Back-to-School: Genetics 101 Quiz Results

Okay students, pencils down!

A week ago Friday we posted the second in a three-part series of educational courses for back-to-school season. The entries are now in. You can see how you did by comparing with the correct answers below. Also, a special congratulations goes out to Damien Marsic for being selected among all the entries. For the rest of you, you’ll have more chances to win an Amazon gift card when we post the last quiz in our series. For those who love learning for the sake of learning, the course is still available here. 1 Question: Approximately how genetically similar are humans to each other? Correct Answer: 99.5% It’s amazing that just 0.5% difference still results in so much genetic variation amongst humans! 2 Question: There are rules for how the bases of DNA pair together. Which is correct? (1) A pairs with A, C pairs with C, G pairs with G, T pairs with T (2) A pairs with G and C pairs with T (3) A pairs with C and G pairs with T (4) A pairs with T and C pairs with G Correct Answer: A pairs with T and C pairs with G 3 Question: How many total chromosomes do humans typically have? Correct Answer: 46 Humans typically have 23 pairs of chromosomes for a total of 46 chromosomes. 4 Question: What inheritance laws did Gregor Mendel characterize? Correct Answer: recessive and dominant Gregor Mendel characterized the idea of recessive and dominant traits. Although other modes of inheritance also exist, Mendel’s experiments laid the groundwork for understanding how a genetic trait is passed to offspring. 5 Question: Gregor Mendel carried out his famous genetic experiments with: (1) Cats (2) Apples (3) Monkeys (4) Peas Correct Answer: Peas! Mendel chose the common garden pea for his first experiments. The pea was good choice because there are different varieties that produce easily distinguishable traits like seed texture (round or wrinkled), flower color (purple or white), seed color (green or yellow), and growth form (tall or short). He could also pollinate them himself. 6 Question: How many total chromosomes do chickens typically have? Correct Answer: 78 Chickens have 39 pairs of chromosomes for a total of 78 chromosomes. Interesting fact – although chickens have more chromosomes than humans, they have roughly the same number of genes as humans. 7 Question: Roughly how many genes do humans have? Correct Answer: 20,000 Humans have approximately 20,000 genes.
  • Adroub

    I have an inquiry related to my knowledge about genetics and chromosomes. I know that in humansthere are 23 pairs of chromosomes (46)… But, I have read that down- syndrome patients “autism” have one chromosome less, (45) chromosome in total. It is known that apes differ from human by two chromosomes or so.
    What is the significance of that? Does it mean that there is an irregularity in the understanding of the genetic relationship between the living things? Even among humans? As ‘autism’ patients lack one chromosome form normal humans.
    Thank you.

    • 23blog

      Autism is not the same things a Downs Syndrome. And your understanding of Downs Syndrome is also not correct. Down syndrome occurs when an individual has a full or partial extra copy of chromosome 21. This in turn can impact development. There are many resources if you are interested in finding out more about the condition. Here is a link to one: