B1 2022

Question 1

1.3 Suggest one reason the scientists used biomass instead of the number of individuals of each plant species when collecting data to measure diversity

Answer 1

Too small to count individuals

Question 2

1.5 Effect of farming on biodiversity of fungal species

Answer 2

Lower plant species
Farming reduces fungal species richness

Question 3

2.1 Explain how the use of antibiotics has led to antibiotics-resistant strains of bacteria becoming a common cause of infection acquired when in hospital

Answer 3

Alleles for resistance in bacteria
Those who do not die will reproduce and pass on alleles that are resistance to offspring
More antibiotics used in hospital so increased resistance

Question 4

2.3 Describe how scientists could use aseptic techniques to transfer 0.3cm3 of C. difficile in liquid culture from a bottle onto an agar plate

Answer 4

Wash hands with soap
Lift lid at an angle
Use sterile spreader
Place pipette into disinfectant

Question 5

3.1 Give two features of all prokaryotic cells that are not features of eukaryotic cells

Answer 5

No membrane bound organelles
Circular DNA

Question 6

3.6 Using TEM observing AP and stained using monoclonal antibody with gold attached to it. How?

Answer 6

Monoclonal antibody would attach to complementary receptor on the prokaryotes.
Gold interacts with electrons
TEM has high resolution

Question 7

4.1 Describe viral replication

Answer 7

Attachment proteins attach to receptors
Nucleic acid enters cell
Reverse transcriptase makes DNA from RNA
Cell produces proteins
Virus assembled and released

Question 8

5.3 Describe what the scientists should place in the control tubes in this investigation

Answer 8

Same volume of buffer
Same conc of substrate
Same conc of denatured enzyme

Question 9

8.1 Explain why a second stain would be needed to stain the red blood cells. Suggest which molecule the stain could bind to in the red blood cells

Answer 9

No nucleus
Haemoglobin

Question 10

8.3 Other than SA:Vol ratio, one way uncontrolled division changes the gills and how it would affect gas exchange

Answer 10

Thicker filaments
Slower gas exchange since longer diffusion pathway

Question 11

9.1 Describe transport of carbohydrates in plants

Answer 11

Sucrose actively transported into phloem by companion cells
Lowers water potential
Produces high hydrostatic pressure
Mass flow to respiring cells
Unloaded by active transport