Viruses are non-living microscopic particles that attack healthy cells within living things. They do not have the characteristics of living things and are not able to metabolize food. To metabolize means to change food energy into chemical energy that the body can use. Viruses are not alive, so they do not have a need for food like living organisms. Viruses do not have an organized cell structure. They are so light that they can float in the air or water, be passed on to other organisms if touched, and fit anywhere. The virus injects its own DNA structure into healthy cells where new virus cells grow.
Characteristic of life
You are an Astrobiologist in search of habitable planets beyond earth. It is your task to identify what what are the Characteristics of Life.
Characteristic of Life <ul><li>Guide Questions: </li></ul><ul><li>What are the Characteristics of Life. </li></ul><ul><li>What is the basic unit of life? Why? </li></ul><ul><li>Why do living organisms need energy? </li></ul><ul><li>What common manifestation that an organism is growing? </li></ul><ul><li>Why is it important that an organism must maintain internal balance? </li></ul><ul><li>Among the Characteristic of Life, what is the most important key for survival? Why? </li></ul>
<ul><li>Organization </li></ul><ul><li>Metabolism </li></ul><ul><li>Growth and Development </li></ul><ul><li>Response to Stimuli/Irritability </li></ul><ul><li>Adaptation </li></ul><ul><li>Reproduction </li></ul>Characteristic of life are all or most exhibit by living organisms:
ORGANIZATION: Being structurally composed of one or more cells , which are the basic units of life.
ORGANIZATION: Being structurally composed of one or more cells , which are the basic units of life. BIOSPHERE COMMUNITY POPULATION ORGANISM ORGAN SYSTEM ORGAN TISSUE CELL
METABOLISM: A process that allow organisms to grow & reproduce, maintain their structures, & respond to their environments. MITOCHONDRIA are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.
GROWTH AND DEVELOPMENT: A growing organism increases in size in all of its parts, rather than simply accumulating matter.
HOMEOSTASIS : the maintenance of a stable internal state within an organism. When we ‘heat up’ we Sweat. When we ‘feel cold’ we Shiver. <ul><ul><li>the ability of an organism to maintain its internal environment despite conditions in the external environment. </li></ul></ul>37° C. Can you give other examples?
What happens when the body doesn’t possess this characteristic? +37° C / -37° C We experience… Heat-stroke Hypothermia
RESPONSE TO STIMULI/ IRRITATION : A reaction or movement involving the senses of an organism from unfavorable to favorable condition to support growth and development, to maintain homeostasis. STIMULUS [singular] , is an agent that influences movement.
STIMULUS, is an agent that influences movement. What do you want to do with the ‘isaw’ ? What bodily sense that was used to identify your action? What is the stimulus?
What caused this flock to migrate from one continent to another? What is the stimulus? STIMULUS, is an agent that influences movement.
STIMULUS, is an agent that influences movement. What caused the tree to grow upside-down? What is the stimulus?
TROPISM , is a biological phenomenon that causes the organism to move towards the stimulus. Chemotropism, movement or growth in response to chemicals. Geotropism (or gravitropism), movement or growth in response to gravity. Hydrotropism, movement or growth in response to water. Phototropism, movement or growth in response to lights. Thermotropism, movement or growth in response to temperature.
ADAPTATION, an inherited behavior or characteristic that enables an organism to survive & reproduce. is the evolutionary process whereby a population becomes better suited to its habitat. Why are Africans have dark complexion? Why are Europeans have light complexion?
Mimicry & Camouflage Mimicry pertains to a similar resemblance either in appearance, behaviour, sound, scent of another organism which acts as a defense against its natural predators. Do you see two snakes? Is it a snake lying on a leaf?
Camouflage , in which a species resembles its surroundings. Can you see clearly the Bengal tiger?
ADAPTATION, enables the species to find suitable partner in the environment. Aint he pretty?
REPRODUCTION: Reproduction: The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms. <ul><li>SEXUAL REPRODUCTION </li></ul><ul><li>ASEXUAL REPRODUCTION </li></ul>
SEXUAL REPRODUCTION, is a biological process by which organisms create descendants that have a combination of genetic material contributed from two (usually) different members of the species. Union between sperm & egg cell. Earthworms are hermaphrodites Can either be male or female Even without a pair can reproduce itself. Hover flies mating in mid air. Cool!
ASEXUAL REPRODUCTION, is the process by which an organism creates a genetically similar or identical copy of itself without a contribution of genetic material from another individual. Alive E.coli bacteria seen under Light Microscope. Binary fission is the normal method of replication among bacteria. Bacteria replicate in a matter of minutes (5 minutes) depending on the type of cell & availability of nutrients !
<ul><li>Viruses on the other hand. </li></ul>"Viruses exist in two distinct states. When not in contact with a host cell, the virus remains entirely dormant. It contains Genetic information. It replicates only with the presence of a host cell. It is made up protein coating not cell. What is your conclusion?