Some cells are visible to the unaided eye
The smallest objects that the unaided human eye can see are about 0.1 mm long. That means that under the right conditions, you might be able to see an ameoba proteus, a human egg, and a paramecium without using magnification. A magnifying glass can help you to see them more clearly, but they will still look tiny.
Smaller cells are easily visible under a light microscope. It's even possible to make out structures within the cell, such as the nucleus, mitochondria and chloroplasts. Light microscopes use a system of lenses to magnify an image. The power of a light microscope is limited by the wavelength of visible light, which is about 500 nm. The most powerful light microscopes can resolve bacteria but not viruses.
To see anything smaller than 500 nm, you will need an electron microscope. Electron microscopes shoot a high-voltage beam of electrons onto or through an object, which deflects and absorbs some of the electrons. Resolution is still limited by the wavelength of the electron beam, but this wavelength is much smaller than that of visible light. The most powerful electron microscopes can resolve molecules and even individual atoms.
The label on the nucleotide is not quite accurate. Adenine refers to a portion of the molecule, the nitrogenous base. It would be more accurate to label the nucleotide deoxyadenosine monophosphate, as it includes the sugar deoxyribose and a phosphate group in addition to the nitrogenous base. However, the more familiar "adenine" label makes it easier for people to recognize it as one of the building blocks of DNA.
No, this isn't a mistake. First, there's less DNA in a sperm cell than there is in a non-reproductive cell such as a skin cell. Second, the DNA in a sperm cell is super-condensed and compacted into a highly dense form. Third, the head of a sperm cell is almost all nucleus. Most of the cytoplasm has been squeezed out in order to make the sperm an efficient torpedo-like swimming machine.
The X chromosome is shown here in a condensed state, as it would appear in a cell that's going through mitosis. It has also been duplicated, so there are actually two identical copies stuck together at their middles. A human sperm cell contains just one copy each of 23 chromosomes.
A chromosome is made up of genetic material (one long piece of DNA) wrapped around structural support proteins (histones). Histones organize the DNA and keep it from getting tangled, much like thread wrapped around a spool. But they also add a lot of bulk. In a sperm cell, a specialized set of tiny support proteins (protamines) pack the DNA down to about one-sixth the volume of a mitotic chromosome.
The size of the carbon atom is based on its van der Waals radius.
More here:
Cell Size and Scale - Learn Genetics
- SCARY GHOST ENCOUNTER! (The Hidden) - Video [Last Updated On: September 7th, 2012] [Originally Added On: September 7th, 2012]
- Human Genetics and Genomics: The Science for the 21st Century - Video [Last Updated On: September 7th, 2012] [Originally Added On: September 7th, 2012]
- DNA Research - 07-09-2012 - Video [Last Updated On: September 7th, 2012] [Originally Added On: September 7th, 2012]
- Replying to Equestions on Junk DNA - Video [Last Updated On: September 7th, 2012] [Originally Added On: September 7th, 2012]
- 2013 Rosalind Franklin Young Investigator Awards Announced [Last Updated On: September 8th, 2012] [Originally Added On: September 8th, 2012]
- Jackson Lab CEO Leads From Heart [Last Updated On: September 28th, 2012] [Originally Added On: September 28th, 2012]
- Love of science lifts Hobe Sound teen to genetics conference in Germany [Last Updated On: September 30th, 2012] [Originally Added On: September 30th, 2012]
- Nobel Laureates and Experts Gather to Discuss Genetics and Society [Last Updated On: September 30th, 2012] [Originally Added On: September 30th, 2012]
- Seattle Genetics and Millennium Complete Enrollment in Phase III AETHERA Trial of ADCETRIS® for Post-Transplant ... [Last Updated On: September 30th, 2012] [Originally Added On: September 30th, 2012]
- GENETICS Journal Highlights for October 2012 [Last Updated On: October 2nd, 2012] [Originally Added On: October 2nd, 2012]
- Myriad Genetics Sponsors Cancer Awareness Initiatives in Support of National Hereditary Breast and Ovarian Cancer Week [Last Updated On: October 3rd, 2012] [Originally Added On: October 3rd, 2012]
- Study Says Genetics Of Intelligence Remains A Riddle, For Now [Last Updated On: October 3rd, 2012] [Originally Added On: October 3rd, 2012]
