WELCOME STUDENTS! FEEL FREE TO READ AND SEARCH FOR SOME LECTURES IN SCIENCE SUBJECTS. ENJOY AND HAVE FUN LEARNING SCIENCE!

Sunday, November 28, 2010

Lesson Plan: Mitosis

A. Subject Name: Mitosis

B. Lesson Reference:
Lesson 47

C. Lesson Title:
Mitosis

D. Lesson Description:

Cell division is an elegant process that enables organisms to grow and reproduce. Through a sequence of steps, the replicated genetic material in a parent cell is equally distributed to two daughter cells. While there are some subtle differences, mitosis is remarkably similar across organisms.

Before a dividing cell enters mitosis, it undergoes a period of growth called interphase. Interphase is the "holding" stage or the stage between two successive cell divisions. In this stage, the cell replicates its genetic material and organelles in preparation for division.

E. Learning Output

E1. Identify the stages of mitosis.
E2. Describe the events occur in each stage of mitosis.
E3. Illustrate the stages of mitosis.

F. Review of Previous Learning/Lesson
The most basic function of the cell cycle is to duplicate accurately the vast amount of DNA in the chromosomes and then segregate the copies precisely into two genetically identical daughter cells. These processes define the two major phases of the cell cycle. DNA duplication occurs during S phase (S for synthesis), which requires 10–12 hours and occupies about half of the cell-cycle time in a typical mammalian cell. After S phase, chromosome segregation and cell division occur in M phase (M for mitosis), which requires much less time (less than an hour in a mammalian cell). M phase involves a series of dramatic events that begin with nuclear division, or mitosis.

G. Learning Presentation
Refer to the two videos below for the lecture on Mitosis.







H. Learning Activity


Refer to the link:
http://bio.rutgers.edu/~gb101/lab2_mitosis/section1_frames.html

I. Learning Evaluation

Refer to this link : http://quizstar.4teachers.org/index.jsp

Wednesday, September 8, 2010

Xylem and Phloem



The xylem is the principal water-conducting tissue of vascular plants. It consists of tracheary elements, tracheids and wood vessels and of additional xylem fibres. All of them are elongated cells with secondary cell walls that lack protoplasts at maturity. Bordered pits are typical for tracheids, while wood vessels are marked by perforated or completely dissolved final walls.

Phloem is the vascular tissue plants use to transfer sugars from sites of production or storage to locations where energy is needed. In contrast to xylem, phloem tissues are living. Sieve tube members connect at specialized areas called seive plates. At maturity the seive tube members lose their nuclei and fill with a complex proteinaceous material called cell sap. Sugars are transported through the cell saps of adjacent cells.

In losing their nuclei, sieve tube members lack the molecular control mechanisms most living cells possess. Nucleated cells adjacent to sieve tube members appear to take over the control of cellular functions within these phloem transport cells. These nucleated cells are appropriately called companion cells.

Sieve plates are specialized areas where materials flow through tiny pores from one sieve tube member to another.
Most phloem cells are parenchyma cell types. Sometimes phloem tissues contain sclerenchyma fibers for support.

External and Internal Parts of Plant Organs














Plant Hormones

Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips. Example: Indole Acetic Acid (IA). Auxin is a plant hormone produced in the stem tip that promotes cell elongation. Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant. This produces a curving of the plant stem tip toward the light, a plant movement known as phototropism.

Auxin also plays a role in maintaining apical dominance. Most plants have lateral (sometimes called axillary) buds located at nodes (where leaves attach to the stem). Buds are embryonic meristems maintained in a dormant state. Auxin maintains this dormancy. As long as sufficient auxin is produced by the apical meristem, the lateral buds remain dormant. If the apex of the shoot is removed (by a browsing animal or a scientist), the auxin is no longer produced. This will cause the lateral buds to break their dormancy and begin to grow. In effect, the plant becomes bushier. When a gardener trims a hedge, they are applying apical dominance.

Gibberellins promote stem elongation. They are not produced in stem tip. Gibberellic acid was the first of this class of hormone to be discovered.

Cytokinins promote cell division. They are produced in growing areas, such as meristems at tip of the shoot.

