Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Clinical Embryologist's exam samples. > MEIOSIS & MITOSIS > Flashcards

MEIOSIS & MITOSIS Flashcards

1
Q

Which is correct about the process of MEIOSIS?

  1. Occurs in all somatic cells
  2. Involves 2 rounds of DNA duplications and 2 cell divisions
  3. Involves genetic recombination and pairing of specific chromosome homologues
  4. Produces daughter cells that are genetically identical to the parent cell
A

2 and 3 are correct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which is true checkpoints during the cell cycle?

  1. Are present only in selected cells in the body.
  2. Occur only in G1 of the cell cycle
  3. Assess DNA damage before entering the Metaphase
  4. Determine whether the cell should enter an Apoptotic pathway
A

3 and 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The stage of meiosis where cells become haploid is:

  1. prophase 1
  2. prophase 2
  3. anaphase 1
  4. anaphase 2
A
  1. anaphase 1 (remember: 2nd meiosis mainly mitosis division)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

During replication of the DNA molecule, one of the original DNA strands:

  1. combines with the other original DNA strand
  2. is broken down for nucleotide units
  3. combines with one the new strands of DNA
  4. is converted in carbohydrates for energy metabolism
A
  1. Combines with one of the new DNA strands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The metaphase spindle has

a. 1 type of microtubes
b. 2 types of microtubules
c. 3 types of microtubules

A
  1. 3 types of microtubules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

which is correct. In meiosis, metaphase 1

  1. The bivalent chromosomes align on the spindle
  2. Microtubules from the same pole of the spindle attach to sister chromatids
  3. The kinetochores of sister chromatids are adjacent to each and orientated in the same direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

e68..In Meiosis Anaphase 1 Is Initiated By The Disruption Of The Chiasmata.

  1. TRUE
  2. FALSE
A
  1. TRUE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Meiosis of vertebrate oocytes is arrested in:

  1. leptotene
  2. pachytene
  3. zygotene
  4. diplotene
  5. diakinesis
A
  1. diplotene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which Is The Correct Sequence Of The Different Stages Of The Prophase In Meiosis 1 ?

  1. leptotene, pachytene, zygotene,diakinesis,diplotene
  2. diplotene, zygotene, diakinese, pachytene, leptotene
  3. diplotene, leptotene, diakinese, pachytene, zygotene
  4. leptotene, zygotene, pachytene,diplotene ,diakinesis
A
  1. correct

*Sequences of prophase 1 of Meiosis–

Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis

remember : (Lazy person die in dikernis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which is correct In prophase of meiosis 1?

  1. zygotene is the second stage
  2. diakinesis is the last stage
  3. pachytene is the fourth stage
  4. leptotene is the third stage
A

1, 2

lepto……zygo….patchy……diplo. dikinasis

(la zy person die in dikenis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which Is True. In Meiosis Methapase 2 Arrest Is .

  1. maintained by c-mos
  2. maintained by Cyclic AMP
  3. maintained by MAP Kinase
  4. maintained by MPF (maturation promoting factor: a complex of Cdc2 and cyclin B)
A

all correct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

which is correct? In humans’ oocytes remain in the diplotene stage of the first meiotic division

  1. only for a few hours
  2. up to 40 years
  3. up to puberty
A
  1. up to puberty
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which Is Correct? During The Diplotene Arrest.

  1. Chromosomes decondense and are actively transcribed
  2. Important amounts of mRNAs and proteins are stored
  3. there is no transcriptional activity
A

1, 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which Is Correct ?

  1. Chiasmata become visible in the diplotene
  2. the “crossing over” starts already in the pachytene
  3. close association of homologous chromosomes (synapsis) starts during leptotene
A

1, 2

close association of homologous chromosomes (synapsis) starts NOT during leptotene (correct is in zygotene)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How Much Percent Oocytes Have the Second Polar Body Extruded 1 Hour After Sperm Injection In ICSI?

  1. already 1 in 2
  2. 78 % (after 3h; after 2h 56%)
  3. about 30 %
  4. none it is far too early
A
  1. about 30 % of Oocytes Have the Second Polar Body Extruded 1 Hour After Sperm Injection In ICSI
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which Is NOT Correct? Maturation Promoting Factor

  1. Is composed of cyclin A and p34cdc2
  2. Is composed of cyclin B and p34cdc2
  3. Is activated by removal of the phosphate from tyrosine 15 of the p34cdc2
  4. Is involved in germinal vesicle breakdown
A

1 not correct

Maturation Promoting Factor MPF composed of cyclin B and p34cdc2,

its involved GV Breakdown , while its inactivated during arrest period by removal of phosphate from tyrosine 15 of p34cdc2

17
Q

Which Factors Have to be Present in High Concentrations to Ensure Germinal Vesicle Breakdown?

  1. phosphorylated p34cdc2
  2. active p34cdc2
  3. MPF
  4. c-mos
  5. MAP kinase
  6. cyclic AMP
A

1,2 and 3

The resumption of meiosis (GV Breakdown) in response to the LH surge is initiated by the cumulus (granulosa) cells, because the oocyte itself does not possess LH receptors. Responding to LH, the cumulus cells shut down their gap junctions . This reduces the transfer of both cAMP and cGMP from the cumulus cells into the oocyte. The resulting reduction of cGMP in the oocyte allows the activation of PDE3A. The activated PDE3A then breaks down the intra-oocytic cAMP into 5′AMP. The decline in the concentration of cAMP sets off a signaling pathway leading to the activation of MPF and the subsequent resumption of meiosis.

