Exam Questions 2022 Flashcards
from ESRE 2022
Which bond links amino acids in the sequence of a protein?
a) Hydrogen
b) Ester
c) Glycosidic
d) Peptide
e) Carbon
d.
Ethylene oxide is commonly used to disinfect:
a) Plastic syringes
b) Incubators
c) Benches
d) Hands
e) Air
b.
.Trophectoderm–derived cells contribute to the:
- a) Fetus
- b) Chorionic villi
- c) Amniotic sac
- d) Uterus
- e) Vitelline sac
b.
Intracellular ice crystal formation is:
- a) Induced by storing embryos at temperatures
- b) Prevented by an increased permeability of the cell membrane
- c) Decreased by removing most of the water from the embryo
- d) Avoided by vitrification
- e) Increased by raising intra‐cellular solute concentration
C.
In PGD for X‐linked recessive disease:
where the female is a heterozygous carrier, and the male is normal, what proportion of the female embryos will be affected?
- a) None
- b) 75%
- c) 50%
- d) 25%
- e) 100%
a.
According to the European Directive 2012/39/EU and as far as partner donatio
the permitted time interval until repeat blood testing is:
- a) Up to 24 months
- b) Every 6 months
- c) Every time the samples are produced
- d) Up to 12 months
- e) Every time the samples are used
a.
The biggest challenge to cells during freezing is:
- a) Their ability to endure storage at very 0 temperatures
- b) Their ability to endure storage at very low temperatures
- c) The lethality of an intermediate zone of temperature (-15 to ‐60ºC) that they must pass during cooling
- d) Tolerance to cryoprotectant agents
- e) The ability to form ice crystals
c.
Vitrified embryos:
- a) Do not contain any ice crystals
- b) Are completely dehydrated
- c) Can be safely stored at ‐80ºC
- d) Can contain ice crystals
- e) Can only be stored in liquid nitrogen
a.
The genes implicated in premature ovarian failure include:
- a) SRY and SOX‐9
- b) AZF and ZFX
- c) ZFX and FMR1
- d) FMR1 and AMH
- e) FSH and LH
c.
FMR1: involve premature ovarian failure
ZFX:
Zinc finger protein X-linked : a sex determination factor and plays a critical role in spermatogenesis.
During female meiosis:
- a) Meiosis I is completed during fetal development
- b) Meiosis II starts during fetal growth
- c) Meiosis I is arrested in diplotene during fetal development
- d) Meiosis II is arrested in diplotene during fetal development
- e) Meiosis I starts after puberty
c.
1. Ultrasound examination of an anovulatory patient with polycystic ovary syndrome (PCOS) reveals that her ovaries contain multiple enlarged but immature follicles. The oocytes within these follicles have advanced to which of the following stages of meiosis?
A. First meiotic prophase
B. First meiotic metaphase
C. Second meiotic prophase
D. Second meiotic metaphase
E. Pronuclear stage
A.
An undescended testis of a prepubertal male is removed since it is at higher risk to develop testicular cancer. Histologic analysis reveals that cells of the germ line in this testis have advanced as far as which of the following stages of development?
A. Primordial germ cell
B. Spermatogonium
C. Primary spermatocyte
D. Secondary spermatocyte
E. Definitive spermatocyte
B.
A female patient with unexplained infertility is treated with menopausal gonadotropin and pure follicle stimulating hormone to induce follicular development. Several oocytes are aspirated from enlarged follicles and cultured in nutrient medium until they reach the normal second stage of meiotic arrest before they are fertilized. Fertilization is therefore carried out at which of the following stages of oocyte development?
A. Prophase of the primary oocyte
B. Metaphase of the primary oocyte
C. Prophase of the Secondary oocyte
D. Metaphase of the Secondary oocyte
E. Prophase of the definitive oocyte
F. Metaphase of the definitive oocyte
D.
A 22 year old male with respiratory difficulties is diagnosed with a mediastinal germ cell tumor. The primordial germ cell that gave rise to this tumor inappropriately migrated to this site from which of the following tissues?
- A. Liver
- B. Testis
- C. Yolk sac
- D. Allantois
- E. Spleen
D.
