In a flowering plant tall t is dominant to short t and blue...

In a flowering plant, tall (T) is dominant to short (t), and blue flowers (B) are dominant to white flowers (b). In a Mendelian breeding experiment, which cross represents the F1 generation (heterozygotes) self-fertilizing, resulting in the F2 generation. Group of answer choices: TTbb X ttBB TTBB X ttbb TtBb X TtBb

Transcript

00:01 Stay there.

00:02 Going to answer your question here.

00:06 This type of question requires a punnet square called a die hybrid cross, where we're comparing two different traits at the same time in a large 16 square punnet square.

00:19 So this will take a minute to explain and to work out, but at the end, we will have our ratios, and it will make a lot of sense, hopefully.

00:27 So this is called a dye hybrid cross.

00:33 And the question sets up in a flowering plant, t, capital t is dominant to short, lowercase t.

00:42 So let's outline this, capital t equals tall, lowercase t equals short.

00:55 And blue flowers are dominant to white flowers.

00:59 So it is blue, lowercase b is white.

01:08 So in these plants, tall is dominant, blue is dominant.

01:12 Short is recessive, white is recessive.

01:19 A tall white flower, capital t, lowercase b, lowercase b, is crossed with a short plant with blue flowers.

01:35 So these are our parents, our parent plants, and they're going to be crossed with each other, and we're going to come up with their offspring in this punnet square here.

02:08 So let's start by outlining what goes what here.

02:13 Let's do the top parent first.

02:17 Each square, each top part is going to have two letters, and i'll show you how to put which letters where they're supposed to be.

02:28 So we'll start with this first t, first letter here.

02:37 So the first one's going to be capital t, lowercase b.

02:42 Second one's going to go capital t the second lowercase b this third one's going to go whoops lowercase b lowercase b and the last one's lowercase lowercase as well we're going to do the same thing down here first first first last so this first square going down is going to be lowercase b lowercase t excuse me capital b.

03:31 Second one's going to be lowercase t, lowercase b.

03:39 Then we're going to do the second first, second, second, so second first is lowercase t, capital b again, and then finally lowercase, lowercase.

04:00 And we're just going to fill out our punnet square.

04:03 T's will go first since it's the first letter.

04:07 So this first square, i'll type it out just to make it easier.

04:12 Whoops.

04:19 We're going to have capital t, lowercase t, capital b, lowercase b.

04:27 So you see how we drop this one down, move this one over, move this one over, drop this one down.

04:34 Same rule still apply in terms of, whoops, what goes first.

04:41 Capital letters are always first, and we're talking about height before color, so t's are going to go before b's.

04:51 And we're just going to do that all around.

04:56 Let me, there we go.

05:04 Capital t, lowercase t, capital b, lowercase b.

05:21 And we have lowercase, lowercase, here, capital b, lowercase b.