- ORF Genetics to Offer endotoxin- and Animal-free FGFb and mLIF for Stem Cell Research [Last Updated On: October 4th, 2012] [Originally Added On: October 4th, 2012]
- Research and Markets: Human Genes and Genomes. Science, Health, Society Provides Students and Professionals Alike With ... [Last Updated On: October 5th, 2012] [Originally Added On: October 5th, 2012]
- Mosquito genetics may offer clues to control malaria, researchers say [Last Updated On: October 5th, 2012] [Originally Added On: October 5th, 2012]
- Delphi Genetics Grants Merck License for the Use of the StabyExpress™ System [Last Updated On: October 8th, 2012] [Originally Added On: October 8th, 2012]
- This Week in PNAS [Last Updated On: October 10th, 2012] [Originally Added On: October 10th, 2012]
- Outsmarting breast cancer [Last Updated On: October 10th, 2012] [Originally Added On: October 10th, 2012]
- Economics and genetics meet in uneasy union [Last Updated On: October 10th, 2012] [Originally Added On: October 10th, 2012]
- Nurture trumps nature in study of oral bacteria in human twins, study finds [Last Updated On: October 12th, 2012] [Originally Added On: October 12th, 2012]
- Nurture trumps nature in study of oral bacteria in human twins, says CU study [Last Updated On: October 12th, 2012] [Originally Added On: October 12th, 2012]
- Claim That Links Economic Success and Genetic Diversity Draws Criticism [Last Updated On: October 12th, 2012] [Originally Added On: October 12th, 2012]
- Master-builder of the Human Genetics Unit [Last Updated On: October 15th, 2012] [Originally Added On: October 15th, 2012]
- Genetics Society of America announces 2013 award recipients [Last Updated On: October 15th, 2012] [Originally Added On: October 15th, 2012]
- Myriad Genetics to Announce First Fiscal Quarter 2013 Results on Monday, November 5, 2012 [Last Updated On: October 15th, 2012] [Originally Added On: October 15th, 2012]
- Petes Wins Lifetime Achievement Award in Genetics [Last Updated On: October 16th, 2012] [Originally Added On: October 16th, 2012]
- 23andMe Names Christine Castro, Neil Rothstein and Jonathan Ward to Leadership Positions [Last Updated On: October 16th, 2012] [Originally Added On: October 16th, 2012]
- Privately owned genetic databases may hinder diagnosis and bar the way to the arrival of personalized medicine [Last Updated On: November 2nd, 2012] [Originally Added On: November 2nd, 2012]
- Neil Risch - Wiki Article - Video [Last Updated On: November 2nd, 2012] [Originally Added On: November 2nd, 2012]
- GHOST DANCE (The Hidden) - Video [Last Updated On: November 2nd, 2012] [Originally Added On: November 2nd, 2012]
- SCARY GAME - "The Hidden" With Mr.Mitch361, Charlie, and ChildDolphin - Video [Last Updated On: November 2nd, 2012] [Originally Added On: November 2nd, 2012]
- International Academy of Cardiology: Neil Bowles, Ph.D.: GENETIC CAUSES OF CONGENITAL HEART DEFECTS - Video [Last Updated On: November 2nd, 2012] [Originally Added On: November 2nd, 2012]
- The Best Of: "The Hidden" - Video [Last Updated On: November 2nd, 2012] [Originally Added On: November 2nd, 2012]
- MEAT SHIELD (The Hidden) - Video [Last Updated On: November 4th, 2012] [Originally Added On: November 4th, 2012]
- The 10000 Year Explosion: How Civilization Accelerated Human Evolution - , Henry Harpending - Video [Last Updated On: November 4th, 2012] [Originally Added On: November 4th, 2012]
- Humans, chimpanzees and monkeys share DNA but not gene regulatory mechanisms [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Surprising findings from NHLBI Exome Sequencing Project reported [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- New method helps link genomic variation to protein production [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Ariosa Diagnostics to Present Clinical Data on the Harmony™ Prenatal Test at American Society of Human Genetics Annual ... [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- ALEX JONES Talks To DAVID ICKE: Human Genetics, Election FRAUD [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- David Icke Exposes ROYAL PAEDOPHILES - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Alex Jones - David Icke: Human Genetics, The Religion Of Death - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- David Icke - Infowars Election Coverage 2012 - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- David Icke: Human Genetics, The Religion of Death - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Evening with the UC Davis Genome Center - Oct 6, 2012 - David Segal - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- The Hidden - (Blood For The Blood God, I Must Feed) - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- GHOST ISSUES (The Hidden) - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- The Hidden - (Fart Grenades And Friendly Fire) - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- GHOST ISLAND (The Hidden) - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Growth Hormone - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Social Anthropology And Human Origins - Alan Barnard - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Protein Structural Biology In Biomedical Research. Advances In Molecular And Cell Biology, Volume 22 - Video [Last Updated On: November 7th, 2012] [Originally Added On: November 7th, 2012]
- Exome sequencing: Potential diagnostic assay for unexplained intellectual disability [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Unexplained intellectual disability explained by state-of-the-art genetic analysis [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- DNA variants explain over 10 percent of inherited genetic risk for heart disease [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Novel type 2 diabetes genetic study involves 5 major ancestry groups [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Significant relationship between mortality and telomere length discovered [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Alex Jones on David Icke 2001 - The Turd - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- David Icke Human Genetics [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- BLINDNESS (The Hidden) - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Human Genetics, The Religion of Death : David Icke - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Alex Jones Show - David Icke: Human Genetics, Paedophile Gov., The Religion of Death - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Human Genetics - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- DAVID ICKE: Human Genetics, The Religion of Death (11/6/2012) - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Human Genetics: The Basics - Ricki Lewis - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- The Hidden - (Meat Shields Everywhere, Face Of Protection) - Video [Last Updated On: November 9th, 2012] [Originally Added On: November 9th, 2012]
- Leading Genomic Services Company and Its Partners Raise More Than $150,000 in Support of Pediatric Genetics Research [Last Updated On: November 11th, 2012] [Originally Added On: November 11th, 2012]
- Verinata Health Announces New Findings At The American Society Of Human Genetics [Last Updated On: November 11th, 2012] [Originally Added On: November 11th, 2012]
- DAVID ICKE: Human Genetics, The Religion of Death! ALEX JONES [INFOWARS Nightly News] - Video [Last Updated On: November 11th, 2012] [Originally Added On: November 11th, 2012]
- ALEX-JONES-Talks-To-DAVID-ICKE--Human-Genetics,-Election-FRAUD-n-The-Religion-Of-DEATH - Video [Last Updated On: November 11th, 2012] [Originally Added On: November 11th, 2012]
- Illumina Bioninformatics Overview at ASHG 2012 - Video [Last Updated On: November 11th, 2012] [Originally Added On: November 11th, 2012]
- The Hidden - Fun With No Silence [Last Updated On: November 11th, 2012] [Originally Added On: November 11th, 2012]
- David Icke - Human Genetics, The Religion of Death [11/06/2012] - Video [Last Updated On: November 11th, 2012] [Originally Added On: November 11th, 2012]
- Genetics Center takes part in global meet [Last Updated On: November 12th, 2012] [Originally Added On: November 12th, 2012]
- Half Life 2 Mods: The Hidden | Part 4 | TO WIN, OR NOT TO WIN! - Video [Last Updated On: November 12th, 2012] [Originally Added On: November 12th, 2012]
- US-X - Video [Last Updated On: November 12th, 2012] [Originally Added On: November 12th, 2012]
- Personalized Medicine From Genomics and Bioinformatics Highlighted at UCSF Genetics Symposium [Last Updated On: November 14th, 2012] [Originally Added On: November 14th, 2012]
- News in Brief: Highlights from the American Society of Human Genetics annual meeting [Last Updated On: November 14th, 2012] [Originally Added On: November 14th, 2012]
- Star Visitors - Dr. Richard Boylan - Coast to Coast AM Classic - Video [Last Updated On: November 14th, 2012] [Originally Added On: November 14th, 2012]
- Protein Structural Biology In Biomedical Research, Part A - C. Woodward - Video [Last Updated On: November 14th, 2012] [Originally Added On: November 14th, 2012]