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All questions of April Week 2 for NEET Exam
Can you explain the answer of this question below:The error in two readings of A are 0.01 and -0.03, then mean absolute error is ?- A:0.002
- B:-0.004
- C:0.02
- D:-0.02
The answer is c.
The error in two readings of A are 0.01 and -0.03, then mean absolute error is ?
A:
0.002
B:
-0.004
C:
0.02
D:
-0.02
|
Bhargavi Bajaj answered |
Mean absolute error = (|0.01|+|-0.03|)/2
= 0.02
= 0.02
Which is the most accurate atomic clock?- a)Carbon-12 clock
- b)Carbon atom clock
- c)caesium atom clock
- d)Stop clock
Correct answer is option 'C'. Can you explain this answer?
Which is the most accurate atomic clock?
a)
Carbon-12 clock
b)
Carbon atom clock
c)
caesium atom clock
d)
Stop clock
|
Nandini Patel answered |
According to the most accurate caesium atomic clock in the world, 1 second is the time that elapses during 9,192,631,770 cycles of the radiation produced by the transition between two levels of the caesium 133 atom.
Can you explain the answer of this question below:The method used to measure the distance of a planet from the earth is- A:Parallax method
- B:Archimedes’ method
- C:Newton’s method
- D:Galileo’s method
The answer is a.
The method used to measure the distance of a planet from the earth is
A:
Parallax method
B:
Archimedes’ method
C:
Newton’s method
D:
Galileo’s method
|
Yash Ghoshal answered |
The astronomers mainly use parallax method to find distances to objects like other planets. To calculate the distance to a star or to a planet, astronomers observe it from different places along Earth's orbit around the Sun.
The most suitable instrument for measuring the size of an atom is.- a)Electron microscope
- b)Vernier calliper
- c)Optical Microscope
- d)Screw gauge
Correct answer is 'A'. Can you explain this answer?
The most suitable instrument for measuring the size of an atom is.
a)
Electron microscope
b)
Vernier calliper
c)
Optical Microscope
d)
Screw gauge
|
Mira Sharma answered |
Only electron microscope has resolution of 0.5-0.6 Angstrom which is less than the size of an atom.
Can you explain the answer of this question below: Which of the following is caused by careless handling?
- A:
Systematic error
- B:
Gross error
- C:
Random error
- D:
None of the mentioned
The answer is b.
Which of the following is caused by careless handling?
Systematic error
Gross error
Random error
None of the mentioned
|
|
Nandini Iyer answered |
Gross errors are mostly due to lack of knowledge, judgment and care on the part of experiment. That is Gross error is caused by careless handling.
Which of the following is caused by careless handling?- a)Systematic error
- b)Gross error
- c)Random error
- d)None of the mentioned
Correct answer is option 'B'. Can you explain this answer?
Which of the following is caused by careless handling?
a)
Systematic error
b)
Gross error
c)
Random error
d)
None of the mentioned
|
Trisha Vashisht answered |
Gross errors are mostly due to lack of knowledge, judgment and care on the part of experiment. That is Gross error is caused by careless handling.
The error in two readings of A are 0.01 and -0.03, then mean absolute error is ?- a)0.002
- b)-0.004
- c)0.02
- d)-0.02
Correct answer is 'C'. Can you explain this answer?
The error in two readings of A are 0.01 and -0.03, then mean absolute error is ?
a)
0.002
b)
-0.004
c)
0.02
d)
-0.02
|
Anagha Sharma answered |
Mean absolute error = (|0.01|+|-0.03|)/2
= 0.02
= 0.02
Error in the measurement of radius of a sphere is 1%. The error in the calculated value of its volume is- a)1%
- b)3%
- c)5%
- d)7%
Correct answer is option 'B'. Can you explain this answer?
Error in the measurement of radius of a sphere is 1%. The error in the calculated value of its volume is
a)
1%
b)
3%
c)
5%
d)
7%
|
Raghav Bansal answered |
∵ V = (4/3)πr3
% error is volume = 3 × error in radius = 3 × 1 = 3%
% error is volume = 3 × error in radius = 3 × 1 = 3%
Angstrom is the unit of- a)time
- b)mass
- c)light
- d)length
Correct answer is option 'D'. Can you explain this answer?
Angstrom is the unit of
a)
time
b)
mass
c)
light
d)
length
|
Vishal Giri answered |
Ya ri8 angstrom this unit used to measure length. 1 A = 10^ - 10 m
1 fermi is equal to:- a)10-10 m
- b)1010 m
- c)1015 m
- d)10-15 m
Correct answer is option 'D'. Can you explain this answer?
1 fermi is equal to:
a)
10-10 m
b)
1010 m
c)
1015 m
d)
10-15 m
|
|
Rohit Shah answered |
One fermi or femtometre is equal 10^-15 m. This unit is used to measure nuclear dimensions.
Can you explain the answer of this question below: Approximate ratio of 1 fermi to 1 angstrom is …………..
- A:
10-5m
- B:
10-15m
- C:
10-9m
- D:
10-6m
The answer is a.
Approximate ratio of 1 fermi to 1 angstrom is …………..
