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Lecture

ANT203 October 4.pdf


Department
Anthropology
Course Code
ANT203Y1
Professor
Xueda Song

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LECTURE 3: THE BIOLOGICAL BASIS OF LIFE AND HEREDITY
the cell, identified by Robert Hooke (1665) as cellula, is the basic unit of life
eukaryote: an organism consisting of a cell or cells in which the genetic material is
DNA in the form of chromosomes contained within a distinct nucleus
structure of eukaryotic cells: cytoskeleton, nucleus, cell membrane, mitochondria,
ribosomes, and cytoplasm
there are somatic cells and gametes
Neoxyribonucleic acid - the Universal Code
protein synthesis
base pairs: A-T, G-C
nucleotides
double helix
Protein Synthesis
proteins have various applications:
structure (ex. collagen)
regulation of chemical reactions (ex. enzymes)
affecting tissues and organs (ex. hormones)
regulation of DNA
amino acids are determined by a sequence of three DNA bases: a triplet
transcription - the first step is to copy the DNA message into a form of RNA called
messenger RNA (mRNA)
translation: turns mRNA into tRN, with the mRNA triplets, or codons, still
specifying one amino acid
Genes are sequences of DNA bases that specify the order of amino acids for a protein, part
of a protein, or another functional product
2% protein coding genes
2% regulatory genes
96% non-coding (doesn't code for a specific protein; formerly known as "junk"
DNA as its function is unclear - but it does fall under selective pressure so it may
have a role in evolution)
mutations can be responses to environmental changes or genetic errors; they are
either beneficial, neutral, or deletarious
they are a source for variation in populations, but they must be inherited and
become common in order for change to occur
point mutation: a change in one of the four DNA bases
Chromosomes are composed of DNA and protein
the number of chromosomes in cells is species specific: humans have 46 (23 pairs)
there are two types of chromosomes - autosomes (physical characteristics other than
sex determination) and sex chromosomes (determine maleness or femaleness)
locus: where a gene is found on a chromosome; alleles are always found in the
same locus in paired (homologous) chromosomes
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