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Human Develop. Ch 21
Human Development and Genetics
| Question | Answer |
|---|---|
| Gestation | the period from fertilization of the egg (zygote) until birth |
| when one of the millions of sperm joins the egg to combine DNA and form a zygote | fertilization |
| occurs in the fallopian tube | fertilization |
| a change or maturation of the sperm that takes place as it is swimming through the uterus and fallopian tubes | Capacitation |
| becomes more fragile | acrosome |
| acrosome | the tip of the head of a sperm cell |
| allows acrosome to burst and digest the | egg membrane |
| once a sperm enters the egg the membrane changes to block another ___________ from entering | sperm |
| Nuclei fuse restoring the | diploid number |
| 22 pairs of | autosomes |
| 23 from | mom |
| 23 from | dad |
| #23 is called the | sex chromesomes |
| xx | females |
| males | xy |
| cleavage | mitotic dividing of the zygote |
| consist of 16 cells | morula |
| the point when the mass becomes hollow | blastocyst |
| blastocoele | hollow space filled with fluid |
| trophoblast | outer cell mass layer of cells |
| what is the inner cell mass of the blastocyst | inner cell mass |
| implantation | bonding of zygote to the uterine wall 5-8 days after fertilization |
| this has four stages | implantation |
| endometrium produces | carbohydrates |
| surface proteins on the blastocyst combine with the | carbohydrates |
| trophoblast secretes | enzymes |
| trophoblast secretes enzymes that digest the surface of the | endometrium |
| blastocyst sinks into the | crater (placenta) |
| chorion | embryonic membrane that forms the fetal portion of the placenta |
| chorion originates as the | trophoblast |
| inner mass | embryonic stem cells |
| all DNA can or cannot be expressed | can |
| 200 kinds of cells at | birth |
| embryo | developing human from implantation to 8th week |
| plate of cells within the blastocyst | embryonic disc |
| germ layers | ectoderm, mesoderm, and endoderm |
| outer germ layer is | ectoderm |
| ectoderm consist of | epidermis and its derivatives, nervous system, lens, cornea, internal ear |
| middle germ layer is | mesoderm |
| mesoderm consist of | dermis, bone, cartilage, muscle, kidneys, and blood |
| inner germ layer is | endoderm |
| endoderm consist of | GI mucosa, respiratory mucosa, liver, thyroid and pancreas |
| distinguished from the embryo at 20 days | embryonic membranes |
| gives rise to the first blood cells and sex stem cells | yolk sac |
| yolk sac becomes part of the | umbilical cord |
| thin membrane that surrounds the embryo (amniotic sac) | amnion |
| amnion contains | amniotic fluid |
| amniotic fluid contains | urine, sloughed off cells |
| sampling of amniotic fluid | amniocentesis |
| what the trophoblast is called as it develops | chorion |
| chorionic villi | projections from the chorion into the endometrium that become the fetal part of the placenta |
| embryo takes form with head and limbs and beating heart | 4-5 weeks |
| 8 week | organ system established |
| this happens 9th until 40th week | fetal growth |
| maternal (endometrium) and fetal (chorion) tissue structure that separates fetal and maternal blood | placenta |
| placenta is formed by the | 12th week |
| placenta is a 7 inch diameter | flat disc |
| produces hormones to maintain pregnancy | placenta |
| hCG | human chorionic gonadotropin |
| hCG is produced by | chorion of embryo |
| hCG stimulates corpus luteum to secrete | estrogen and progesterone |
| corpus luteum to secrete estrogen and progesterone to prevent | uterine contractions |
| produced by uterus within a few weeks | progesterone and estrogen |
| progesterone and estrogen prepare | mammary glands |
| inhibits FSH and LH and further ovarian follicle development | estrogen and progesterone |
| inhibits uterine contractions | relaxin |
| permits stretching of | pubic symphysis and ligaments |
| chorionic villi project into | maternal blood sinuses |
| placenta birthed after the fetus | after birth |
| connects fetus to placenta | umbilical cord |
| umbilical cord | transfers blood back and forth |
| 2 arteries away from | fetus |
| 1 vein towards | fetus |
| labor | sequence of events that occur during birth |
| there are three stages of | labor |
| dilation and effacement of the | cervix |
| usually 8-12 hours, mucus plug released, amniotic sac breaks, dilation and effacement of the cervix | first stage |
| caesarion section | surgical removal of fetus |
| head up | breech |
| oxytocin from posterior pituitary increases | uterine contractions |
| delivery of the infant | second stage |
| third stage | delivery of the placenta |
| as soon as birth occurs the fetus is called an | infant |
| chemo receptors | stimulates medulla which starts respiration |
| breathing promotes pulmonary circulation which closes the | foramen ovale |
| may occur as liver immaturity does not excrete bilirubin well | jaundice |
| study of inheritance | genetics |
| hereditary material | DNA |
| double helix | double strand of nucleotides twisted together |
| A, T, G, C | double helix |
| sequence of A, T, G, C determines the | genetic code |
| genome | the entire code |
| gene | the genetic code for one protein |
| each amino acid comes from a triplet of 3 bases called a | codon |
| protein synthesis occurs in the | ribosome |
| messenger RNA (mRNA) | a mirror image of DNA made in nucleus |
| genetics | chromosomes and genes |
| mRNA leaves the nucleus and attaches to a | ribosome |
| mRNA-> protein (via tRNA) | translation |
| anticodon | transfer RNA (tRNA) attaches to the mRNA at a site called |
| anticodon complimentary to the | codon |
| tRNA picks up the correspomding______ and forms peptide bonds to make a protien | amino acids |
| DNA-> mRNA-> tRNA-> | protein |
| if a gene's information is used for something such as making a protein it is said to be | expressed |
| genotype | the actual physical genetic makeup |
| the sequence of bases on the | DNA |
| phenotype | the appearance of how the alleles are expressed |
| the genotype determines the | phenotype |
| alleles | the 2 or more possibilities for the expression of a pair of genes |
| both alleles are the same | homozygous |
| heterozygous | the 2 alleles are different |
| dominant vs. recessive genes only matter in | heterozygous alleles |
| the gene that is expressed of the 2 | dominant |
| recessive | the gene that is not expressed |
| must be homozygous recessive to be | expressed |
| a diagram to illustrate how genes are expressed | Punnett square |
| Punnett square | dominant gene is capitalized |
| simplified eye color, sickle cell anemia | dominant recessive |
| multiple alleles | more than 2 alleles possible |
| mom type O, dad type AB | 50% chance of A or B 0% chance of O |
| 4 types | O=OO AB=AB A=AA or AO B=BB or BO |
| sex linked traits | X linked |
| recessive, but always expressed in ______ because there is no dominant gene to suppress its _________ | males, expression |
| only expressed in females if | homozygous recessive |
| heterozygous female | carrier |
| most traits are not this simple as they are results of | multiple genes |
| environmental factors are also important in determining | phenotype |
| human genome project | every gene has been mapped |
| diseases that are a result of malfunctioning DNA | genetic disease |
Created by:
tiffanyheffernon
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