Heredity and environment

Genetics and Prenatal Development • The Beginning of Life • Conception The Human Cell • The human body is comprised of over 200 different kinds of cells which are the smallest selfcontained structures – Cell membrane: the outside layer of the cell – Cytoplasm: is comprised of specialized structures – Mitochondria: are the powerhouses that process nutrients and provide the cell’s energy – Endoplasmic reticulum, Golgi apparatus, and ribosomes: produce proteins – Neucleus: The inner part of the cell The Nucleus • Chromosomes • Genes • Deoxyribonucleic acid (DNA) Chromosomes • Rod shaped structures found in the center of the nucleus of every cell in the body • Each sperm and each ovum contains 23 chromosomes • The chromosomes contain the DNA and genes • The fertilized egg (zygote) and all the body cells that develop from it (except the sperm cells and the ova) contain 46 chromosomes 10 75 Genetic Engineering • Alteration of Human Genes • 1- Gene Therapy • 2- Germ-line Genetic Alterations Germ-line Genetic Intervention • 3- Genetic Enhancement 76 1- Gene Therapy • Genetic alteration of somatic cells to treat disease • Researchers inject genes that are targeted to treat a particular disease in to a patient’s blood stream • When the genes arrive at the site of the defective genes, they produce chemicals that can treat the problem 77 2-Germ-line Genetic Alteration • Can correct problems for unborn individuals and future generations • It targets the genes in the reproductive cells – the egg and the sperm that combine the DNA to conceive a new human • Scientist might detect defective cells soon after conception, removing them from the mother and placing them in a test-tube culture • Gene therapy could be employed to correct the defects in the cells • The result could be cloning Parents could some day customize their children 78 3-Genetic Enhancement • Non therapeutic genetic alteration • An attempt to enhance an already healthy genetic makeup by inserting a gene for improvement (e.g height, intelligence, eye color) 79 What Do You Think? Genetic Engineering Gene Therapy Germ-Line Genetic Alterations Genetic enhancement 80 Cloning • Producing genetic replicas of the organism 81 Stop and Discuss • In the light of scriptural truth, how ethical are these issues? • 1-Amniocentesis • 2-Chronic villus sampling • 3-Gene therapy • 4-Germ-line genetic alteration • 5-Genetic enhancement 82 Stages of Prenatal Period 1- Germinal Stage (fertilization to weeks) Blastocyst Cell Division Specialized Cells 83 2- Embryonic Stage (2 weeks to weeks) • 1-Ectoderm (outer layer) Skin, teeth, hair, sense organs, brain, spinal cord • 2-Endoderm (inner layer) Digestive system, pancreas, respiratory system • 3-Mesoderm (in between both) Muscles, bones, blood, circulatory system 84 3- Fetal Stage (8 weeks to birth) Fetus Increases in size Proportions similar to adults 85 86 Environmental Influences 1- Habituation 2- Classical Conditioning 3- Operant Conditioning 4- Social Learning 87 Sociocultural Influences Paul Blates (87, 88) • Normative Age-Graded Influence The biological and social changes (e.g aging, entering school, marriage) • Normative History-Graded Influence Historical events (e.g wars, depression) • Nonnormative Influences Individual environmental factors (e.g divorce, unemployment) 88 Prenatal Care • • • • • • • Diet The father’s involvement Age of mother Illness of mother Drug use Alcohol Teratogens 89 [...]... undesirable ? What about employers not hiring people with bad genomes and insurance companies refusing to insure them? 29 Cell Division and Reproduction When the cell is ready to divide and reproduce: the DNA staircase unwinds and the two long chains separate each chain attracts new biochemical material from the cell to synthesize a new and complementary chain Ultimately a new cell is formed 30 Terms •... Proteins are molecules that perform an array of crucial functions in the human body: Enzymes: break down and altar biochemicals Hemoglobin: binds with oxygen allowing it to be transported to cells throughout the body Collagen: in bones and connective tissues Hormones: regulate physical growth 20 Genes and Protein Synthesis • A nuclear enzyme attaches to a segment of DNA causing nucleotide bonds to separate... species All organisms use just these 4 bases, but with different numbers and arrangements 15 DNA There are 3.12 billion base pairs in human DNA The DNA in each normal human being is about 99.9% the same as every other normal human being Only 1% accounts for the biological contribution to all our individual differences in physical and psychological characteristics 16 DNA Single Nucleotide Polymorphisms... of the genome in making and maintaining a living human being are fully understood 27 Scientific Breakthroughs Greater insights into disease will be achieved Cures may be found Incurable diseases may be prevented There will be new insights into the evolutionary origins of humans 28 Controversial Issues Will it be ethical for parents to have their children screened prior to birth and decide not to have... They determine the nature of each cell in the body and how it will function • At each level of the spiral or rungs of the ladder are particular chemical pairs The arrangement of these pairs along the DNA molecule determines which kind of proteins will be formed in the cell 18 Genes • The basic unit of genetic information • They determine the nature and the function of the cell • The human genes (about... chromosome • Haploid gametes: Gametes having 1 copy of each chromosome 31 Meiosis • Meiosis takes place in the testicles and ovaries • A diploid cell (having 2 copies of each chromosome) undergoes a special form of cell division to create haploid gametes (having 1 copy of each chromosome) • An egg and a sperm fuse together to form a new diploid cell called zygote (a process called fertilization) 32 33 Mitosis...Chromosomes • 22 of the pairs are called autosomes and are numbered from largest to smallest • The autosomes are not involved in determining sex • The 23rd pair are the sex chromosomes: – XX in females – XY in males 11 Karyotype A photograph of a cell’s... copies, the cell briefly has 4 copies of each chromosome • Shortly afterwards, the cell divides in half, resulting in two cells each has a complete copy of the genetic information • These cells grow larger and eventually undergo mitosis 34 35 36 ... sperm and each ovum contains 23 chromosomes • The chromosomes contain the DNA and genes • The fertilized egg (zygote) and all the body cells that develop from it (except the sperm cells and the... companies refusing to insure them? 29 Cell Division and Reproduction When the cell is ready to divide and reproduce: the DNA staircase unwinds and the two long chains separate each chain attracts... • These cells grow larger and eventually undergo mitosis 34 35 36 • Mitosis: each cell divides and duplicates itself exactly • Meiosis: How reproductive cells (ova and sperm) are produced • Results