10-5m
10-15m
10-9m
10-6m
|
|
Shreya Gupta answered |
As, 1 fermi = 10-15 m and 1 angstrom = 10^-10 m;
So, approximate ratio = 10^-5 m
The minimum mass of mixture of A2 and B4 required to produce at least 1 kg of each product is:
(Given At. mass of ‘A’ = 10; At mass of ‘B’ = 120) 5A2 + 2B4 → 2AB2 + 4A2B- a)2120 gm
- b)1060 gm
- c)560 gm
- d)1660 gm
Correct answer is option 'A'. Can you explain this answer?
The minimum mass of mixture of A2 and B4 required to produce at least 1 kg of each product is:
(Given At. mass of ‘A’ = 10; At mass of ‘B’ = 120) 5A2 + 2B4 → 2AB2 + 4A2B
(Given At. mass of ‘A’ = 10; At mass of ‘B’ = 120) 5A2 + 2B4 → 2AB2 + 4A2B
a)
2120 gm
b)
1060 gm
c)
560 gm
d)
1660 gm
|
|
Neha Sharma answered |
Here limiting product is AB2 = 500 gm
So, A2 needed = 10 × 20 = 200 gm
B2 needed = 480 × 4 = 1920 gm
Total mass of mixture = 2120 gm
Equal volumes of 10% (v/v) of HCl is mixed with 10% (v/v) NaOH solution. If density of pure NaOH is 1.5 times that of pure HCl then the resultant solution be :- a)basic
- b)neutral
- c)acidic
- d)can’t be predicted.
Correct answer is option 'A'. Can you explain this answer?
Equal volumes of 10% (v/v) of HCl is mixed with 10% (v/v) NaOH solution. If density of pure NaOH is 1.5 times that of pure HCl then the resultant solution be :
a)
basic
b)
neutral
c)
acidic
d)
can’t be predicted.
|
Rahul Chaudhary answered |
Both have equal volume = V
NaOH mole > HCl mole
Basic Solution
NaOH mole > HCl mole
Basic Solution
The accuracy in the measurement of time for 20 oscillations of pendulum for the following measurements, t1 = 39.6 s, t2 = 39.9 s and t3 = 39.5 s is:
- a)± 0.005 s
- b)± 0.3 s
- c)± 0.5 s
- d)± 0.4 s
Correct answer is option 'A'. Can you explain this answer?
The accuracy in the measurement of time for 20 oscillations of pendulum for the following measurements, t1 = 39.6 s, t2 = 39.9 s and t3 = 39.5 s is:
a)
± 0.005 s
b)
± 0.3 s
c)
± 0.5 s
d)
± 0.4 s
|
Niharika Nair answered |
Given,
t1 = 39.6 s
t2 = 39.9s
t3 = 39.5 s
Least count of measuring instrument = 0.1 s
[As measurements have only one decimal place] Percision in the measurement = Least count of the measuring instrument =0.1 s
Mean value of time for 20 oscillations
t1 = 39.6 s
t2 = 39.9s
t3 = 39.5 s
Least count of measuring instrument = 0.1 s
[As measurements have only one decimal place] Percision in the measurement = Least count of the measuring instrument =0.1 s
Mean value of time for 20 oscillations
Absolute errors in the measurements
Δt1 = t - t1 = 39.7 - 39.6 = 0.1s
Δt2 = t - t2 = 39.7 - 39.9 = -0.2 s
Δt3 = t - t3 = 39.7 - 39.5 = 0.2 s
Δt1 = t - t1 = 39.7 - 39.6 = 0.1s
Δt2 = t - t2 = 39.7 - 39.9 = -0.2 s
Δt3 = t - t3 = 39.7 - 39.5 = 0.2 s
Mean absolute error
(rounding-off upto decimal place)∴ Accuracy of measurement = ±0.2 s
Can you explain the answer of this question below:Ratio of masses of H2SO4 and Al2 (SO4)3 is grams each containing 32 grams of S is _____- A:0.86
- B:1.72
- C:0.43
- D:2.15
The answer is a.
Ratio of masses of H2SO4 and Al2 (SO4)3 is grams each containing 32 grams of S is _____
A:
0.86
B:
1.72
C:
0.43
D:
2.15
|
Preeti Iyer answered |
=3*Mass of h2so4/mass of al2(so4)3
=3*98/342
=0.86
Read the following statements regarding methanogens and select the correct option.
(i) They are included in the group Archaebacteria.
(ii) They are responsible for the production of biogas in gobar gas plants.
(iii) They live in hot sulphur springs.
(iv) They are strictly anaerobic.
- a)Statements (i), (ii) and (iv) are correct
- b)Statements (i) and (ii) are correct
- c)Statements (ii), (iii) and (iv) are correct
- d)All statements are correct
Correct answer is option 'B'. Can you explain this answer?
Read the following statements regarding methanogens and select the correct option.
(i) They are included in the group Archaebacteria.
(ii) They are responsible for the production of biogas in gobar gas plants.
(iii) They live in hot sulphur springs.
(iv) They are strictly anaerobic.
(i) They are included in the group Archaebacteria.
(ii) They are responsible for the production of biogas in gobar gas plants.
(iii) They live in hot sulphur springs.
(iv) They are strictly anaerobic.
a)
Statements (i), (ii) and (iv) are correct
b)
Statements (i) and (ii) are correct
c)
Statements (ii), (iii) and (iv) are correct
d)
All statements are correct
|
|
Mira Joshi answered |
Archaebacteria differ from other bacteria in having a different cell wall structure and this feature is responsible for their survival in extreme conditions. Methanogens are present in the gut of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals. Methanogens are obligate anaerobes.
