School of Life Sciences | Ask A Biologist

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Parts of the Cell

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Parts of the Cell

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  • ATP: adenosine triphosphate. ATP is the energy-carrying molecule of all cells... more
  • Cellulose: the structural material found in the cell wall in most plants. Cellulose is used to make many products, including paper and cloth... more
  • Chromosome: a long, thread-like molecule made of the chemical called DNA (deoxyribonucleic acid) that is held together with special proteins and is visible (with strong microscopes) during cell division... more
  • Molecule: a chemical structure that has two or more atoms held together by a chemical bond. Water is a molecule of two hydrogen atoms and one oxygen atom (H2O)... more
  • Organelle: "little organ". An internal organ of a cell... more
  • Phospholipid: is a special kind of lipid that is made up of two fatty acid chains. These phospholipids are present in the plasma membrane of any cell... more
  • Photosynthesis: a set of chain reactions that convert light energy into chemical energy. Photosynthesis also produces energy-rich carbohydrates like starch. Photosynthesis occurs in the chloroplast of a plant cell... more
  • Tomography: process used to make a tomogram (picture) which is a two-dimensional slice of a three-dimensional object. A computer can then be used to build a three-dimensional image of the object by stacking the tomograms together.

nucleus centriols Vesicles lysosomes lysosomes

Atoms & Life

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Atoms & Life

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  • Element: in chemistry a substance that cannot be broken down (separated) by a chemical process... more
  • Trace: a quantity of something in extremely small amounts... more

What Elements Are Found in the Human Body?

There are 92 elements that occur naturally on Earth. For living things, only 11 of these elements are found in larger than trace quantities. Any amount 0.01% or less is considered a trace element. For vertebrates, such as humans, there are two additional elements that occur in larger than trace amounts these are Iodine and Iron. The periodic table of elements below is color coded to show the elements found in the human body.

Ingredients for Life

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Ingredients for Life

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  • Macromolecule: a very large molecule such as a protein.
  • Molecule: a chemical structure that has two or more atoms held together by a chemical bond. Water is a molecule of two hydrogen atoms and one oxygen atom (H2O)... more

What Are the Ingredients for Life?

If you look around your neighborhood you will see homes, stores, streets and cars. All of these things are made from different building materials. The homes and stores are made from bricks, cement, wood and nails. The roads are made from asphalt or cement. All the cars are made from metal, glass, rubber and plastic.

When you look around you also see plants and animals. Just like the buildings and cars in your neighborhood, living things are made from building materials.

Did You Know Butterflies are Legally Blind?

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Did You Know Butterflies are Legally Blind?

By Kasey Yturralde
Illustrated by Sabine Deviche

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  • Acute: very sensitive to specific stimuli (input) such as light and sound.
  • Legally blind: if a person has to stand 20 feet or closer to recognize an object that a normal vision person can see from 200 feet, that person is legally blind (20/200 vision).
  • Ommatidium: the cone-shaped parts of an insect eye. Each ommatidia has a lens on the end to gather light... more
  • Resolution: the ability to distinguish objects that are close to each other as two separate objects.
  • Ultraviolet: (1) light waves at wavelengths less than those visible to humans. Also called UV light. (2) invisible light rays just below the violet end of the spectrum... more

Butterflies are legally blind - How can this be?

what butterflies see

As you watch a butterfly navigate the flowers in your back yard, or a pesky fly avoid your flyswatter, keep in mind their vision is quite different than yours and mine. In fact, most insects are legally blind, but you would not know it from looking at them.

Collecting Ants

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Collecting Ants

By Rebecca Clark
Illustrated by Sabine Deviche

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  • Colony: a group of the same kind (species) of plants or animals living together... more
  • Mature: when an animal reaches a point where it is able to reproduce.
  • Monsoon: a sudden rainstorm that happens during hot summer weather... more
  • Mounds: small piles of soil that have been heaped up.
  • Queen: a female ant that lays eggs.
  • Worker: a female ant that performs jobs other than reproduction.

Collecting Ants

While it can be fun to watch ants outside, or perplexing to find them in your house, one of the most exciting ways to study ants is to keep them in an ant farm so you can see all of the action that goes on underground. But before you can keep them in an ant farm, you have to collect them first!