Abscisic Acid promotes seed dormancy by inhibiting cell growth. It is also involved in opening and closing of stomata as leaves wilt.

Ethylene is a gas produced by ripe fruits. Why does one bad apple spoil the whole bunch? Ethylene is used to ripen crops at the same time. Sprayed on a field it will cause all fruits to ripen at the same time so they can be harvested.

Friday, June 25, 2010

Nine Environmental Principles

1. Nature knows best
This principle is the most basic and, in fact, encompasses all the others. In essence people must not go against the natural process if they would like to ensure a continuous and steady supply of resources. In nature, nutrients pass from the environment to the organism and back to the environment. Any disruption in the cycle can bring about imbalance. For example, burning of farm wastes instead of allowing them to decompose naturally disrupts the cycle.

2. All forms of life are important.
Each organism plays a fundamental role in nature. All living things must be considered valuable in the maintenance of stability in an ecosystem. It is easy to appreciate the beautiful butterflies, especially knowing their important role in pollination. Giant beasts like whale, alligator, and elephant are objects of wonder and respect.

3. Everything is connected to everything else.
In an ecosystem, all components interact with each other to ensure the system is continued. Any outside interference may result in an imbalance. Deforestation in the mountains may affect the lowlands, resulting in floods, drought, or erosion. What happens in one country may even affect other countries.

4. Everything changes.
The only permanent thing is change. Change may be linear, cyclical, or random. An example of linear change is the evolution of a species. Cyclical changes is the eruption of a volcano, like Mt. Pinatubo bringing great upheaval in many parts of Luzon.

5. Everything must go somewhere.
When a piece of paper is thrown away, it disappears from sight but it does not cease to exist. It simply goes somewhere else. Wastes can either be pollutants or resources. We need to change or "throw-away" society attitude in order to develop better methods of waste management and recycling.

6. Ours is a finite earth.
The earth's resources can be classified as either renewable or nonrenewable. Renewable resources, like water, air, plants, and animals, can easily be replenished by natural cycles. Nonrenewable resources, like minerals, oil, and coal cannot be replenished through natural cycles. Awareness of the earth's limited resources should lead to a conscious effort to change one's attitude as a consumer.

7. The amount of life nature can support is limited.
Carrying capacity is the maximum number of individuals of a given species which can be supported by a particular habitat or ecosystem without damaging it. For example, a typical Filipino bahay kubo can only support a limited number of family members; the presence of too many residents results in overcrowding. Therefore, nature nature has its own processes or mechanisms to regulate the population of a species within or environment.

8. Human progress must consider its effect on nature.
Sustainable development meets the needs of the present without comprising the ability of future generations to meet their own needs. Development is viewed as essential in improving the quality of human life, yet human activities often change the environment and destroy or damage natural resources. Sustainable development strives for human progress without threatening the environment.

9. Nature is beautiful and we are stewards of God's creation.
This principle is inherent in most religious and tribal beliefs. teachings of Christianity, Buddhism, and Islam enjoin everyone to respect all life and order of nature.

NOTE: Guys, you will work by three or by four. Think of a situation or a scenario on how you can role play or simulate the each principle of environment. You will perform on Monday.

Thursday, April 8, 2010

Branches of Biology




These are the main branches of biology:[65][66]

* Aerobiology - study of airborne organic particles

* Agriculture - study of producing crops from the land, with an emphasis on practical applications

* Anatomy - the study of form and function, in plants, animals, and other organisms, or specifically in humans

* Astrobiology- the study of evolution, distribution, and future of life in the universe. Also known as exobiology, exopaleontology, and bioastronomy.

* Biochemistry - the study of the chemical reactions required for life to exist and function, usually a focus on the cellular level

* Bioengineering - the study of biology through the means of engineering with an emphasis on applied knowledge and especially related to biotechnology.

* Bioinformatics - the use of information technology for the study, collection, and storage of genomic and other biological data

* Biomathematics or Mathematical Biology - the study of biological processes through mathematics, with an emphasis on modeling.

* Biomechanics - often considered a branch of medicine, the study of the mechanics of living beings, with an emphasis on applied use through artificial limbs, etc.