So the correct option is "Statement(i) and (ii) are correct".
The most suitable instrument for measuring the size of an atom is.- a)Electron microscope
- b)Vernier calliper
- c)Optical Microscope
- d)Screw gauge
Correct answer is option 'A'. Can you explain this answer?
The most suitable instrument for measuring the size of an atom is.
a)
Electron microscope
b)
Vernier calliper
c)
Optical Microscope
d)
Screw gauge
|
Rashi Sharma answered |
Only electron microscope has resolution of 0.5-0.6 Angstrom which is less than the size of an atom.
How many moles of NaCl should be dissolved in 100 mL of water to get 0.2 M solution?- a)0.2
- b)0.02
- c)0.01
- d)0.1
Correct answer is option 'B'. Can you explain this answer?
How many moles of NaCl should be dissolved in 100 mL of water to get 0.2 M solution?
a)
0.2
b)
0.02
c)
0.01
d)
0.1
|
|
Raghav Bansal answered |
Molarity = no of moles /volume( in litre) 0.2 =no of moles / 0.1 No of moles =0.2 × 0.1 = 0.02
Which one of the following is an incorrect statement regarding mycoplasma?
- a)They lack a cell wall.
- b)They are the smallest living cells.
- c)They cannot survive without oxygen.
- d)They are pathogenic in plants and animals.
Correct answer is option 'C'. Can you explain this answer?
Which one of the following is an incorrect statement regarding mycoplasma?
a)
They lack a cell wall.
b)
They are the smallest living cells.
c)
They cannot survive without oxygen.
d)
They are pathogenic in plants and animals.
|
|
Mira Joshi answered |
The Mycoplasma are organisms that completely lack a cell wall. They are the smallest living cells known and can survive without oxygen. Many mycoplasma are pathogenic in animals and plants.
Which of the following is caused by careless handling?- a)Systematic error
- b)Gross error
- c)Random error
- d)None of the mentioned
Correct answer is 'B'. Can you explain this answer?
Which of the following is caused by careless handling?
a)
Systematic error
b)
Gross error
c)
Random error
d)
None of the mentioned
|
.mie. answered |
Ys the answr is B ... as systematic errors arises due to faulty instruments.... random errors are those errors, which occur irregularly and hence are random. These can arise due to random and unpredictable fluctuations in experimental conditions For example, when the same person repeats the same observation, it is very likely that he may get different readings every time... Gross Errors: This category basically takes into account human oversight and other mistakes while reading, recording and the readings ...(^_^)
What is the percentage error in the physical quantity A if it is related to four other physical quantities a, b, c and d as 
The percentage error in measurement of a, b, c and d are 1%, 3%, 2% and 2% respectively.
Correct answer is '14'. Can you explain this answer?
What is the percentage error in the physical quantity A if it is related to four other physical quantities a, b, c and d as The percentage error in measurement of a, b, c and d are 1%, 3%, 2% and 2% respectively.
The percentage error in measurement of a, b, c and d are 1%, 3%, 2% and 2% respectively.
|
Soumya Mukherjee answered |
Percentage error in A
A student measures the distance covered and time taken by a body under free fall which was intially at rest. He uses this data for estimating g, the acceleration due to gravity. If the maximum percentage error in measurement of the distance and the time are e1 and e2 respectively, then the maximum possible percentage error in the estimation of g is- a)e2 - e1
- b)e1 + 2e2
- c)e1 + e2
- d)e1 - 2e2
Correct answer is option 'B'. Can you explain this answer?
A student measures the distance covered and time taken by a body under free fall which was intially at rest. He uses this data for estimating g, the acceleration due to gravity. If the maximum percentage error in measurement of the distance and the time are e1 and e2 respectively, then the maximum possible percentage error in the estimation of g is
a)
e2 - e1
b)
e1 + 2e2
c)
e1 + e2
d)
e1 - 2e2
|
|
Priya Deshpande answered |
From the releation
h= 1/2gt2 ⇒ g = 2h/t2
h= 1/2gt2 ⇒ g = 2h/t2
Taking natural logarithms on both sides, we get
ln (g) = ln (h) - 2ln (t) + ln (2)
Differentiating
for maximum permissible errors , we add both the errors . so
At a certain place, the acceleration due to gravity is determined using a simple pendulum. The length of the pendulum is 25.0 cm and a stopwatch with least count is 1 s measures the time taken by the pendulum for 40 oscilations to be 50 s. the accuracy in the measurement of g is- a)4.40 %
- b)3.40 %
- c)2.40 %
- d)5.40 %
Correct answer is option 'A'. Can you explain this answer?
At a certain place, the acceleration due to gravity is determined using a simple pendulum. The length of the pendulum is 25.0 cm and a stopwatch with least count is 1 s measures the time taken by the pendulum for 40 oscilations to be 50 s. the accuracy in the measurement of g is
a)
4.40 %
b)
3.40 %
c)
2.40 %
d)
5.40 %
|
|
Tanishq Unni answered |
Cyanobacteria are used in agricultural fields for improvement because they cause- a)N2 fixation
- b)algal blooms
- c)photosynthesis
- d)all of these.
