AP Biology Trivia 2 — Questions and Answers
Question 1: What is the largest organ in the human body?
- Liver
- Brain
- Skin (Correct answer)
- Lungs
Correct answer: Skin
The skin is the largest organ, covering approximately 20 square feet in adults.
The skin (integumentary system) is the largest organ by both weight and surface area, weighing about 8 pounds and covering approximately 22 square feet in an average adult.
Question 2: How many chromosomes do humans have?
- 23
- 44
- 46 (Correct answer)
- 48
Correct answer: 46
Humans have 46 chromosomes (23 pairs) in most body cells.
Normal human somatic cells contain 46 chromosomes arranged in 23 pairs — 22 pairs of autosomes and 1 pair of sex chromosomes (XX for females, XY for males). Gametes contain only 23 chromosomes (haploid).
Question 3: Which blood type is considered the universal donor?
- A
- B
- AB
- O negative (Correct answer)
Correct answer: O negative
O negative blood can be given to any blood type because it lacks A, B antigens and Rh factor.
Type O negative blood lacks A antigens, B antigens, and the Rh factor, so it won't trigger an immune response in any recipient. This makes it safe for emergency transfusions when the patient's blood type is unknown.
Question 4: What percentage of the human body is water?
- 40-50%
- 50-60%
- 60-70% (Correct answer)
- 70-80%
Correct answer: 60-70%
The adult human body is approximately 60-70% water.
Water makes up about 60-70% of adult body weight. The brain and heart are about 73% water, lungs about 83%, skin about 64%, muscles about 79%, and bones about 31% water.
Question 5: Which vitamin is produced when skin is exposed to sunlight?
- Vitamin A
- Vitamin C
- Vitamin D (Correct answer)
- Vitamin E
Correct answer: Vitamin D
Vitamin D is synthesized in the skin when exposed to UVB radiation from sunlight.
When UVB rays from sunlight hit the skin, they convert 7-dehydrocholesterol to previtamin D3, which is then converted to vitamin D3 (cholecalciferol). Vitamin D is essential for calcium absorption and bone health.
Question 6: How many bones does an adult human have?
- 186
- 206 (Correct answer)
- 226
- 246
Correct answer: 206
An adult human skeleton has 206 bones.
Adults have 206 bones, while babies are born with about 270 soft bones that gradually fuse together during growth. The smallest bone is the stapes in the middle ear, and the largest is the femur (thigh bone).
AP Biology Trivia 2
What is the largest organ in the human body?