When does the total number of chromosomes get reduced from 46 pairs to 23 individual chromosomes? view available hint(s) when does the total number of chromosomes get reduced from 46 pairs to 23 individual chromosomes? during metaphase ii during mitosis during interphase during meiosis i

23 pairs of chromosomes (46 individual chromosomes) are redued to 23 individual chromosomes in meiosis I.

During Meiosis I

Explanation:

Meiosis is a type of cell division that results in four daughter cells with each having half the number of chromosomes as in the parent cell. During meiosis, cell division occurs twice because before the two halves of a duplicated chromosome (sister chromatids) is separated, it still needs to separate homologous pair of chromosomes, which is a similar but non-identical pair of chromosomes received from both parent. Hence, meiosis occurs in a two step division process; Meiosis I and Meiosis II.

Note that, a diploid cell contains 23 pairs of chromosomes ( 46 chromosomes in total). Each pair of chromosome is from the haploid gamete produced by each parent after meiosis.

Before going into meiosis I, the cell must first undergo growth and replicate its DNA in the interphase stage just like in mitosis. In the Prophase I of meiosis I, chromosomes condense as in mitosis but also pair up. Each chromosome aligns with its homologue pair to form a structure called TETRAD or BIVALENT.

Homologous pairs, not individual chromosomes (23 pairs in number) line up at the metaphase plate for separation during metaphase I.

In anaphase I, the homologues are pulled apart by the spindle fibres and move apart to opposite ends of the cell. The sister chromatids of each chromosome, however, remain attached to one another and don't come apart. Hence, the cell now has 23 chromosomes on one side of the cell, and another 23 on the other side.

After cytokinesis (division of the cytoplasm) in meiosis I, two daughter cells are produced and each now possesses 23 individual chromosomes (haploid) different from the parental 23 pairs (diploid).

N.B: Sister chromatids separate in the anaphase of meiosis II, where each chromatid is counted as an individual chromosome.

i think the answer is g1

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-lavira: )

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.