Monthly Archives: June 2014

Mendel’s Peas

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Learning Intention: Students will understand the significance of Gregor Mendel in the history of genetics and be able to use the following terms correctly: dominant, recessive, alleles, genotype, phenotype, homozygous, heterozygous, cross-pollination, self-pollination and F1 generation.

Success Criteria: Students will complete the following three activities and be able to describe what they have learned in a class discussion.

Gregor Mendel (1822-1884) was an Austrian monk who is known as the father of modern genetics due to his experimental work with plant hybridization. It was Mendel who first coined the terms “dominant” and “recessive” and he formulated generalizations that have become known as “Mendel’s Laws of Inheritance”. “Mendel’s Pea Genetics – Experiments that changed the world” is a twenty-five minute documentary that describes his life. Complete the following three activities:

 

DNA makes RNA makes Proteins

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DNAreplication

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If DNA is the ‘blueprint’ of a living organism, RNA is a photo-copy of the blueprint (a working plan, if you like) and amino acids and proteins are the building materials. The human genome contains around 30 000 genes, each of which codes for one protein. There are three main processes in turning DNA into proteins – Replication of the DNA, Transcription (DNA to RNA)  and Translation (RNA to proteins). Read about Replication, Transcription and Translation at atdbio. DNA is replicated in the nucleus, prior to mitosis and meiosis. DNA in the nucleus of all eukaryotic cells must then be ‘transcribed’, forming a complementary RNA strand that travels out of the nucleus, into the cytoplasm. From the single strand of messenger RNA, a ribosome ‘reads’ the triple codon and ‘chooses’ a specific amino acid that corresponds with the triplet code. Transfer RNA carries amino acids to the ribosome and serves as the link between the RNA molecule and the forming polypeptide.

DNAreptran

 

Introduction to Genetics

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genetics_Tagxedo

In this class you are going to create your own word cloud and mind map to show me what you already know about genetics. Go to the google doc at http://moourl.com/biology and add at least ten words that come to mind when you think of ‘genetics’. Copy and paste all the terms into Tagxedo and customise your word cloud. Download a copy and send it to me. Now you have two choices:

  1. Go to Bubbl.us and create a mindmap using the key terms from Chapter 9. Download and send a copy.
  2. Go to Quizlet and create a set of flashcards using the terms and definitions from Chapter 9. Send me a link to your work. The Quizlet below was created by Mr Flattery and can be used and adapted.

Week 8: Unit 4: Continuity and Change

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Sky_spectral_karyotype

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Area of Study 1: Heredity

This area of study focuses on molecular genetics and the investigation not only of individual units of inheritance, but also of the genomes of individuals and species. Students investigate inheritance in asexually reproducing organisms and the mechanism and patterns of transmission of heritable traits in sexually reproducing organisms.

Students examine the process of meiosis in terms of inputs and outputs and, in accounting for variations in offspring, consider the interplay between genotype and environmental factors, the significance of mutations in DNA, and the relationship between alleles.

All prokaryotes reproduce asexually, without the formation and fusion of gametes. Many plants and fungi also reproduce asexually, meaning that they are genetically identical to their parent. Types of asexual reproduction include:

  • Binary fission (bacteria)
  • Budding (yeast)
  • Vegetative reproduction (strawberry runners, aloe)
  • Sporulation (fungi, algae, ferns)
  • Fragmentation (annelids, sea-stars)
  • Parthenogenesis (some lizards, sharks and stick-insects)

This week we will begin to study molecular genetics – the foundations of ‘who we are’, before environmental factors play a role. Half your DNA comes from your mother (eggs produced in the ovaries) and half from your father (sperm produced in the testes). This DNA contains genes and genes code for proteins, so the gametes (eggs and sperm) contain the genetic instructions that cross the generation gap, giving you the characteristics that you share with your biological parents.  The genetic instructions in an organism make up it’s genotype, which is expressed visually as the phenotype (physical, biochemical and physiological traits).

Humans have 23 pairs of chromosomes, often referred to as the diploid number or 2n=46. The image above is called a karyotype, used to assist with chromosomal analysis – is this one from a male or female? Chromosomes can be distinguished by their relative size, position of the centromere and the patterns of light an dark bands. Matching pairs are said to be homologous. A human male has non-homologous sex chromosomes (XY).

More Resources for this Unit: