9700_w10_qp_12
A paper of Biology, 9700
Questions:
40
Year:
2010
Paper:
1
Variant:
2
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4
The diameter of living cells varies considerably. The typical diameters are a eukaryote, such as a white blood cell 1.5 × 101 µm a prokaryote, such as Streptococcus 7.5 × 102 nm Use these measurements to find the maximum number of each cell type which could fit along a line 1 cm long. number of white blood cells number of Streptococcus cells A 6.7 × 103 1.3 × 105 B 6.7 × 102 1.3 × 104 C 6.7 × 101 1.3 × 103 D 6.7 × 100 1.3 × 102
1. Cell structure  →  1.2. Cells as the basic units of living organisms
1. Cell structure  →  1.1. The microscope in cell studies
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13
The diagram shows the transport of ions across the cell surface membrane. Inside the cell there is a low concentration of sodium ions (Na+) and a high concentration of potassium ions (K+). Outside the cell there is a low concentration of K+ and a high concentration of Na+. The carrier molecule is a pump which exchanges Na+ for K+ ions. cell surface membrane inside cell outside cell carrier molecule Which ionic movements are represented by the arrows?
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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21
A culture of bacteria had all its DNA labelled with the heavy isotope of nitrogen (15N). A sample was taken and spun in a centrifuge. The diagram shows the position of the DNA band at Z in the centrifuge tube. X Y Z The culture was then allowed to reproduce using nucleotides containing the normal isotope of nitrogen (14N). Samples were taken and spun in a centrifuge after one generation and again after two generations. In which pattern would the DNA be found after the first and after the second generations?
6. Nucleic acids and protein synthesis  →  6.1. Structure of nucleic acids and replication of DNA
19. Genetic technology  →  19.1. Principles of genetic technology
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25
Water passes across leaf tissues by different routes as a result of • differences in water potential • the pull transmitted by cohesive forces between water molecules. The diagram shows three routes by which water can travel. cuticle cuticle epidermal cell epidermal cell xylem vessel palisade cell cells of the spongy mesophyll route 1 = apoplastic route 2 = vacuolar route 3 = symplastic key atmosphere Which row correctly identifies why water passes across leaf tissues by the different routes?
4. Cell membranes and transport  →  4.2. Movement into and out of cells
7. Transport in plants  →  7.2. Transport mechanisms
Open
36
The data shows how the number of human deaths caused by the bacterium Staphylococcus aureus has changed from 1997 to 2005. Methicillin is an antibiotic used to treat a disease caused by S. aureus. MRSA is methicillin-resistant S. aureus. year total number of death certificates with S. aureus total number of death certificates with MRSA Which statement is not supported by this data?
10. Infectious diseases  →  10.2. Antibiotics
10. Infectious diseases  →  10.1. Infectious diseases
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