* Biomedical research - the study of the human body in health and disease

* Biophysics - the study of biological processes through physics, by applying the theories and methods traditionally used in the physical sciences

* Biotechnology - a new and sometimes controversial branch of biology that studies the manipulation of living matter, including genetic modification

* Building biology - study of the indoor living environment

* Botany - the study of plants

* Cell biology - the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell.

* Conservation Biology - the study of the preservation, protection, or restoration of the natural environment, natural ecosystems, vegetation, and wildlife

* Cryobiology - the study of the effects of lower than normally preferred temperatures on living beings.

* Developmental biology - the study of the processes through which an organism forms, from zygote to full structure.

* Ecology - the study of the interactions of living organisms with one another and with the non-living elements of their environment.

* Embryology - the study of the development of embryo (from fecondation to birth). See also topobiology.

* Entomology - the study of insects

* Environmental Biology - the study of the natural world, as a whole or in a particular area, especially as affected by human activity

* Epidemiology - a major component of public health research, it is the study of factors affecting the health and illness of populations

* Ethology - the study of animal behavior.

* Evolutionary Biology - the study of the origin and descent of species over time

* Genetics - the study of genes and heredity.

* Herpetology - the study of reptiles and amphibians

* Histology - the study of cells and tissues, a microscopic branch of anatomy.

* Ichthyology - the study of fish

* Integrative biology - the study of whole organisms

* Limnology - the study of inland waters

* Mammalogy - the study of mammals

* Marine Biology - the study of ocean ecosystems, plants, animals, and other living beings.

* Microbiology - the study of microscopic organisms (microorganisms) and their interactions with other living things

* Molecular Biology - the study of biology and biological functions at the molecular level, some cross over with biochemistry

* Mycology - the study of fungi

* Neurobiology - the study of the nervous system, including anatomy, physiology, even pathology

* Oceanography - the study of the ocean, including ocean life, environment, geography, weather, and other aspects influencing the ocean.

* Oncology - the study of cancer processes, including virus or mutation oncogenesis, angiogenesis and tissues remoldings

* Ornithology - the study of birds

* Population biology - study of the populations of organisms - most often referred as ecology, or used to point out biology adaptations, biology events sum up

* Population ecology - the study of populations of organisms, including how they increase and go extinct (dynamics

* Population genetics - the study of changes in gene frequencies in populations of organisms

* Paleontology - the study of fossils and sometimes geographic evidence of prehistoric life

* Pathobiology or pathology - the study of diseases, and the causes, processes, nature, and development of disease

* Parasitology - the study of parasites and parasitism

* Pharmacology - the study and practical application of preparation, use, and effects of drugs and synthetic medicines.

* Physiology - the study of the functioning of living organisms and the organs and parts of living organisms

* Phytopathology - the study of plant diseases (also called Plant Pathology)

* Psychobiology - study of the biological bases of psychology

* Sociobiology - study of the biological bases of sociology

* Structural biology - a branch of molecular biology, biochemistry, and biophysics concerned with the molecular structure of biological macromolecules

* Virology - the study of viruses and some other virus-like agents

* Zoology - the study of animals, including classification, physiology, development, and behavior (See also Entomology, Ethology, Herpetology, Ichthyology, Mammalogy, and Ornithology)

Sunday, March 28, 2010

Respiratory System





The Pathway

* Air enters the nostrils
* passes through the nasopharynx,
* the oral pharynx
* through the glottis
* into the trachea
* into the right and left bronchi, which branches and rebranches into
* bronchioles, each of which terminates in a cluster of
* alveoli

Only in the alveoli does actual gas exchange takes place. There are some 300 million alveoli in two adult lungs. These provide a surface area of some 160 m2 (almost equal to the singles area of a tennis court and 80 times the area of our skin!).


Breathing
In mammals, the diaphragm divides the body cavity into the

* abdominal cavity, which contains the viscera (e.g., stomach and intestines) and the
* thoracic cavity, which contains the heart and lungs.

