Question

review questions

1. scientists use _____________ instead of words to represent genetic traits.
2. by agreement scientists represent the dominant trait by its ________ letter and the recessive trait by the _______________ of the same letter.
3. an organism usually has _______ genes for every trait.
4. in guinea pigs, rough coat is dominant to smooth coat.

(a) what symbol should be used to represent the gene for rough coat? ______
(b) what symbol should be used to represent the gene for smooth coat? _______
(c) what symbols should be used to represent a pure (homozygous) rough pig? ______
(d) what symbols should be used to represent a pure (homozygous) smooth pig? ______
(e) what symbols should be used to represent a hybrid (heterozygous) rough pig: ______
j. predicting genetic results. you can predict genetic results if you understand that predicting the results of genetic crosses is based on the laws of chance or probability. probability tells you how much chance there is for something to happen. for example, when you pick a playing card out of a deck, the probability that it will be red is one out of two. you know that when you toss a coin, the probability that the coin will turn up heads is 50 - 50 or one chance out of two. however, it is necessary to toss thousands of coins to get these results. try it yourself by tossing a coin 100 times. did you get 50 heads and 50 tails? you would need to

Explanation:

1. Scientists use symbols (like letters) to represent genetic traits instead of words for clarity and standardization in genetics.
2. Dominant traits are represented by uppercase letters, recessive by lowercase (the same letter's lowercase form) as per genetic notation conventions.
3. Organisms usually have two genes for each trait (one from each parent, following Mendelian genetics).
4. (a) For dominant rough coat, use uppercase letter (e.g., R). (b) Recessive smooth coat uses lowercase of the same letter (r). (c) Homozygous rough: RR (two dominant alleles). (d) Homozygous smooth: rr (two recessive alleles). (e) Heterozygous rough: Rr (one dominant, one recessive).

Answer:

1. symbols
2. uppercase; lowercase (or "lowercase form")
3. two
4. (a) R (or any uppercase letter)

(b) r (lowercase of the same letter as dominant)
(c) RR
(d) rr
(e) Rr