Human Genetics and Chromosome Disorders

<p>Prophase I (D)</p> Signup and view all the answers

<p>Interchange of chromatid segments takes place (A)</p> Signup and view all the answers

<p>Unipotent (B)</p> Signup and view all the answers

<p>Double-stranded with deoxyribonucleotides (C)</p> Signup and view all the answers

<p>23 (B)</p> Signup and view all the answers

<p>45, X karyotype (A)</p> Signup and view all the answers

<p>Turner syndrome (A)</p> Signup and view all the answers

<p>Partial deletion of chromosome 5 (C)</p> Signup and view all the answers

<p>Chromosome 15 (C)</p> Signup and view all the answers

<p>The result is an individual with 47 chromosomes. (D)</p> Signup and view all the answers

<p>Cri-du-chat syndrome (C)</p> Signup and view all the answers

<p>An extra sex chromosome (C)</p> Signup and view all the answers

<p>Environmental factors (B)</p> Signup and view all the answers

<p>Prader-Willi syndrome (C)</p> Signup and view all the answers

<p>Congenital heart defects (B)</p> Signup and view all the answers

<p>Presence of a Barr body (A), Testicular atrophy (C)</p> Signup and view all the answers

<p>Males are affected more often than females (C)</p> Signup and view all the answers

<p>Loss of essential genetic material (A)</p> Signup and view all the answers

<p>1 in 2000 (A)</p> Signup and view all the answers

<p>Flexion of fingers and hands (C)</p> Signup and view all the answers

<p>An extra copy of chromosome 13 (D)</p> Signup and view all the answers

<p>Crossover of genetic material (A)</p> Signup and view all the answers

<p>23 chromosomes (D)</p> Signup and view all the answers

<p>They are eliminated and degenerate (D)</p> Signup and view all the answers

<p>45,X (D)</p> Signup and view all the answers

<p>46 (B)</p> Signup and view all the answers

<p>Chromosome number classifications (B)</p> Signup and view all the answers

<p>Aneuploid (B)</p> Signup and view all the answers

<p>23 pairs (D)</p> Signup and view all the answers

<p>Fourth week (C)</p> Signup and view all the answers

<p>Mitosis (A)</p> Signup and view all the answers

<p>They undergo apoptosis (A)</p> Signup and view all the answers

<p>To reach the gonads for gamete formation. (D)</p> Signup and view all the answers

<p>Differentiation (D)</p> Signup and view all the answers

<p>They move actively towards the gonads. (A)</p> Signup and view all the answers

<p>To ensure only competent PGCs survive. (D)</p> Signup and view all the answers

<p>Initially passive, then active (A)</p> Signup and view all the answers

<p>The nuclear envelope is broken (B)</p> Signup and view all the answers

<p>To control the entry into anaphase (A)</p> Signup and view all the answers

<p>Sister chromatids split at the centromere (D)</p> Signup and view all the answers

<p>The nuclear envelope reassembles (C)</p> Signup and view all the answers

<p>Formation of the cleavage furrow (B)</p> Signup and view all the answers

<p>They revert to a less condensed state (B)</p> Signup and view all the answers

<p>Metaphase checkpoint influence of the kinetochore (B)</p> Signup and view all the answers

<p>Early G1 phase (D)</p> Signup and view all the answers

The process by which a cell transforms into a specialized cell type with a specific function. For instance, a stem cell may differentiate to become a muscle cell, a neuron, or a red blood cell.

The movement of primordial germ cells (PGCs) from their initial location in the yolk sac to the gonads, the developing sex organs.

The increase in the number of primordial germ cells (PGCs) through cell division, a crucial process for ensuring a sufficient supply of germ cells for gamete production.

A process in which cells that fail to migrate properly or reach the gonads are eliminated through programmed cell death. It's like a natural selection process for PGCs.

The time during which an individual develops sexually mature characteristics, leading to the ability to reproduce.

The study of the formation and development of an embryo from fertilization to birth. It involves understanding the processes of cell division, growth, and specialization.

The science that investigates developmental abnormalities and malformations, focusing on factors causing congenital defects.

Centrioles play a crucial role in forming the microtubules that make up the mitotic spindle, which is responsible for separating chromosomes during cell division.

Microtubules from the mitotic spindle attach to kinetochores, specialized protein structures on chromosomes. This attachment allows the spindle to align chromosomes at the middle of the cell during metaphase, ensuring equal distribution of genetic material into daughter cells.

Metaphase is a stage of mitosis characterized by the alignment of chromosomes along the equator of the cell. This arrangement ensures that each daughter cell receives a complete set of chromosomes.

Anaphase marks the separation of sister chromatids, which are identical copies of a chromosome, at the centromere. These chromatids are pulled apart by the shortening of microtubules towards opposite poles of the cell.

Telophase is characterized by the re-formation of the nuclear envelope around the separated chromosomes at each pole of the cell. This process also involves the uncoiling of chromosomes and the reappearance of nucleoli.