The inner surface of the thoracic cavity and the outer surface of the lungs are lined with pleural membranes which adhere to each other. If air is introduced between them, the adhesion is broken and the natural elasticity of the lung causes it to collapse. This can occur from trauma. And it is sometimes induced deliberately to allow the lung to rest. In either case, reinflation occurs as the air is gradually absorbed by the tissues.
Because of this adhesion, any action that increases the volume of the thoracic cavity causes the lungs to expand, drawing air into them.

* During inspiration (inhaling),
o The external intercostal muscles contract, lifting the ribs up and out.
o The diaphragm contracts, drawing it down .
* During expiration (exhaling), these processes are reversed and the natural elasticity of the lungs returns them to their normal volume. At rest, we breath 15-18 times a minute exchanging about 500 ml of air.
* In more vigorous expiration,
o The internal intercostal muscles draw the ribs down and inward
o The wall of the abdomen contracts pushing the stomach and liver upward.
Under these conditions, an average adult male can flush his lungs with about 4 liters of air at each breath. This is called the vital capacity. Even with maximum expiration, about 1200 ml of residual air remain.

Digestive System




The digestive system is made up of the digestive tract—a series of hollow organs joined in a long, twisting tube from the mouth to the anus—and other organs that help the body break down and absorb food (see figure).

Organs that make up the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine—also called the colon—rectum, and anus. Inside these hollow organs is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food. The digestive tract also contains a layer of smooth muscle that helps break down food and move it along the tract.

Two “solid” digestive organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes called ducts. The gallbladder stores the liver’s digestive juices until they are needed in the intestine. Parts of the nervous and circulatory systems also play major roles in the digestive system.


Why is digestion important?

When you eat foods—such as bread, meat, and vegetables—they are not in a form that the body can use as nourishment. Food and drink must be changed into smaller molecules of nutrients before they can be absorbed into the blood and carried to cells throughout the body. Digestion is the process by which food and drink are broken down into their smallest parts so the body can use them to build and nourish cells and to provide energy.


How is food digested?

Digestion involves mixing food with digestive juices, moving it through the digestive tract, and breaking down large molecules of food into smaller molecules. Digestion begins in the mouth, when you chew and swallow, and is completed in the small intestine.

Saturday, March 27, 2010

Photosynthesis Song

Plant and Animal Cell




Plant Cells Compared with Animal Cells

Animal cells do not have a cell wall. Instead of a cell wall, the plasma membrane (usually called cell membrane when discussing animal cells) is the outer boundary of animal cells. Animal tissues therefore require either external or internal support from some kind of skeleton. Frameworks of rigid cellulose fibrils thicken and strengthen the cell walls of higher plants. Plasmodesmata that connect the protoplasts of higher plant cells do not have a counterpart in the animal cell model. During telophase of mitosis, a cell plate is formed as the plant cell begins its division. In animal cells, the cell pinches in the center to form two cells; no cell plate is laid down. Centrioles are generally not found in higher plant cells, while they are found in animal cells. Animal cells do not have plastids, which are common in plant cells (chloroplasts). Both cell types have vacuoles, however, in animal cells vacuoles are very tiny or absent, while in plant cells vacuoles are generally quite large.

Tuesday, March 23, 2010

Active and Passive Transport





Passive Transport Versus Active Transport

Passive transport involves carriers, channels, or direct diffusion through a membrane.
This type of transport always operates from regions of greater concentration to regions of lesser concentration.
No external source of energy is required.

Examples of passive transport include
·Simple diffusion
·Channel diffusion
·Facilitated diffusion


In active transport it is possible to go against the concentration gradient.
In active transport, a source of energy is required to move the carrier and its materials.










Endocytosis is a general term for a group of processes that bring macromolecules, large particles, small molecules, and even small cells into the eukaryotic cell. There are three types of endocytosis: phagocytosis, pinocytosis, and receptor-mediated endocytosis. In all three, the plasma membrane invaginates (folds inward) around materials from the environment, forming a small pocket. The pocket deepens, forming a vesicle. This vesicle separates from the plasma membrane and migrates with its contents to the cell’s interior.


Exocytosis is the process by which materials packaged in vesicles are secreted from a cell when the vesicle membrane fuses with the plasma membrane. The initial event in this process is the binding of a membrane protein protruding from the cytoplasmic side of the vesicle with a membrane protein on the cytoplasmic side of the target site on the plasma membrane. The phospholipid regions of the two membranes merge, and an opening to the outside of the cell develops. The contents of the vesicle are released to the environment, and the vesicle membrane is smoothly incorporated into the plasma membrane.

