AP PSYCHOLOGY

BIOLOGICAL BASES OF BEHAVIOR

THE NERVOUS AND ENDOCRINE SYSTEMS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A human usually has ____ total chromosomes.
A
6
B
22
C
4
D
46
Explanation: 

Detailed explanation-1: -In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females.

Detailed explanation-2: -Humans typically have 23 pairs of chromosomes, or 46 chromosomes in total. Chromosomes are made up of long strands of DNA, which contain all the body’s genes.

Detailed explanation-3: -Humans, like many other species, are called ‘diploid’. This is because our chromosomes exist in matching pairs – with one chromosome of each pair being inherited from each biological parent. Every cell in the human body contains 23 pairs of such chromosomes; our diploid number is therefore 46, our ‘haploid’ number 23.

Detailed explanation-4: -Sex chromosomes. The human body has 46 chromosomes of which 44 are called autosomes and 2 are called sex chromosomes. They exist as 44+XX in females and 44+XY in males.

Detailed explanation-5: -Females have two X chromosomes, while males have one X and one Y chromosome. A picture of all 46 chromosomes in their pairs is called a karyotype. A normal female karyotype is written 46, XX, and a normal male karyotype is written 46, XY.

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