What are the normal chromosome numbers of a sperm egg and zygote?
Healthy humans have 46 chromosomes, 23 from the sperm and 23 from the egg. An embryo with the wrong number of chromosomes is usually miscarried, or develops disorders such as Down’s syndrome, which is caused by an extra copy of chromosome 21.
What does a duplicated chromosome consist of?
sister chromatids
What is the difference between unduplicated and duplicated chromosomes?
Chromosomes may exist as either duplicated or unduplicated. Unduplicated chromosomes are single linear strands, whereas duplicated chromosomes contain two identical copies (called chromatids or sister chromatids) joined by a centromere.
What are the two halves of a duplicated chromosome called?
A chromatid is one of two identical halves of a replicated chromosome.
Can a chromosome have one chromatid?
The chromosome consists of a single chromatid and is decondensed (long and string-like). The DNA is copied. The chromosome now consists of two sister chromatids, which are connected by proteins called cohesins.
What is the difference between chromatin threads and chromosomes?
The main difference between chromatin and chromosome is that chromatin consists of the unravelled condensed structure of DNA for the purpose of packaging into the nucleus whereas chromosome consists of the highest condensed structure of the DNA doublehelix for the proper separation of the genetic material between …
Which is bigger a gene or a chromosome?
Genes exist on chromosomes, which are large strands of DNA. A gene is always smaller than its host chromosome, but not all chromosomes are the same length. That’s larger than many bacterial chromosomes.
What exactly is a gene?
A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins. Alleles are forms of the same gene with small differences in their sequence of DNA bases.