Correct answer is option 'A'. Can you explain this answer?
Cyanobacteria are used in agricultural fields for improvement because they cause
a)
N2 fixation
b)
algal blooms
c)
photosynthesis
d)
all of these.
|
|
Mira Joshi answered |
Several cyanobacteria have the ability of nitrogen fixation. The filamentous forms possess special large pale cells or heterocysts for this. Some of the fixed nitrogen comes out as excretion. After death of cyanobacteria the substratum becomes rich in nitrogen. Such nitrogen fixing cyanobacteria are now regularly inoculated in the rice fields This saves application of nitrogen fertilizers.
Can you explain the answer of this question below: Approximate ratio of 1 fermi to 1 angstrom is …
- A:
10-5m
- B:
10-15m
- C:
10-9m
- D:
10-6m
The answer is a.
Approximate ratio of 1 fermi to 1 angstrom is …
10-5m
10-15m
10-9m
10-6m
|
|
Bhargavi Bajaj answered |
To find the approximate ratio of 1 fermi to 1 angstrom, we need to convert both units to a common unit of length.
1 fermi (fm) is a unit of length in the metric system, and it is equal to 10^-15 meters (m).
1 angstrom (Å) is also a unit of length in the metric system, and it is equal to 10^-10 meters (m).
To find the ratio, we can divide 1 fermi by 1 angstrom:
Ratio = 1 fm / 1 Å
Since both units are in meters, we can convert the units before dividing:
Ratio = (1 fm / 10^-15 m) / (1 Å / 10^-10 m)
Simplifying the expression:
Ratio = (1 fm * 10^-10 m) / (1 Å * 10^-15 m)
Ratio = 10^-10 / 10^-15
Using the rules of exponents, we can subtract the exponents:
Ratio = 10^5
Therefore, the approximate ratio of 1 fermi to 1 angstrom is 10^5.
1 fermi (fm) is a unit of length in the metric system, and it is equal to 10^-15 meters (m).
1 angstrom (Å) is also a unit of length in the metric system, and it is equal to 10^-10 meters (m).
To find the ratio, we can divide 1 fermi by 1 angstrom:
Ratio = 1 fm / 1 Å
Since both units are in meters, we can convert the units before dividing:
Ratio = (1 fm / 10^-15 m) / (1 Å / 10^-10 m)
Simplifying the expression:
Ratio = (1 fm * 10^-10 m) / (1 Å * 10^-15 m)
Ratio = 10^-10 / 10^-15
Using the rules of exponents, we can subtract the exponents:
Ratio = 10^5
Therefore, the approximate ratio of 1 fermi to 1 angstrom is 10^5.
What is the number of significant figures in 0.310×103 ?- a)6
- b)2
- c)4
- d)3
Correct answer is option 'D'. Can you explain this answer?
What is the number of significant figures in 0.310×103 ?
a)
6
b)
2
c)
4
d)
3
|
|
Suresh Kumar answered |
10^ powers are not considered as significant figures....
& in the case of decimal points....the zero present at the beginning & in between the numbers is considered as significant digit....
Hence;in this case the significant figures are 3...
& in the case of decimal points....the zero present at the beginning & in between the numbers is considered as significant digit....
Hence;in this case the significant figures are 3...
For the reaction 2A + 3B + 5C → 3DInitially if 2 mole of A, 4 mole of B and 6 mole of C is taken, With 25% yield, moles of D which can be produced are _____________.- a)0.75
- b)0.5
- c)0.25
- d)0.6
Correct answer is option 'A'. Can you explain this answer?
For the reaction 2A + 3B + 5C → 3D
Initially if 2 mole of A, 4 mole of B and 6 mole of C is taken, With 25% yield, moles of D which can be produced are _____________.
a)
0.75
b)
0.5
c)
0.25
d)
0.6
|
Subham Roy answered |
Limiting reactant is A
Ideally with 2 moles of A, D formed = 3 moles But yield = 25%
So, moles of D formed = 3 × 0.25 = 0.75 mol
Ideally with 2 moles of A, D formed = 3 moles But yield = 25%
So, moles of D formed = 3 × 0.25 = 0.75 mol
Which of the following is true about cyanobacteria (blue-green algae)?- a)They are unicellular, colonial, or filamentous and are capable of nitrogen fixation in specialized cells called heterocysts.
- b)They are heterotrophic bacteria that obtain nutrients by consuming other organisms.
- c)They lack chlorophyll and are incapable of photosynthesis.
- d)They exclusively thrive in marine environments and are never found in freshwater.
Correct answer is option 'A'. Can you explain this answer?
Which of the following is true about cyanobacteria (blue-green algae)?
a)
They are unicellular, colonial, or filamentous and are capable of nitrogen fixation in specialized cells called heterocysts.
b)
They are heterotrophic bacteria that obtain nutrients by consuming other organisms.
c)
They lack chlorophyll and are incapable of photosynthesis.
d)
They exclusively thrive in marine environments and are never found in freshwater.
|
Ciel Knowledge answered |
Cyanobacteria (also known as blue-green algae) are photosynthetic autotrophs and possess chlorophyll a, similar to green plants. They can be unicellular, colonial, or filamentous and are capable of nitrogen fixation in specialized cells called heterocysts, which helps in converting atmospheric nitrogen into a usable form for the ecosystem. They are found in both freshwater and marine environments.
