Biology Essay

In: Science

Submitted By ram123
Words 304
Pages 2
GM tube

The GM tube is a hollow cylinder filled with a gas at low pressure. The tube has a thin window made of mica at one end. There is a central electrode inside the GM tube. A voltage supply is connected across the casing of the tube and the central electrode as shown in the following diagram.
When an alpha or beta or gamma radiation enters the tube it produces ions in the gas. The ions created in the gas enable the tube to conduct. A current is produced in the tube for a short time. The current produces a voltage pulse. Each voltage pulse corresponds to one ionising radiation entering the GM tube. The voltage pulse is amplified and counted.
Sources of background radiation
Background radiation is all around us. Some of it comes from natural sources and some comes from artificial sources.
Natural sources
Natural sources of background radiation include: * Cosmic rays - radiation that reaches the Earth from space * Rocks and soil - some rocks are radioactive and give off radioactive radon gas * Living things - plants absorb radioactive materials from the soil and these pass up the food chain

For most people, natural sources contribute the most to their background radiation dose.

Average contribution of different sources to natural background radiation

Artificial sources
There is little we can do about natural background radiation. After all, we cannot stop eating, drinking or breathing to avoid it!
However, human activity has added to background radiation by creating and using artificial sources of radiation. These include radioactive waste from nuclear power stations, radioactive fallout from nuclear weapons testing and medical x-rays.
Artificial sources account for about 15 per cent of the average background radiation dose. Nearly all artificial background radiation comes from medical procedures such as receiving x-rays for x-ray…...

Similar Documents


...Pre-AP Biology Chapter 2 Test Chemistry of Life Multiple Choice (1 point each) Identify the choice that best completes the statement or answers the question. ____b 1. The space surrounding the nucleus of an atom contains |a. |protons. |c. |neutrons. | |b. |electrons. |d. |ions. | ____c 2. If an atom contains 3 protons, 4 neutrons, and 3 electrons, its mass number would be |a. |3. |c. |7. | |b. |4. |d. |11. | c____ 3. Isotopes are atoms of the same element with the same number of protons and |a. |a different number of |c. |a different number of neutrons.| | |electrons. | | | |b. |a different number of |d. |the same number of neutrons. | | |molecules. | | | ___d_ 4. Which of the following......

Words: 1501 - Pages: 7

Biology 101 Review Essay

...Bio 101 Review Sheet Test #1 (Chapters 1-3) Chapter 1 1. Cell is basic unit of life 2. Hierarchy of life figure 3. 3 Energy categories and examples of each Producer-plants and some microbes Consumer-humans and other animals Decomposer-fungi and other animals 4. Energy transfers are not 100% efficient – why? Cant capture all of the energy supplied by one source a. Where does all energy for biology come from? sun 5. Homeostasis- state of internal consistency or equilibrium 6. 2 types of reproduction asexual and sexual b. Benefits to sexual reproduction benefit of tremendous variation 7. Adaptation inherited characteristics or behaviors that enables an organism to survive and reproduce successfully in a given environment c. How it contributes to natural selection and evolution individuals with the better combinations of genes survive and reproduce 8. Evolution change in genetic makeup of a population 9. Why it’s important to take all your antibiotics so all of the bacteria can be eliminated, some of the bacteria can become stronger. 10. Taxonomy classification of life’s diversity 11. What our species name is homo sapiens 12. Order of taxonomic categories – mnemonic device! Domain, kingdom, phylum, class, order, family, genus, species 13. 3 domains bacteria, archaea, eukaryote d. Basic differences e. What our domain is f. What domain universal ancestor likely is in archaea ...

