9700_m24_qp_12
A paper of Biology, 9700
Questions:
40
Year:
2024
Paper:
1
Variant:
2
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4
When mucus is secreted from a goblet cell, these events take place. addition of carbohydrate to protein fusion of a vesicle with the cell surface membrane extracellular release of a glycoprotein separation of a vesicle from the Golgi body What is the sequence in which these events take place?
4. Cell membranes and transport  →  4.1. Fluid mosaic membranes
15. Control and coordination  →  15.1. Control and coordination in mammals
9. Gas exchange  →  9.1. The gas exchange system
Open
11
Many flowers produce a sweet solution called nectar. Bees provided with nectar use enzyme Q to change the nectar into honey. After testing a sample of nectar for the presence of reducing sugar using standard laboratory reagents, the sample was blue. After testing a sample of honey in the same way, the sample was orange. Which conclusion about the reaction catalysed by enzyme Q is consistent with these results?
2. Biological molecules  →  2.1. Testing for biological molecules
3. Enzymes  →  3.2. Factors that affect enzyme action
Open
13
A scientist investigated the progress of two enzyme-catalysed reactions in separate test-tubes, X and Y. Both reactions result in colour changes that can be detected using colorimetry. 0.5 cm3 samples were taken from each test-tube at the start of the investigation and at regular intervals for the next 5 minutes. Copper ions were added to each sample as soon as the sample was collected to inactivate the enzymes and stop the reactions from progressing further. The absorbance of each sample was measured using a colorimeter. The graph shows the results of this investigation. percentage absorbance time / minutes X Y Which statement is consistent with the results shown...
3. Enzymes  →  3.1. Mode of action of enzymes
3. Enzymes  →  3.2. Factors that affect enzyme action
2. Biological molecules  →  2.1. Testing for biological molecules
Open
18
The diagram shows how an artificial partially permeable membrane was used to separate a 5% sodium chloride solution and a 10% sodium chloride solution in a beaker. The two sides of the beaker were labelled R and S. partially permeable membrane 5% sodium chloride solution 10% sodium chloride solution R S Which row correctly describes and explains what will happen in the half of the beaker labelled S?
4. Cell membranes and transport  →  4.2. Movement into and out of cells
15. Control and coordination  →  15.1. Control and coordination in mammals
Open
19
Agar cubes can be used to demonstrate the effect on diffusion of changing the surface area to volume ratio. Three different agar cubes made using a coloured indicator solution were placed into a dilute acid that diffused into the cubes. As the acid diffused into the agar cubes, the colour of the indicator solution changed. The cubes had volumes of 1 cm3, 2 cm3 and 3 cm3 and were left in the dilute acid for 10 minutes. All other variables were kept the same. After 10 minutes, the agar cubes were removed from the dilute acid and cut in half. The cut surfaces were observed and the results were recorded as diagrams. All diagrams were drawn to the same scale. The results for the 2 cm3 cube are shown...
4. Cell membranes and transport  →  4.2. Movement into and out of cells
Open
26
During the mitotic cell cycle, the chromosomal DNA is replicated. The specific points in DNA molecules where replication is occurring are known as replication forks. A typical human chromosome has about 150 million base pairs of DNA. It takes about 1 hour to replicate the DNA of a typical human chromosome. The rate of replication using a single replication fork is approximately 50 base pairs per second. Approximately how many replication forks must occur in a typical human chromosome during DNA replication?
5. The mitotic cell cycle  →  5.1. Replication and division of nuclei and cells
6. Nucleic acids and protein synthesis  →  6.1. Structure of nucleic acids and replication of DNA
Open
29
A maize seedling was grown in soil that contained lanthanum ions labelled with a chemical that fluoresces under ultraviolet light. The diagram represents what was observed when a section of root was examined using a light microscope with ultraviolet illumination. xylem Casparian strip root hair key fluorescence What is a correct conclusion about the transport of lanthanum ions in maize roots?
7. Transport in plants  →  7.2. Transport mechanisms
7. Transport in plants  →  7.1. Structure of transport tissues
Open
38
Antibiotic-resistant strains of Mycobacterium tuberculosis are a major problem when treating TB. A new antibiotic, teixobactin, could be very effective at killing M. tuberculosis with only a small risk that the bacteria will evolve teixobactin resistance. Penicillin and similar antibiotics bind to a single protein, but teixobactin binds to two lipids that are needed for the formation of the bacterial cell wall. Teixobactin binds to regions of the two lipids that do not vary across many different species of bacteria. Which statements help to explain why the use of teixobactin is thought to be less likely to lead to the evolution of antibiotic resistance than the use of many other antibiotics, such as penicillin?
10. Infectious diseases  →  10.2. Antibiotics
17. Selection and evolution  →  17.2. Natural and artificial selection
Open