The % by volume of C4H10 in a gaseous mixture of C4H10, CH4 and CO is 40. When 200 ml of the mixture is burnt in excess of O2. Find volume (in ml) of CO2 produced.- a)220
- b)340
- c)440
- d)560
Correct answer is option 'C'. Can you explain this answer?
The % by volume of C4H10 in a gaseous mixture of C4H10, CH4 and CO is 40. When 200 ml of the mixture is burnt in excess of O2. Find volume (in ml) of CO2 produced.
a)
220
b)
340
c)
440
d)
560
|
|
Mira Sharma answered |
There is one Carbon atom in the molecule of CO2.
Volume of C4 H10 in the mixture = 80 ml
volume of CO2 produced by combustion of C4H10 = 4 * 80 = 320 ml
as there are 4 Carbons in each molecule.
volume of CH4 + CO in mixture = 120 ml
volume of CO2 produced = 120 ml
Total volume of CO2 = 320 + 120 = 440 ml
C6H5OH(g) + O2(g) → CO2(g) + H2O(l)
The magnitude of volume change if 30 ml of C6H5OH (g) is burnt with an excess amount of oxygen, is
- a)30 ml
- b)60 ml
- c)20 ml
- d)10 ml
Correct answer is option 'B'. Can you explain this answer?
C6H5OH(g) + O2(g) → CO2(g) + H2O(l)
The magnitude of volume change if 30 ml of C6H5OH (g) is burnt with an excess amount of oxygen, is
a)
30 ml
b)
60 ml
c)
20 ml
d)
10 ml
|
|
Madhurima Joshi answered |
Balanced Reaction: C6H5OH(g)+7O2(g) ——> 6CO2(g)+3H2O(l)
8 moles of the reactants get reduced to 9 moles of products.
Now, 30 ml of Phenol will react (30 x 7) = 210 ml of oxygen.
So, (30+210) = 240 ml of the reactants will after reaction will give = (30 x 6) + (30 x 3) = 270 ml of products.
Since the water formed is in the liquid state will not contribute to the volume increase, the resultant mixture will contain 270 ml.
So, the volume change is of 270 – 240 = 30 ml.
8 moles of the reactants get reduced to 9 moles of products.
Now, 30 ml of Phenol will react (30 x 7) = 210 ml of oxygen.
So, (30+210) = 240 ml of the reactants will after reaction will give = (30 x 6) + (30 x 3) = 270 ml of products.
Since the water formed is in the liquid state will not contribute to the volume increase, the resultant mixture will contain 270 ml.
So, the volume change is of 270 – 240 = 30 ml.
Number of moles of hydroxide ions in 0.3L of 0.005M solution of Ba (OH)2 is:- a)0.0015
- b)0.003
- c)0.0050
- d)0.0075
Correct answer is option 'B'. Can you explain this answer?
Number of moles of hydroxide ions in 0.3L of 0.005M solution of Ba (OH)2 is:
a)
0.0015
b)
0.003
c)
0.0050
d)
0.0075
|
|
Bhavana Tiwari answered |
0.3 L = 0.3 L of 0.005 M Ba(OH)2
0.3 x 0.005 = 0.0015 moles of Ba(OH)2
It will dissociate into 0.0015 moles of Ba and 2 x 0.0015 = 0.003 moles of OH ions.
0.3 x 0.005 = 0.0015 moles of Ba(OH)2
It will dissociate into 0.0015 moles of Ba and 2 x 0.0015 = 0.003 moles of OH ions.
74 gm of sample on complete combustion gives 132 gm CO2 and 54 gm of H2O. The molecular formula of the compound may be- a)C5H12
- b)C4H10O
- c)C3H6O2
- d)C3H7O2
Correct answer is option 'C'. Can you explain this answer?
74 gm of sample on complete combustion gives 132 gm CO2 and 54 gm of H2O. The molecular formula of the compound may be
a)
C5H12
b)
C4H10O
c)
C3H6O2
d)
C3H7O2
|
|
Preeti Iyer answered |
Mass of C in 132g CO2 = 12/44*132 = 36g
Mass of H in 54g H2O = 2/18*54 = 6g
Missing mass is O = 74g - ( 36+6) = 32g
Divide each mass by atomic mass :
C = 36/12 = 3
H = 6/1 = 6
O = 32/16 = 2
Identify the incorrect statements -- a)Bacteria reproduce mainly by fission
- b)Bacteria reproduce by production of gametes .
- c)Under unfavourable conditions, Bacteria produce spores.
- d)Bacteria reproduce by a sort of sexual reproduction
Correct answer is option 'B'. Can you explain this answer?
Identify the incorrect statements -
a)
Bacteria reproduce mainly by fission
b)
Bacteria reproduce by production of gametes .
c)
Under unfavourable conditions, Bacteria produce spores.
d)
Bacteria reproduce by a sort of sexual reproduction
|
|
Maheshwar Iyer answered |
Understanding Bacterial Reproduction
Bacteria are unicellular organisms that exhibit unique modes of reproduction. Here’s a breakdown of the statements provided:
Statement A: Bacteria reproduce mainly by fission
- This statement is correct.