Words: 1102 - Pages: 5


...ology Chapter 13 Lecture Outline Introduction Clown, Fool, or Simply Well Adapted? A. Review: Evolution is the central theme of biology. Evolutionary adaptation is a universal characteristic of living things (see Module 1.6). NOTE: More than any other idea in biology, evolutionary theory serves to tie the discipline together. T. Dobzhansky: “Nothing in biology makes sense except in the light of evolution.” B. If you look at any organism critically, you are first struck by the differences from other organisms. 1. Further observation often reveals that an organism’s features show some relationship to where the organism lives and what it does in its environment. 2. The blue-footed booby has enormous webbed feet, an oil producing gland that keeps the booby afloat, a nostril that can close under water that prevents water from entering the lungs, a gland that secrets salt from consumed sea water, and a torpedo-like body—all adaptations that make life on the sea feasible. I. Darwin’s Theory of Evolution Module 13.1 A sea voyage helped Darwin frame his theory of evolution. A. Awareness of each organism’s adaptations and how they fit the particular conditions of its environment helps us appreciate the natural world (Figure 13.1A). B. Early Greek philosophers held various views. Anaximander (about 2,500 years ago) suggested that life arose in water and that simpler......

Words: 3614 - Pages: 15


...“The longer you live the longer you should live” –Wiley “Evolution’s a bitch” –Wiley “Suckers are good to eat” –Wiley WHAT HAS EVOLUTION DONE FOR ME What has evolution done for me • Agricultural crops and animal breeding for the past 8,000 years • With the discovery of methods to reconstruct evolutionary relationships there is been a vast increase in the relevance of evolutionary biology to human society. Reconstructing Phylogenies • 1859-1950- No coherent empirical methods • 1950-1966- Emergence of Phylogenetic Systematics • Phylogeny by discovery of the order of evolutionary innovation Ribotyping • Fingerprinting or sequencing RNA • Many diseases have unknown causes • However, diseased tissues can be ribotyped. (Wiley Death Fish) • This process involves extracting DNA from diseased tissues and then sequencing the DNA that codes for rRNA. • If a disease agent such as a bacteria is present, then we will get ribosomal DNA sequences from the host (you) and the bacteria (the infection agent). Ribotyping: Phylogeny matching • Once we have the rDNA sequences, we can plug them into a sequence matrix of all life and see where our unknowns appear on the tree of life. Our Food Chain • Some products are easy to identify, but others are not. • A slab of fish fillet from a sea bass looks like a slab of sih fillet from a farmed Asian catfish. • But the sea bass costs $10/pound while the Asian......

Words: 6776 - Pages: 28


...Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, evolution, distribution, and taxonomy.[1] Modern biology is a vast and eclectic field, composed of many branches and subdisciplines. However, despite the broad scope of biology, there are certain general and unifying concepts within it that govern all study and research, consolidating it into single, coherent fields. In general, biology recognizes the cell as the basic unit of life, genes as the basic unit of heredity, and evolution as the engine that propels the synthesis and creation of new species. It is also understood today that all organisms survive by consuming and transforming energy and by regulating their internal environment to maintain a stable and vital condition. Subdisciplines of biology are defined by the scale at which organisms are studied, the kinds of organisms studied, and the methods used to study them: Biochemistry examines the rudimentary chemistry of life; molecular biology studies the complex interactions among biological molecules; botany studies the biology of plants; cellular biology examines the basic building-block of all life, the cell; physiology examines the physical and chemical functions of tissues, organs, and organ systems of an organism; evolutionary biology examines the processes that produced the diversity of life; and ecology examines how organisms interact in their environment. History The term......

