Which of the following most influences a major shift in how...

Which of the following MOST influences a major shift in how the entire nucleotide sequence is read? A base-pair substitutions and point mutations B silent mutations and nonfunctioning proteins C missense mutations and nonsense mutations D base-pair insertions and deletions

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Transcript

00:01 Hi there.

00:02 In this question, we are asked which of these is going to cause a major shift in how an entire nucleotide sequence is read? so we know when proteins are being made from rna, and of course the rna came from the dna.

00:17 They are read in three -letter segments known as codons.

00:23 So i'm just going to do a segment of a simple strand here, and i am going to...

00:36 Make all three letters in each of these four codons the same letter, because this is going to make it easier for us to see why the answer is the answer.

00:48 Okay, so when we have a sequence, so this is a four codon sequence, i have four groups of three, if we simply substitute in a wrong letter.

01:03 So maybe that a becomes a t there, right, wrote it in blue.

01:07 Well, that affects that one amino acid possibly.

01:12 It depends because most amino acids have more than one set of codes, that code for them.

01:18 But it doesn't affect the rest of the sequence just by a substitution.

01:28 Similarly, a silent mutation.

01:31 So a silent mutation doesn't cause an outward change.

01:35 But what would cause a change, let's say, we have a base pair insertion or a deletion.

01:44 Let me just go with a deletion here.

01:46 Let's take out this a.

01:49 This a is lost.

01:51 Well, remember, these are going to be read in three -letter sequences...