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76 Cards in this Set
- Front
- Back
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Gametes
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- when the sperm and egg unit and for the diploid number of chromosomes
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o Germ cells
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either the egg or the sperm cell; a reproductive cell. Each mature germ cell is haploid, meaning that it has a single set of 23 chromosomes containing half the usual amount of DNA and half the usual number of genes. Except for the egg and the sperm, most cells in the human body contain the entire human genome. Also known as a gamete.
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o Somatic cells
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s generally taken to mean any cell forming the body of an organism.
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o Haploid
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n=23
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o Diploid
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2n=46 (23 pairs)
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• Gametogenesis in the female and male
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o Uneven distribution of cytoplasm
o Female meiosis II only happens if the female encounters sperm o Female cyclical process, male continuous and constantly o Female 1 gamete larger o Male 4 gametes o Location: male- tubule female: ovary and oviduct |
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• Process of fertilization (numbers of gametes, location, process)
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o Sexual intercourse
o Semen ejaculated near cervix o Millions of sperm o Journey to find secondary oocyte o Sperm live in female for average 48 hours up to 5 days o Must find secondary oocyte or will die o Only 100-200 sperm reach the single secondary oocyte in one fallopian tube o After ovulation secondary oocyte alive in fallopian tube 12-24 hours o Period of conception o Several sperm reach secondary oocyte o Begin process of penetration through 2 protective layers o Enzymes released from acrosome speed penetration o When 1 sperm reaches cell membrane of secondary oocyte cell membrane thickens o Thickening prevents other sperm from entering o Sperm stimulates Meiosis II- secondary oocyte ovum with egg nucleus o Sperm loses tail, sperm nucleus o Sperm nucleus unites with egg nucleus- zygote-2n diploid |
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• Early development - zygote, cleavage, early differentiation, blastocyst, gastrula, neurula
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o Zygote begins mitotic division- cleavage
o Day 4- morula= ball of 16-32 cells o Blastomeres- smaller and smaller cells formed from these divisions (no growth yet, nutrients internal) o By day 5 blastomeres separate- blastocyst o Outer cells trophoblast- placenta o Inner cells- inner cell mass- embryo o Cavity in blastocyst- blastocoel o Inner cell mass of embryonic stem cells: ancestors of all tissues and organs, can be grown in culture, transplanted into a patient to grow into health adult cells- show less rejections o Days 6-7 after fertilization (day 21 of cycle) implantation o Blastocyst adheres to uterine endometrium o Women now considered pregnant due date 40 weeks past 1st day of cycle (3 weeks ago) o By day 14 blastocyst well implanted into uterine endometrium o Stem cells of inner cell mass begin to separate to form embryonic disk o Embryo o 3 weeks gastrula forms o cells in gastrula differentiate to form 3 primary germ layers o weeks 2-4 trophoblast differentiates into 3 different layers of placenta o from weeks 3-4 rapid growth development of germ layers embryo called the neurula |
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• Embryonic stem cells – sources, understand the controversy and the goals for their use
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o Sources of these stem cells- blastocysts created in excess at fertility clincs, cord blood, others
o Challenges: sources, differentiation, targeting/delivery, immunity o Adult bone marrow also has stems cells but only for blood o Goals for use: could be used to treat someone with Parkinson’s disease, diabetes, leukemia, spinal cord injuries, stroke, heart disease, arthritis, blindness, others |
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• Structure and function of the placenta
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o Weeks 2-4 trophoblast differentiates into 3 layers of placenta
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1 outer chorion
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attaches to uterine endometrium by chorionic villi- blood vessels form in chorionic villi, gases, nutrients, and wastes exchanged between embryo and mother
also secretes human chorionic gonadotropin (HCG), acts on corpus luteum stimulates production of estrogen and progesterone, present in urine, detected in pregnancy test |
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2 yolk sac-
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begins to form fetal blood cells and umbilical blood vessels
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3 inner protective amnion
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around embryo filled with amniotic fluid- moms plasma fluid functions: shock absorption, temp regulation, moisture
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o 4-6 weeks
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embryo shows rapid development but does not yet look human, head with gill slits, heart begins to beat, muscles appear as somite, limb buds, tail
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o 6-8 weeks
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eyes, ears visible, 4 limbs with fingers, toes, skeleton cartilaginous, heart circulatory system functional, if XY burst of testosterone stimulates testes, develop male characteristics, if XX absence of testosterone- ovaries
