genetics and heredity. genetics and traits genetics: the study of how certain features are passed...
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Genetics and Heredity
Genetics and traits
• Genetics: the study of how certain features are passed from parents to their offspring
• Trait: a distinguishing quality that all members of a species have in common (eyes, chin, etc.)
• Variations: Different forms of the same trait (blue/brown/or green eyes, cleft chin)
Traits• Heredity: the passing of traits from
parents to offspring.• Heredity plus your environment will
work together to influence who you will become–“Nature Vs. Nurture
• Which do you think bear a greater impact on your development?
Reproduction and Heredity• Four basic methods of asexual reproduction:–1.Rooting: a cutting is taken from a mature
plant and rooted to create a new plant (often used to get desirable traits in agriculture)–2.Spores: like seeds can grow into new
organisms–3.Budding: small bud forms on the parent and
breaks off to form a new organism’–4.Fission: (most common) dna is copied, cell
divides, new cell membrane encases new daughter cells
Sexual Reproduction• Requires male and female cells (sperm and
egg) called gametes.• Does asexual or sexual reproduction generate
greater variety?• Sexual reproduction creates greater variety
due to a greater variety of trait possibilities.• Traits are passed from parent to offspring in
the form of genes• Genes: small segment of DNA that carries
hereditary info.
Genes
• Genes have all info needed to build, maintain, and reproduce an organism.
• Genes link together to form chromosomes• Organisms’ cells can read the codes in
chromosomes just like we read a book
Genetic Code
Genetic Code/Traits
• Some genes determine on trait:–Straight hairline or widow’s peak–Earlobes are attached or free
Heredity Recessive trait
Dominant trait
This woman’s genotype
This woman’s genotype
homozygousheterozygous
DNA
• http://www.youtube.com/watch?v=8kK2zwjRV0M
• DNA is a molecule shaped like a twisted ladder called a double helix• Sugar and phosphate make the
support/legs of the ladder• Nitrogen bases such as adenine (A),
thymine (T), guanine (G), and cytosine (C) are paired together to make the “rungs” of the ladder
• Nucleotide: the “rungs,” or the combination of bases• Certain nitrogen bases always pair
up:–A-> T–C->G
• Replication: The DNA strand unwinds, unzips, new nucleotides pair up with existing, exposed nitrogen bases and new sugar/phosphate support is produced.
Mutations
• Mutations are “errors” in genetic code• Seedless grapes are an example. • Mutation: a change in the sequence
of one or more nucleotides in a DNA molecule
• Substitution: Sickle Cell Anemia
• Insertion: Huntington’s disease
• Deletion: Cystic Fibrosis
• Inversion: Hemophilia
Mutations Cont• Some mutations do not effects the organism• Some affect appearance and health, some only one
of these• Some mutations are caused by a mistake in DNA
replication and take years to develop.• Some are uncontrollable, others are not• Mutagen is a physical or chemical agent that
causes mutations to occur• Radiation, smoke, chemicals, pesticides, drugs, x-
rays, ultraviolet light, radiation.
Chernobyl
• http://www.youtube.com/watch?v=IEmms6vn-p8