1 birds and the bees

Question 1

Which types of cell-division exist and how do they differ?

Answer 1

somatic cells
gametes

meiosis 1
meiosis 2

Mitosis and Meiosis , differences
Mitosis: the process of cell duplication
Chromosomes duplicate and split into two cells
Contain the exact same information
New cells are daughter cells

Meiosis: cell division, but the end product is a sex cell
Meiosis 1: diploid cell to haploid cell
Meiosis 2: haploid cells to haploid cells
Only one of the four daughter cells become an ovum

Question 2

What is DNA and how is DNA copied during cell division/can it change?

Question 3

How does inheritance of traits in humans work? How do you calculate risks and what are
basis principles of inheritance?

Answer 3

Genotype: the actual games
Phenotype: the physical characteristics
Dominant alles: need only one to be that expressed
Recessive alles: need two in order to be expressed
Punnet squares: a way to calculate the likelihood of gene expression

Calculated using probability
Homozygous: the same alles, so it will have the trait
Heterozygous: gene expression decided by the relationship between the alleles
Codominance: if there is two dominant, they are both expressed fully(ex. Blood type A and blood type B, create blood type AB)
Polygenetic traits: some characteristics are influenced by multiple genes (intelligence, etc.)
Incomplete dominance: the allele are expressed in a mix
X-linked inheritance: males more likely to express, because they one have one x chromosome so there is no way to cancel out
Fragile x syndrome, asd, color blindness

Question 4

Which periods of prenatal development are there, and what develops when?

Answer 4

Germinal stage – zygote
* First 2 weeks of life from fertilization
* Rapid cell division
* Implants itself in the wall of the uterus
* From this point on the zygotes becomes dependent on the mother
* Until this point, alcohol, drugs etc. won’t harm the organism
Embryonic stage – embryo
* 3
rd – 8
th week of gestation (carrying of the embryo/fetus)
* Development of
o Amniotic sac (filled with amniotic fluid which serves as a protective buffer against physical shock and
temperature changes)
o Placenta – transfers O2 and nutrients, removes CO2, does not permit direct blood exchange –
however some drugs, viruses and antibodies are able to pass to the embryo
o Umbilical cord – transmits between placenta and embryo
* Inner mass differentiates into
o Endoderm becomes – gastrointestinal tract, trachea, bronchi, glands, and vital organs (lungs,
pancreas, liver)
o Mesoderm – muscles, skeleton, circulatory and excretory systems, and inner skin layer
o Ectoderm – sensory cells, nervous system (and skin, nails, hair, teeth…)
* 4
th week → head begins to take shape, eyes, nose and mouth
o Blood vessels that will become the heart start to pulsate
* 5
th week → buds that will become limbs start to form
* End of embryonic stage – 8
th week (10th of pregnancy)
o Face, fingers, toes, external genitalia
o Most common miscarriages often unnoticed (1 in 4 pregnancies)
Development in directions
- Cephalocaudal: development starts at the brain and proceeds down to trunk and legs (from head to tail)
- Proximal-distal: development from center to more distant areas (from middle out)
The fetus
* From 3rd month of gestation to delivery
* Development of muscles and the nervous system
* By the 3rd month the fetus has all its body parts including organs and external genitalia
* 4
th months – starts moving
* 5 months – reflexes (suckling, swallowing, hiccupping)
* Develops nails, sweat glands, more adult-like skin
* 6 months – eyes open and close
* Age of viability (22-26 weeks → app. 6 months)
o Point at which the fetus has physically advanced systems to survive even if born prematurely
(reasonable chances not 100%)
o However, can have difficulties mainly depending on the environmental conditions

Question 5

What possible external harm could the child suffer during pregnancy?

Answer 5

teratogens – environmental factors that may cause developmental deviations (most threatening in the embryonic
stage)
* Medications
* Drugs
* Environmental toxins
* Other factors: age, diet, emotional state affect the response of the mother to the teratogens

Question 6

When do these affect the child? What are the effects?

Question 7

What types of genetic disorders are there?

Answer 7

• Most genetic problems are recessive traits – does not appear unless both of the parents carry the harmful
  allele and a child inherits it from each
• Sex-linked defects are more common in males because the alleles are often on the X-chromosome which he
  inherits from the mother and only owns one (if it is defected, does not have an extra X that could be healthy
  as females do)
• E.g. colorblindness = X-linked
• Sickle-cell anemia = 2 recessive alleles
• Dominant allele → the parent will display the disability e.g. Huntington’s disease (nervous system
  degenerates but often displays late in life once the person already has children)
• Mutations – change the genetical information into harmful, non-harmful, beneficial or fatal
  o Occurs spontaneously
  o Can be induced by environmental hazards – toxic waste, radiation, chemicals etc.