- Bacteria primarily reproduce asexually through a process called binary fission, where one cell divides into two identical daughter cells.
Statement B: Bacteria reproduce by production of gametes
- This statement is incorrect.
- Bacteria do not reproduce by gametes (reproductive cells like sperm and egg). Instead, they reproduce asexually, primarily through binary fission.
Statement C: Under unfavourable conditions, Bacteria produce spores
- This statement is correct.
- Many bacteria can form endospores when conditions become unfavorable. This allows them to survive extreme environments until conditions improve.
Statement D: Bacteria reproduce by a sort of sexual reproduction
- This statement can be misleading but is partially correct.
- Some bacteria exchange genetic material through processes like transformation, transduction, and conjugation, which is not true sexual reproduction but allows for genetic diversity.
Conclusion
- In summary, option 'B' is the only statement that incorrectly describes bacterial reproduction. Bacteria do not produce gametes; they mainly reproduce asexually through binary fission, with alternative methods for genetic exchange that do not involve the formation of gametes.
Bacteria are unicellular organisms that exhibit unique modes of reproduction. Here’s a breakdown of the statements provided:
Statement A: Bacteria reproduce mainly by fission
- This statement is correct.
- Bacteria primarily reproduce asexually through a process called binary fission, where one cell divides into two identical daughter cells.
Statement B: Bacteria reproduce by production of gametes
- This statement is incorrect.
- Bacteria do not reproduce by gametes (reproductive cells like sperm and egg). Instead, they reproduce asexually, primarily through binary fission.
Statement C: Under unfavourable conditions, Bacteria produce spores
- This statement is correct.
- Many bacteria can form endospores when conditions become unfavorable. This allows them to survive extreme environments until conditions improve.
Statement D: Bacteria reproduce by a sort of sexual reproduction
- This statement can be misleading but is partially correct.
- Some bacteria exchange genetic material through processes like transformation, transduction, and conjugation, which is not true sexual reproduction but allows for genetic diversity.
Conclusion
- In summary, option 'B' is the only statement that incorrectly describes bacterial reproduction. Bacteria do not produce gametes; they mainly reproduce asexually through binary fission, with alternative methods for genetic exchange that do not involve the formation of gametes.
Select the correct statement regarding heterocysts.- a)These are present in some filamentous cyanobacter such as Nostoc and Anabaena.
- b)These cells are specialized to perform N2-fixation
- c)These cells contain enzyme nitrogenase.
- d)All of these.
Correct answer is option 'D'. Can you explain this answer?
Select the correct statement regarding heterocysts.
a)
These are present in some filamentous cyanobacter such as Nostoc and Anabaena.
b)
These cells are specialized to perform N2-fixation
c)
These cells contain enzyme nitrogenase.
d)
All of these.
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Mira Joshi answered |
Heterocyst is a large-sized pale coloured thick-walled cell which occurs in terminal, intercalary or lateral position in filamentous cyanobacteria, e.g., Nostoc. The thick wall impermeable to oxygen but permeable to nitrogen. Mucilage sheath is absent. Photosystem II is absent. Thylakoids laid phycobilisomes. Therefore, photosynthesis is absent but cyclic photophosphorylation occurs. Heterocyst is dependent for its nourishment on adjacent vegetative cells. It has enzyme nitrogenase and so, it is specialised to perform nitrogen fixation.
Cyanobacteria are classified under which of the following kingdoms?- a)Monera
- b)Protista
- c)Algae
- d)Plantae
Correct answer is option 'A'. Can you explain this answer?
Cyanobacteria are classified under which of the following kingdoms?
a)
Monera
b)
Protista
c)
Algae
d)
Plantae
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Mira Joshi answered |
Cyano bacteria or blue-green algae are Gram + photosynthetic prokaryotes which perform oxygenic photo- synthesis. Photosynthetic pigments include chlorophyll a, carotenoids and phycobilins. Cyanobacteria are classified under kingdom Monera. Cyanobacterial cell structure is typically prokaryotic - one envelope organisation with peptidoglycan wall, naked DNA, 70S ribosomes and absence of membrane bound structures like endoplasmic reticulum, mltochondria, Golgi bodies, plastids, lysosomes, sap vacuoles. The outer part of the protoplast, called chromoplasm, contains a number of photosynthetic thylakoids.
If 50 gm oleum sample rated as 118% is mixed with 18 gm water, then the correct option is- a)The resulting solution contains 18 gm of water and 118 gm H2SO4
- b)The resulting solution contains 9 gm of water and 59 gm H2SO4
- c)The resulting solution contains only 118 gm pure H2SO4
- d)The resulting solution contains 68 gm of pure H2SO4
Correct answer is option 'B'. Can you explain this answer?
If 50 gm oleum sample rated as 118% is mixed with 18 gm water, then the correct option is
a)
The resulting solution contains 18 gm of water and 118 gm H2SO4
b)
The resulting solution contains 9 gm of water and 59 gm H2SO4
c)
The resulting solution contains only 118 gm pure H2SO4
d)
The resulting solution contains 68 gm of pure H2SO4
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Pranav Saha answered |
118 % ⇒ 100 g sample uses 18 g water
⇒ 50 g sample need 9 g water
(50 g + 18 g water)
⇒ 59 g H2SO4 + 9 g water
⇒ 50 g sample need 9 g water
(50 g + 18 g water)
⇒ 59 g H2SO4 + 9 g water
Assertion (A): Cyanobacteria are capable of photosynthesis and nitrogen fixation due to the presence of chlorophyll and specialized cells called heterocysts.
