IGCSE Biology Paper-4: Specimen Questions with Answers 191 - 192 of 279

Question 191

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Short Answer▾

Describe how DNA can be used to classify organisms.

Explanation

For example, scientists can use DNA sequences to help determine if they have discovered a new species. Scientists can also compare DNA sequences from different organisms and measure the number of changes (mutations) between them to infer if species are closely or distantly related.

Passage

Penicillin is produced commercially in fermenters as shown in Fig. below.

Penicillin Producing Microorganisms

Question 192 (1 of 2 Based on Passage)

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Short Answer▾

Table shows some names of the parts of the fermenter and their functions.

Complete Table.

Some Names of the Parts of the Fermenter and Their Functions
letter from Fig.namefunction
water jacket
nutrient inlet
air supply
outletallows collection of the liquid containingpenicillin after fermentation

Explanation

Some Names of the Parts of the Fermenter and Their Functions
letter from Fig.namefunction
Rwater jacketA water jacket surrounding the fermenter maintains an optimum temperature so the proteins do not become denatured.
PPressure sensorA pressure sensor may be used to measure the pressure inside a fermentation vessel
Qnutrient inletnutrients are put into the fermenter
SPaddle wheelFor uniform mixing of nutrients
Tair supplyoxygen is well mixed and distributed uniformly
Uoutletallows collection of the liquid containingpenicillin after fermentation
Nutrient or Inoculant