecules are generated. The terminal group of a mole of ATP has around 10 kcal. Thus, 38 ATP molecules represent a yield of 380 kcal of energy.  

So the correct option is '380'

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell
How many ATP and NADPH molecules are respectively required to make one molecule of glucose through the Calvin cycle?

  1. 3 and 2

  2. 9 and 6

  3. 18 and 12

  4. 12 and 18
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For every $CO _{2}$ molecule entering the Calvin cycle, $3$ molecules of $ATP$ and $2$ molecules of NADPH are required. To make one molecule of glucose, $6$ turns of the cycles are required 

$(6\times 3 ATP =18 ATP$ and $6\times 2 NADPH=12 NADPH)$.

In                            Out   
$6$ $CO _{2}$ $1\,\, glucose$
$18 ATP$ $18 ADP$
$12 NADPH$  $12 NADP$ So, the correct answer is '

18 and 12'.

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

If two moles of glucose are oxidized in the body through respiration, the number of moles of ATP produced are.

  1. 19

  2. 38

  3. 57

  4. 76
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Cellular respiration can be an anaerobic or aerobic respiration, depending on whether or not oxygen is present. Anaerobic respiration makes a total of 2 ATP. Aerobic respiration is much more efficient and can produce up to 38 ATP with a single molecule of glucose.
Anaerobic respiration consists of two steps.
               1. Glycolysis (2 ATP)
               2. Fermentation 
               Total = 2 ATP
Aerobic respiration consists of three steps.
               1. Glycolysis (2 ATP)
               2. Krebs Cycle (2 ATP) 
               3. Electron Transport Chain (34 ATP)
               Total = 38 ATP
If two moles of glucose is oxidized in the body through respiration, the number of moles of ATP produced are 38 x 2 = 76.
So the answer is option D '76'. 
Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

The number of ATP molecules produced during the oxidation of $1$ molecule of glucose is 

  1. $12$
  2. $18$
  3. $32$
  4. $38$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
1. Glycolysis: 
 C$ _{6}$H$ _{12}$O$ _{6}$ +  2 ATPs  → 2 Pyruvic Acid + 4 H$ _{2}$ + 4 ATPs
2. Formation of Acetyl CoA:
 2 Pyruvic Acid + 2 CoA → 2 Acetyl CoA + 2 CO$ _{2}$ + 2 H$ _{2}$
3. Krebs Cycle:
 2 Acetyl CoA + 3 O$ _{2}$ → 6 H$ _{2}$ + 4 CO$ _{2}$ + 2 ATPs
4. Electron Transport System:
 12 H$ _{2}$+ 3 O$ _{2}$ → 6 H$ _{2}$O + 34 ATPs
Overall Reaction:
C$ _{6}$H$ _{12}$O$ _{6}$ + 6 O$ _{2}$→ 6 CO$ _{2}$ + 6 H$ _{2}$O + 38 ATPs
So, the correct option is '38'.
Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

At the end of Krebs cycle, but before the electron transport chain, the oxidation of glucose has produced a net gain of -

  1. $ 3CO _2 , 5 NADH _2 , 1 FADH _2 , 2 ATP$
  2. $ 6CO _2 , 10 NADH _2 , 2 FADH _2 , 4 ATP$
  3. $ 6CO _2 , 10 NADH _2 , 2FADH _2 , 38 ATP$

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

One molecule of the glucose that enters in the glycolysis produces 2 molecules pyruvate and 2 molecules of NADH$ _{2}$ and 2 ATP.  2 molecules of pyruvate will form 2 molecules of Acetyl Co-A and this will release 2 molecules of CO$ _{2}$ and 2 NADH$ _{2}$. These 2 Acetyl Co-A will enter into Kreb's cycle and will release 4CO$ _{2}$, 6NADH$ _{2}$, 2FADH$ _{2}$ and 2ATP.

so, the total gain before the ETC comes out to be 6 CO$ _{2}$, 10NADH$ _{2}$, 2FADH$ _{2}$ and 4ATP.
Hence, the correct answer is '6CO$ _{2}$, 10NADH$ _{2}$, 2FADH$ _{2}$, 4ATP'.