18
Q

During Meiosis Tetrads become Visible in

  1. Telophase 2
  2. Prophase 2
  3. Anaphase 1
  4. Prophase 1
A
  1. Tetrad become visible in prophase 1 (zygotene)
19
Q

The Stage of Meiosis I During Which Recombination (synapsis) Takes Place Between Homologous Chromosomes is Called

  1. leptotene
  2. zygotene
  3. pachytene
  4. diplotene
  5. diakinesis
A
  1. Pachytene- Prophase1: recombination or synapsis between homologous chromosomes

leptotene: chromosomes appear thin and long, in initial stage of the extended prophase of meiosis 1 ,the homologous chromosomes pair before condensation.

zygotene: Tetrad appear ,chromosomes side by side by their length

pachytene: synapsis, crossing over, recombinant chromatids or homologous chromosomes

diplotene: chiasmata, DNA sequences exchange(Homologous Chromosomes Separate Along Their Length But Remain Associated At Chiasmata)

diakinesis: final stage of prophase 1 and start metaphase1 of Meiosis

20
Q

the stage of meiosis 1 during which homologous chromosomes separate along their length but remain associated at chiasmata is called:

  1. leptotene
  2. zygotene
  3. pachytene
  4. diplotene
  5. diakinesis
A

diplotene stage (chiasmata)

21
Q

The Final Stage Of Prophase Of Meiosis 1 During Which The Chromosomes Fully Condense And The Cell Progress To Metaphase Is Called

  1. leptotene
  2. zygotene
  3. pachytene
  4. diplotene
  5. diakinesis
A
  1. diakinesis
22
Q

The Initial Stage Of The Extended Prophase Of Meiosis 1 During Which Homologous Chromosomes Pair Before Condensation Is Called

  1. Leptotene
  2. zygotene
  3. pachytene
  4. diplotene
  5. diakinesis
A
  1. Leptotene
23
Q

During meiosis:

when does chromosome disjunction occur?

When does chromatid disjunction occur?

A

Chromosome disjunction occurs during anaphase I.

Chromatid disjunction occurs during anaphase II.

24
Q

Perform a chi-square test to determine if an observed ratio of 30 tall to 20 dwarf pea plants is consistent with an expected ratio of 1:1 from the cross Dd × dd.

A

X2​= (O-E)2/E

(O) Observed= 30 (E) Expected= 25 (المتوقع من اجمالي 50)

x2 = (30 − 25)2 /25 + (20 − 25)2 /25 = 2,

which is less than 3.84, the 5% critical value for a chi-square statistic with 1 degree of freedom من الجدول; consequently,

the observed segregation ratio is consistent with the expected ratio of 1:1

25
Q

Albinism in humans is caused by a recessive allele

  • a. From marriages between people known to be carriers (Aa) and people with albinism (aa), what proportion of the children would be expected to have albinism?
  • Among three children, what is the chance of one without albinism and two with albinism?
A

Half the children from Aa × aa matings would have albinism.

In a family of three children, the chance that one will be unaffected and two affected is

3 × (1/2)1 × (1/2)2 = 3/8.

26
Q

If both husband and wife are known to be carriers of the allele for albinism, what is the chance of the following combinations in a family of four children:

  • (a) all four unaffected.
  • (b) three unaffected and one affected.
  • (c) two unaffected and two affected.
  • (d) one unaffected and three affected.
A

(a) (3/4)4 = 81/256.
(b) 4 × (3/4)3 × (1/4)1 = 108/256.
(c) 6 × (3/4)2 × (1/4)2 = 54/256.
(d) 4 × (3/4)1 × (1/4)3 = 12/256.

27
Q

If a man and a woman are heterozygous for a gene, and if they have three children, what is the chance that all three will also be heterozygous?

A

Aa * Aa

AA, Aa, AA, Aa

Aa = 0.5

chance of all heterozygous = (probability of event)3

=(1/2)3 =1/8

28
Q

In fetal Ovary: Germ cells divided ……… But at ……. weeks start………. division then before birth meiotic arrest at …………………………………………

A

In fetal Ovary: Germ cells divided mitotically But

at 11-12 weeks start Meiotic division then before birth meiotic arrest at prophase (diplotene stage) of 1st meiosis GV stage

29
Q

Pros and cons Sexing by FISH to exclude X-linked affected males?

A

affected and unaffected males will be discarded, and can’t distinguish between carrier and unaffected females

30
Q

compare twining differences

A

1. Dizygotic (fraternal) twins

  • a. Result from the fertilization of two different secondary oocytes by two different sperm; the resulting two zygotes form two blastocysts, which implant separately into the endometrium of the uterus.
  • b. Hence, the twins are no more genetically alike than are siblings born at different times.
  • c. Dizygotic twins and 35% of monozygotic twins have two placentas, two amniotic sacs, and two chorions (i.e., a diamnionic-dichorionic membrane).

2. Monozygotic (identical) twins

  • a. Result from the fertilization of one secondary oocyte by one sperm. The resulting zygote forms a blastocyst in which the inner cell mass (embryoblast) splits into two.
  • b. Hence, the twins are genetically identical.
  • c. In 65% of the cases, monozygotic twins have one placenta, two amniotic sacs, and one chorion (i.e., a diamnionic-monochorionic membrane).

3. Conjoined (Siamese) twins

  • a. Form exactly like monozygotic twins, except that the inner cell mass (embryoblast) does not completely split.
  • b. Hence, two embryos form, but they are joined by tissue bridges at various regions of the body (e.g., head, thorax, or pelvis)
31
Q

Syndactyly ?

A

Syndactyly is the most common congenital malformation of the limbs fusion of fingers or toes

Clinical Embryologist's exam samples. (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions