Questions tagged [chromosome]

A single piece of DNA coiled and organized along with RNA and proteins found in the cell.

Filter by
Sorted by
Tagged with
0
votes
0answers
16 views

How much of the 23 chromosomes of two humans of same gender match?

Like, if there are 2 guys who produce sperm. Each sperm contain 23 chromosomes, when randomly taken, how much difference do both of them show? And the difference between two sperms from the same ...
0
votes
2answers
2k views

Barr body Giemsa staining

Not all the female cheek cells show Barr Bodies when stained with Giemsa stain? Only 30 to 40% female cells show Barr Bodies. Why? Our Experiment: We washed mouth twice with listerine to reduce ...
5
votes
4answers
5k views

The human has 46 double chromosomes or simple chromosomes?

What I mean: does the human cell have 46 of these: or 46 of these: Thank you in advance.
0
votes
0answers
14 views

Is it possible to assemble chromosomes from different parent cells?

Assuming that one or two parents are carrying a genetic defect/disease which is localised on a specific chromosome, would it be possible to assemble a new haploid cells taking a (half) chromosome from ...
4
votes
1answer
1k views

What is a holocentric chromosome?

I was doing this question that asked: "How many centromeres does a typical chromosome have?" I thought one and the answer was:"One, except for holocentric chromosomes." So then what are "...
1
vote
2answers
45 views

Why do chromosomes uncoil back to chromatin after cell divisions?

At the telophase of meiotic and mitotic cell divisions, the chromosomes of daughter cells uncoil back to chromatin, but after interphase, it coils up again to form visible chromosomes. Why do this ...
-1
votes
2answers
64 views

Identify which of the two columns A and B represent gene and chromosome

I am a bit confused on this question in my Textbook (STD 12) and have got all sorts of answers on searching it but I am still not able to comprehend it literally. Can someone answer this and explain ...
0
votes
0answers
22 views

Are human cells tetraploid during cell division?

If human cells are diploid, and DNA replicates before cell division, does it mean that our cells are tetrapolid for a short period of time (DNA replication - cell division). Photos of chromosomes are ...
5
votes
1answer
405 views

Do telomeres appear at just one end of the chromosome?

I have just studied DNA Replication for my Biology Class and I have this question that leaves me stuck, though I have tried to figure it out myself. During telomere replication, I am aware Telomerase ...
1
vote
0answers
25 views

chromosome 19 and recombination

Im doing a project with structural variation created by recombination within the human genome during spermatogenesis, where im especially examining intrachromatid homolog recombination. I find that ...
4
votes
1answer
49 views

Chromosome naming convention: Why are there chromosomes named “1” and “1A”?

I've been stumbling on multiple genome of birds where there is a "1A" chromosome and a "1" chromosome. For example, the zebra finch has 1A and 4A. What does that mean? Do you have any resource about ...
0
votes
1answer
30 views

Chromosome size without heterochromatin

Im doing different analysis of the human chromosomes and diffent loci, however when using different databases, the heterochromatin structures are not part of the human genomes. I know that ...
1
vote
1answer
42 views

Barr body in mitosis

In early embryonic development, some female cells pass through a process called lionization and one of the X chromosomes get condensed and began to be called Barr body. What I don't understand is ...
21
votes
2answers
4k views

Why is Chromosome 1 called Chromosome 1?

Chromosome 1 is the designation for the largest human chromosome. Humans have two copies of chromosome 1, as they do with all of the autosomes, which are the non-sex chromosomes. Chromosome 1 spans ...
0
votes
1answer
71 views

What is the Definition of Homologous Chromosomes? length, gene position are the same or similar? [duplicate]

what is the Definition of Homologous Chromosomes? this post says Homologous chromosomes are chromosome pairs (one from each parent) that are similar in length,...
-4
votes
1answer
41 views

In a Chromosome, 2 nm is the length of what?

this figure comes from the nature 2 nm at the top right hand corner is the length of what?
1
vote
0answers
84 views

Number of DNA strands per chromosome

As I was reading Griffith's Introduction to genetic analysis this evidence was provided for single DNA makes single chromosome. Eventually geneticists demonstrated directly that certain chromosomes ...
2
votes
0answers
30 views

My understanding of chromosomes and the processes related to them is lacking [closed]

I'm sorry for the incredibly simple question, I just can't seem to find any answers elsewhere online. I am a high school student currently studying for the upcoming AP biology exam, and recently I ...
0
votes
2answers
580 views

Is a microspore diploid?

