Solutions of NCERT Exemplar, Ch 13, Class 7

 1. The answer is (d) Blinking of eyes.

Explanation:

Blinking of the eye is not a periodic phenomenon. Eyes do not blink at a fixed interval of time. Hence Blinking of eyes cannot be used for measurement of time.

2. The answer is (c) Time interval of 5 minutes can be measured by both A and B.

Explanation:

Clock A doesn’t have a seconds hand. Hence seconds cannot be measured by clock A. 5 minutes can be measured by using both the clocks.

3. The answer is (a) both A and B.

Explanation:

Since speed for A and B is constant, graph for A and B is a straight line as shown in the figure.

4. Answer is (b) 10 m/s

Explanation:

Speed = Distance / Time

Distance = 54km = 54 x1000 = 54000m

Time = 90 minutes = 90×60= 5400s

Speed = 54000/5400 = 10 m/s

5. Answer is (c) S = 1/SxD

Explanation:

Option c) is the correction equation because Speed = Distance/Time

6. The answer is (a) A to B and back to A.

7. Unit of speed is meter/ second hence the answer is (a) 5 m/s .

NCERT Exemplar, Ch 13 (MOTION and TIME), Class 7

 1. Which of the following cannot be used for measurement of time?

(a) A leaking tap.

(b) Simple pendulum.

(c) Shadow of an object during the day.

(d) Blinking of eyes.

2. Two clocks A and B are shown in Figure 13.1. Clock A has an hour and a minute hand, whereas clock B has an hour hand, minute hand as well as a second hand. Which of the following statement is correct for these clocks?

(a) A time interval of 30 seconds can be measured by clock A.

(b) A time interval of 30 seconds cannot be measured by clock B.

(c) Time interval of 5 minutes can be measured by both A and B.

(d) Time interval of 4 minutes 10 seconds can be measured by clock A.

3. Two students were asked to plot a distance-time graph for the motion described by Table A and Table B.

The graph given in Figure 13.2 is true for

(a) both A and B.

(b) A only.

(c) B only.

(d) neither A nor B.

4. A bus travels 54 km in 90 minutes. The speed of the bus is

(a) 0.6 m/s

(b) 10 m/s

(c) 5.4 m/s

(d) 3.6 m/s

5. If we denote speed by S, the distance by D and time by T, the relationship between these quantities is

(a) S = D × T

(b) T = S/D

(c) S = 1/SxD

(c) S = T/D

6. Observe Figure 13.3.

The time period of a simple pendulum is the time taken by it to travel from

(a) A to B and back to A.

(b) O to A, A to B and B to A.

(c) B to A, A to B and B to O.

(d) A to B

7. The correct symbol to represent the speed of an object is

(a) 5 m/s

(b) 5 mp

(c) 5 m/s-1

(d) 5 s/m

Class Test, GENOMICS (Information Sources), Class 12

 1. What is BLAST? What are the various principles involved? Difference between homologs and paralogs.                                                        (5)

2.      What are the functions of NCBI?              (3)

3.      Name the various resources available from NCBI.              (3)

4.      Which information can be retrieved from the following databases: EMBL and PDB           (2)

5.      What kind of analysis can be undertaken using various bioinformatics tools?     (3)

6.      What is RefSeq?              (1)

7.     Who is curator? What is curation?          (2)

8.      Name the database that have the information of orthologs and homologs.            (1)

CLASS TEST, GENOMICS PART-2, CLASS XII

 1. Explain how cDNA microarray technique can be used to study cellular response to the environment? support your answer with the help of a flowchart.        (5)

2. Number of genes is not related to the number of proteins. Justify.        (3)        

3. CML patients have the ‘Philadelphia Chromosome”. How is this chromosome detected? Explain the technique with a diagram. He has been put on a combination drug therapy for the past 2 months How can this technique be used to monitor the effect of chemotherapy?                                        (5)

4. With the help of  a flowchart show different types of proteomics and the scientific knowledge that can be gained from them. Also explain the main types of  proteomics.(5)

5. What is a proteome? Why it is termed that proteome of a given cell is dynamic?(2)

CLASS TEST, GENES AND GENOMES, CLASS XI

1. Give an account of post-transcriptional modifications of a eukaryotic mRNA.  (3)

2. Discuss the process of translation in detail.                    (5)

3.  Give an account of the Hershey and Chase experiment. What did it conclusively prove? If both DNA and proteins contained phosphorus and sulphur do you think the result would have been the same.             (5)

4. There is only one possible sequence of amino acids when deduced from given nucleotides. But multiple nucleotides sequence can be deduced from a single amino acid sequence. Explain this phenomenon.            (2)

5. Who revealed the biochemical nature of the transforming principle? How was it done?    (3)

6. Given below is the sequence of the coding strand of DNA in a transcription unit 3 'A A T G C A G C T A T T A G G – 5’ write the sequence of a) its complementary strand b) the mRNA        (2)

