Concept 13.1 Lecture Outline

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Concept 13.1 Lecture Outline

Parents endow their offspring with coded

information in the form of genes.

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Your genome is made up of the genes that

you inherited from your mother and your father.

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Genes program specific traits that emerge

as we develop from fertilized eggs into adults.

·

Genes are segments of DNA. Genetic

information is transmitted as specific sequences of the four

deoxyribonucleotides in DNA.

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This process is analogous to the symbolic

information of language, in which words and sentences are translated into

mental images.

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Cells translate genetic “sentences” into

freckles and other features that have no resemblance to genes.

·

Most genes program cells to synthesize

specific enzymes and other proteins whose cumulative action produces an

organism’s inherited traits.

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The transmission of hereditary traits has

its molecular basis in the precise replication of DNA.

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The replication of DNA produces copies of

genes that can be passed from parents to offspring.

·

In plants and animals, reproductive cells

called gametes transmit genes from

one generation to the next.

·

After fertilization (fusion of a sperm

cell and an ovum), genes from both parents are present in the nucleus of the

fertilized egg, or zygote.

·

Almost all the DNA in a eukaryotic cell

is subdivided into chromosomes in the nucleus.

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Tiny amounts of DNA are also found in the

mitochondria and chloroplasts.

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Every living species has a characteristic

number of chromosomes.

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Humans have 46 chromosomes in their somatic cells – cells other than the

gametes and their precursors.

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Each chromosome consists of a single DNA

molecule associated with various proteins.

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Each chromosome has hundreds or thousands

of genes, each at a specific location, or locus,

along the length of the chromosome.