9700_w23_qp_13
A paper of Biology, 9700
Questions:
40
Year:
2023
Paper:
1
Variant:
3
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18
The statements are comparisons of endocytosis and exocytosis. ● Both are mechanisms that involve vesicles or vacuoles and the transport of materials across the cell surface membrane. ● Both mechanisms occur to allow bulk transport across the cell surface membrane. ● Endocytosis involves taking materials into the cell, whereas exocytosis involves the release of materials from the cell. ● Some of the cell surface membrane is lost when endocytosis occurs and there is an increase in the cell surface membrane when exocytosis occurs. How many statements are correct?
4. Cell membranes and transport  →  4.2. Movement into and out of cells
4. Cell membranes and transport  →  4.1. Fluid mosaic membranes
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26
Ammonium ions, NH4 +, can enter the xylem of plant roots by two pathways. ● In the apoplast pathway, ammonium ions move through cell walls until this pathway is blocked by the Casparian strip. Ammonium ions then enter the cytoplasm of root cells. ● In the symplast pathway, ammonium ions move through the cytoplasm of root cells. A scientist measured the uptake of ammonium ions into the xylem of Arabidopsis thaliana. The sgn3 mutant of A. thaliana does not have a Casparian strip. In the sgn3 mutant, ammonium ions can enter the xylem without entering the cytoplasm of root cells. The bar charts show the scientist’s results. non- mutant sgn3 mutant low concentration NH4 + plant variety non- mutant sgn3 mutant high concentration NH4 + uptake of NH4 + into xylem / μmol g–1 h–1 Which conclusion is correct?
7. Transport in plants  →  7.2. Transport mechanisms
4. Cell membranes and transport  →  4.2. Movement into and out of cells
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31
The diagram shows how tissue fluid is formed. +4.3 kPa +1.1 kPa –3.3 kPa –1.3 kPa direction of blood flow arteriole end venous end net flow out of capillary +1.6 kPa +1.1 kPa –3.3 kPa –1.3 kPa net flow into capillary key blood pressure water potential What is the net pressure causing tissue fluid to flow out of the capillary at the arteriole end?
8. Transport in mammals  →  8.1. The circulatory system
4. Cell membranes and transport  →  4.2. Movement into and out of cells
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38
The diagram shows one way of testing the effect of an antibiotic on bacteria. Petri dish with nutrient agar containing bacteria disc of filter paper soaked in antibiotic colonies of bacteria grown for 5 days diameter of zone measured every day for 5 days The table shows the results of testing five different types of bacteria. Zones of less than 13.0 mm show the presence of resistant bacteria. type of bacteria diameter of zone / mm day 1 day 2 day 3 day 4 day 5 24.1 21.9 19.0 17.6 14.3 18.6 15.4 12.2 9.0 2.0 17.9 12.8 12.4 11.1 10.9 19.4 15.3 13.2 8.1 2.0 22.0 21.0 20.5 20.4 20.4 Which statement can be supported by this data?
10. Infectious diseases  →  10.2. Antibiotics
17. Selection and evolution  →  17.2. Natural and artificial selection
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40
Some vaccines do not contain antigens. The vaccines contain a molecule of mRNA. Cells in the immune system use the mRNA molecule to make a protein antigen. The statements describe the stages of how mRNA vaccines work when they enter a cell of the immune system. B-lymphocytes and T-lymphocytes with complementary receptors bind to the protein. Lymphocytes differentiate into memory cells that give long lasting immunity. Ribosomes translate the mRNA molecule to make a protein. The cell displays the protein on its cell surface membrane. What is the correct order of the stages of how mRNA vaccines work?
11. Immunity  →  11.2. Antibodies and vaccination
6. Nucleic acids and protein synthesis  →  6.2. Protein synthesis
11. Immunity  →  11.1. The immune system
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