Part I
Original DNA Strand:
3’-TACCCTTTAGTAGCCACT-5’
Transcription (base sequence of RNA):
5’-UTGGGUUUTCUTCGGTGU-3’
Translation (amino acid sequence):
3’-TACCCTTTAGTAGCCACT-5’
What is the significance of the first and last codons?
Explanation: The first and last codons are very essential in that they dictate and command the direction of the transcription and synthesis of mRNA from the 5’ end towards the 3’ ends. Additionally, the first and last codons act like terminal points where protein synthesis begins and where it actually ends hence these codons actually determine the size of the animo acids produced which determine the type of and size of protein synthesized (Hartl, 2011).
What meaning do these codons have for protein synthesis?
Explanation: These codons are very essential in protein synthesis since they determine and direct the ribosomes on which points to start and which points to stop the process of protein synthesis which is very essential in determining the size of protein produced and synthesized (Krebs et al., 2010).
Mutation Transcriptions
Original sequence:
3’- TACCCTTTAGTAGCCACT-5’
Transcribe the Mutations of RNA:
3’-TACGCTTTAGTAGCCATT-5'
3’-TAACCTTTACTAGGCACT-5’.
Transcriptions of Mutations:
5’-UTGCGUUUTCUTCGGTUU-3’
5’-UTTGGUUUTGUTCCGTGU-3’
Does the protein sequence change for either of these?
Response: Yes
Explain why a change in amino acid sequence might affect protein function.
Explanation: A change in amino acid sequence might affect protein function because each protein actually is defined by a specific arrangement or sequence of amino acids aligned in a specific manner. Therefore, alteration of this sequence really by a mutation means that the protein produced will not actually be the one intended hence altering the functions of that protein. For example, a mutation in the gene cystic fibrosis transmenbrane conductance regulator (CFTR) caused by a removal of three genes is responsible for the alteration of membrane proteins in the secretory glands responsible to regulate and control the occurrence of the disease (Strachan & Read, 2004).
GRAPHIC ORGANIZER
Part II
Punnett Square
a. Chances (%) for healthy child
b. Chances (%) for child that is carrier for cystic fibrosis trait
c. Chances (%) for child with cystic fibrosis
a. Chances (%) for healthy child:
1
=
×100%
4
=25%
b. Chances (%) for child that is carrier for cystic fibrosis trait:
2
=
× 100%
4
= 50%.
c. % for child with cystic fibrosis:
1
=
× 100%
4
=25%
Part III
How do both meiosis and sexual reproduction (fertilization) produce offspring that differ genetically from the parents?
Include steps in meiosis that increase variability. Include the process of fertilization.
Explanation: To begin with, meiosis can be defined as the process whereby cells in the gonads divide to produce gamete cells in animals that is, sperms in males and eggs in females. The process of meiosis occurs in two steps; meiosis Ι and meiosis ΙΙ which eventually leads to the production of four cells having 23 chromosomes each. During anaphase Ι of the first meiotic division, there is crossing over of the genetic material when the homologous chromosomes separate, these actually leads to the genetic variability in the offsprings produced since each haploid cell will contain genetic material from both parents (Yeargers, Shonkwiler & Herod, 1996). On the other hand, fertilization is described as the fusion of the two gametic cells, an egg from the mother and a sperm from the father resulting to formation of a zygote. Therefore, a zygote contains a combination of different chromosomes containing different genes from both the parents which actually produces variability. Additionally, it is very significant to note that every individual has really numerous genes on the 46 chromosomes; therefore two parents can actually produce very many varied genetic combinations (Minkoff, 2008).
References
Minkoff, E. C. (2008). Biology. New York, NY: Barron’s Educational Series, Inc. Retrieved on 19 January, 2011. From <http://books.google.co.ke/books?id=sUbctGQE_HYC&printsec=copyright#v=onepage&q&f=false>
Yeargers, E. K., Shonkwiler, R. W., & Herod, J. V. (1996). An Introduction to the Mathematics of Biology: With Computer Algebra Models. Cambridge: Birkhauser Boston. Retrieved on 19 January, 2011. From <http://books.google.co.ke/books?id=HrpWwTbJV_sC&printsec=copyright#v=onepage&q&f=false>
Hartl, D. L. (2011). Essential Genetics: A Genomics Perspective. London: Jones and Bartlett Publishers. Retrieved on 19 January, 2011. From <http://books.google.co.ke/books?id=bhFubwD1JlkC&printsec=copyright#v=onepage&q&f=false>
Strachan, T., & Read, A. P. (2004). Human Molecular Genetics. New Delhi, ND: Garland Publishing. Retrieved on 19 January, 2011. From <http://books.google.co.ke/books?id=8U0VAAAAIAAJ&printsec=copyright#v=onepage&q&f=false>
Krebs, J. E., et al. (2010). Lewin’s Essential Genes. Mississauga, Ontario: Jones and Bartlett Publishers. Retrieved on 19 January, 2011. From <http://books.google.co.ke/books?id=kEtMNqEu7MYC&printsec=copyright#v=onepage&q&f=false>.
