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Published byEarl Fields Modified over 9 years ago
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1.2 DNA: Your Genetic Code Nitrogenous Base Codon Gene DNA Chromosome Your future is in your “genes”
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Chromosomes & DNA the nucleus of almost every cell contains chromosomes chromosomes act like a master set of instructions that determine: what each cell’s job is how it will function how long it will live before being replaced
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chromosomes come in pairs every plant or animal species that reproduce sexually get 1 chromosome from their mother, 1 from their father this means you are 50% your mom, 50% your dad depending on the species, there could be just a few pairs of chromosomes or many humans have 23 pairs (46 chromosomes) 22 pairs, 1 pair of sex chromosomes everyone’s chromosomes are a little different, which is why we are all different (except identical twins) chromosomes are composed of coiled strands of genetic information called DNA
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How many chromosomes? Take a look at the difference in # of chromosome pairs: human 23 pairs (46 chromosomes) butterfly 190 pairs (380 chromosomes) elephant 28 pairs (56 chromosomes) ant 1 pair + (2+ chromosomes) tomato plant 12 pairs (24 chromosomes) shark 41 pairs (82 chromosomes) mosquito 3 pairs (6 chromosomes)
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Chromosomes of a Human Male Karyotype
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The genetic material that acts like a master set of instructions for the organism Coiled up strands of genetic information that make up a chromosome Is divided into many genes that control protein production DNA (deoxyribonucleic acid) gene = part of a DNA strand
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DNA Made of nitrogen bases, ribose sugars, and phosphate backbones these 3 parts all together are called a nucleotide There are 4 nitrogen bases: adenine thymine cytosine guanine
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2 nitrogen bases always pair up: adenine + thymine cytosine + guanine think AT the Golf Course it’s in the gene sequence that we get differences among individuals hair colour, how tall you are, what allergies you have, how quickly your fingernails grow, etc.
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Codons: 3-letter words the genetic code is like a book that only has words that are 3 letters long the letters are nitrogen bases (nucleotides) codons are 3-letter words that code for a certain protein to be made ex: CAT, GAG, TAG, … the sequence of codons decides which protein is produced if there’s a mistake in the sequencing of a codon, we get what we know as a mutation ex: CAT, GCG, TAG, …
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Comparing Genetic Information to a Book Book component Biological equivalent Letters Words Sentences Paragraph Chapters Book Nucleotides (nitrogen bases) Codons Genes DNA Chromosomes Organism (human, butterfly, ant)
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