Cytokinesis is the process of cell division that follows mitosis. During cytokinesis, the cytoplasm of the parent cell divides, forming two daughter cells, each with its own nucleus and complete set of organelles.

The metaphase checkpoint ensures that all chromosomes are properly aligned at the equator of the cell before proceeding to anaphase. This checkpoint prevents daughter cells from receiving an unequal number of chromosomes.

The nuclear envelope disintegrates during prophase, allowing chromosomes to be accessible to the microtubules of the mitotic spindle. This disintegration is triggered by the phosphorylation of the nuclear lamina proteins, which are responsible for maintaining the structural integrity of the nuclear envelope.

The process where homologous chromosomes exchange genetic material during meiosis, leading to increased genetic diversity amongst offspring.

A germ cell (sperm or egg) contains half the number of chromosomes found in a normal body cell.

During meiosis, one primary oocyte produces four daughter cells, but only one develops into a mature egg. The other three, smaller cells with less cytoplasm, are called polar bodies and degenerate.

A primary spermatocyte undergoes meiosis to produce four sperm cells. Two of these sperm cells have 22 chromosomes and an X chromosome, while the other two have 22 chromosomes and a Y chromosome. All four sperm cells are functional.

Chromosomes are like organized packages of genetic information in cells. Humans have 23 pairs of chromosomes, with one copy received from each parent. These pairs are organized into 22 pairs of autosomes and one pair of sex chromosomes (XX for females, XY for males).

Any chromosome number that is not a multiple of the haploid number (n) is considered aneuploid. An extra chromosome is called trisomy, and a missing chromosome is called monosomy.

During meiosis, homologous chromosomes should separate. When they fail to separate properly (nondisjunction), one daughter cell gets too many chromosomes and the other gets too few.

A normal somatic cell has 46 chromosomes, while a germ cell has 23 chromosomes. This difference is due to meiosis, which reduces the number of chromosomes in half.

DNA is organized into structures called chromosomes, which are made up of two strands of deoxyribonucleotides twisted together in a helix. Each strand consists of alternating deoxyribose sugar molecules (S) and phosphate groups (P), with each deoxyribose unit connected to a nitrogenous base.

Human cells normally contain 46 chromosomes (diploid number), arranged as 22 pairs of autosomes and 2 sex chromosomes (XX for female, XY for male).

During the S phase of the cell cycle, each chromosome is duplicated, resulting in two identical copies called sister chromatids. These chromatids are attached at a constricted region called the centromere.

The DNA within each chromosome has a strong association with histone proteins, which help package and organize the DNA within the nucleus.

Karyotyping is a process of examining chromosomes of dividing cells to analyze their number and structure. It is used to diagnose chromosomal abnormalities in individuals or malignant tumors.

Stem cells are undifferentiated cells that have the potential to divide and differentiate into various cell types. Totipotent stem cells can become any cell type, while multipotent stem cells can produce multiple lineages, and unipotent stem cells can only produce one type of cell. Pluripotent stem cells can form all three basic body layers and germ cells.

Meiosis is a type of cell division that occurs in germ cells to produce gametes (sperm and egg cells). It involves two divisions (meiosis I and meiosis II) that reduce the chromosome number to the haploid number (23).

During meiosis I, homologous chromosomes pair up in a process called synapsis, and then separate into two daughter cells. Meiosis II then separates the sister chromatids.

A chromosomal abnormality where an individual has an extra copy of a chromosome (47 chromosomes instead of 46).

A chromosomal abnormality where an individual has one less copy of a chromosome (45 chromosomes instead of 46).

A change in chromosome structure where a piece of one chromosome breaks off and attaches to another chromosome.

A translocation where no genetic material is lost, resulting in a normal phenotype.

A translocation where some genetic material is lost, resulting in an altered phenotype.

A condition where some cells in the body have a normal chromosome number, while others have an abnormal chromosome number, leading to a mosaic of different cell types.

A genetic disorder caused by an extra copy of chromosome 21, resulting in a range of physical and developmental challenges.

A chromosomal condition where an individual has only one X chromosome, resulting in female characteristics but with specific features. This is the only monosomy compatible with life.

A rare genetic disorder where women have three X chromosomes, often leading to few symptoms.

A type of chromosomal abnormality that occurs due to breakage of one or more chromosomes, often caused by environmental factors.

A type of chromosomal abnormality involving small deletions of a segment of a chromosome. This can lead to specific genetic syndromes.

A rare genetic disorder caused by a deletion on the long arm of chromosome 15, inherited from the mother. It is characterized by developmental delays, speech difficulties, and happy demeanor.

A rare genetic disorder caused by a deletion on the long arm of chromosome 15, inherited from the father. It is characterized by developmental delays, excessive hunger, and short stature.

Regions of chromosomes that are prone to breakage under certain conditions. Fragile X syndrome, caused by a break on the X chromosome, is a common example.

A change in the structure or function of a single gene, responsible for numerous inherited conditions. Mutations can affect both copies of a gene, inherited from either parent.