Meiosis, Gametogenesis and Reproduction Flashcards

1
Q

Know the stages of meiosis and a brief statement about what occurs in each stage.

A

Meiosis I: Reductional division (reduced in 1/2) into 2 daughter cells. (diploid to haploid)
Meiosis II: Equational division: 4 cells with 2 chromatids each.

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2
Q

When does crossing over occur in meiosis?

A

During Prophase I

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3
Q

When do the centromeres divide in meiosis?

A

Anaphase II

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4
Q

When does independent assortment occur in meiosis?

A

Anaphase I (maternal and paternal chromosomes divide to each pole)

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5
Q

What is synapsis and when does it occur in meiosis?

A

Prophase I (Pairing of 2 homologous chromosomes)

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6
Q

Meiosis causes an increase in variability from generation to generation in two ways. Describe these 2 ways.

A

Crossing over

Independent assortment

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7
Q

Relate oogonium to meiosis and know the number of chromosomes it has.

A

Diploid: Goes through mitosis to form the primary oocyte

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8
Q

Relate primary oocyte to meiosis and know the number of chromosomes it has.

A

Diploid: Goes through meiosis I to form polar body and secondary oocyte

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9
Q

Relate secondary oocyte to meiosis and know the number of chromosomes it has.

A

Haploid: Goes through meiosis II to form gametes

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10
Q

Relate ootid to meiosis and know the number of chromosomes it has.

A

Haploid: The cell that matures into an ovum

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11
Q

Relate ovum to meiosis and know the number of chromosomes it has.

A

Haploid: the egg

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12
Q

Relate spermatogonium to meiosis and know the number of chromosomes it has.

A

Diploid: Goes through mitosis

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13
Q

Relate primary spermatocyte to meiosis and know the number of chromosomes it has.

A

Diploid: Goes through meiosis I

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14
Q

Relate secondary spermatocyte to meiosis and know the number of chromosomes it has.

A

Haploid: Goes through meiosis II

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15
Q

Relate spermatid to meiosis and know the number of chromosomes it has.

A

4 Haploid cells that mature to become sperm

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16
Q

Relate sperm to meiosis and know the number of chromosomes it has.

A

Final product of Spermatogenesis

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17
Q

Other than the terminology and the fact that one occurs in males and the other in females, describe several differences between oogenesis and spermatogenesis.

A

Location: female ovaries/fallopian tubes vs. male testis
# of functional gametes: 1 female and 4 male
Female: Discontinuous, Male: Continuous
Females form 400-500 gametes, Males form billions per week

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18
Q

Approximately how may sperm can a healthy college-aged male make per week?

A

About a billion per week

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19
Q

How long does the process of spermatogenesis take?

A

48 days

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20
Q

True or False: Oogenesis is a noncontinuous process.

A

True

21
Q

What is a polar body?

A

The byproduct of Oogenesis

22
Q

Oogenesis stalls prior to birth in females. At which stage of meiosis does oogenesis stall?

A

Prophase I

23
Q

About how many primary oocytes does a female have at birth? About how many will she ovulate during her life?

A

500,000 to 750,000

24
Q

Where does meiosis occur in each sex (what tissues)?

A

Female: ovaries/fallopian tubes
Male: Testies

25
Q

Which sex is more likely to produce gametes with the incorrect chromosome number?

A

Females

26
Q

Which sex is more likely to produce gametes with a new mutation?

A

Males

27
Q

What is nondisjunction and how does it effect gamete production?

A

Mistakes in separation of chromosomes in meiosis causing mutations

28
Q

Be familiar with the anatomy of the male and female reproductive system at the level discussed in lecture.

A

a

29
Q

Describe the relative sizes of the egg and sperm.

A

Egg: size of a period on a piece of paper
Sperm: 60 Microns

30
Q

Which (egg or sperm) contains more genetic information? Why?

A

Both the same because they both carry 1/2 of the genetic info from each parent: 23 chromosomes each to make 46.

31
Q

Where are sperm made? Where are eggs made?

A

Sperm: testis
Egg: ovary/fallopian tube

32
Q

About how many sperm are typically deposited into the vagina during sexual intercourse?

A

200 million

33
Q

Approximately how many sperm reach the egg?

A

50

34
Q

What are some of the barriers that a sperm faces when it tries to reach the egg?

A

Acid from the inner lining of the uterus,
mutations,
crowding

35
Q

Where does fertilization occur? Distinguish between fertilization and syngamy.

A

In the uterus or fallopian tube.

Syngamy occurs after fertilization where the nuclei of the egg and sperm fuse to form a zygote. Upper 1/3 of oviduct.

36
Q

About how long after fertilization does implantation occur? Where does implantation occur?

A

In the uterus about a week after fertilization.

37
Q

About how long after fertilization does the placenta start to develop?

A

Second week after fertilization

38
Q

Whose cells (mother’s or baby’s) are use to make the following structures: placenta, umbilical cord, chorion, amnion?

A

Placenta: both mother and embryo
Umbilical cord: baby’s blood
Amnion: inner membrane
Chorion: outer membrane

39
Q

Whose gamete determines the sex of the baby - Mom’s or Dad’s?

A

Dads

40
Q

The developing child is called an embryo up to 8 weeks after fertilization. From 8 weeks to birth, the developing child is called a fetus.

A

a

41
Q

Identify the meaning of AID and AIH. Be able to give an example of when each could be used.

A

Artificial Insemination by Donor

Artificial Insemination by Husband

42
Q

What does CVS stand for?

A

Chorionic Villus Sampling

43
Q

Describe the process of CVS.

A

Catheter is inserted into mother’s cervix,
cells are collected from the chorion membrane,
6-10 weeks of pregnancy,
1 in 100 miscarriage

44
Q

Describe the process of amniocentesis.

A

Amniotic fluid removed,
14-18 weeks pregenant,
cells from fetus are cultured,
1 in 200 miscarriage

45
Q

Compare the pros and cons of CVS and amniocentesis. What factors would you need to consider if you had to choose one of these procedures over another?

A

1:100 vs. 1:200 miscarriage
Early pregnancy vs. later in pregnancy
Cost the same

46
Q

Rank these in order of least risky to the fetus to most risky: amniocentesis, fetoscopy, ultrasound, CVS

A

Ultrasound, amniocentesis, CVS and fetoscopy

47
Q

What are some ethical concerns regarding in vitro fertilization and pre-implantation genetic diagnosis?

A

How many embryos should the doctor implant?

Having a child just for a bone marrow transplant for another child?

48
Q

What guidelines are used regarding in vitro fertilization?

A

Guidelines on how many embryos to implant based on age and other factors

49
Q

What is a “favorable” situation regarding IVF?

A

Embryos haven’t been frozen, good quality, first cycle, previous success with IVF