Free OCR GCSE Combined Science B (Twenty First Century) (J260) Exam Questions and Answers

The diagrams in the table show different types of cells. Identify the type of cell shown in each diagram. Tick one box in each row. Options: Plant, Animal, Bacterial. Identify the type of cell shown in the first diagram (cell membrane, nucleus, cytoplasm).

• AA. Plant
• BB. Animal
• CC. Bacterial

The diagrams in the table show different types of cells. Identify the type of cell shown in each diagram. Tick one box in each row. Options: Plant, Animal, Bacterial. Identify the type of cell shown in the second diagram (cell wall, plasmid DNA, chromosomal DNA, cytoplasm).

• AA. Plant
• BB. Animal
• CC. Bacterial

The diagrams in the table show different types of cells. Identify the type of cell shown in each diagram. Tick one box in each row. Options: Plant, Animal, Bacterial. Identify the type of cell shown in the third diagram (cell wall, nucleus, cell membrane, cytoplasm, vacuole, chloroplast).

• AA. Plant
• BB. Animal
• CC. Bacterial

Hormones control many processes in the human body. Complete the sentences about hormones using words from the list. Each word may be used once, more than once or not at all. blood, glands, nerves, organs, receptors, response, stimuli Hormones enable the body to respond to internal or external ____ . Hormones are secreted by ____ . Hormones are transported by the ____ . Hormones attach to ____ on effectors. This causes a ____ .

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Hormones control many processes in the human body. The menstrual cycle is controlled by hormones. The graph in Fig. 2.1 shows changes in the levels of these hormones during the menstrual cycle when an egg is not fertilised. Look at the graph in Fig. 2.1. Describe how the hormone levels change after an egg has been released.

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Contraceptive pills contain hormones that can prevent pregnancy. Which statement gives the best explanation of how the hormones in a contraceptive pill prevent pregnancy? Tick (✓) one box.

• AA. The hormones speed up the menstrual cycle.
• BB. The hormones slow down the menstrual cycle.
• CC. The hormones prevent ovulation.
• DD. The hormones kill sperm.

Contraceptive pills contain hormones that can prevent pregnancy. Give one disadvantage of relying only on a hormone contraceptive pill to prevent pregnancy.

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This question is about the genome. Which two statements about the genome are correct? Tick (✓) two boxes.

Select 2 answers.

• AA. The genome is the entire genetic material of an organism.
• BB. Each organism’s genome is identical.
• CC. In most organisms, the genome is packaged into chromosomes.
• DD. Only some organisms have a genome.
• EE. The genome of animal cells is stored in the cytoplasm.

This question is about the genome. A student makes some notes about genomes. 1. The genome is made from DNA. 2. Genes are sections of DNA. 3. DNA is wound into a triple helix. 4. DNA is a polymer. 5. DNA is made from amino acids. The teacher spots some mistakes. Write down the numbers of the two sentences that contain mistakes. Sentences ____ and ____

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This question is about the genome. The sequence of bases in a whole human genome can be worked out. It cost £1 000 000 000 to sequence a human genome in 2003. It can now be done for £1000. How many times more expensive was it in 2003 than it is now to sequence a human genome? Put a ring around the correct answer in standard form.

• AA. 10⁴
• BB. 10⁵
• CC. 10⁶
• DD. 10⁷