Why We Need ATP Quiz / Test | Biology

Quiz Answer Key and Fun Facts

1. First of all what is ATP? It is a molecule synthesised during respiration which is used as a source of immediate energy. When 6 molecules of oxygen react with 1 molecule of glucose (i.e. respiration) what is the maximum yield of ATP?

Answer: 38

ATP stands for Adenosine Triphosphate.

The energy released from the oxidation of glucose during aerobic respiration is used to attach a third phosphate group to ADP (Adenosine Diphosphate), forming ATP. Energy is readily released by hydrolysing the terminal bond holding the third phosphate group to the molecule.

2. As well as being involved with respiration, ATP also plays a vital role in photosynthesis. One molecule of ATP provides the energy needed to convert two molecules of glycerate-3-phosphate (GP) into two molecules of glyceraldehyde-3-phosphate (GALP). In what cycle does this occur?

Answer: The Calvin cycle

ATP and NADPH are both involved in converting GP into GALP. After 6 cycles, enough GALP has been synthesised to produce one molecule of glucose. This is the light independent phase of photosynthesis.

Both ATP and NADPH are produced in the light dependent phase of photosynthesis. After light falls on chlorophyll, electrons become excited and can escape from the molecule. Electrons are then passed along an electron transfer chain and they lose is used to synthesise ATP. The electrons eventually reduce NADP to NADPH.

3. In the human body ATP is used for a huge range of actions. One such action includes muscle contraction. Which mechanism involves the drawing of actin microfilaments between myosin microfilaments?

Answer: The ratchet mechanism

Muscle fibres are made up of myofibrils. Actin and myosin microfilaments make up these myofibrils.

ATP is attached to the head of a myosin filament and this head attaches to an "actin binding site" forming a "cross-bridge". The ATP molecule is then hydrolysed, changing its shape, allowing actin microfilaments to be drawn between the myosin. When a new molecule of ATP attaches to the myosin head the "cross-bridge" is broken and the muscle can then return to its original shape by the action of an antagonistic muscle.

4. The muscle contractions which ATP facilitates allow mammals to maintain a constant body temperature. One obvious example is shivering, as this releases heat. Which action involving ATP is another example of how mammals raise their body temperatures?

Answer: Hairs standing on end

ATP is required for erector pili muscles in the skin to contract, causing hairs to stand on end. When the hairs rise there is a layer of air trapped between the tips of the hairs and the surface of the skin, which insulates the skin. This causes the temperature gradient between the skin and the air to decrease and so less heat is lost from the blood via radiation.

5. In order to succeed in the hourly games which are primarily based on speed you have to have nerves of steel! In neurones the cation pump in the axon membrane maintains the resting potential needed before an impulse can be sent from the central nervous system. How is this resting potential maintained?

Answer: Transporting 3 sodium ions out of the axon and 2 potassium ions in

Sodium ions which are transported out of the axon remain there, but many of the potassium ions transported into the axon diffuse out via the potassium leakage channel. There is therefore a positive charge built up outside the axon and a negative charge built up of the inside.

The energy released by ATP is used to change the shape of the cation pump, allowing sodium and potassium ions to be transported against a concentration gradient (i.e. by active transport).

6. Sometimes you have to work to get what you need and this is just as true in living cells. Plant cells require ATP to absorb essential mineral ions from the soil against a concentration gradient. Which plant cells are involved in the active uptake of ions?

Answer: Root hair cells

As well as containing a large supply of ATP needed for the active transport of mineral ions, root hair cells have a large surface area, in order to maximise the rate of ion absorption.

The mineral ions are then transported throughout the cell by xylem vessels.

7. As well as keeping you alive, if it were not for ATP we would not be alive in the first place. ATP provides the energy to move the "tail" of a sperm cell to move, allowing it to reach an egg cell. What feature of a sperm cell means that many ATP can be produced?

Answer: Many mitochondria

Mitochondria are the site of respiration in eukaryotic cells. They consist of a double membrane, the inner of which is folded to produce finger like projections known as cristae. Enzymes involved in respiration are found on the cristae.

8. As well as being produced in respiration, ATP is needed to carry out respiration. In which stage of respiration is ATP required?

Answer: Glycolysis

During glycolysis glucose is oxidised to two molecules of pyruvate by two molecules of NAD. Initially two molecules of ATP are required to provide the energy for this reaction, however four molecules of ATP are later synthesised in glycolysis.

As well as the ATP made in this stage, the reduced co-enzymes NADH (produced in glycolyis, link reaction and Kreb's cycle) and FADH (produced in Kreb's cycle) later enter the electron transport chain, producing more ATP.

9. If it were not for ATP, much of the glucose in our blood would pass out of our system in urine. In which part of the kidney is all of the glucose actively reabsorbed from the filtrate back into the blood?

Answer: Proximal convoluted tubule

Blood enters the glomerulus in the renal capsule under high pressure and so small molecules such as glucose are forced out of the blood into the filtrate.
Whereas all of the glucose is reabsorbed by active transport, other substances such as urea, excess ions and excess water pass out in urine.

10. Finally, without ATP you would not be able to see this quiz. Once light has fallen on the light receptive cells in the eye, photo-pigments within these cells are broken down and so must be re-synthesised so that other images can be seen. What are the names of the two photo-pigments found on the retina?

Answer: Iodopsin and rhodopsin

Rhodopsin is found in rod cells in the retina. Although completely broken down (bleached) in daylight, rods can function in relative darkness due to their high sensitivity.

Iodopsin is found in cone cells in the retina. There are three types of iodopsin, one sensitive to green light, one to blue and the other to red. Cones therefore allow us to see colour.

Rhodopsin is broken down to retinal and opsin by sunlight. Upon entering a relatively dark room ATP begins to re-synthesise rhodopsin, explaining why it is possible to see objects in a dark room which you could not see before.

Source: Author doublemm

This quiz was reviewed by FunTrivia editor crisw before going online.
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Why We Need ATP Trivia Quiz

ATP? It is a molecule needed by plants and animals alike to carry out functions essential to their survival. Take this quiz to see how ATP carries out its role.

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