Answer:
22. GCGCAAU
23. 20%
25. 1. AABB , AABb , AaBB , AaBb , AAbb , Aabb , aaBB , aaBb , aabb (see attachment)
2. 4
27. Non- viable e.g. a deletion of a key developmental gene, or no effect, e.g. a base substitution in a non-coding region.
28. Put your gene of interest into a vector, incubate it with competent bacteria that will take the vector into their cells and transcribe and translate the gene into protein.
Step-by-step explanation:
22. In the genetic code, Adenosine (A) is complementary to Thymidine (T), and Guanine (G) is complementary to Cytidine (C). However, in a molecule of RNA, Uracil (U) replaces T. Therefore, the complementary mRNA sequence is to CGCGTTA, is GCGCAAU. If the question had asked for a complementary DNA sequence, the answer would be GCGCAAT.
23. There are two classes of nucleotides that correspond to their structure. The two carbon nitrogen ring nucleotides are purines (adenine and guanine), and the one-carbon nitrogen ring nucleotides are pyrimidines (thymine and cytosine [and uracil]).
In a strand of DNA, the number of purines and pyramidines is equal. (according to Chargaff's rules ). That is, the ratio of A:C and G:T is 1:1. If the DNA contains 30% A, it must also contain 30% C, adding up to 60%. The total must be 100%, leaving 40% for the total of G:T. This ratio should also be 1:1, therefore, there will be 20% G.
25. 1. See the attached punnet square. To do this, you take each parent and list the possible combination of alleles they could pass on. (for AaBb a parent could pass on AB, Ab, aB, or ab). You then draw up the potential genotypes using the punnet square (see attached). There are 9 different genotypes shown in the answer
2. The genotypes we are given for the parents are two heterozygotes for two different genes. The phenotype refers to how these genotypes are expressed. A is dominant, a is recessive, B is dominant, b is recessive. Lets imagine A is the allele for tall, and a is the allele for short. B is the allele for red, and b is the allele for purple. Since A and B are dominant alleles, their presence will give tall and red organisms, respectively. However, organisms could also be tall and purple, short and red, or short and purple, which equates to 4 phenotypes.
27. The organism could be non-viable. This could occur if a crucial gene is affected by a mutation. For example, if a part of the protein coding sequence of a gene encoding early developmental genes such as the Hox genes. While a heterozygote might be unaffected or only mildly affected (one copy of the gene might be sufficient), homozygotes would not be able to develop properly as a fetus, and the mutation would be lethal
The organism could be unaffected. A small base substitution, deletion, or inversion might be inconsequential if it is in a non-important region of the DNA (for example in a non-coding region) or if it affects an unimportant part of the protein (for example if it is not crucial to the enzymes structure or activity).
28. If you know the sequence of the gene, you could excise the sequence from DNA (you can either extract DNA from a healthy person, amplify the region of interest using PCR primers surrounding the gene, or you could order from a company who synthesises stretches of DNA, often called oligos). You would then insert the DNA into a vector that can be delivered into the bacteria (such as a plasmid). This vector will be circular DNA, so to get your gene of interest in, you would have to cut the vector (using restriction enzymes) and paste your DNA of interest in (using a DNA ligase enzyme)
To get the gene and vector into the bacteria, the bacteria need to be made "competent". This means they have to have holes punched in their membrane, which can be done by heat shock". You then incubate your vector + gene with the competent bacteria. The holes in the membrane will allow your vector to enter the cell, where it can be transcribed and translated into the protein by the bacterial transcription and translation machinery.