Grade 11 Practical Task 1.3 2020 - Grey College

LIFE SCIENCES GRADE 11 PRACTICAL TASK 1.2

DATE: 17 September 2020

TIME: 30 minutes

CELLULAR RESPIRATION

NAME: ........................................................ QUESTION 1

MARKS 30

1.1 Learners wanted to investigate if germinating seeds release carbon dioxide during respiration.

The learners: - Set up the investigation as indicated below - Sterilised both sets of seeds before they placed it inside the test tubes - Left the apparatus in a safe place - Recorded any colour change of the clear lime water in both test tubes after TWO days

dead seeds

A

B

rubber stopper

cotton wool

germinating seeds

clear lime water

1.1.1 Provide an investigative question for the experiment. _________________________________________________________ _________________________________________________________ (2)

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Life Sciences Practical Task 1.2

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Grade 11

FS/Sept 2020

1.1.2 State the following for the investigation:

(a) Dependent variable

__________________________________________________ (1)

(b) Independent variable

__________________________________________________ (1)

(c) TWO fixed (controlled) variables

__________________________________________________

__________________________________________________ (2)

1.1.3 Why were the seeds sterilised at the start of the investigation?

______________________________________________________

______________________________________________________ (1)

1.1.4 What colour change was observed in test tube:

A _______________________________________________________ (1)

B _______________________________________________________ (1)

1.1.5 Give a reason for the colour change in test tube B.

_______________________________________________________ (1)

1.1.6 Why can experiment A serves as a control?

_______________________________________________________ (2) (12)

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1.2 The following table shows the relation between the amount of FOUR gasses present in exhaled air. Other gasses contribute to more or less 1%.

Type of gas

Water vapour Nitrogen Oxygen Carbon dioxide

Average percentage of gas per volume of exhaled air (%) 5 78 12 4

Draw a bar graph of the information in the table.

(6)

QUESTION 2

2.1 A group of Grade 11 learners conducted an investigation after having gathered facts about cellular respiration and photosynthesis.

The learners set up the investigation as shown in the diagram. They: Placed small living animals and a healthy plant onto thin discs cut from a spongy material into two test tubes Kept a third test tube without any living organisms Placed all three test tubes in a room with bright, natural sunlight

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2.1.1 What is the purpose of using:

(a) Rubber stoppers in each test tube

_______________________________________________________ (1)

(b) The spongy disks

_______________________________________________________ (1)

2.1.2 State TWO ways in which the reliability of this investigation can be improved.

_______________________________________________________

_______________________________________________________ (2)

2.1.3 Predict the results expected in the following test tubes after a few hours:

A _______________________________________________________

C _______________________________________________________ (2)

2.1.4 Give a reason for your answer in QUESTION 2.1.3 - Test tube C

_______________________________________________________

_______________________________________________________

_______________________________________________________ (2) (8)

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QUESTION 3

3.1 Answer the questions on the schematic presentation of the process of cellular respiration.

A

(takes place in the cytoplasm)

1

2

B

(takes place in the

mitochondrion)

3

4

C 5 6

3.1.1 Name the following phases in the process of respiration:

A

____________________________________________________

(1)

B

____________________________________________________

(1)

3.1.2 Name the gas:

2 _____________________________________________________ (1)

3 _____________________________________________________ (1)

(4)

TOTAL: 30

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