Question 8

types of cell-division and differences

Question 9

DNA

Question 10

inheritance

Question 11

teratogens

Answer 11

A teratogen exerts its effects largely during critical periods of development
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a. Embryonic stage
b. Each organ has a more specific period e.g. heart → 20-40 days after conception
2. Teratogens have specific effects → different teratogens influence different developmental processes
3. Maternal or fetal genotypes may counteract a teratogen’s effect (their vulnerability to a specific one or not)
4. Effects of one teratogen may intensify effect of another
a. Mothers physiological status, nutritional and hormonal balance modify the impact of a teratogen
b. E.g. nutritional deficiencies intensify effects of drugs ingested by the mother
5. Different teratogens may produce the same defect
6. The longer and the more intensely a fetus is exposed to a teratogen, the more likely it is to be harmed

Question 12

somatic cells

Answer 12

for repair and growth

Question 13

gametes

Answer 13

reproduction and its variety

Question 14

meiosis

Answer 14

process of cell division into gamete production, diploid → haploid

Question 15

diploid

Question 16

haploid

Question 17

booty hole

Answer 17

`

Question 18

homologous chromosomes

Question 19

fertilization

Answer 19

combination of 2 random gametes

Question 20

crossing over

Question 21

How is genetic material present in the body and how is it passed on?

Answer 21

In the nucleus → chromosomes → DNA → genes → alleles → sequences of base pairs

• DNA usually free in the nucleus, when cell divides → coils into chromosomes
• Homologous chromosomes: same genes but not always the same alleles
• Homozygous: 2 identical alleles of a gene (AA)
• Heterozygous: 2 different alleles of a gene (Aa)
• Diploid and haploid: diploid are all somatic cells (2n), haploid are gamete (n)

Question 22

condominance

Answer 22

– two heterozygous alleles are equally powerful → phenotype fully and equally expressed e.g. bloodtype AB

Question 23

polygenic traits

Answer 23

characteristics influenced by many genes not a single one e.g. weight, height, intelligence, skin
color

Question 24

chromosomal abnormalities

Answer 24

Too many or too few – if meiosis or mitosis does not proceed well
2. Broken or damaged chromosomes
3. Sex or autosomal chromosomes
Sex chromosomes:
* Involve the 23rd pair = sex chromosomes
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* Turner’s syndrome (X0) – sterile, females but need more estrogen to look womanly, struggles with spatial
and verbal abilities
* Poly-X “superfemale” (XXX, XXXX or XXXXX) – female and fertile, somewhat below average intelligence,
developmental delays and intellectual problems the more X chromosomes
* Klinefelter’s syndrome (XXY or XXXY) – sterile male with some secondary sex characteristics of a female,
taller than XY males, intellectual problems the more X chromosomes
* Supermale syndrome (XYY, XYYY, XYYYY) – typically fertile, phenotypic males who are taller, and develop
more acne, intellectual characteristics similar to normal XY male
➔ Problems in meiosis (mostly anaphase), wrong attachment of spindle
➔ X chromosome is larger thus is more harm when there are more than 2 present (too much genetic
information being produced)
Autosomes:
* Problems with the 22 non-sex chromosomes
* Most commonly happens when an gamete carries an extra autosomal chromosome and combines with a
normal one = 47 chromosomes
o 3 chromosomes of one type =trisomy
o Most common = Down syndrome = trisomy-21
o Chromosome 21 is the smallest, trisomy’s of other chromosomes usually lead to death
* Down syndrome – trisomy-21
o Mentally retarded
o Average IQ around 55
o Congenital eye, ear, and heart defects
o Physiological features: almond eyes, protruding tongue, short stubby limbs, flattened nose
o Developmental progress is the greatest when they are included, with lots of emotional support

Question 25

how teratogens exert effects on prenatal development?