In gymnosperms the plant body is predominantly sporophytic. It produces microspores or megaspores my textbook says that these undergo reduction division in order to form male gametophytes pollen ...
0
votes
1answer
66 views

Possible combinations in the Meiosis' Telophase 1

As you might already know Meiosis is the process in eukaryotic, sexually-reproducing animals that reduces the number of chromosomes in a cell before reproduction $^{[1]}$ One of the reasons why ...
12
votes
1answer
824 views

Why does size decrease across the sequence of human chromosomes?

The following graph shows a decrease in the number of base pairs per chromosome across the sequential set of human chromosomes: Is this because chromosomes were originally numbered by their size on ...
18
votes
5answers
5k views

Are there examples of cells with more than one nucleus?

I've always wondered why cells have only one nucleus, as having multiple would seemingly prevent mutation. Are there examples of organisms with multiple nucleuses? If not, is there a reason?
15
votes
5answers
10k views

Do men and women have the same number of genes?

As far as I know, humans have 23 pairs of chromosomes, each one which contains a particular amount of genes. But in the "last" pair, men have a XY pair chromosome, and women have a XX pair chromosome. ...
0
votes
0answers
31 views

How did the molecular machinery for recombination originate?

I'm wondering about the origins of genetic recombination. During crossover new chromosomes are created. They have different allele combinations from the original two chromosomes. This process allows ...
1
vote
2answers
81 views

Is it possible for a sex chromosome to be homologous?

I am following a great introductory biology course online, MITx: 7.00x on edX. A question in the course assumes a cross between a pure-breeding male fly and a pure-breeding female fly: You are ...
-1
votes
1answer
79 views

The organisms of the same species with a different number of chromosomes [closed]

I am looking for some specific creatures. The organisms of the same species that have different chromosome numbers. Just like male grasshopper (23 chromosomes) and female grasshopper (24 chromosomes). ...
2
votes
1answer
158 views

Is there random assortment in metaphase II?

First, a little notation. Call a the first chromosome from my mother and A its homologous partner from my father. ...
-1
votes
2answers
7k views

Unsure about definition of “n” and “C” values in mitosis

I am preparing for a Biology exam and I'm reviewing the "n" and "C" notation used in mitosis. My professor said that when the cell replicates its DNA in S phase of mitosis, we get twice the "amount" (...
5
votes
0answers
74 views

Is there a practical upper limit to ploidy?

In my AP Biology class, we were discussing polyploidy, specifically, its deleterious nature in mammals and its prevalence in plants. We also learned that commercial crops, especially fruit, are often ...
1
vote
0answers
48 views

Why more than one chromosome in an organism?

Why not one chromosome to house genome in organisms but multiple? Is it for epigenomic purposes?
1
vote
2answers
1k views

Why are GC-rich regions less condensed than GC-poor regions?

As far as I know, chromatin consists of two kinds: Heterochromatin is more condensed so translational factors have less access to this region, and this region is poor in GC. Euchromatin is less ...
0
votes
0answers
22 views

Factors affecting which chromosome will come from the father

Tell me please. In course of biology, I remember that a man has XY chromosomes, and a woman has only X. Accordingly, depending on which chromosome comes from Father(man) Y or X, a girl (XX) or a boy (...
5
votes
1answer
49k views

Chromosome and chromatid numbers during cell cycle phases

A diploid cell in G1 has 6 chromosomes. How many chromosomes and how many chromatids are present in each of the following stages? Here is what I am guessing G1: 6 chromosomes ; 6 chromatids G2: 6 ...
3
votes
0answers
48 views

Offspring of parents with different number of chromosomes

Many papers report that dog-whelks (Nucella lapillus) show a distinct chromosomal polymorphism between populations of 2n = 24 up to 2n = 36. Could somebody please tell me how many chromosomes the F1 ...
-2
votes
1answer
38 views

Do we know which traits reside in which chromosome? If not, how about the next 10 years? [closed]

Assuming we develop a technology that allows us to make human gametes (sperm & eggs) combining chromosomes from different persons. Thus we take 1st chromosome from 1st person, 2nd chromosome from ...
0
votes
2answers
98 views

How much shorter is the short arm of a chromosome? And why?