7.What is the cause of discontinuous synthesis of DNA on one of the parental strands of DNA? What happens to these short stretches of synthesized DNA?        (3)

8. Differentiate between

    (a) Aneuploids and euploids

    (b) Inversion and translocation

    (c) Transition and transversion                    (3)

9. Write the genetic make up of Down Syndrome and Klienfelters Syndrome?        (2)

10. For a X linked disease if a carrier mother marries to a normal male. What is the probability of having:

a. a normal daughter

b. a diseased son

c. normal children

d. diseased daughter                (2)

SOLUTIONS of Chapter 13 Motion and Time, CLASS 7 SCIENCE

 1. Classify the following as motion along a straight line, circular or oscillatory motion:

(i) Motion of your hands while running.

(ii) Motion of a horse pulling a cart on a straight road.

(iii) Motion of a child in a merry-go-round.

(iv) Motion of a child on a see-saw.

(v) Motion of the hammer of an electric bell.

(vi) Motion of a train on a straight bridge.

Solution:

i) oscillatory

ii) Motion along a straight line

iii) Circular motion

iv) Oscillatory motion

v) Oscillatory motion

vi) Motion along a straight line.

2. Which of the following are not correct?

(i) The basic unit of time is second.

(ii) Every object moves with a constant speed.

(iii) Distances between two cities are measured in kilometres.

(iv) The time period of a given pendulum is constant.

(v) The speed of a train is expressed in m/h.

Solution:

Incorrect statements are:

(ii) Every object moves with a constant speed.

(iv) The time period of a given pendulum is constant.

(v) The speed of a train is expressed in m/h.

3. A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum?

Solution:

Number of oscillations = 20

Total time taken to complete 20 oscillations = 32 s

4. The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train.

Solution:

Distance between two stations = 240 kms

Total time take = 4 hrs/240 minutes

=60Km/hr

5. The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also.

Solution:

Initial reading of the odometer = 57321.0

Final reading of the odometer = 57336.0

Distance covered by the car = Final reading of the odometer – Initial reading of the odometer

= 57336.0 – 57321.0 = 15 kms

Starting time of car is 8:30 and it stops at 8: 50

Hence, time taken by car = 20 mins

= 45Km/Hr

6. Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school.

Solution:

Time taken by Salma to reach her school by bicycle = 15 mins= 15 x 60 = 90 s

Speed of Salma’s bicycle= 2m/s

Distance covered = speed x time taken

= 2 x 900 = 1800 m

1000m = 1 km

= 1.8Km

7. Show the shape of the distance-time graph for the motion in the following cases:

(i) A car moving with a constant speed.

(ii) A car parked on a side road.

Solution:

8. Which of the following relations is correct?

(i) Speed = Distance × Time

(ii) Speed = Distance/Time

(iii) Speed = Time/Distance

(iv) Speed = 1/Distance x Time

Solution:

Answer is (ii) Speed = Distance/Time

9. The basic unit of speed is:

(i) km/min

(ii) m/min

(iii) km/h

(iv) m/s

Solution:

Answer is (iv) m/s

10. A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:

(i) 100 km (ii) 25 km (iii) 15 km (iv) 10 km

Solution:

The answer is (ii) 25 km

Calculation:

When the speed of the car is 40 km/h

Time taken = 15 min = 15/60 = 0.25 h

Distance covered d1 = speed x time taken

                                                                                        = 40 x 0.25 = 10 kms

                                                        When the speed of the Car is 60 km/ h

Distance covered d2 = speed x time taken

= 60 x 0.25= 15 kms

Total distance covered by the car = d1 + d2

= 10 + 15

= 25 kms

11. Suppose the two photographs, shown in Fig. 13.1 and Fig. 13.2, had been taken at an interval of 10 seconds. If a distance of 100 metres is shown by 1 cm in these photographs, calculate the speed of the fastest car.

Solution:

The distance covered by the blue car (as evident from the photograph) from one horizontal white strip to another, which is measured by scale is 1.2 cm.

It is given that 1 cm is equivalent to 100 m.

Therefore, 1.2 cm is equivalent to 120 m.

Distance travelled by the car = 120 m

Time taken to cover this distance = Time interval between the two photographs = 10 s

= 120/10

= 12 m/s

12. Fig. 13.15 shows the distance-time graph for the motion of two vehicles A and B. Which one of them is moving faster?

Solution:

Vehicle A is moving faster than vehicle B.

