HAPPY THANKSGIVING TO ALL MY USA FANS!

For all my readers from USA, I want to wish you all

HAPPY THANKSGIVING!

As you eat your turkey, meticulously identify the epithelial tissues, the connective tissues, the muscle tissues, etc. Dissect the turkey with care!

Let your mind wonder about how its proteins were made. PROTEIN SYNTHESIS!

Remember the blood cells are formed in the bone marrow so savor the juicy marrow to derive some iron. IRON is needed for the formation of the hemoglobin in the red blood cells.

Explore the cartilage at the end of the bones and enjoy the sight of its glassy appearance!

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HAVE FUN WITH YOUR TURKEY!

STRUCTURE AND FUNCTIONS OF THE EYE

This is a link to a good lesson on the eye for those interested in learning more about how the eye works. It consist of the anatomy and physiology of the eye with animations.  Click here.

STUDY GUIDE FOR THE SCIENCE TEST

SCIENCE REVIEW-Overview

SCIENCE REVIEWThe topics that are generally covered in the test have been grouped into twelve instructional modules below. You will be tested only on the basic concepts of physics, chemistry and biology. Click on science topics and select any of the topics listed in the module to review.

Lesson 1:	Basic structure of atom Cell structure and function Functions of cell organelles Types of tissues
Lesson 2:	Movement of substances across the cell membrane Acids and bases, pH scale Carbohydrates, proteins, lipids and nucleic acids
Lesson 3:	Basic structure of the eye Basic structure of the ear Nervous system
Lesson 4:	Circulatory system Introduction to mechanics (motion/forces) Electrical circuits
Lesson 5:	Balancing chemical equations and writing formulas Essentials of photosynthesis and respiration Classifying organic compounds Magnetism Electromagnetism
Lesson 6:	Interpretation of graphs and pictograms Analyzing and making conclusions from experiments Data analysis
Lesson 7:	Endocrine system Digestive system Genitourinary system
Lesson 8:	Reproduction in mammals Basic parts of a flower Reproduction in plants (the process of pollination Genetics
Lesson 9:	Modes of heat transfer Calculating heat energies and phase diagrams Temperature conversions (Kelvin, Celsius, Fahrenheit)
Lesson 10:	Gas laws (Boyle, Charles, Gay-Lussac) Types of energy (Potential, kinetic, etc…..) Chemical bonds, equilibrium and equilibrium constants Mixtures, types of solutions, solubility
Lesson 11:	Concepts of the food pyramid, food web and food chain Light (diffraction, refraction, reflection, dispersion) Basic concepts on waves Sound waves Catalyst and enzymes
Lesson 12:	Symbiosis Ecology The Electroscope Radioactivity and half-life Tropism Tropism

QUESTIONS FOR THE DAY

1. A student was looking at a cell under the microscope and noticed that centrosomes were present. Which  type of cell was the person looking at?
       A. Bean cell
       B. Carrot cell
       C. Cat cell
       D. Cabbage cell

2. A certain drug inhibited the production of adenosine triphosphate (ATP). This drug acted on which of the        following organelles?
       A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium
       D. Ribosmes

3. A student was looking at a cell under the microscope and noticed that chloroplasts were present. Which   type of cell was the person looking at?
       A. Dog cell
       B. Mouse cell
       C. Cat cell
       D. Cabbage cell

4. Nucleus is to DNA as chloroplast is to _________________ .
       A. RNA
       B. Plant
       C. ATP
       D. Chlorophyll

5. The genetic blueprint of life can be found in which of the following structure?
       A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium
       D. Ribosmes

6. Which of the following is not involved in protein synthesis?
      A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium
       D. Ribosmes

******************************The answers ********************************

The answers are in bold fonts with explanations.

1. A student was looking at a cell under the microscope and noticed that centrosomes were present. Which   type of cell was the person looking at?
       A. Bean cell
       B. Carrot cell
       C. Cat cell (Centrosomes occur only in animal cells)
       D. Cabbage cell

2. A certain drug inhibited the production of adenosine triphosphate (ATP). This drug acted on which of the  following organelle?
       A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium (Mitochondrium is involved in ATP production so inhibiting it will lead to decreased production)
       D. Ribosmes

3. A student was looking at a cell under the microscope and noticed that chloroplasts were present. Which  type of cell was the person looking at?
       A. Dog cell
       B. Mouse cell
       C. Cat cell
       D. Cabbage cell (Chloroplast is found only in plant cells)

4. Nucleus is to DNA as chloroplast is to _________________ .
       A. RNA
       B. Plant
       C. ATP
       D. Chlorophyll (Nucleus contains the DNA and Chloroplast contains the chlorophyll)

5. The genetic blueprint of life can be found in which of the following structure?
       A. Endoplasmic reticulum
       B. Nucleus (Nucleus contains the DNA, the genetic blueprint of life)
       C. Mitochondrium
       D. Ribosmes

6. Which of the following is not involved in protein synthesis?
      A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium

       D. Ribosmes

OVERVIEW OF THE CELL

In today's lesson, we want to look at the basic structure of the cell. The cell theory states that
All organisms contain one or more cells which are capable of carrying on the life activities needed by the organism.