Words: 1279 - Pages: 6


... AP Biology Exam Review: Lab Essays At least one essay (FRQ) on the exam will be based on an AP laboratory. To prepare for this question, review the objectives for all twelve laboratory exercises. The College Board does not necessarily expect that you have completed that lab, but rather that you have investigated the objectives of the lab. You may be asked to “design an experiment to determine….” You don’t necessarily need to create a new lab; if you have done an activity that would answer the question, simply describe it. For a good response, you should include the following. 1. State a hypothesis [as an “if…..(conditions), then….(results)” statement] Be sure your hypothesis is testable. 2. Identify the variable factor. 3. Identify the control. Be certain to explain the control for the experiment. 4. Hold all other variables constant. 5. Manipulate the variable. 6. State how you would measure the results. 7. Discuss the expected results. Relate the results to your hypothesis. 8. Include steps to replicate or verify. You may be asked to graph data. Be sure to use a graph that is appropriate for you data. Bar graphs are used when data points are discrete (not related to one another), while line graphs are used with the data are continuous. If there is a data point at zero, be certain to extend your line to 0, but do not extend the line to 0 if there is no data point at zero. Other points to keep in mind:...

Words: 2702 - Pages: 11


...This is an annotated list of biological websites, including only notable websites dealing with biology generally and those with a more specific focus. Actionbioscience -- sponsored by the American Institute of Biological Sciences (AIBS) -- providing articles by scientists, science educators, and science students on issues related to seven bioscience challenges: environment, biodiversity, genomics, biotechnology, evolution, new frontiers in science, and bioscience education Animal Diversity Web -- created by the staff at the Museum of Zoology at the University of Michigan -- collecting the natural history, classification, species characteristics, conservation biology, and distribution information of thousands of species of animals Animal Genome Size Database -- created by Dr. T. Ryan Gregory of the University of Guelph in Canada -- publishing genome size estimates for vertebrate and invertebrate animals Animal Science Image Gallery -- a work of the United States Federal Government -- containing images, animations, and video for classroom and outreach learning Bioinformatic Harvester -- a bioinformatic meta search engine at KIT Karlsruhe Institute of Technology -- working for human, mouse, rat, zebrafish, drosophila and arabidopsis thaliana information Catalogue of Life -- compiled with sectors provided by 52 taxonomic databases from around the world -- planned to become a comprehensive catalogue of all known species of organisms on Earth ......

Words: 645 - Pages: 3


...and altruism, endosymbiosis and eukaryotic cell evolution, evolutionary developmental biology, phenotypic plasticity, epigenetic inheritance and molecular evolution, experimental bacterial evolution, and computer simulations (in silico evolution of digital organisms). In addition, we discuss the expansion of the modern synthesis, embracing all branches of scientific disciplines. It is concluded that the basic tenets Dedicated to Prof. Dr. Dr. hc mult. Ernst Mayr on the occasion of his 100th birthday U. Kutschera ()) Institut für Biologie, Universität Kassel, Heinrich-Plett-Strasse 40, 34109 Kassel, Germany e-mail: Fax: +49-561-8044009 K. J. Niklas Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA of the synthetic theory have survived, but in modified form. These sub-theories require continued elaboration, particularly in light of molecular biology, to answer openended questions concerning the mechanisms of evolution in all five kingdoms of life. Introduction Physicists and chemists investigate the properties and interactions of objects, such as electrons, photons, and atoms, which are physically uniform and invariant in their characteristic traits and behavior. Accordingly, a single experiment adducing the properties of a single entity (e.g., electron or proton) can be used to extrapolate the properties of all comparable entities in the universe. In biology, the “science of the living world,” both past and present (Mayr 1997), the......

Words: 17126 - Pages: 69


...Biology: Concepts and Connections, 6e (Campbell) Chapter 12 DNA Technology and Genomics Multiple-Choice Questions 1) When DNA fingerprinting was first used, A) genetic evidence was collected using only DNA from blood. B) blood samples from theGenomic libraries can be constructed using either bacterial plasmids or what other vector? crime scene were used to match the blood of a person who confessed. C) the two semen samples did not match the person who initially confessed. D) genetic testing revealed that the two murdered girls were killed by two different people. E) the DNA evidence was not convincing enough to convict the suspect. Answer: C Topic: Opening Essay Skill: Factual Recall 2) Biotechnology A) is a modern scientific discipline that has existed for only a few decades. B) is strictly concerned with the manipulation of DNA. C) has only been used successfully in the area of forensic science. D) has been around since the dawn of civilization. E) is generally considered more harmful than valuable to society. Answer: D Topic: 12.1 Skill: Factual Recall 3) When DNA from two sources is combined into one single piece of DNA, it is known as A) cloned DNA. B) recombinant DNA. C) a vector. D) a plasmid. E) a DNA library. Answer: B ......

