Lunularia cruciata is a primitive plant．Its body consists of a flattened sheet of photosynthetic tissue called a thallus． Fig． 5.1 shows L．cruciata with two different types of reproductive structure，labelled $$$\mathbf{A}$$$ and $$$\mathbf{B}$$$ ，on its surface． Fig． 5.1 （a）Structures $$$\mathbf{A}$$$ and $$$\mathbf{B}$$$ and the thallus of $$$L$$$ ．cruciata are haploid． Explain what is meant by haploid． ............................................................................................................................................... . ............................................................................................................................................... . ............................................................................................................................................... . ......................................................................................................................................... ［2］

Biology

IGCSE&ALevel

CAIE

Exam No：9700_w24_qp_41 Year：2024 Question No：5(a)

Answer:

Knowledge points:

16.1.1 explain the meanings of the terms haploid (n) and diploid (2n)

16.1.2 explain what is meant by homologous pairs of chromosomes

16.1.3 explain the need for a reduction division during meiosis in the production of gametes

16.1.4 describe the behaviour of chromosomes in plant and animal cells during meiosis and the associated behaviour of the nuclear envelope, the cell surface membrane and the spindle (names of the main stages of meiosis, but not the sub-divisions of prophase I, are expected: prophase I, metaphase I, anaphase I, telophase I, prophase II, metaphase II, anaphase II and telophase II)

16.1.5 interpret photomicrographs and diagrams of cells in different stages of meiosis and identify the main stages of meiosis

16.1.6 explain that crossing over and random orientation (independent assortment) of pairs of homologous chromosomes and sister chromatids during meiosis produces genetically different gametes

16.1.7 explain that the random fusion of gametes at fertilisation produces genetically different individuals

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