BIOLOGY

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1. First watch the video below on Mendelian genetics and monohybrid crosses.

This week you are to discuss the experiments conducted by Mendel and discuss the role of transcription and translation from the Central Dogma of Biology that connects “genotype” to “phenotype.”

(1) Provide a general overview of Mendel’s experiment.

(2) What was the organism that Mendel studied (provide the genus and species name as well as the common name)?

(3) Why was this organism ideal to study the law of independent assortment?

(4) List one dominant and one recessive example for a phenotype that Mendel found and describe the phenotypic ratio expected to result from crossing two parents heterozygous for only that trait.

(5) In simple terms discuss gene transcription and translation. What type of molecule results from translation? How do gene transcription and translation lead to a specific phenotype? Most importantly for this question: what does transcription and translation have to do with the inheritance of Mendelian traits? 

2. Why Bees are Disappearing, by Marla Spivac ( watch and comment

3. (2) Photosynthesis – Mr Anderson’s lecture ( Watch and comment)

4. How important is the protein called ATP synthase in this process?

5. Which ingredients are needed for photosynthesis and why?

6. Respond to the following post below with references.

(a) Provide a general overview of Mendel’s experiment. 

Mendel’s experiment was to understand genetic inheritance. When Mendel first began his work with pea plants, the scientific concept of heredity was rooted in the concept of blended inheritance, which held that parental traits were somehow mixed into offspring in the manner of different-colored plants, producing a result that was not quite the mother and not quite the father every time, but that clearly resembled both. Mendel was not interested in the appearance of his pea plants per se. He examined them in order to understand which characteristics could be passed on to future generations and exactly how this occurred at a functional level, even if he didn’t have the literal tools to see what was occurring at the molecular level. 

Mendel’s experiment consisted of cross breading 2 types of Pisum sativum (peas). The primary purpose of using this pea was due to the ability to self-fertilize and the ease of cross breading. He specifically was concentrated on the cross breeding of seven different features of the peas such as height, flower color, seed color and seed shape.

Mendel studied inheritance in peas (Pisum sativum). He chose peas because they had been used for similar studies, are easy to grow and can be sown each year. Pea flowers contain both male and female parts, called stamen and stigma, and usually self-pollinate. Self-pollination happens before the flowers open, so progeny are produced from a single plant.

Peas can also be cross-pollinated by hand, simply by opening the flower buds to remove their pollen-producing stamen (and prevent self-pollination) and dusting pollen from one plant onto the stigma of another. Mendel crossed pure lines of pea plant. 

(2) What was the organism that Mendel studied (provide the genus and species name as well as the common name)?                                                                Mendel studied Pisum sativum (peas) 

(3) Why was this organism ideal to study the law of independent assortment?

Peas were ideal to study the law of independent assortment because dominant traits appear in the first generation and recessive traits appear in the second generation. The inheritance of one trait does not depend on the inheritance of any other trait.

4). List one dominant and one recessive example for a phenotype that Mendel found and describe the phenotypic ratio expected to result from crossing two parents heterozygous for only that trait.

One dominant example for a phenotype that Mendel found is the purple pea plant’s flower which is the parental variety that is SEEN in F1 progeny or F1 generation, one recessive example for a phenotype that Mendel found is the white pea plant’s flower which is the parental variety that’s HIDDEN or ABSENT in the F1 progeny. Heterozygous means that there are different alleles. given that the purple pea plant flower is the dominant allele (P) and the white pea plant flower is the recessive allele (p), a heterozygous plant will have Pp alleles. A cross between two heterozygous parents would result in a phenotypic ratio of 3 dominant : 1 recessive, which means 3 purple pea plant flowers and 1 white pea plant flower using the Punnett square. In summary dominant traits, like purple flower color, appeared in the first-generation hybrids (F1), whereas recessive traits, like white flower color, were masked. However, recessive traits reappeared in second-generation (F2) pea plants in a ratio of 3:1 (dominant to recessive).

5) In simple terms discuss gene transcription and translation. What type of molecule results from translation? How do gene transcription and translation lead to a specific phenotype? Most importantly for this question: what does transcription and translation have to do with the inheritance of Mendelian traits?

Gene transcription is the first step in gene expression. It involves copying a gene’s DNA sequence to make an RNA molecule.

Transcription is performed by enzymes called RNA polymerases, which link nucleotides to form an RNA strand (using a DNA strand as a template). The goal of transcription is to make a RNA copy of a gene’s DNA sequence. Transcription has three stages: initiation, elongation, and termination. 

Gene translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process transcription of DNA to RNA in the cell’s nucleus 

The molecule that results from translation is protein –translation produces short sequences of amino acids called peptides that get stitched together and become proteins.                      

Gene transcription and translation leads to a specific phenotype by which the RNA copies the genetic sequence of a DNA strand which translates to produce amino acids. The RNA polymerase enzyme copies gene-encoded information noting the nature and composition of genes in the DNA strand. If a dominant gene is copied, this will be carried to the translation phase and the resulting proteins produced will be a dominant phenotype. Transcription, and Translation are the three main processes used by all cells to maintain their genetic information and to convert the genetic information encoded in DNA into gene products, which are either RNAs or proteins, depending on the gene.

In eukaryotic cells, or those cells that have a nucleus, transcription take place within the nucleus while translation takes place outside of the nucleus in cytoplasm. In prokaryotic cells, or those cells that do not have a nucleus, all processes occur in the cytoplasm. 

Respond to the post below with references.

B. Provide a general overview of Mendel’s experiment.

 Mendel’s experiment consisted of cross breading 2 types of Pisum sativum (peas). The primary purpose of using this pea was due to the ability to self-fertilize and the ease of cross breading. He specifically was concentrated on the cross breeding of seven different features of the peas such as height, flower color, seed color and seed shape. (Kahn Academy, n.d)

· What was the organism that Mendel studied (provide the genus and species name as well as the common name)?

 Mendel carried out his key experiments using the garden pea, Pisum sativum, as a model system. Pea plants make a convenient system for studies of inheritance, and they are still studied by some geneticists today. (Kahn Academy, n.d)

· Why was this organism ideal to study the law of independent assortment?

 Peas were ideal to study the law of independent assortment because dominant traits appear in the first generation and recessive traits appear in the second generation. The inheritance of one trait does not depend on the inheritance of any other trait.

· List one dominant and one recessive example for a phenotype that Mendel found and describe the phenotypic ratio expected to result from crossing two parents heterozygous for only that trait. 

Tall plants were dominant, and the short plants were recessive. (Science Learning Hub – Pokapū Akoranga Pūtaiao, 2011) With the change, he noted three were dominate and one showed the recessive gene (3:1).

· In simple terms discuss gene transcription and translation. What type of molecule results from translation? How do gene transcription and translation lead to a specific phenotype? 

 Gene transcription and translation is the process of building and converting genetic information into proteins. Transcription is the non-coding strand of DNA acts like a template for the matching RNA polymerase. Translation is in which the mRNA directs the protein synthesis.