Answer 25

– environmental factors that may cause developmental deviations (most threatening in the embryonic stage) * Medications * Drugs * Environmental toxins * Other factors: age, diet, emotional state affect the response of the mother to the teratogens

Question 26

teratogens -- legal and illegal drugs heavy use of aspirin too much caffeine smoking

Answer 26

Heavy use of Aspirin → low birth weight, lower IQ, and poor motor control * Too much Caffeine → higher risk of miscarriage, low-birth-weight infants * Smoking → disturbance in placental functioning o changes in maternal physiology which leads to oxygen deprivation o changes in fetal brain

Question 27

teratogens -- legal and illegal drugs nicotine and alcohol

Answer 27

lower birth weight o more prenatal growth deficiencies for mothers that do both than those that only use one substance o Sudden infant death syndrome SIDS – more common in mothers who smoke, drink or take narcotics during pregnancy

Question 28

teratogens -- legal and illegal drugs passive smoke

Answer 28

Low birth weight (when e.g. father smokes) o Can delay intellectual and behavioral development o Increased risk for various illnesses

Question 29

teratogens -- legal and illegal drugs alcohol

Answer 29

o Fetal alcohol syndrome (FAS) – stunned growth, physiological abnormalities, mental retardation o Facial, heart and limb defects o 20% shorter than average children o Mental retardation – mainly because of lack of oxygen ▪ Only 0,3 ml of vodka can stop respiratory actions of the fetus for more than half an hour o Damage from alcohol is greatest in the last trimester o Men who drink excessively may sustain genetic damage that leads to defects in their offspring

Question 30

teratogens -- legal and illegal drugs FAS

Answer 30

Children with FAS may be excessively irritable, distractible, hyperactive o May repeatedly bang their heads or rhythmically rock their bodies o Slow in turning head or suckling o Lower IQ

Question 31

teratogens-- legal and illegal drugs cocaine

Answer 31

Brian hemorrhages (bleeding), neuron damage o Children → irritable, higher pitched prolonged crying, depressed, unresponsive behavior

Question 32

teratogens-- legal and illegal drugs addicted mother

Answer 32

Offspring also addicted to this drug o Following birth babies undergo withdrawal symptoms ▪ Irritability, minimal ability to control arousal, trembling, shrill crying, rapid respiration, hyperactivity ▪ These symptoms can be so severe, they result in death in the first few days of life o If the mother stops taking the drug in the 3rd trimester, the infant is less likely to be affected o May contribute to problematic attachment relationship formation ▪ Infants not as alert and may not maintain visual or physical contact

Question 33

teratogens-- environmental toxins

Answer 33

Radiation, lead, mercury, herbicides, pesticides, household cleaners, food additives, cosmetics Downloaded by: lisawatermann1 | lisawatermann1@gmail.com Distribution of this document is illegal Want to earn $103 per month? Stuvia.com - The Marketplace to Buy and Sell your Study Material * Automobile exhaust fuels, contaminated drinking water, lead-based paint * Prematurity * Low birth weight * Brian damage * Problems in cognitive and intellectual functioning * PCB contaminated fish o Babies were smaller, weighed less, less responsive, neurologically advanced o Lower IQ, memory, higher impulsivity o PCB in breast milk * Fathers exposure to environmental toxins → chromosomal abnormalities

Question 34

Medical interventions in pregnancy and childbirth

Answer 34

Diethylstilbestrol – to prevent miscarriage → caused vaginal abnormalities, cancer of cervix and risk of breast cancer in the female offspring * Thalidomide – anti-anxiety, anti-nausea drug → children born with abnormalities of face, fusing fingers, malformation of heart etc. o Available only for treatment of cancer, AIDS etc.

Question 35

parental factors

Answer 35

Age and parity (how many children the mother had) o Under 15 and over 35 → experience more problems o Older women more difficulty conceiving (by 40 it is less than 5%) o Chances of miscarriage and chromosomal abnormality increases with age o Emerging health risks of mothers such as hypertension, diabetes, alcoholism increases with age, it not the age per se o Higher age of the father also causes more birth defects o Too young women → unhealthy habits o Usually connected to SES * Diet o Deficiencies in vitamins, minerals, and proteins o Increased risk of miscarriage o Lower social and motor development, cognitive abilities o Supplements of folic acid daily in the last 2 months of pregnancy reduce the risks of premature birth * Emotional state o Mother’s emotionality can lead to metabolic and biochemical changes ▪ Stress ▪ Anxiousness o Fetuses more active in the uterus o Hyperactive infants, irritable, tend to cry more, feeding and sleep problems o At the age of 7 more likely to be depressed and anxious o More likely to develop schizophrenia * Diseases and disorders o Rh factor incompatibility – mother’s blood produces antibodies that attack the fetal blood cells → death of fetus ▪ Less likely in first time mothers o Hypertension (high blood pressure) and diabetes → underdeveloped immune system o Genital herpes – one of the most harmful viruses ▪ Can cause blindness, motor abnormalities, mental retardation, neurological disorders ▪ 60% babies die, 90% survive with serious problems o HIV and AIDS ▪ 25% chance that the mother transmits it to child, however greater if she breastfeeds ▪ If use of drug therapy and Caesarean delivery → rate of transmission reduced to 1%