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o By end of 8 weeks
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all human features present- embryo now a fetus, most organs begin to function, about 1 ½ inches long
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First 8 weeks
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sensitive period of development external factors can cause birth defects
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• Smoking
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stunted growth, increased heart rate, higher risk for hyperactivity, premature birth, increased changes for chromosomal damage may increase childhood cancers
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• Alcohol Use
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Fetal Alcohol Syndrome- stunted growth, microcephaly- small brains and mental deficiencies, facial defects
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o Second Trimester
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fetal movements obvious- fetus grows to 12 inches l-2 lbs, kidneys develop, begin to produce urine, ossification, liver and bone marrow begin producing blood cells, nervous system and skeletal muscles allow for fetal movement
Chances of survival outside of the uterus are low, body temperature cannot be regulated, digestive organs and lungs barely functional |
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o Third Trimester
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growth- fetus rapidly gains weight- 7lbs +, fetal movements increase then decrease, male- testes descend through inguinal canal into scrotum, digestive and respiratory systems become fully functional
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o 266 days after conception
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, starts with labor- triggered by baby, rhythmic contraction of uterine muscles
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Dilation
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stretching opening of cervix, early- active labor, may be accompanied by rupture of amnion (water breaks), 6-12 hours up to days, contractions increase in strength/intensity
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• Transition
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shortest phase- 15-30 minutes, most intense, dilation 7-10 cm
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Delivery/Pushing Phase
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usually head first, vaginal birth- a few minutes- several hours, descends and rotates, position helps, with first breath the three fetal shortcuts close off to restore a complete pulmonary circuit-ductus arteriosus, foramen ovlae, ductus venous
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Delivery of Placenta-
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called afterbirth) about 15-30 minutes after birth of baby, uterus contracts constricts blood vessels so blood loss is minimal
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o Vaginal Birth
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less risky to mom and baby, no side-effects on baby, alertness (not drugged), no need for IV or monitor- free to move, pain- endorphins stronger than morphine, individualized, empowerment, CONS: painful
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o Cesarean Section
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serious complications such as: dilation, umbilical cord compression, fetus in improper position, fetal distress- Major surgery, abdominal wall uterus opened- birth, WHO estimates 10-15% ideal in the US 32% of all births, steady increase, induction increases the risk of C-section, risky
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process of lactation
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o After birth anterior pituitary gland- prolactin prolactin- mammary glands- stimulated mil production, suckling stimulated posterior pituitary- oxytocin- oxytocin muscle contraction in mammary gland- flow of milk= letdown- mil released by breast tissue
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benefits of lactation
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TO BABY: complete balanced nutrition easy to digest, steady growth, higher IQ?, lower SIDS risk, “more healthy” TO MOTHER: less bleeding, weight loss, saves time/money, always available, bonding, birth control- hormonal suppression of ovulation TO SOCIETY: health care costs, workplace productivity, environment
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o Fraternal Twins
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2 oocytes ovulated fertilized by 2 sperm 2 zygotes with own placenta genetically siblings- often different sexes
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o Identical Twins
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single sperm and secondary oocyte early cleavage, blastomeres separate- 2 groups shared placenta, identical genes and appearance
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o Chromosomes
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thread like strand tightly coiled when loose=chromatin components DNA and protein=histones human diploid number=23 pairs (homologous) chromosomes=46 one from each parent
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o Genes
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transmission of single trait controlled by 2 genes at same position on homologous chromosomes alternate forms of gene=alleles
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o Alleles
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pair of alleles-expression, dominant-always expressed in offspring that have a copy or 2 or recessive- “hidden” if paired with a dominant allele; expressed only if both alleles recessive- 2 copies
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o Genotype
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allelic composition, BB, Bb, bb
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o Phenotype
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trait that is expressed, B or b
