Chapter 2 Notes
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This 4 page Class Notes was uploaded by Anna Dosso on Tuesday September 15, 2015. The Class Notes belongs to HDFS 230 at a university taught by Candace Philbrick in Summer 2015. Since its upload, it has received 52 views.
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Date Created: 09/15/15
Chapter 2 Notes 0 Beginning of life 0 Zygote The product of the combined nuclei of the ovum and sperm which contains parent genes DNA deoxyribonucleic acid is made up of genes Each molecule of DNA is known as a chromosome Every cell except one has copies of that individuals 46 chromosomes divided into 23 pairs 0 Except the Gamete which is the reproductive cell It has only 23 chromosomes half of each pair At conception half of the males chromosomes in his gamete match up with the females chromosomes to create a full set of chromosomes for their offspring 0 Amino Acids DNA can be coded by dividing into sets of three Each triplet codes for one of 20 amino acids These amino acids combine to make proteins 0 Errors in code 0 Transpositions o Deletions o Repetitions o Mutations Variations that occur with these genes are known as alleles 0 Ex In order to have different colored eyes there must be different alleles for each color 0 Multiple alleles is known as Polymorphic Each single allele is known as a singlenucleotide polymorphis SNP Genotype is the collection of genes for each person Phenotype is the physical expression that a genotype shows 0 Genome It39s basically a really long string of all the genes in a species The human genome project was completed in 2003 o The human genome consists of approximately 23000 genes 0 With 11 million variations discovered by the HapMap project The primary discovery in determining the genomes of multiple species was how many similarities there were between species 0 Ex Humans and Chimpanzees are 98 the same 0 The 23rd pair of Chromosomes The Sex chromosomes XX Female 0 Only pass on a X XY Male 0 Pass on either a X or a Y which means they are the factor in determining the sex of the offspring In most countries the ratio of malefemale chromosomes slightly favors males 0 Twins Monozygotic one zygote that splits into two or more Identical twins odds of 1250 0 However even though their genotypes are the same their phenotypes may differ Dizygotic two zygotes present during implantation Not identical 0 Also known as fraternal twins much more frequent Additive Genes this is when genes add together make a certain phenotype DominantRecessive Pattern These are the nonadditive genes this is when there is usually a dominant phenotype which has more in uence than the other gene 0 A genotype is expressed like the following with two alleles AA Aa aa 0 The upper case letter is the dominant allele 0 The lower case letter is the recessive allele 0 Carrier when someone inherits a recessive allele but doesn39t show that phenotype expressed as 39Aa39 View table 21 for information regarding xlinked traits Xlinked traits are usually recessive 0 Since females have XX they are less likely to present with an X linked trait since they most likely have one good X o Males however only get one X so if their X is linked with a recessive trait it will be expressed Pregnancy Stages of Life Geminal period 12 weeks 0 Only hrs after conception the zygote duplicates and divides in 2 than 4 than 8 ect o The initial cells are called Stem cells 0 They are directed later to be speci c types of cells during differentiation 0 After a week the placenta outer cells and embryo inner cells form The outer cells take charge of implantation 0 Embryonic period 38 weeks 0 It39s called an embryo now 0 Day 22 is when the neural tube forms which later becomes the brain and spinal cdumn 0 Week 4 is when the head and heart begin to form 0 Week 5 limbs 0 5254 days ngers and toes separate from webbing 0 Fetal period 9 40 weeks 0 Know it39s a fetus instead of an embryo 0 At 3 months the fetus weighs about 3 ounces and is 3 inches long 0 Between the 4th and 6th moth the brain increases to 6x its size Creating up to 12 million brain cells per minute 0 It is brain growth that allows a fetus to reach the age of viability age where a preterm baby can survive Approximately 22 weeks 0 Humans have larger brains proportional to their bodies as compared to other animals 0 At 38 weeks the fetus releases oxytocin which prepares the baby for delivery 0 At birth the baby breathes for the rst time and usually cries o Apgar Scale The assessment at birth that rates babies based on ve vital signs Color heart rate cry muscle tone breathing This was a way to determine if the baby was at risk or not A 7 or higher is considered good Cesarean section csection 0 Delivery through incisions made in the woman39s abdomen 0 Becoming more and more common 0 Could lead to higher rate of obesity 0 Less than 1 of US births are performed at home half of those were unexpected because they occurred so fast 0 In Europe home births are much more common with the Netherlands having 30 of their births at home Doula A woman trained to support laboring women Re ex Involuntary reaction to a stimulus Important re exes o Re exes that maintain oxygen supply 0 Re exes that maintain constant body temperature shiver cry tuck legs in o Re exes that manage feeding Sucking re ex sucking anything that touches their lips Rooting re ex turning their mouths towards stimuli felt on their cheeks Crying when hungry spitting up when full swallowing Couvade The fathers experience of pregnancy and birth Postpartum Depression 815 of women have this after giving birth it39s a feeling of depression and failure Parentinfant bond The bond a parent and infant feels that rst moment they meet each other and hold each other Kangaroo Care The act of lying an infant between moms breasts for skin to skin touch hearing mothers heartbeat and feeling body heat to help premature or low birth weight children become healthy 0 It39s helpful for any newborn Approximately 12 of zygotes have abnormalities in their chromosomes leading to spontaneous abortion before proper implantation There are always possibilities of children being born with the incorrect number of chromosomes 45474849 These differences have adverse side effects the most common being trisomy21 or down syndrome 3 copies of chromosome 21 0 Another common discrepancy occurs at the 23rd chromosome the sex chromosome sometimes you are XXY or XYY or X ect View table 25 types of tests Teratogens anything that could increase the chance of having a prenatal abnormality Behavioral teratogen when no physical abnormality occurs but behavioral ones are present Time is key during developmental issues depending on when the teratogen is present there may be more or less risk o If a teratogen is present when limbs are being formed the child might not develop properly o If a teratogen is present during spinal cord development they may have a severe neurological problem Woman do not nd out they are pregnant until the 2nCI or 3rd week after conception has occurred It is important to avoid teratogens before getting pregnant because you never know when conception will occur Woman under 16yrs old and over 40yrs old have a higher risk of genetic prenatal and birth complications Anoxia lack of oxygen Threshold effect Meaning it has no effect until levels get too high Fetal alcohol syndrome FAS If a mother drinks at the beginning of a pregnancy the embryo can develop FAS and have distorted facial features View table 26 Not every birth effect has a reason and not every teratogen causes harm LBW Low Birthweight 0 Anything less than 5 12 lbs VLBW Very low birthweight 0 Under 3bs 5 ounces ELBW Extremely low birthweight 0 Under 2bs 3 ounces Preterm 3 or more weeks early of being born SGA Small for gestational age 40 of pregnancies are unintended If planning a pregnancy take folic acid stop drinking maintain a healthy weight ect Nearsightedness the ability to see near but not far 0 Age genes amp culture affect vision 0 Starting at birth we can only see about 2 ft which increases through life 0 Nearsightedness has been increasing greatly over the years in the US from 25 in 1970 to 42 in 2000 Genetic risks can be maintained or controlled if we are aware of them and take preventative measures such as alcoholism families with alcoholics should probably avoid alcohol so that the disease doesn39t take over their lives
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