What are the IQ ranges and classifications?
Wechsler Intelligence Scales
| Corresponding IQ Range | Classifications | More value-neutral terms |
|---|---|---|
| 120–129 | Superior | Well above average |
| 110–119 | High average | High average |
| 90–109 | Average | Average |
| 80–89 | Low average | Low average |
Is there such thing as up syndrome?
Up Syndrome is a 2001 American documentary directed by Duane Graves. Its director and subject, both lifelong friends, took home the National Media Award from the National Down Syndrome Congress in 2002. …
What is the karyotype of Down syndrome?
The trisomy 21 karyotype figure shows the chromosomal arrangement, with the prominent extra chromosome 21. Trisomy 21 is the cause of approximately 95% of observed Down syndrome, with 88% coming from nondisjunction in the maternal gamete and 8% coming from nondisjunction in the paternal gamete.
What does 47xy mean?
| Klinefelter syndrome | |
|---|---|
| 47,XXY karyotype | |
| Pronunciation | /ˈklaɪnfɛltər/ |
| Specialty | Medical genetics |
| Symptoms | Above average height, weaker muscles, poor coordination, less body hair, breast growth, less interest in sex, infertility. |
What stage of meiosis does Down syndrome occur?
Down syndrome (trisomy 21) Most cases of trisomy of chromosome 21 are caused by a nondisjunction event during meiosis I (see text).
Does polyploidy occur in humans?
True polyploidy rarely occurs in humans, although polyploid cells occur in highly differentiated tissue, such as liver parenchyma, heart muscle, placenta and in bone marrow. Aneuploidy is more common.
Do humans have homologous chromosomes?
The homologous chromosomes of humans based on the gene sequences, loci, and centromere location. A somatic cell (2n) contains 46 chromosomes and 22 of them are homologous. If the sex chromosomes are both X chromosomes, then the total number of homologous chromosomes is 23.
How many chromosomes are in each human karyotype?
46 chromosomes
Which karyotype is from a human?
Human karyotype The most common karyotypes for females contain two X chromosomes and are denoted 46,XX; males usually have both an X and a Y chromosome denoted 46,XY. Approximately 1.7% percent of humans are intersex, sometimes due to variations in sex chromosomes.
What are the two types of chromosomes?
Chromosomes in humans can be divided into two types: autosomes (body chromosome(s)) and allosome (sex chromosome(s)).
What are paired chromosomes called?
homologous chromosomes
Why is crossing over important?
Crossing over is essential for the normal segregation of chromosomes during meiosis. Crossing over also accounts for genetic variation, because due to the swapping of genetic material during crossing over, the chromatids held together by the centromere are no longer identical.
What is the most metabolically active phase of cell division?
Interphase is the ‘daily living’ or metabolic phase of the cell, in which the cell obtains nutrients and metabolizes them, grows, replicates its DNA in preparation for mitosis, and conducts other “normal” cell functions. Interphase was formerly called the resting phase.
What are the stages of prophase 1?
Prophase I is divided into five phases: leptotene, zygotene, pachytene, diplotene, and diakinesis.
What happens during Leptotene?
The leptotene stage, also known as the leptonema, is the first of five substages of prophase I in meiosis. During the leptotene stage those duplicated chromosomes—each consisting of two sister chromatids—condense from diffuse chromatin into long, thin strands that are more visible within the nucleoplasm.
Which is the most longest and complex phase of meiosis describe it in brief?
Prophase I is by far the longest phase of meiosis (lasting 13 out of 14 days in mice). During prophase I, homologous maternal and paternal chromosomes pair, synapse, and exchange genetic information (by homologous recombination), forming at least one crossover per chromosome.
At what stage of prophase in which synapsis occurs?
prophase I
In which phase of cell cycle proteins are synthesized?
The g1 phase, gap 1 phase, or growth 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. In this part of interphase, the cell synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis.
When does human cell division stop?
Multicellular organisms replace worn-out cells through cell division. In some animals, however, cell division eventually halts. In humans this occurs, on average, after 52 divisions, known as the Hayflick limit.