Diffision and Osmosis




Diffusion - the process by which molecules spread from areas of high concentratiion, to areas of low concentration. When the molecules are even throughout a space - it is called EQUILIBRIUM

Concentration gradient - a difference between concentrations in a space.

Selectively Permeable - membranes that allow some things through, the cell membrane is selectively permeable, water and oxygen move freely across the cell's membrane, by diffusion

Osmosis - the diffusion of water (across a membrane)

Water will move in the direction where there is a high concentration of solute (and hence a lower concentration of water.

Type of Solutions


If the concentration of solute (salt) is equal on both sides, the water will move back in forth but it won't have any result on the overall amount of water on either side.

"ISO" means the same


The word "HYPO" means less, in this case there are less solute (salt) molecules outside the cell, since salt sucks, water will move into the cell.

The cell will gain water and grow larger. In plant cells, the central vacuoles will fill and the plant becomes stiff and rigid, the cell wall keeps the plant from bursting

In animal cells, the cell may be in danger of bursting, organelles called CONTRACTILE VACUOLES will pump water out of the cell to prevent this.


The word "HYPER" means more, in this case there are more solute (salt) molecules outside the cell, which causes the water to be sucked in that direction.

In plant cells, the central vacuole loses water and the cells shrink, causing wilting.

In animal cells, the cells also shrink.

In both cases, the cell may die.

This is why it is dangerous to drink sea water - its a myth that drinking sea water will cause you to go insane, but people marooned at sea will speed up dehydration (and death) by drinking sea water.

This is also why "salting fields" was a common tactic during war, it would kill the crops in the field, thus causing food shortages.

Diffusion and Osmosis are both types of PASSIVE TRANSPORT - that is, no energy is required for the molecules to move into or out of the cell.

Sometimes, large molecules cannot cross the plasma membrane, and are "helped" across by carrier proteins - this process is called facilitated diffusion.

Course Outline in Earth and Envi. Sci.

Regional Science High School
Malasiga, San Roque, Zamboanga City

COURSE OUTLINE IN EARTH & ENVIRONMENTAL SCIENCE
S.Y. 2008 – 2009

First Grading Period
I. Introduction to Earth and Environmental Science
o Scope and Benefits of Earth & Environmental Science
o Composition of Environment
o Environment Sustains Life
o Role of Humans in Maintaining the Quality of Life
o Origin of the Earth
o Effects of the Motion of the Earth
o Locate Directions & Predict Approximate Time in Designated Places
II. The Earth’s Past
o Unique Features of the Earth’s Geologic Time
o Evidence of Geologic Events in Rocks
o Records of Living Things in Rocks
o Methods Used in Determining the Age of Fossils on Rocks
o Changes Undergone by the Continents
o Human Activities Contributed to the Changes by the Earth

Second Grading Period
III. Structure of the Earth
o Layers of the Earth
o Studying the Earth’s Interior
IV. Plate Tectonics
o Drifting Continents
o Theory of Plate Tectonic
o Physics of Plate Movement
V. Movement of the Crust
o Folding and Faulting
o Mountains and Plateaus
VI. Earthquakes and Volcanoes
o Earthquakes
o Earthquake Evidence
o Volcanoes

Third Grading Period
VII. Minerals
o Mineral Formation & Structure
o Mineral Identification & Uses
VIII. Rocks & Rock Cycle
o Rocks
o Igneous Rocks
o Sedimentary Rocks
o Metamorphic Rocks
IX. Weathering, Soil, Erosion
o Weathering
o Soil
o World Soil Type
o Force of Erosion


X. Waters of the Earth
o Distribution of the Waters of the Earth
o Philippines Territorial Waters
o Origin of the Earth’s Waters
o Properties of the Waters
o Ocean Bottom
o Inland Waters

Fourth Grading Period
XI. The Air Around Us
o The Composition of Air
o The Pressure of Air
o Sunlight Affects the Atmosphere
o Air Movements
o The Wind Systems in the Philippines
XII. Climate
o Causes of Climate
o Climate Classification
o Climate Change
XIII. Earth and the Moon
o Earth in Space
o Earth’s Moon
o Earth-Moon System
XIV. The Solar System
o The Sun
o Planets in the Solar System
o Asteroids, Meteoroids, Comets
XV. Stars and Galaxies
o The Study of Stars
o Characteristics of Stars
o Life Cycles of Stars
o Galaxies and Star Groups

References:

Our Changing Environment
By: Mercelita C. Magno


Science Insights
By: Marylyn Lisowski, Ph.D.


