View all 45 cards in this deck

#	Question	Answer
1	What is the basic unit from which all organisms start life?	A single cell.
2	Which three processes must occur in a coordinated way during cell division?	Cell division, DNA replication, and cell growth.
3	What does interphase represent?	The phase between two successive M phases.
4	What is karyokinesis?	Nuclear division corresponding to the separation of daughter chromosomes.
5	What occurs during S phase?	DNA synthesis or replication takes place.
6	What occurs during G2 phase?	Proteins are synthesised in preparation for mitosis and cell growth continues.
7	Give an example where haploid cells divide by mitosis in animals.	Male honey bees.
8	What marks the beginning of prophase?	Initiation of condensation of chromosomal material.
9	What is the inactive stage entered by cells that no longer divide?	Quiescent stage (G0).
10	Why is mitosis called equational division?	Because the chromosome number remains the same in parent and progeny cells.
11	Which phases of interphase precede prophase?	S phase and G2 phase.
12	What are asters?	Microtubules radiating from centrosomes.
13	Why can chromosomes be clearly observed during metaphase?	Because chromosome condensation is completed.
14	What is the metaphase plate?	The plane of alignment of chromosomes at metaphase.
15	Towards where do daughter chromosomes move during anaphase?	Opposite poles of the cell.
16	What happens to chromosomes at the beginning of telophase?	They decondense and lose their individuality.
17	What is cytokinesis?	Division of the cytoplasm into two daughter cells.
18	How does cytokinesis occur in plant cells?	By cell wall formation starting from the centre and growing outward.
19	Give an example of syncytium mentioned in the text.	Liquid endosperm in coconut.
20	Why must cells divide as they grow?	To restore the nucleo-cytoplasmic ratio.
21	Why is meiosis important in sexual reproduction?	It produces haploid gametes.
22	What important event occurs between homologous chromosomes during meiosis?	Pairing and recombination between non-sister chromatids.
23	Into how many stages is prophase I subdivided?	Five stages.
24	What is synapsis?	The pairing of homologous chromosomes.
25	During which stage are tetrads clearly visible?	Pachytene.
26	Which enzyme is involved in crossing over?	Recombinase.
27	How long can diplotene last in vertebrate oocytes?	Months or years.
28	Diakinesis represents transition to which stage?	Metaphase I.
29	What reappears during telophase I?	Nuclear membrane and nucleolus.
30	How is prophase II compared to prophase I?	It is much simpler.
31	What occurs during metaphase II?	Chromosomes align at the equator.
32	With which stage does meiosis end?	Telophase II.
33	How does meiosis maintain chromosome number despite reducing it by half?	Fertilisation restores the diploid chromosome number.
34	From what does every sexually reproducing organism begin its life cycle?	A single-celled zygote.
35	What is M phase?	The actual period of cell division.
36	What occurs during G2 phase?	Cytoplasmic growth.
37	What begins to appear during prophase?	Spindle fibres.
38	What follows nuclear division in mitosis?	Cytoplasmic division or cytokinesis.
39	Into which two phases is meiosis divided?	Meiosis I and Meiosis II.
40	What chromosome number reaches each pole during anaphase I?	Half the chromosome number of the parent cell.
41	What is the average cell cycle span for a mammalian cell?	About 24 hours.
42	Why is mitosis called equational division?	Because chromosome number remains the same in daughter cells.
43	What is synapsis?	Pairing of homologous chromosomes.
44	In which stage of mitosis do sister chromatids separate?	Anaphase.
45	What happens to chromosome number (N) during mitosis?	It remains constant.