Words: 3377 - Pages: 14


...AS Biology: OCR Syllabus Module 1.1.1 3.1 AS Unit: Cells, Exchange and Transport Module 1: Cells 1.1.1 Cell Structure Candidates should be able to: (a) state the resolution and magnification that can be achieved by a light microscope, a transmission electron microscope and a scanning electron microscope; Light Microscope Transmission Electron Microscope Scanning Electron Microscope Resolution 0.2 μ (200nm) 0.2nm 0.2nm Magnification ≈ ×1500 / 2000 Over 500 000 250 000 (b) explain the difference between magnification and resolution; Resolution “the ability of an optical system to distinguish between two adjacent objects” Magnification increases the apparent size of an object” Resolving power “the degree of detail that can be seen with a microscope” The resolving power is inversely proportional to the wavelength of the radiation used (i.e. the shorter the wavelength, the greater the resolution). (c) Stains: (d) explain the need for staining samples for use in light microscopy and electron microscopy; - most biological structures are transparent the stain gives a contrast between different structures the stain combines with certain chemicals in the structure - Iodine solution: Starch → blue-black - Eosin solution: cytoplasm → pink - Feulgens agent DNA → dark red / purple - Aceto-orcein agent calculate the linear magnification of an image (HSW3); Page 1 of 8 AS Biology:......

Words: 1909 - Pages: 8

Biology 330 Essay

...demonstrated evidence of laboratory defects in blood clotting in Aaron  Chan   Biology  330   06261560     1893. Our forces strengthened exponentially in 1937 after Patek and Taylor found the role of the soon to be named factor VIII describing its action in hemostasis. They characterized and named it an “antihemophilic globulin substance”. Not long after, the protein was purified and the gene was open to study for many scientists. The root of this evil The mastermind behind Hemophilia A is the gene coagulant factor VIII. The factor VIII gene sits on the long arm of chromosome 10 at location 28, more specifically, from base pairs 154,064,062 to 154,255,350. Its protein sequence is 2351 amino acids long transcribed from a 191,288 mRNA. This gene produces two alternatively spliced transcripts. Transcript variant 1 consists of 26 exons that encodes a large glycoprotein called isoform a, which circulates in the plasma and undergoes multiple cleavage events. Transcript variant 2 encodes a small protein, isoform b, which consists of a unique 5' exon located within intron 22 of transcript variant 1. This exon codes for eight amino acids and is spliced to exons 2326 maintaining the reading frame. It is composed primarily of the phospholipid-binding domain of factor VIIIc. This binding domain is essential Aaron  Chan   Biology  330   06261560     for coagulant activity. Normally this gene,......

Words: 2699 - Pages: 11

Biology Essay Questions

...Essay Questions 10/11/15 1. Directional selection occurs when one of the extreme traits of distribution is eliminated and causing a shift in the frequency. For example, the beak length of finches changed due to the food sources that were available. The finches with larger beaks survived because they were able to crack seeds that they could eat. As time went on, insects became plentiful and now finches with smaller beaks were now favored by the directional selection. Disruptive selection occurs when the average phenotype is selected against. For example, in a population of white, grey, and black rabbits if the grey rabbit dies the white and black rabbits become concentrated. 2. Populations of bacteria evolve to become resistant to antibiotics through the process of natural selection. When a population of bacteria gets exposed to any give antibiotic, most of the bacteria will die. However, if some bacteria cells have resistance due to plasmids, they will survive. They will then pass this trait to their offspring, which will be a fully resistant generation. 3. Tooth reduction is one of the major evolutionary trends that developed among major vertebrate groups that allowed for the transition from aquatic to terrestrial life. Evolution of limbs and being able to breath air are other evolutionary trends that took place. 4. The nonvascular plants and even a few vascular plants like ferns reproduce by having the sperm swim through the external environment. This......

