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The Y chromosome is one of the two sex chromosomes in humans (the other is the X chromosome). The sex chromosomes form one of the 23 pairs of human chromosomes in each cell. The Y chromosome spans more than 59 million building blocks of DNA (base pai READ MORE

The X chromosome is one of the two sex chromosomes in humans (the other is the Y chromosome). The sex chromosomes form one of the 23 pairs of chromosomes in each cell. The X chromosome spans about 155 million DNA building blocks (base pairs) and repr READ MORE

Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Each cell contains hundreds to thousands of mitochondria, which are located in the fluid that surrounds the nucleus (the cytoplasm). Although m READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 9, one copy inherited from each parent, form one of the pairs. Chromosome 9 is made up of about 141 million DNA building blocks (base pairs) and represe READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 8, one copy inherited from each parent, form one of the pairs. Chromosome 8 spans more than 146 million DNA building blocks (base pairs) and represents READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 7, one copy inherited from each parent, form one of the pairs. Chromosome 7 spans about 159 million DNA building blocks (base pairs) and represents more READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 6, one copy inherited from each parent, form one of the pairs. Chromosome 6 spans about 171 million DNA building blocks (base pairs) and represents betw READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 5, one copy inherited from each parent, form one of the pairs. Chromosome 5 spans about 181 million DNA building blocks (base pairs) and represents almo READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 4, one copy inherited from each parent, form one of the pairs. Chromosome 4 spans about 191 million DNA building blocks (nucleotides) and represents mor READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 3, one copy inherited from each parent, form one of the pairs. Chromosome 3 spans about 198 million base pairs (the building blocks of DNA) and represen READ MORE

Humans normally have 46 chromosomes (23 pairs) in each cell. Two copies of chromosome 22, one copy inherited from each parent, form one of the pairs. Chromosome 22 is the second smallest human chromosome, spanning more than 51 million DNA building bl READ MORE

Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 21, one copy inherited from each parent, form one of the pairs. Chromosome 21 is the smallest human chromosome, spanning about 48 million base pairs (th READ MORE