There are several different ways to get ants for an ant farm, depending on when you would like to start the farm and how long you would like for your ant farm to last.

I want ants right now!

Robert Hooke

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Robert Hooke

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  • Bubonic plague: bacterial disease carried by fleas of infected Old English rats. At its worst, it killed two million people a year. Those that caught the disease had a 90% chance of dying from it.
  • Great Plague of London: there have been several large outbreaks of the bubonic plague in Europe beginning in 1347. In 1665 London fell victim to the plague that has since been called the Great Plague of London... more
  • Microscope: an instrument used to see objects or parts of objects, which are too small to be seen with only our eyes... more

Robert Hooke (28 July 1635 – 3 March 1703)

Micrographia by Robert Hooke

Building Blocks of Life

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Building Blocks of Life

By Shyamala Iyer
Illustrated by Dr. Biology

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  • Carbohydrates: chemical groups that include both simple sugars like glucose and complex building blocks like starch and cellulose... more
  • Cell: a tiny building block that contains all the information necessary for the survival of any plant or animal. It is also the smallest unit of life. ... more
  • DNA: deoxyribonucleic acid is the information "blue-print" of the cell. It is a nucleic acid and is made from building blocks called nucleotides. This genetic information is passed from parent to child... more
  • Lipid: a building block of life (molecule) made from smaller pieces (fatty acids). There are several kinds of lipids - fats, waxes, sterols,... more
  • Nucleic acids: are compounds that make up the DNA strand. Nucleic acids include deoxyribonucleic acids (DNA) and ribonucleic acids(RNA).
  • Proteins: are the business end of the DNA in the cell. Proteins are very important in the proper functioning of cell.

How Many Cells Are in the Human Body?

All living beings are made up of cells. Some of them are made up of only one cell and others have many cells. The average adult human body has around 37.2 trillion cells. WOW, that's a lot of cells. So many, in fact, that it's hard to picture. But let's try to imagine it: If we lined up all the cells in a human body end to end, could the line reach around the Earth? If so, how many times?

He Ain't Tasty He's My Brother

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He Ain't Tasty He's My Brother

By Steve Koppes

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  • Cannibal: an organism that feeds on other members of its species.
  • Crustacean: an animal with an exoskeleton, and gills for breathing. Crustacean bodies are often divided into distinct segments. Examples of crustaceans are lobster, shrimp, and crabs... more
  • Extinct: no longer existing; an animal or species that no longer exists due to disease or other environmental conditions... more
  • Kin: family, a relative like your mother, father, or sister and brother.
  • Plankton: a group of free floating organisms living in water that includes many kinds of plants and animals... more
  • Vertebrate: the major division of animals that have a backbone (spinal column) which is made up of several different sections... more
  • Virulent: very harmful or hostile.

Cannibals in the Water

salamander

While cannibalism is fairly common among insects and crustaceans, most backboned animals avoid feeding on their own kind. The tiger salamander of the arid Southwestern United States is another case entirely.

Bee Movie Maker

Bee Movie Maker

By CJ Kazilek
Illustrated by Sabine Deviche

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  • Aroma: the smell or odor that comes from different plants, animals, and objects. Sometimes you will hear the words fragrance and scent used in place of aroma.
  • Nectar: sugary liquid made by flowers.
  • Proboscis: a long mouth part found in most insects and some other animals used to suck up food.

Okay, so he's not your typical movie director. He doesn't work with the usual actors. The locations of his films are, well, a bit dull. The fact is his work is not likely to come to a theater in your neighborhood anytime in the future. In spite of these shortcomings there is a buzz about his work.

Ecosystem Connections

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Ecosystem Connections

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  • Essential: required, or necessary.
  • Nutrient: a vitamin, mineral, or chemical in food that the body uses to grow, repair, or do work... more

How are ecosystems related?

Nutrients, organisms, water, air, and any of the other parts of ecosystems can move in and out of ecosystems. The boundaries that we can draw around an ecosystem aren't solid walls, but instead allow materials to pass across them. For example, in the ecosystem of your mouth, food, oxygen, and water come in from outside the ecosystem, and these materials also leave the mouth ecosystem when you swallow or exhale. Flows of materials into and out of ecosystems cross boundaries between ecosystems and connect them together.

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