IB Diploma · Biology D3.1
IB Biology D3.1: Reproduction — Practice Questions & Answers
IB Biology D3.1 study notes: sexual and asexual reproduction, meiosis, gametes, fertilisation, hormones and reproduction in flowering plants.
Here are 10 practice questions with full answers and explanations.
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Practice questions with answers
1
Multiple choice
What is the function of gonadotropin-releasing hormone (GnRH) in the hypothalamus?
- Triggering glycogen breakdown.
- Binding to oestradiol.
- Activating protein kinase A.
- Regulating the release of FSH and LH.
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WhyGnRH from the hypothalamus stimulates the anterior pituitary to release the gonadotropins FSH and LH.
2
Multiple choice
Asexual reproduction primarily results in:
- Increased variation
- Genetically diverse offspring
- New gene combinations
- Genetically identical offspring
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WhyAsexual reproduction involves one parent and mitosis, producing offspring genetically identical to the parent.
3
Multiple choice
Sexual reproduction contributes to evolutionary adaptation by:
- Producing offspring with new gene combinations
- Increasing the rate of individual mutations within the genome of each offspring
- Ensuring that all offspring are genetically identical to their parents, preserving successful traits
- Directly improving the fitness of every offspring, making them perfectly suited for their current environment
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WhySexual reproduction shuffles alleles into new combinations, increasing variation on which selection can act.
4
Multiple choice
Meiosis plays a crucial role in sexual reproduction by:
- Breaking up parental allele combinations
- Maintaining diploid chromosome numbers
- Directly creating gametes for asexual reproduction.
- Producing genetically identical cells
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WhyMeiosis, through crossing over and independent assortment, breaks up parental allele combinations to create variation.
5
Multiple choice
The fusion of gametes during sexual reproduction is called:
- Meiosis
- Fertilization
- Budding
- Mitosis
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WhyFertilisation is the fusion of male and female gametes to form a diploid zygote.
6
Multiple choice
Compared to female gametes, male gametes are typically:
- Containing more food reserves
- Equal in size and mobility
- Smaller and more mobile
- Larger and less mobile
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WhyMale gametes are typically small and motile, adapted to travel to and reach the larger, immobile egg.
7
Multiple choice
The primary function of the human female reproductive system is to:
- Produce testosterone
- Regulate blood pressure and fluid balance
- Produce sperm
- Produce eggs and support fetal development
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WhyThe female reproductive system produces eggs and provides the environment for fertilisation and fetal development.
8
Multiple choice
Gametes in flowering plants are produced in:
- Leaves and stems
- Roots and flowers
- Fruits and seeds
- Ovules and pollen grains
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WhyFemale gametes form within ovules while male gametes are carried in pollen grains in flowering plants.
9
Multiple choice
Insect-pollinated flowers are typically:
- Small and inconspicuous
- Adapted for underwater pollination, with highly specialized, filamentous pollen grains
- Brightly colored and scented
- Reduced in size, with absent petals and feathery stigmas to catch airborne pollen
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WhyInsect-pollinated flowers are brightly coloured and scented to attract pollinating animals.
10
Multiple choice
Cross-pollination is promoted by:
- b) Dichogamy (stamens and pistils maturing at different times)
- b) and c) only
- b) only
- a) b) and c)
- a) Dioecy (separate male and female plants)
- c) Heterostyly (different anther and stigma heights)
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WhySeveral mechanisms together, including separate sexes, timing, and self-incompatibility, promote cross-pollination.
Key terms in Reproduction
Asexual reproduction: Reproduction from a single parent producing genetically identical offspring (clones) by mitosis, with no gamete fusion.
Sexual reproduction: Reproduction involving the fusion of two haploid gametes to produce genetically varied diploid offspring.
Gamete: A haploid sex cell (such as a sperm, egg or pollen nucleus) that fuses with another gamete at fertilisation.
Meiosis: A nuclear division producing four haploid cells from one diploid cell, halving the chromosome number and generating variation.
Fertilisation: The fusion of a male and a female gamete to form a diploid zygote, restoring the full chromosome number.
Crossing over: The exchange of DNA segments between homologous chromosomes during meiosis, creating new allele combinations.
Independent assortment: The random arrangement of homologous chromosome pairs during meiosis, mixing maternal and paternal chromosomes in gametes.
Pollination: The transfer of pollen from an anther to a stigma in flowering plants, often by wind or insects.
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