Notes
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.
·
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.
·
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.
·
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.
·
Each chromosome consists of a single DNA
molecule associated with various proteins.
·
Each chromosome has hundreds or thousands
of genes, each at a specific location, or locus,
along the length of the chromosome.