Misdirected primordial germ cells that lodge in extragonadal sites usually die, but if such cells survive, they may develop into teratomas.
Teratomas are bizarre غير طبيعي growths that contain scrambled mixtures of highly differentiated tissues, such as skin, hair, cartilage, and even teeth .
They are found in the mediastinum, the sacrococcygeal region, and the oral region.
Chromosome analysis is carried out on the polar bodies of a woman for screening prior to in vitro fertilization. Polar bodies removed from some oocytes contain two copies of chromosome 21 while others contain no copies of chromosome 21. The woman displays none of the characteristics of Down syndrome and so the nondisjunction that resulted in this condition must have occurred in which of the following cells?
A. Primary oocyte in her mother’s germline
B. Secondary oocyte in her mother’s germline germline
C. Blastomere in her mother’s germline
D. Primary oocyte in her own germ line
E. Secondary oocyte in her own germline
F. Blastomere in her own germ line
D.
Normally, chromosomes are visible only during mitosis and meiosis.
When cells are not undergoing division, ⇒ the genetic material making up chromosomes unfolds and uncoils into a diffuse network within the nucleus, generally referred to as chromatin.
true
(essential repro book)
Various receptor molecules are also found on the surfaces of cells. These molecules act as……………………
recognition sites that transfer specific chemical signals across the cell membrane into the cell
nucleolus organizer region, or the NOR?
nucleolus present in the nucleus , where ribosomal RNA (rRNA) is synthesized and where the initial stages of ribosomal assembly occur►. The portions of DNA that encode rRNA
nucleoid
In eubacteria, such as Escherichia coli,
the genetic material is present as a long,
circular DNA molecule that is compacted into an unenclosed region called
the nucleoid.
endoplasmic reticulum (ER) appears of two Regions??
The ER appears smooth ER in places where it serves as the site for synthesizing fatty acids and phospholipids;
in other places, it appears
rough ER because it is studded with ribosomes. Ribosomes serve as sites where genetic information contained in messenger RNA (mRNA) is translated into proteins.
Mitochondria
Mitochondria
are found in most eukaryotes, including both animal and plant cells, and are the sites of the oxidative phases of cell respiration.
These chemical reactions generate large amounts of the energy-rich molecule Adenosine Triphosphate (ATP).
Chloroplasts
Chloroplasts,
found in plants, algae, and some protozoans, are associated with photosynthesis,
the major energy-trapping process on Earth.
Both mitochondria and chloroplasts contain DNA in a form distinct from that found in the nucleus.
They are able to duplicate themselves and transcribe and translate their own genetic information.
Centrioles & Centrosome
Animal cells and some plant cells also contain
a pair of complex structures called centrioles.
These cytoplasmic bodies, each located in a specialized region called
the centrosome, are associated with the organization of
spindle fibers that function in mitosis and meiosis
spindle fibers
spindle fibers organized by the centrioles ►occurs during the early phases of mitosis and meiosis.
These fibers play an important role in the movement of chromosomes as they separate during cell division.
They are composed of arrays of microtubules consisting of ≈≈►
polymers of the protein tubulin.
Centromere
the site connect homologous chromosome, location establishes the general appearance of each chromosome.
Extending from either side of the centromere are the arms of the chromosome.
double structure consisting of two parallel sister chromatids connected by a common centromere.
Had these chromosomes been allowed to continue dividing, the sister chromatids, which are replicas of one another, would have separated into the two new cells as division continued. The haploid number (n) of chromosomes is equal to one-half the diploid number.
Depending on the position of the centromere, different arm ratios are produced.
figure**Centromere locations and the chromosome designations that are based on them. Note that the shape of the chromosome during anaphase is determined by the position of the centromere during metaphase.
chromosomes are classified as ……..,………,……,… according the centromere position?
chromosomes are classified as metacentric, submetacentric, acrocentric, or telocentric on the basis of the centromere location.
The shorter arm, by convention, is shown above the centromere and is called the p arm (p, for “petite”).
The longer arm is shown below the centromere and is called the q arm
(q because it is the next letter in the alphabet).
