Lesson 4: Abnormalities in Sexual Reproduction Flashcards

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1
Q

what is our (humans) sex chromosomes like? how does each sex differ

A
  • males have X and Y chromosome
  • females have a pair of X chromosomes
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2
Q

what are non-sex chromosomes called

A

autosomes

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3
Q

what are some ways sex can be determined?

A
  1. xx/xy (mammals, some insects)
  2. zz/zw (birds)
  3. temperature (crocodiles, turtles; if the eggs are kept relatively warm, most or all eggs hatch as females- if the eggs are kept relatively cool, most or all eggs hatch as males
  4. age (some fish, some mollusks; all young are born as male- as they become older and larger, they change into females
  5. social structure (some fish; all young fish are females, when the dominant male fish dies, a large female changes into a male
  6. fertilization (haploid and diploid): bees, wasps, ants; fertilized eggs (2n) becomes females and unfertilized eggs (n) becomes males
  7. infection (some insects; variable- in one form, infected individuals develop into females)
  8. none (earthworms and other hermaphroditic organisms; all individuals have both female and male reproductive organs)
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4
Q

what are some factors that can impact meiosis and fertilization (sexual reproduction)

A

several, including:
- these factors would be random meiotic errors
- environmental factors

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5
Q

what are some ways meiosis can become abnormal?

A

chromosome seperation during anaphase 1 or 2 of meiosis 1 or 2

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6
Q

what does abnormal meiosis seperation do? what does it result in? what is the name of THIS

A

results in one daughter cell having an extra chromosome and one daughter cell having a missing chromosome; known as non-disjunction

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7
Q

example/explain non-disjunction in humans

A

results in gametes with 22 or 24 chromosomes, not the expected 23; this means that the resulting zygote would have 45 or 47 chromosomes, not the expected 46 (after fertilization)

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8
Q

karyotype (how does it work and what is it)

A

non-disjunction can be easily observed through the use of a karyotype- it is a picture of chromosomes that have been arranged according to number, size, shape, and other characteristics
- it takes a snapshot of the chromosomes in the cell and you can identify any errors
- during cell division, chromosomes can be stated and photographed so they can be counted and compared

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9
Q

types of non disjunction

A
  1. trisomy: a chromosomial abnormality in which there are 3 homologous chromosomes in place of a homologous pair (when theres an extra chromosome)
  2. monosomy: a chromosomal abnormality in which there is a single chromosome in place of a homologous pair (when theres a missing chromosome)
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10
Q

non-disjunction disorders (what is it and what is an example of it)

A

many human genetic conditions are a result of non-disjunction
- down syndrome is an example

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11
Q

down syndrome (whats it caused by, symptoms..)

A

caused by trisomy 21, or having 3 copies of the 21st chromosome
- the extra chromosome means theres an excess of genetic information
- symptoms: round full face, short statue, intellectual disabilities, poor immune function, etc.

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12
Q

turner syndrome

A
  • one X and no Y sex chromosome
  • approximately one in 2500 female births
  • female in appearance but do not mature sexually and are sterile
  • most turner syndrome fetuses are miscarried before the 20th week of pregnancy
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13
Q

Klinefelter syndrome

A
  • two X and one Y sex chromosome
  • approximately one in 500 male births
  • males are usually sterile and exhibit some feminine body characteristics, but severity varies
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14
Q

patau syndrome

A
  • trisomy of chromosome 13
  • approximately one in 25000 live births
  • many serious developmental problems including brain, kidney, and heart defects
  • children rarely live more than a few months
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15
Q

edwards syndrome

A
  • trisomy of chromosome 18
  • approximately one in 6000 live births
  • many organ system defects
  • very low survival rate
  • most fetuses die before birth
  • average life expectancy of live-born infants is less than one month
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16
Q

how do genetic disorders get diagnosed prior to birth?

A

pre-natal testing

17
Q

how does pre-natal testing work at 8 weeks? (what are the different processes/procedures for this)

A

you can collect fetal cells
- chorionic villus sampling (CVS) removes cells from placenta for testing
- amniocentesis involves the use of a syringe to collect cells from the amniotic sac for testing

18
Q

how does pre-natal testing work at 15-20 weeks?

A

you can do multiple marking screening
- this accesses hormone levels in the mothers blood to check for markers of increased risk of genetic conditions

19
Q

what are some causes of problems with fertilization

A
  • poor or reduced egg and sperm quality or quantity
  • blocked fallopian tube of the female
  • blocked epididymis or vas deferens of the male
20
Q

what are assistive reproductive technologies (ARTs) used for?

A

can be used to increase reproductive success

21
Q

ARTS: In Vitro Fertilization (IVF) what is the process like?

A
  • hormone treatments are given to the woman to increase egg production
  • those eggs are retrieved through a minor procedure
  • fertilization occurs outside the body using a sample from the male, and the embryo is then implanted in the uterus
22
Q

Assistive Reproductive Technologies: Artificial insemination (what is this process like and what is this technique used for)

A
  • this is when sperm is placed into the reproductive tract of a female through a process called intrauterine insemination
  • a sperm sample, which can be fresh or frozen, is washed and concentrated then inserted directly into the uterus
  • this technique has also been used in non-humans to help save endangered species, including pandas