Earth Science – The Philippines in Focus
By: Leticia P. Cortes

Prepared

LYLWYNN B. LOZANO

Cell Song


So why do cells build us up
Nucleus, cell membrane, and cytoplasm
Mitochondria, vacuoles, and golgi bodies
Lysosomes, ribosomes, and centrioles
ER, chloroplast
We need you (2x)
More than anything darling
You’re all that we have from the start
So build us up
Cell organelles with your functions

Our body is made of microscopic cells
We’re unique, oh yes that’s true
The plant cells are diff’rent from animal cell
With its structures and components, hey, hey, hey
Nucleus is the brain, hey, hey, hey
Cell membrane, regulates the entry and exit of
materials in and out of the cell. ..oooohhh…oooohhh…..

So why don’t you build us up
Mitochondria baby, you give energy through ATP
And the lysosomes, the scavengers baby
Cleaning up our cells
And digest the food
We need you (2x)
More than anything darling
Endoplasmic re-ti-cu-lum,
It's the transport channel
And the ribosomes they make proteins

Chloroplasts are the plastids inside the plant cells,
The makers of glucose
They are together with numerous tiny vacuoles,
Containing cell sap, hey, hey, hey
Cell wall, a rigid wall, hey, hey, hey
Maintaining the shape of the cell because of
the water causing turgor pressure…inside…ooohhh….

So why don’t you build us up
Golgi bodies, baby shippers of the cell
By packing products
And the centrioles, aid in division of the nucleus
To form daughter cells
We need you (2x)
More than anything darling
You have to be part of our lives
So build us up
Cell organelles don’t break our hearts

We, we, we, we need you
More than anything darling
You have to be part of our lives
So build us up
Cell organelles don't break our hearts

So build us up
Cell organelles don't break our hearts

So build us up
Cell organelles don't break our hearts

NOTE: Listen to the Instrumental Version. Just don't mind the picture in the video.

Mitosis





Prophase
• chromatin begins to coil and condense to form chromosomes each chromosome appears to have two strands (each containing a single molecule of DNA)
• each strand is called a chromatid
• each chromatid is attached to its sister chromatid at the centromeres
• at this stage, the number of chromosomes (containing a pair of chromatids) is considered to be equal to the number of centromeres
• the two chromatids are the result of DNA replication that takes place just before mitosis starts.
• the nuclear envelope disappears
• the nucleolus disappears
• in cytoplasm, the spindle apparatus forms
• eventually the spindle guides the separation of sister chromatids into the two daughter cells

Metaphase
• spindle grows and forms attachments to the chromosomes at the centromeres
• chromosomes move to an equatorial plate (metaphase plate) which is formed along the midline of the cell between the poles
• chromosomes are at their most condensed state now
• metaphase chromosomes can be stained and will show distinctive banding patterns
Anaphase
• centromeres divide to create two chromosomes instead of a pair of attached chromatids
• spindle fibers shorten and the sister chromosomes are drawn to the opposite poles of the cell
• poles of the spindle apparatus are pushed apart as the cell elongates
• anaphase results in the exact division of chromosome, distributing one complete diploid complement of genetic information to each daughter cell
Telophase
• nuclear envelopes reassemble and surround each set of daughter chromosomes
• nucleoli reappear inside the newly formed nuclei
• in animal cell, a furrow appears around the cell that eventually pinches the cell into two new cells
• in plants, a cell plate forms between the two daughter nuclei as the cell wall divides the cell
• chromosomes decondense in the daughter cells to become chromatin and the cells are once again in Interphase.