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o Dominant
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always expressed in offspring that have one copy
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o Recessive
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“hidden” if paired with a dominant allele expressed only if both alleles recessive
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disorders
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o Nondisjunction of Sex Chromosomes
o Nondisjunction of Autosomes common autosomal nondisjunction chromosome #21 results in 3 copies= trisomy 21 o Abnormal genes: mistakes can be made in cell division, resulting in abnormal genes- mutation, may produce altered proteins o Defective Genes – several human disorders are the result of the inheritance of defective genes from the parents Defective Sex-Linked Recessive Genes |
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o Nondisjunction of Sex Chromosomes
XXX metafemale |
sterile female often cognitively impaired
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o Nondisjunction of Sex Chromosomes
XYY metamale |
tall male with some mental deficiencies
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o Nondisjunction of Sex Chromosomes
XO Turner’s Syndrome |
sterile female often cognitively impaired
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o Nondisjunction of Sex Chromosomes
XYY Klinefelter’s Syndrome |
male with underdeveloped testes enlarged breasts learning disabilities
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o Nondisjunction of Sex Chromosomes
YO |
lethal
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nondisjunction of autosomes
Down syndrome |
short stature, flat faces, poor reflexes, and mental impairments average life span 56 years
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abnormal genes
sicle cell anemia |
hemoglobin composed of 267 amino acids, GAA codes for proper amino acid in sickle cell code mutated to GTA a different amino acid added to hemoglobin protein, result: abnormally shaped RBC, negative pathology, positive malaria resistance
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o Defective Genes
Autosomal Dominant Disorders • Huntington’s Disease |
brain disorder abnormal proteins produced that damages brain cells and causes a loss of motor control genes on chromosomes #4 H- Huntington Disease h- normal Symptoms do not appear until ages 35-45 Affected person often begins a family before the disease appears and may have given it to his/her offspring
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o Defective Genes
Autosomal Dominant Disorders • High Cholesterol |
high levels of cholesterol in blood can cause atherosclerosis in coronary arteries- may have early heart attacks
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o Defective Genes
Autosomal Dominant Disorders • Achondroplasia |
dwarfism
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Abnormal Autosomal Recessive Genes
• Cystic Fibrosis |
transmitted by a defective recessive gene on chromosome #7 C- normal c- cystic fibrosis transmitted by normal parents who are heterozygous Cc x Cc
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Abnormal Autosomal Recessive Genes
• Albinism |
A normal a albino
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Defective Sex-Linked Recessive Genes
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sex linked recessive disorders present on the X chromosome If female trait not shown it is recessive although females do not show the trait they are carriers In male trait appears due to presence of a single X chromosome
• Red- Green Colorblindness • Hemophilia • Duchenne muscular dystrophy |
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o Recombinant DNA Technology
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forms new genetic combinations Process involves: removal of DNA from one species, insertion into another species typically a bacterium, due to rapid multiplication of bacteria many new copies of gene are produced, can be inserted into another organism
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Applications of DNA Technology
• Agriculture |
- bovine growth hormone (BGH) produced from genetically engineered bacteria injected into cows, plants have been engineered with bacterial genes- more resistant to diseases, able to tolerate herbicides, more hardy, grow faster ripen slower/more quickly, possible manufacture pharmaceuticals, energy, nutrition
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Applications of DNA Technology
• Environment |
genetically altered oil eating bacteria have been deployed to clean up oil spills
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Applications of DNA Technology
• Medicine |
DNA technology can diagnose 1400 human genetic disorders, genetic testing can be done to determine if any one’s genes contain abnormal traits, it may be possible to develop your own genetic report card to show you potential health problems that may occur, gene therapy used to correct for an abnormal gene, normal gene is placed into virus that is inserted into a human cell, viral DNA with normal gene is copied into human DNA as cells divide by mitosis, new vaccines are developed using DNA technology, human hormones can be produced in large quantities from bacteria
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Applications of DNA Technology
• Forensics |
DNA fingerprinting, DNA isolated from blood and cells, amplified in whole or part, placed into a gel exposed to electrical current=electrophoresis, current pulls negatively charged DNA bigger fragments move more slowly- separation of bands, fragments of DNA appear as separate dark mark areas in the gel
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o Population
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same species characteristics- habitat, range, size, growth rate and potential
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o Community
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populations interacting niche- role in community