• The cell is the unit of structure in all living things.
• The cell is the unit of function in all living things.
• All cells come from preexisting cells.

 Exception: Viruses lack typical cellular structure.

CATALYST AND ENZYMES

A catalyst is any substance that speeds up the rate of any chemical reaction. It does not take part in the reaction itself. It is only there to increase the rate at which the reaction proceed. It can therefore be used over and over again.

In the living organism, the biological catalyst is referred to as an enzyme.
Characteristics of enzymes:

• Enzymes are proteins in nature. They can, therefore, be denatured. That is, they can be destroyed or damaged by extreme conditions of temperature and pH. 
• Enzymes work within a narrow temperature  and pH ranges. 
• Enzymes have active sites when the substrate binds. Substrate is the substance that the enzyme binds to for chemical reaction to occur.
• Enzymes work by lowering the activation energy. Activation energy is the minimum energy that is needed to be overcome before the reactants can be converted into products. 
• Enzyme activity increases with increase in the substrate until saturation is reached and then the rate of activity slows down.
• Enzymes are specific in nature, that is, they work on only specific substances. It is like lock and key. For every lock, there is a particular key that fits it.
• Certain drugs can compete with the substrate for the active site. This can lead to inhibition ot the enzyme. This is referred to as competitive inhibition. 
• There is also non-competitive inhibition where the drug competes for sites other than the active sites. These sites are know as allosteric site. 

CELL STRUCTURE AND FUNCTION

Functions of some cell organelle:

1.      Nucleus: Control center of the cell. Contains DNA which directs the synthesis of  

      proteins by the cell.

2.      Mitochondria: Carries on the process of cell respiration by converting glucose to 

      ATP energy.

3.  Ribosome: Found on the endoplasmic reticulum and free within the cell. 

Responsible for the synthesis of proteins for the cell.

4.  Endoplasmic reticulum: Transport channels within the cell.

5.  Food vacuole: stores and digests food.

6.  Lysosomes: Contain digestive enzymes. Breaks down substances in the cell.

7. Contractile vacuoles: Pumps out wastes and excess water from the cell.

8.  Cell membrane: Selectively regulates the materials moving to and from the cell.

 9.  Chloroplast: Found only in plant cells and algae. Contains chlorophyll (the green   

     coloring substance in plants) which carries on the process of photosynthesis.

10. Cell wall: Surrounds and supports plant cells. Only in plants. The cell wall is formed  

     from the cell plate during cell division.

EXAM TIPS:

• If you see centriole and centrosome in a question, think of an animal cell. They occur only in animal cells and they are involved in cell division where they produce spindles.
•  If you see cell plate and chloroplasts in a question, think of a plant cell. They occur only in plant cells.

TEST YOUR KNOWLEDGE

1. A student was looking at a cell under the microscope and noticed that centrosomes were present. Which   type of cell was the person looking at?
       A. Bean cell
       B. Carrot cell
       C. Cat cell
       D. Cabbage cell

2. A certain drug inhibited the production of adenosine triphosphate (ATP). This drug acted on which of the  following organelle?
       A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium
       D. Ribosmes

3. A student was looking at a cell under the microscope and noticed that chloroplasts were present. Which  type of cell was the person looking at?
       A. Dog cell
       B. Mouse cell
       C. Cat cell
       D. Cabbage cell

4. Nucleus is to DNA as chloroplast is to _________________ .
       A. RNA
       B. Plant
       C. ATP
       D. Chlorophyll

5. The genetic blueprint of life can be found in which of the following structure?
       A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium
       D. Ribosmes

6. Which of the following is not involved in protein synthesis?
      A. Endoplasmic reticulum
       B. Nucleus
       C. Mitochondrium

       D. Ribosmes

Answers: 
1. C. Cat cell (Centrosomes occur only in animal cells)
2. C. Mitochondrium (Mitochondrium is involved in ATP production so inhibiting it will lead to decreased production)
3. D. Cabbage cell (Chloroplast is found only in plant cells)
4.  D. Chlorophyll
5. B. Nucleus (Nucleus contains the DNA, the genetic blueprint of life)

6. C. Mitochondrium

WELCOME MESSAGE

Welcome to the Elementary PRAXIS Exam Review blog. I hope it will help you prepare very well for this exam. This is the exam required for certification for those who want to pursue careers in elementary education in the USA. I will attempt to break down the review materials into manageable parts so that you can systematically and efficiently prepare for the test with less stress. I will guide you to prepare for the entire content of the test. Hopefully, you will be able to pass after going through these series.

Best of luck!