Summer 2026 Predicted
Turn over
for more papers: tyrionpapers.com
, DO NOT WRITE IN THIS AREA
1 A student is investigating bacterial growth using aseptic techniques.
(a) State what is meant by the term aseptic techniques.
(1)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
(b) The student needs to transfer bacterial cells growing on an agar plate to a tube
containing sterile nutrient broth.
Describe how the student would use aseptic techniques to transfer the
bacterial cells safely and prevent contamination.
(5)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
DO NOT WRITE IN THIS AREA
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
for more papers: tyrionpapers.com
, DO NOT WRITE IN THIS AREA
(c) The table below shows information about culture media.
Type of medium Description Example
Supports growth of
Broad spectrum many microorganism Nutrient agar
types
Supports growth of
Selective only specific MacConkey agar
microorganisms
The student inoculates a mixed culture containing both Gram-positive and Gram-
negative bacteria onto MacConkey agar. Only Gram-negative bacteria grow.
DO NOT WRITE IN THIS AREA
Explain why a microbiologist might use a selective medium like MacConkey agar
rather than a broad spectrum medium.
(2)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
for more papers: tyrionpapers.com
, DO NOT WRITE IN THIS AREA
(d) Explain why the student should hold the inoculating loop at an angle when
transferring bacteria from a broth culture, rather than holding it horizontally.
(2)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
(e) State one safety precaution the student should take when working with
DO NOT WRITE IN THIS AREA
bacterial cultures in the laboratory.
(1)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
(Total for Question 1 = 11 marks)
for more papers: tyrionpapers.com
Turn over
for more papers: tyrionpapers.com
, DO NOT WRITE IN THIS AREA
1 A student is investigating bacterial growth using aseptic techniques.
(a) State what is meant by the term aseptic techniques.
(1)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
(b) The student needs to transfer bacterial cells growing on an agar plate to a tube
containing sterile nutrient broth.
Describe how the student would use aseptic techniques to transfer the
bacterial cells safely and prevent contamination.
(5)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
DO NOT WRITE IN THIS AREA
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
for more papers: tyrionpapers.com
, DO NOT WRITE IN THIS AREA
(c) The table below shows information about culture media.
Type of medium Description Example
Supports growth of
Broad spectrum many microorganism Nutrient agar
types
Supports growth of
Selective only specific MacConkey agar
microorganisms
The student inoculates a mixed culture containing both Gram-positive and Gram-
negative bacteria onto MacConkey agar. Only Gram-negative bacteria grow.
DO NOT WRITE IN THIS AREA
Explain why a microbiologist might use a selective medium like MacConkey agar
rather than a broad spectrum medium.
(2)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
for more papers: tyrionpapers.com
, DO NOT WRITE IN THIS AREA
(d) Explain why the student should hold the inoculating loop at an angle when
transferring bacteria from a broth culture, rather than holding it horizontally.
(2)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
(e) State one safety precaution the student should take when working with
DO NOT WRITE IN THIS AREA
bacterial cultures in the laboratory.
(1)
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
(Total for Question 1 = 11 marks)
for more papers: tyrionpapers.com