Reason (R): Cyanobacteria can only perform photosynthesis in aquatic environments due to the absence of light in terrestrial environments.- a)Both (A) and (R) are true, and (R) is the correct explanation of (A).
- b)Both (A) and (R) are true, but (R) is not the correct explanation of (A).
- c)(A) is true, but (R) is false.
- d)(A) is false, but (R) is true.
Correct answer is option 'C'. Can you explain this answer?
Assertion (A): Cyanobacteria are capable of photosynthesis and nitrogen fixation due to the presence of chlorophyll and specialized cells called heterocysts.
Reason (R): Cyanobacteria can only perform photosynthesis in aquatic environments due to the absence of light in terrestrial environments.
Reason (R): Cyanobacteria can only perform photosynthesis in aquatic environments due to the absence of light in terrestrial environments.
a)
Both (A) and (R) are true, and (R) is the correct explanation of (A).
b)
Both (A) and (R) are true, but (R) is not the correct explanation of (A).
c)
(A) is true, but (R) is false.
d)
(A) is false, but (R) is true.
|
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Geetika Iyer answered |
Assertion (A) Explained
Cyanobacteria are indeed capable of photosynthesis and nitrogen fixation. They possess chlorophyll, which allows them to capture light energy and convert it into chemical energy through photosynthesis. Additionally, they have specialized cells known as heterocysts that facilitate nitrogen fixation, converting atmospheric nitrogen into a usable form for the organism.
Reason (R) Explained
The statement that cyanobacteria can only perform photosynthesis in aquatic environments is not accurate. While they thrive in aquatic settings where light is abundant, cyanobacteria can also be found in various terrestrial environments, such as soil and on rocks, where they can still engage in photosynthesis, especially when moisture is available.
Conclusion
Therefore, the correct interpretation is:
The correct answer is option 'C', indicating that while the assertion is true, the reasoning provided is incorrect. Cyanobacteria's ability to perform photosynthesis is not restricted to aquatic environments, making (R) false.
Cyanobacteria are indeed capable of photosynthesis and nitrogen fixation. They possess chlorophyll, which allows them to capture light energy and convert it into chemical energy through photosynthesis. Additionally, they have specialized cells known as heterocysts that facilitate nitrogen fixation, converting atmospheric nitrogen into a usable form for the organism.
Reason (R) Explained
The statement that cyanobacteria can only perform photosynthesis in aquatic environments is not accurate. While they thrive in aquatic settings where light is abundant, cyanobacteria can also be found in various terrestrial environments, such as soil and on rocks, where they can still engage in photosynthesis, especially when moisture is available.
Conclusion
Therefore, the correct interpretation is:
- (A) is true: Cyanobacteria can photosynthesize and fix nitrogen.
- (R) is false: Cyanobacteria are not limited to aquatic environments for photosynthesis.
The correct answer is option 'C', indicating that while the assertion is true, the reasoning provided is incorrect. Cyanobacteria's ability to perform photosynthesis is not restricted to aquatic environments, making (R) false.
Which of the following is NOT a characteristic of eubacteria or 'true bacteria'?- a)Presence of a rigid cell wall
- b)Motility through flagella
- c)Ability to fix atmospheric nitrogen
- d)Lack of chlorophyll
Correct answer is option 'D'. Can you explain this answer?
a)
Presence of a rigid cell wall
b)
Motility through flagella
c)
Ability to fix atmospheric nitrogen
d)
Lack of chlorophyll
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EduRev NEET answered |
Eubacteria, also called true bacteria, often have a rigid cell wall and flagella for motility. Some eubacteria, such as cyanobacteria, possess chlorophyll (specifically chlorophyll a) and are capable of photosynthesis. Hence, they can fix atmospheric nitrogen, unlike other eubacteria.
In 5-kingdom classification system, the kingdom that includes the blue-green algae, nitrogen-fixing bacteria and methanogenic archaebacteria, is- a)Plantae
- b)Fungi
- c)Protista
- d)Monera.
Correct answer is option 'D'. Can you explain this answer?
In 5-kingdom classification system, the kingdom that includes the blue-green algae, nitrogen-fixing bacteria and methanogenic archaebacteria, is
a)
Plantae
b)
Fungi
c)
Protista
d)
Monera.
|
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Mira Joshi answered |
Monera kingdom includes prokaryotes - mycoplasma bacteria, actinomycetes and cyanobacteria or blue greet algae. Alongwith fungi, they are decomposers and mineralisers of the biosphere.
Identify the incorrect statement regarding bacteria:- a)Bacteria are the most abundant microorganisms.
- b)Bacteria live in extreme habitats where very few other life forms can survive.
- c)Bacteria as a group show the most extensive metabolic diversity.
- d)They are obligate intracellular parasites.
Correct answer is option 'D'. Can you explain this answer?
Identify the incorrect statement regarding bacteria:
a)
Bacteria are the most abundant microorganisms.
b)
Bacteria live in extreme habitats where very few other life forms can survive.
c)
Bacteria as a group show the most extensive metabolic diversity.
d)
They are obligate intracellular parasites.