Words: 401 - Pages: 2

Essay Questions Biology

... Lesson 3 essay questions Exam # 25085400 1. Directional and disruptive selection can be compared because they both favor extreme phenotypes, they adjust to their environments over time and they both cause a shift in the distribution curve. The contrast in directional selection is the distribution curve shifts one way and only focuses on one extreme phenotype. An example of directional selection would be the gradual increase in size of the modern horse. This change occurred due to the environment changing from forest conditions to grassland conditions. The contrast in disruptive selection is the distribution curve shifts both ways and focuses on two or more phenotypes versus intermediate phenotypes. An example of disruptive selection is the British snails. They live in low-vegetation areas and in forest areas. Thrushes feed on the the snails with dark shells and no bands in the vegetation areas and they feed on the snails with the light bands in the forest areas. Therefore, these snails had to adapt to their own environment. 2. Overuse and misuse of antibiotics can cause resistant bacteria to form through natural selection. When you introduce selective pressure (antibiotics) to a bacterial infection, some of the bacteria can acquire “free” DNA from its environment. Which can mimic the antibiotics genetic make up. This causes some bacteria to create a resistant gene that can be passed to the next generation. As a......

Words: 500 - Pages: 2

Biology Essay

...Lee, Cynthia. “Walking fish reveal how our ancestors evolved onto land” Biology News Net Aug. 2014. This article was about how fish evolved onto land, which could have led to how our ancestors evolved onto land. About 400 million years ago, fish began exploring the land around them and soon, they evolved into tetrapods. Tetrapods are today’s reptiles, amphibians, birds, and mammals. A fish called Polypterus can breathe air, walk on land, and they look a lot similar to ancient fish that evolved the same way. For example, when the fish walked on land, they would place their fins close to their bodies and lift their heads. Soon, their skeleton changed to become more elongate to adapt with how the fish walked by supporting their head and neck. The scientists have hypothesized that the behavioural changes reflect what may have occurred when fossil fish first started walking. One of the main issues in this article was how the scientists were going to compare fish walking and our ancestors walking on land today. The main question the author was investigating was how fish walking on land could have led our ancestors in the same direction. The evidence that supports the findings is found in old fossils of fish. By examining the fossils, they can see that the fish adapted to their environment by adapting their skeletons to walk on land. Often, there was controversy about how......

Words: 492 - Pages: 2


...Biology: Concepts and Connections, 6e (Campbell) Chapter 1 Introduction: The Scientific Study of Life 1) Which of the following statements about the leopard is false? A) Leopards are the largest cat in the genus Panthera. B) Leopards, like lions, can roar. C) Leopards prefer to eat their kill in trees. D) Leopards are well-adapted for nocturnal hunting. E) Leopards are normally solitary animals. Answer: A Topic: Opening Essay Skill: Factual Recall 2) Life is organized in a hierarchical fashion. Which of the following sequences correctly lists that hierarchy as it increases in complexity? A) ecosystem, population, organ system, cell, community, molecule, organ, organism, tissue B) cell, molecule, organ system, organ, population, tissue, organism, ecosystem, community C) organism, organ system, tissue, population, organ, community, cell, ecosystem, molecule D) molecule, cell, tissue, organ, organ system, organism, population, community, ecosystem E) ecosystem, molecule, cell, tissue, organism, organ system, organ, community Answer: D Topic: 1.1 Skill: Factual Recall 3) What is the difference between a tissue and an organ system? A) The tissue level of organization is more inclusive than the organ system level. B) Tissues are not composed of cells; organ systems are composed of......

Words: 9744 - Pages: 39