I keep reading that the p arm is shorter than the q arm. But I cannot find an explanation of how much shorter nor an explanation for the difference.
2
votes
1answer
720 views

What is an “end-to-end fusion” in the context of telomerase? [closed]

Telomerase is said to prevent "end-to-end fusion" of chromosomes. My question is threefold: What is an "end-to-end fusion"? How does Telomerase prevent end-to-end fusions? Why do end-to-end ...
1
vote
1answer
579 views

Do chromosomes line up as pairs in mitosis or meiosis?

Here is a question from the book SAT II Success Biology E/M (where the SAT is the exam taken by the American high school students): Homologous chromosomes line up in pairs in (A) metaphase of ...
3
votes
2answers
602 views

What is a chromosome?

I read the wikipedia article and am confused if a chromosome is the pair of two chromotoids or if each chromatoid is considered a chromosome. I've heard someone say we have 23 pairs of chromosomes ...
1
vote
1answer
221 views

How do parents give their offspring a chromosome?

Whenever an organism sexually reproduces, it gives its offspring one chromosome from each of its pairs of chromosomes. My questions are Is this done randomly? Is it uniformly random? If so, what ...
1
vote
1answer
531 views

Genotypes of gametes produced by an F1 individual?

I have an urgent question as I have an exam tomorrow. I was skimming some past exam papers and one question came up which has me completely confused. A cross was made between a pure breeding ...
1
vote
2answers
72 views

What is the chance a given gene will end up in a given gamete?

Let us say a somatic cell had a desired gene. This somatic cell was replicated during interphase so that it had two of the desired gene. It then underwent meiosis. My question then is, what is the ...
1
vote
1answer
60 views

Are there chromosomes that we inherit that are not recombinated? [closed]

We do have chromosomes that recombinated ,but aren't there pure chromosomes that are not recombinated that people would have?
2
votes
2answers
130 views

Is there any system how genes are spread across chromosomes?

Every chromosome being a wrapped DNA molecule contains thousands or more genes. Now, is there any system why a gene A goes to a chromosome K and gene B to chromosome J?
5
votes
3answers
8k views

How many recombination events are there per generation in humans?

I'm looking for a reference that tells me how many recombenation events occur in humans from one generation to the next. Assuming that the human genome is a 3.3 GigaBases long DNA sequence, how many ...
1
vote
1answer
176 views

With over 400 chromosomes, does mitosis in a species of butterfly happen in the same way as in humans?

The beginning of the Ars Technica article Gene editing crunches an organism’s genome into single, giant DNA molecule begins: Complex organisms have complex genomes. While bacteria and archaea keep ...
2
votes
1answer
101 views

How do the chromosomes arrange themselves after fertilization in humans?

In human reproduction the male produces sperm containing 23 chromosomes and the female has the oovum containing 23 chromosomes , so after fertilization the zygote contains 46 chromosomes. What I want ...
1
vote
0answers
30 views

Did the chromosomal fusion within humans affect phenotypical change compared to the separated chromosomes in the other apes?

I just read this article on the evolutionary divergence between humans and chimps, and how the most significant event was when the 24 number of chromosomes in chimps was reduced to 23 in humans due to ...
5
votes
1answer
6k views

Examples of animals with different number of chromosomes that can interbreed?

When I was first started to write this question, I wanted to know how species evolve to have a different chromosomal arrangement, such as having two pairs of chromosomes instead of one? However, I ...
0
votes
1answer
44 views

Human genome, chromosomes

I have a very basic question, but it seems the hardest to me. So we have 46 chromosomes (23, 2 copies of each). Do all chromosomes have the same DNA? If so, does it mean that in different cells with ...