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Lead Academy answered |
To identify the incorrect statement regarding bacteria:
- A: Bacteria are the most abundant microorganisms.
- B: Bacteria live in extreme habitats where very few other life forms can survive.
- C: Bacteria as a group show the most extensive metabolic diversity.
- D: They are obligate intracellular parasites.
The incorrect statement is: D: They are obligate intracellular parasites.
Explanation: Bacteria can be classified as intracellular or extracellular, with many living freely outside cells. While some bacteria can be obligate intracellular parasites, not all bacteria exhibit this behavior.
- A: Bacteria are the most abundant microorganisms.
- B: Bacteria live in extreme habitats where very few other life forms can survive.
- C: Bacteria as a group show the most extensive metabolic diversity.
- D: They are obligate intracellular parasites.
The incorrect statement is: D: They are obligate intracellular parasites.
Explanation: Bacteria can be classified as intracellular or extracellular, with many living freely outside cells. While some bacteria can be obligate intracellular parasites, not all bacteria exhibit this behavior.
Which feature differentiates archaebacteria from other bacteria and contributes to their survival in extreme environments?- a)Presence of flagella
- b)Different cell wall structure
- c)Ability to form spores
- d)Ability to photosynthesize
Correct answer is option 'B'. Can you explain this answer?
a)
Presence of flagella
b)
Different cell wall structure
c)
Ability to form spores
d)
Ability to photosynthesize
|
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Arya Nambiar answered |
Understanding Archaebacteria
Archaebacteria, also known as archaea, are a distinct group of microorganisms that differ significantly from other bacteria in several ways, particularly in their adaptation to extreme environments.
Cell Wall Structure
- The most defining feature of archaebacteria is their unique cell wall composition. Unlike other bacteria that typically have peptidoglycan in their cell walls, archaebacteria possess pseudopeptidoglycan (or other polymers) that provide structural integrity.
- This unique cell wall structure is essential for survival in extreme conditions such as high temperatures, salinity, or acidity, where many other organisms cannot thrive.
Membrane Lipids
- Archaebacteria also have distinct membrane lipids. Their membranes are composed of ether-linked lipids, which are more stable than the ester-linked lipids found in other bacteria.
- This enhances their ability to withstand extreme heat and harsh chemical environments, contributing to their resilience.
Metabolic Pathways
- Archaebacteria exhibit unique metabolic pathways that allow them to utilize different energy sources, such as hydrogen gas or sulfur, making them versatile in extreme habitats.
- Many archaea are also extremophiles, thriving in environments like hot springs, salt lakes, and deep-sea vents where other forms of life struggle to survive.
Conclusion
In summary, the different cell wall structure of archaebacteria is crucial for their survival in extreme environments, setting them apart from other bacteria. This unique adaptation enables them to thrive in conditions that are inhospitable to most life forms, showcasing the incredible diversity of life on Earth.
Archaebacteria, also known as archaea, are a distinct group of microorganisms that differ significantly from other bacteria in several ways, particularly in their adaptation to extreme environments.
Cell Wall Structure
- The most defining feature of archaebacteria is their unique cell wall composition. Unlike other bacteria that typically have peptidoglycan in their cell walls, archaebacteria possess pseudopeptidoglycan (or other polymers) that provide structural integrity.
- This unique cell wall structure is essential for survival in extreme conditions such as high temperatures, salinity, or acidity, where many other organisms cannot thrive.
Membrane Lipids
- Archaebacteria also have distinct membrane lipids. Their membranes are composed of ether-linked lipids, which are more stable than the ester-linked lipids found in other bacteria.
- This enhances their ability to withstand extreme heat and harsh chemical environments, contributing to their resilience.
Metabolic Pathways
- Archaebacteria exhibit unique metabolic pathways that allow them to utilize different energy sources, such as hydrogen gas or sulfur, making them versatile in extreme habitats.
- Many archaea are also extremophiles, thriving in environments like hot springs, salt lakes, and deep-sea vents where other forms of life struggle to survive.
Conclusion
In summary, the different cell wall structure of archaebacteria is crucial for their survival in extreme environments, setting them apart from other bacteria. This unique adaptation enables them to thrive in conditions that are inhospitable to most life forms, showcasing the incredible diversity of life on Earth.
Similar to the % labelling of oleum, a mixture of H3PO4 and P4O10 is labelled as (100 + x) % where x is the maximum mass of water which can react with P4O10 present in 100 gm mixture of H3PO4 and P4O10. If such a mixture is labelled as 127% Mass of P4O10 is 100 gm of mixture, is- a)71 gm
- b)47 gm
- c)83 gm
- d)35 gm
Correct answer is option 'A'. Can you explain this answer?
Similar to the % labelling of oleum, a mixture of H3PO4 and P4O10 is labelled as (100 + x) % where x is the maximum mass of water which can react with P4O10 present in 100 gm mixture of H3PO4 and P4O10. If such a mixture is labelled as 127% Mass of P4O10 is 100 gm of mixture, is
a)
71 gm
b)
47 gm
c)
83 gm
d)
35 gm
|
|
Mira Sharma answered |
P4O10 + 6 H2O --------> 4 H3PO4
(284 gm + 6*18 = 108 gm)
mass of P4O10 = (127 – 100)*284 / 108 = 71 gm
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