BIOL10005 Lecture Notes - Lecture 1: Cytosine, Methylation, Thymine

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rubyswan228

9 Aug 2018

School

University of Melbourne

Department

Biology

Course

BIOL10005

Professor

Dawn Gleeson

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Document Summary

Genetics: study of variation b/w and among living things. Half from male parent and half from female parent (haploid) Phenotype: morphological, biochemical and behavioural properties of an organism resulting from a specific genotype and its interaction with environment. Genome: total amount of genetic material in a chromosome set (in humans or a diploid organism - one set of chromosomes) Sequencing a genome: working out the base sequence (adenine, thymine, cytosine, and guanine) of the dna. Humans have 2 genomes - nuclear genome and mitochondrial genome. Environmental factors (eg. alcohol during pregnancy -> fasd) Combination of genetic and environmental factors (most common) (eg. person inherits tendency to be tall, but poor diet during childhood causes poor growth) (eg. twins are genetically identical, but environment causes differences) Mother drinking alcohol during pregnancy -> deformed babies fasd. Huntington disease: change in dna on chromosome #4 (entirely genetic onset) Humans have 2 copies of huntington protein gene.

Related Questions

Ploidy refers to the number of complete sets of chromosomes (genes) present in a cell. The number of chromosomes in a complete set is a fixed characteristic of a species. Humans are diploid with two sets of 23 chromosomes. Fruit flies are diploid with two sets of 4 chromosomes. Sexually reproducing organisms are diploid, each somatic cell of an organism has two complete sets ("di" is a prefix indicating 2.). To complete a life cycle and reproduce new members of a species, mating is required. Mating brings a donation from a male and a donation from a female together. However, if the male and female cells remain diploid, the fertilization will result in a tetraploid zygote. In general, these are not viable. A mechanism is needed to form special haploid cells, gametes. The diploid set is split precisely into two complete haploid sets. That mechanism is meiosis.

The complete set of chromosomes of a species is also the complete set of genes of a species, the genome. (Yes, there is a minor contribution from mitochondria and chloroplasts. Inheritance of this information is "cytoplasmic".)

Please answer the following questions:

1. How many chromosomes in a brain cell of a fruit fly? How many chromosomes are in a liver cell of a human? Explain both answers.

2. How many chromosomes are in a fruit fly unfertilized egg? How many chromosomes are in a human egg? Explain both answers.

3. Why is meiosis necessary for sexually reproducing organisms? How many chromosomes are in a human zygote? Relate the two answers.

4. What is a gene allele? Suppose there is a gene called "bingo" and it is present once in a complete haploid set. How many alleles of "bingo" does a diploid individual have? How many copies or versions of the gene "bingo" are present in a diploid individual?

5. Modern DNA sequencing clearly identifies alleles by showing the different DNA sequence of each allele. These alleles may be termed structural alleles (I coined the term for this problem.). Classical genetics only dealt with phenotypes or visible traits. As a result, alleles of genes were identified by functionality, usually normal or non-functional. Using your knowledge of gene structure and gene expression, postulate a relationship between structural alleles and functional alleles. (include relative amounts; more, less, or equal).

BIOL10005 Lecture Notes - Lecture 1: Cytosine, Methylation, Thymine

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