13. Which of the following distance-time graphs shows a truck moving with speed which is not constant?

Answer is iii)

Link for BIOTECH Sample Papers

 https://coolgyan.org/previous-year-question-paper/cbse-previous-year-question-papers-class-12-biotechnology/

CLASS TEST - Genomics (SNP, Gene Prediction), Class 12

 1. C.elegans is a eukaryotic organism with a genome of 97 Mb and about 20,000 genes. What organizational features of this genome are unusual when compared to the genomes of other eukaryotes, such as yeast and Drosophila?          (2)

2. Indicate the inheritance pattern, genomic location and mutation in any two diseases caused by single gene mutations which follow mendelian inheritance. Also, specify the genomic location in any two diseases resulting from gene polymorphisms with complex inheritance.      (5)

3. What are SNPs?Explain the relevance of studying these citing any two of their important applications.(3)

4. Gene Prediction by computers is different from number of genes identified by experimental methods. Why is it so? Is there any correlation between the complexity of an organism and the total number of genes in its genome? Justify.       (3)

5. Define SNPs. Describe a possible use of this technique in medicine. How do the physicians decide our susceptibility or resistance to a particular disease through this technique ? Explain with the help of an example.      (5)

6. Define the term genome and genomics.      (2)

Protein Structure and Engineering, CBSE Question discussion (Part 1)

PROTEIN FINGERPRINTING

Information Sources, NCBI, GENOMICS, Class XII, BIOTECHNOLOGY

Motion and Time, Lect 2, Ch 13, Class 7

Motion and Time, Lect 1, Ch 13, Class 7,

Motion and Time, NOTES, Class 7 , Ch 13

 

What is Motion?
If an object keeps on changing its position with time, it is said to be moving or in motion. Motion can be of different types:
Linear or straight or Rectilinear in which the object travels in a straight line.
Circular in which the object travels along a circular path.
Curvilinear in which the object moves along a curve.
Slow and Fast Motion
If one object covers a particular distance in less time and another object covers the same distance in more time then the first object is said to be moving slowly while the second object is said to be moving faster.
The Speed of an object
The distance travelled by an object in unit time is called its Speed.
Types of Speed:
Uniform Speed - When the object travels a fixed distance same time gaps, it is said to have a uniform speed.
Non-uniform speed - When an object covers different distances in different time gaps, it is said to have a non-uniform speed.
Average speed - The total distance travelled by an object divided by the total time taken by the object is called its average speed
Measuring Time
There are many events in nature that repeat after a time interval:
Morning – The rising of the sun
Day and Night – The time between the sunrise and sunset
Month – The time between two new moons
Year – The time the earth takes to complete its one revolution around the sun
Time measuring devices or clocks - Clocks use the concept of periodic motion to measure time. It means that it uses motion that repeats itself in equal amounts of time. There are different types of time measuring devices. Sundial – It uses the position of the sun to depict timeSand Clock (hourglass) – It uses sand to measure time Water Clock – It uses water to measure timePendulum Clock – It uses a pendulum to measure time Quartz Clocks – They have an electric circuit that works with the help of cells. They provide accurate time.
Periodic Motion of a Simple Pendulum

A simple pendulum contains a Bob. It is a metallic ball or a stone which is suspended from a rigid stand with the help of a thread.
Oscillatory motion - The to and fro motion of the pendulum is called as Oscillatory Motion. The bob of the pendulum does move from the centre (mean position) of the pendulum to its extreme positions on the other side.
Oscillation - When the bob moves from its centre (mean position) to its extreme ends it is said to complete one oscillation.
Time Period of a pendulum - The time taken by the pendulum bob to complete one oscillation is called its Time Period.
Units to Measure Time Speed
Time
Second (s)
Minutes (min)
Hours (h)
Speed = Distance/time 
Meter/Second (m/s)
Meter/minute (m/min)
Kilometer/hour (km/h)
 Speedometer - It is a device which is used in vehicles such as cars and trucks which measures the speed in kilometer per hour.
Odometer - It is a device which measures the distance travelled by a vehicle in meters or kilometers.
Distance-time Graph
A graph which represents the distance travelled by an object with respect to time is called a distance-time graph.
Making a distance-time graph:
1. Mark the x-axis and y-axis and divide them in equal quantities.
 
Figure 11: Take the first quadrant
2. Choose one scale to represent distance (for example, x-axis to represent distance where 1 km = 1 cm) and the other to represent time (for example, y-axis to represent the time where 1 min = 1 cm).
 
Figure 12: Choosing the scale
3. Mark the values of time and distance in the graph.
4. Mark the set of values of time taken and distance covered in that time by the object in the graph. For example, if 1 km is covered in 1 minute then mark 1 unit on both the x-axis and y-axis.
Figure 13: Marking the values for time and distance
5. Now draw lines parallel to x-axis and y-axis at the points that you have marked.
6. Mark the points where these lines intersect on the graph. These points show the position of the moving object.
7. Now join all the points of intersection and obtain a straight-line graph.
8. This is the distance-time graph of a moving object.
 
Figure 14: Obtaining a straight line graph
To find the speed of the distance-time graph
Speed = distance/time = (final position of object – initial position of object)/time taken by object
Also, the speed of the distance-time graph can be calculated by the Slope of a graph. The steeper the slope of the graph, the more is the speed of the object. For example, in the graph given below object A has a steeper slope. This means that object A is moving at a higher speed than object B.