Question 36

parental factors

Answer 36

Age and parity (how many children the mother had) o Under 15 and over 35 → experience more problems o Older women more difficulty conceiving (by 40 it is less than 5%) o Chances of miscarriage and chromosomal abnormality increases with age o Emerging health risks of mothers such as hypertension, diabetes, alcoholism increases with age, it not the age per se o Higher age of the father also causes more birth defects o Too young women → unhealthy habits o Usually connected to SES * Diet o Deficiencies in vitamins, minerals, and proteins o Increased risk of miscarriage o Lower social and motor development, cognitive abilities o Supplements of folic acid daily in the last 2 months of pregnancy reduce the risks of premature birth * Emotional state o Mother’s emotionality can lead to metabolic and biochemical changes ▪ Stress ▪ Anxiousness o Fetuses more active in the uterus o Hyperactive infants, irritable, tend to cry more, feeding and sleep problems o At the age of 7 more likely to be depressed and anxious o More likely to develop schizophrenia * Diseases and disorders o Rh factor incompatibility – mother’s blood produces antibodies that attack the fetal blood cells → death of fetus ▪ Less likely in first time mothers o Hypertension (high blood pressure) and diabetes → underdeveloped immune system o Genital herpes – one of the most harmful viruses ▪ Can cause blindness, motor abnormalities, mental retardation, neurological disorders ▪ 60% babies die, 90% survive with serious problems o HIV and AIDS ▪ 25% chance that the mother transmits it to child, however greater if she breastfeeds ▪ If use of drug therapy and Caesarean delivery → rate of transmission reduced to 1%

Question 37

stages of pregnancy: germinal state

Answer 37

zygote First 2 weeks of life from fertilization * Rapid cell division * Implants itself in the wall of the uterus * From this point on the zygotes becomes dependent on the mother * Until this point, alcohol, drugs etc. won’t harm the organism

Question 38

stage of pregnancy: embryonic stage

Answer 38

embryo 3rd – 8th week of gestation (carrying of the embryo/fetus) * Development of o Amniotic sac (filled with amniotic fluid which serves as a protective buffer against physical shock and temperature changes) o Placenta – transfers O2 and nutrients, removes CO2, does not permit direct blood exchange – however some drugs, viruses and antibodies are able to pass to the embryo o Umbilical cord – transmits between placenta and embryo * Inner mass differentiates into o Endoderm becomes – gastrointestinal tract, trachea, bronchi, glands, and vital organs (lungs, pancreas, liver) o Mesoderm – muscles, skeleton, circulatory and excretory systems, and inner skin layer o Ectoderm – sensory cells, nervous system (and skin, nails, hair, teeth…) * 4 th week → head begins to take shape, eyes, nose and mouth o Blood vessels that will become the heart start to pulsate * 5 th week → buds that will become limbs start to form * End of embryonic stage – 8 th week (10th of pregnancy) o Face, fingers, toes, external genitalia o Most common miscarriages often unnoticed (1 in 4 pregnancies)

Question 39

development in directions Cephalocaudal Proximal-distal

Answer 39

Cephalocaudal: development starts at the brain and proceeds down to trunk and legs (from head to tail) - Proximal-distal: development from center to more distant areas (from middle out)

Question 40

stages of pregnancy: fetal stage

Answer 40

From 3rd month of gestation to delivery * Development of muscles and the nervous system * By the 3rd month the fetus has all its body parts including organs and external genitalia * 4 th months – starts moving * 5 months – reflexes (suckling, swallowing, hiccupping) * Develops nails, sweat glands, more adult-like skin * 6 months – eyes open and close * Age of viability (22-26 weeks → app. 6 months) o Point at which the fetus has physically advanced systems to survive even if born prematurely (reasonable chances not 100%) o However, can have difficulties mainly depending on the environmental conditions