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o Ecosystem
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community of organisms plus non-living complex- intact sustaining
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o Biosphere
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planetary ecosystem
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o Biotic Potential
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population growth under “ideal” conditions depends on reproductive output, age to maturity, sex ratio, age distribution, follows exponential growth curve, growth limited by resource availability, disease, predation pressure, changes in environment, factors determine carrying capacity k= number of organisms that can be supported, creates equilibrium, k plastic (changeable)
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• History of human population and projections
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o In one minute 250 humans born 50 die, in one week 2 million humans added to the population, in one year 100 million humans added present population over 6.6 billion by 2050 as many as 8.5 billion or more
o Resource consumption and waste generation not shared equally, 80% of the energy industrial nations wealthiest 20% of the world population 86% of resources 53% of worlds CO2 poorest 20% 1.3% of resources generates 3% of world’s CO2 |
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consumption
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- a linear system in a non-linear environment planned obsolescence and perceived obsolescence 1% of purchases in the US are still in use after 6 months
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o Global Climate Change
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mainstream science agrees global climate is changing, human-induced, potential for dramatic negative impacts, intergovernmental panel on climate change to understand climate change greenhouse effect, gases in stratosphere= glass water vapor, CO2 methane CFC’s halons and others, solar radiation in, sunlight=heat, gasses insulate, greenhouse effect makes earth habitable, without it the average surface area temps well below freezing, the greenhouse effect is your friend, humans added greenhouse gasses, CO2 from fossil fuel, insulation, raised overall temp of earth, 1 degree F in past 100 years, trend predicts 3.6 degrees F by 2100,
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What difference is a few degrees
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polar ice melts- ocean levels rise, increase evaporation=more water vapor= more warming, widespread flooding of costal areas, marked regional variations in climate- precipitation, drought, extremes (storms) some models suggest pos feedback- neg, threatens agriculture, alter ecosystems, if local climate changes what do organisms do, increased human death due to extreme weather events, flooding, increase disease ranges and longer lived vectors,
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What should we do
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Reduce CO2 emissions, cleaner technology, fossil fuel alternatives US has 5% of world population responsible for 25% of CO2
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o Invasive Species
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human mobility- increased mobility for other species, some introductions intentional, some accidental, invasive non- natives not co-evolved in new ecosystems, out-compete, displace natives, contribute to extinction
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o Deforestation
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loss of forest habitats, <1/3 of world’s forests logged, replanting and conservation efforts have not kept pace with losses
Problems: CO2 added to air trees not available to consume CO2 burning trees increases CO2 levels, erosion of soil and flooding, lost habitat for many species, |
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Air pollutants
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- CO2 and CO nitrogen oxide sulfur oxide lead and ozone, major source of burning of fossil fuels (cars, homes, industry)- bronchitis, asthma
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Water Pollution
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fresh water less than 1% of earth’s surface portable water decreasing as world’s population increases Causes: drought, water pollution, agricultural runoff- fertilizers and pesticides, oil and other petroleum spills, heavy metals from industries mines automobile exhaust mercury- nerve and kidney damage, lead-brain development in children Alzheimer’s?
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desertification
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previously productive soil desert overuse of fertilizers overgrazing erosion of top soil light pollution
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o Species, Extinction
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succession and evolution, human expansion habitat alterations has increased rates of extinction, current extinction rates 50 times higher than in the past 100,000 years losing biodiversity, value? - Intact ecosystems, nutrient cycling, valuable species lost? (20% of medicinces are plant based)
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o Modern, non sustainable agriculture
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monoculture farming, high energy, chemical inputs, irrigation, CAFO’s, distances for processing and distribution
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• Sustainability
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meeting the demands of human population today without limiting the ability in the future in terms of population growth, development, resource consumption/waste generation, agriculture, energy
o Sustainable population growth- increase security, family planning education and birth control, laws improve economic social and political standing of women |
