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Chromosomes
Chromosomes contain the genetic material DNA
1,309 Questions
What chromosome is the BRCA2 gene on?
Breast cancer, as all cancers, is highly complex and caused by mutations in numerous genes - each cancer, however, will likely have different gene mutations.
However, there are some genes which are commonly mutated in a small proportion of breast cancers (a mutation in these genes shows increased susceptibility in a number of families) - the most commonly referred to are BRCA1 and BRCA2.
BRCA1 is found on 17q21 (chromosome 17, q arm, band 21) and BRCA2 on 13q12.
A segment of chromosome responsible for a particular characteristic?
DNA or genens these are the segments of the chromosome.
What is the chance that a zygote will receive one x chromosome and one y chromosome?
The chance is 50%.
What do dark bands in the chromosome indicate?
When DNA coils into a chromosome, it keeps its shape with the help of associated proteins. Where the DNA is very tightly coiled, and the proteins very condensed, that region appears as a dark band (G-band). G-bands are not very rich in genes, which means that it's ok that the DNA is tightly coiled, because it does not have to be very accessible anyway. Note that these bands are only visible when certain types of dye are used. Other types of dye will case gene-rich regions to stain darker and gene-poor regions to stain more brightly. See also: Chromosomes: Organization and Function By Adrian Thomas Sumner, 10.2.2
Why do chromosome have an x -shape?
chromatids have centraly located centriols which gives them U shape. they are attached together by a centromere resulting in X
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Chromosome are a structure in a cell's nucleus that contains hereditary material.
What is a picture called of all the chromosome in a cell?
A picture of chromosomes is called a "karyotype."
What is chromosome half come from?
Each half of your DNA (DeoxyriboNucleic Acid) comes from your parents. A genetic mutation is a permenent change in your DNA.
Is it True or false that chromosomes which carry genes are found in the nucleus of the cell?
True.
Mitochondria contain their own DNA - and the chromosomes present in mitochondria are much smaller than those found in the nucleus (they are much more similar to Prokaryotic chromosomes). Mitochondrial DNA is not involved in the central processes of the cell.
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Which pair of chromosomes can be different in size and banding pattern?
In humans, the twenty-third chromosome is different than the others. The last pair indicates whether male or female; this is why they are different
How many chromosomes do protists have?
Protists can have a wide range of chromosome numbers, which can vary from species to species. They may have a haploid number (n) or a diploid number (2n) or other variations, depending on the specific protist.
What effect does Down syndrome have on the chromosomes?
Down syndrome is usually caused by a condition known as Trisomy 21, which means that a person has three copies of Chromosome 21, rather than the usual two copies. An extra chromosome is added. The normal amount is 46, but people with Down syndrome have 47.
Occasionally, the condition is a result of part of Chromosome 21 becoming fused to the end of another chromosome.
More info on Chromosome 21
While Chromosome 21 isn't the shortest chromosome, it is the one that contains the fewest genes (other than the Y chromosome). This is because genes on Chromosome 22 are more closely spaced, and thus the chromosome contains more genes, despite its smaller size.
What chromosomes are found in body cells but not sex cells?
Sex cells (better known as gametes) being product of meiosis have single set (haploid number) of chromosomes whereas body cells have diploid number. Thus, 22 pairs of autosomes and one pair of sex chromosomes (XY), thus 46 chromosomes are present in our body cells. The gametes (sex cells) contain only 23 chromosomes in each.
mieosis.
What effect does non disjunction have on the chromosome number of the gametes?
A gamete can possess n+1 or n-1 chromosomes as a result of nondisjunction.
Why do spieces have homologous chromosomes?
Species have homologous chromosomes because these pairs consist of one chromosome inherited from each parent, ensuring genetic diversity and stability during reproduction. Homologous chromosomes carry genes for the same traits, although they may have different alleles. This arrangement allows for the proper segregation of genetic material during meiosis, facilitating the formation of gametes, and contributes to the evolutionary adaptability of the species.
How many chromosomes are present when meiosis is started?
In humans, 46 chromosomes are present when meiosis begins. The four daughter cells that result from meiosis have 23 chromosomes.
Is it a change in the chromosomes or a gene in hemophilia?
Hemophilia itself is really just a genetic disorder. It causes problems with blood coagulation and people with the disorder tend to bleed a lot if cut, hence the name "bleeders." The disorder is caused by a mutation in the factor VIII gene, leading to a deficiency in factor VIII. (Factor VIII is a protein that is associated with blood clotting.) The deficiency in the blood clotting factor causes the affected person's blood to clot improperly. The factor VIII gene is located on the X-chromosome and is transmitted by recessive inheritance. Males have an X-chromosome and and a Y-chromosome and females have two X-chromosomes. This means that females would only carry one of the mutant alleles for hemophilia and are said to be carriers. Females are usually found to be only carriers and rarely express hemophilia. Males, on the other hand, will receive one X-chromosome from their mother and a Y-chromosome from their father, leading to hemophilia.
What are statements that are true about chromosomes?
Selected Answer: The father donated one of each pair of homologous chromosomes, and the mother donated the other.
How many chromosomes does a normal individual have?
The average human has 24 chromosomes, and autistic people have two copies of the 23rd in place of the 24th
