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Published byNigel Lawson Modified over 9 years ago
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WHAT CREATED YOU AT THE VERY BEGINNING? Heredity & Environment
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What are genes? DNA (deoxyribonucleic acid) The basis of heredity Humans = 46 (23 pairs) of chromosomes Chromosome Molecule of DNA Make up chromosomes Genes = Section of chromosomes Allele = Slight normal variation in a gene DNA Genes Chromosomes In cell nucleus
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What is the code for making an individual? Genome = The full set of genes for a specific organism (entire genetic inheritance) 20,000 genes (99% in other creatures also) Phenotype What you look like based on your genes Appearance, personality, intelligence Genotype = Hidden in your genes (e.g. Cancer) Phenotype = Observable characteristics based on genes – E.g. brown eyes
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Do you remember? You have how many pairs of chromosomes? Your chromosomes are made up of what type of molecule? What is the genome for a human? What is the difference between your genotype and phenotype?
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How does life begin?
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What are gamete? Sperm Ovum (egg) Each has 23 chromosomes (one half of 46)
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What happens after fertilization? A zygote develops Single cell from two gametes The first stage of development after fertilization of the egg (ovum).
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Male or female? 23 rd pair of chromosomes Female = XX Male = XY
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What creates twins? Monozygotic (identical) twins From one zygote (One egg & sperm) Share 100% genes Dizygotic (fraternal) twins Two sperm penetrating two ova Share 50% of their genes
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Do you remember? After an egg is fertilized, it is called what? The 23 rd. Pair of chromosomes in women are: The 23 rd. Pair of chromosomes in men are: What is the monozygotic and dizygotic twins?
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How can we help fertilization occur? ART = Assisted Reproduction Technology IVF = In Vitro Fertilization Sperm mixed with ova in glass dish Viable embryos implanted ICSI (Intracytoplasmic sperm injection) Intrafallopian sperm injection
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From one cell to many:
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How do genes affect appearance and behavior? Genes + Environment = Phenotype (Appearance & behavior) E.g. Alcoholism Genes(Varies in intensity) + Environment (Encourages or discourages drinking) = Result Large breasts and shyness
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If something is epigenetic, what is it? Characteristics that are determined by both genes and environment E.g. height and nutrition
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Additive heredity Some alleles (gene variations) combine to affect appearance and behavior
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Are some genes more powerful than others? Dominant – recessive heredity Dominate genes are more influential than recessive genes. E.g. Brown eyes (Mother-dominate) + Blue eyes (Father-recessive) = Brown eyed child Being a carrier for blue eyes can effect this
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What can cause genetic abnormalities? Most often related to age of mother E.g.: Extra chromosome E.g. Down Syndrome = 47 chromosomes
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Abnormalities of the 23 rd. Pair Humans have 44 chromosomes + one X + an “X” or ”Y” Embryos do not develop without one X Missing chromosome E.g. XO = Turner’s syndrome (looks female) Three sex chromosomes XXY = Klienfelters Syndrome (Looks male) XYY = “XYY” Syndrome (looks male) Appear normal until puberty
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What is the effect of genetic counseling? Find harmful conditions Affect insurance coverage Jeopardize the marriage
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Do you remember? What are some methods of assisted reproduction? How do genes and the environment interact? How do dominate and recessive genes control who you became? What is the most common cause of genetic abnormalities? What are some abnormalities of the sex chromosomes? What are some of the positive and negative effects of genetic counseling?
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