Homologous Chromosomes
somatic chromosomes (44), exist in pairs (22), each pair are called homologous chromosomes.
With the exception of sex chromosomes
locus
Homologous chromosomes have important genetic similarities.
They contain identical gene sites along their lengths ►;
each site is called
a locus (pl. loci).
alleles
An allele is a variant form of a gene.
Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome.
Humans are called diploid organisms because they have two alleles at each genetic locus,
one allele inherited from each parent.
During interphase: the replication of the DNA of each chromosome. this period of DNA synthesis before the cell entering mitosis is called…………………
S phase. (s: from synthesis), period of interphase where DNA synthesis before the cell enter mitosis.
Before and after S phas e⇒ there are two (Gaps) periods of interphase where No DNA syntheses called : G1 & G2
During both of these intervals (G1 & G2), as well as during S, intensive metabolic activity, cell growth, and cell differentiation .
By the end of G2, the volume of the cell has roughly doubled,⇒ DNA has been replicated, and mitosis (M) is initiated.
Following mitosis, continuously dividing cells then repeat this cycle
(G1, S, G2, M) over and over, as shown in Figure
The cell stay most time in the interphase …………
true
stages of Mitosis
prophase, prometaphase, metaphase, anaphase, and telophase.
see the fig
Prometaphase & Metaphase
term prometaphase refers to the period of chromosome movement
Migration is made by the binding of spindle fibers to the chromosome’s kinetochore Once properly attached to the spindle fibers, ……… is degraded by an enzyme, appropriately named …………..
Migration of chromosomes is made by the binding of spindle fibers to the chromosome’s kinetochore
Once properly attached to the spindle fibers ► Cohesin is degraded by an enzyme, appropriately named Separase
Ccohesin is degraded Except at the centromere region.?
due to the presence of shugoshin protein ► protects cohesin from being degraded by separase at the centromeric regions
Gene expression consists …………
Gene expression consists of transcription of DNA into mRNA ⇒ and the translation (⇒) of mRNA (with the help of a ribosome) into a protein
chiasma
chiasma (pl., chiasmata),
point where nonsister chromatids (one paternal and one maternal chromatid) have undergone genetic exchange through the process of crossing over.
nondisjunction
describes such an error. At the completion of a normal anaphase I,
At anaphase I, one-half of each tetrad (the dyad) is pulled toward each pole of the dividing cell.
This separation process is the physical basis of disjunction,
the separation of chromosomes from one another. Occasionally, errors in meiosis occur and separation is not achieved.
The term nondisjunction describes such an error ►at anaphase I
Spermatogenesis and oogenesis
There is a major difference between meiosis in males and in females.
spermatogenesis partitions the cytoplasmic volume equally and produces four haploid sperm cells.
Oogenesis, on the other hand, collects the bulk of cytoplasm in one egg cell and reduces the other haploid products to polar bodies.
arrest meiosis in oocyte
Meiosis is initiated in all the eggs of a human female when she is still a fetus, until the point where the homologs synapse and recombination has begun. Then oocyte development is
arrested in meiosis I in diplotene stage of prophase 1.
Thus, all primary oocytes have been formed by birth.
When ovulation begins at puberty, meiosis is reinitiated in one egg during each ovulatory cycle and continues into meiosis II.
The process is once again arrested after ovulation and is not completed unless fertilization occurs.
The neural crest cells
The neural crest cells differentiate from ⇒neuroectoderm of the neural tube and form ►a column of cells along both sides of the neural tube.
Neural crest cells undergo a prolific migration throughout the embryo (both the cranial region and the trunk region) and ultimately differentiate into a wide array of adult cells and structures. as in the figure
true or fulse?
Johnson score for detection of testicular spermatogenesis affected by testicular size?
not affected
Tumor arises from primitive streak remnants is …………
Sacrococcygeal Teratoma (ST)
- More commonly in female infants
- must be removed by 6 month age
true or false??
Caudal dysplasia (sirenomelia) refer to syndromes caused by fusion of upper limbs.
false
Caudal dysplasia (sirenomelia). caused by abnormal gastrulation in which the migration of mesoderm through primitive streak is disturbed. causing complete fusion of lower limbs.
