VIDEO LESSON ON NATURAL SELECTION

VIDEO LESSONS AND PRACTICE QUESTIONS

VIDEO QUIZ ON MOVEMENT ACROSS THE CELL MEMBRANE

PRACTICE QUESTIONS ON MOVEMENT ACROSS THE CELL MEMBRANE

ANSWERS TO QUESTION FOR THE DAY

1. A student placed a blue ink drop in a jar of water. After some time, the whole water turned blue. Which of the following processes occurred?
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

2. Water enters the roots of plants by which of the following process?
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

3. Oxygen from the atmosphere enters the blood from the lung by ____________________ .
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

4. The Na+/K+ ATPase pumps sodium and potassium in  and out of the cell by ____________ .
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

5. When a red blood cell (RBC) is placed in a hypertonic solution, it will ____________________ .
A. Increase in size
B. Shrink
C. Rupture
D. Remain the same

6. When a red blood cell (RBC) is placed in a hypotonic solution, it will ____________________ .
A. Increase in size and rupture
B. Shrink
C. Crenate
D. Remain the same

QUESTION FOR THE DAY

1. A student placed a blue ink drop in a jar of water. After some time, the whole water turned blue. Which of the following processes occurred?
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

2. Water enters the roots of plants by which of the following process?
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

3. Oxygen from the atmosphere enters the blood from the lung by ____________________ .
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

4. The Na+/K+ ATPase pumps sodium and potassium in  and out of the cell by ____________ .
A. Osmosis
B. Simple Diffusion
C. Active Diffusion
D. Facilitated diffusion

5. When a red blood cell (RBC) is placed in a hypertonic solution, it will ____________________ .
A. Increase in size
B. Shrink
C. Rupture
D. Remain the same

6. When a red blood cell (RBC) is placed in a hypotonic solution, it will ____________________ .
A. Increase in size and rupture
B. Shrink
C. Crenate
D. Remain the same

QUESTION FOR THE DAY

1. How would cream crackers taste if it is chewed slowly?

A. Sweet     B. Bitter     C. Sour      D. Tasteless

2. What will be the end-product of maltose digestion?

A. glucose     B. glucose and galactose    C. galactose     D. glucose and fructose

3. What will be the end-product of sucrose digestion?

A. glucose     B. glucose and galactose    C. galactose and fructose     D. glucose and fructose

4. What will be the end-product of lactose digestion?

A. glucose     B. glucose and galactose    C. galactose and fructose     D. glucose and fructose

5. Which of the following will turn blue-black when test with Lugol's solution?

A. protein     B. starch    C. glucose     D.  fructose

CELL CHEMISTRY

There are three types of substances that life is dependent on. These are carbohydrates, proteins, and lipids (fats).                                                                                                                                                      

C  

1. Carbohydrates: These are used to produce energy for cellular activities.                                          

Types of carbohydrates:                                                                                                                            (a) simple sugars (monosaccharides): One sugar molecule–  Examples: Glucose, fructose and galactose.            

                               

(b) disaccharides: Two monosaccharide joined together.                  

Examples: Lactose = glucose + galactose; Sucrose = glucose + fructose; Maltose = glucose + glucose 

   

Exam hints: Memorize what the disaccharides are composed of.  In order words, what are the end products if you break down or digest a disaccharide.

                                                                                

(c) Complex sugars: Starch, cellulose and glycogen are made up of so many glucose joined together.

Exam hints: Glycogen is the storage form of carbohydrate in animals only . Cellulose is only found in plant cells.

2. Proteins are made up of amino acids. Proteins are the structural building blocks of the organism.

3. Lipids (Fats and oil) are made up of fatty acids and glycerol.

Test for some food substances:

Type of food substance	Test
Starch	Iodine test: Turns blue-black
Simple sugar (Glucose)	(a) Benedicts test: Brick-red coloration (b) Fehlings test: brick red coloration
Protein	Biuret test: light-blue color becomes purple
Lipid	Paper test: Oil stains paper

Exam hints: Memorize the test for the food substances.

WHAT IS MATTER?

Matter is anything that occupies space and has mass. There are three states of matter:

•  solid
•  liquid
• gas. 

Matter can be classified according to two properties:

•  physical (properties observed without changing the composition of the substance)
•  chemical (properties that describe the tendency of a substance to undergo chemical reactions that change its chemical composition)

Physical properties can be described as:

• intensive or 
• extensive. 

What is an intensive property?

Intensive properties are the same for all samples and do not depend on sample size. Examples: color, physical state, melting and boiling points, optical density. 

What is an extensive property?

Extensive properties depend on the amount of material. and include mass and volume. 

The ratio of two extensive properties, mass and volume, is an important intensive property called density.

What is a physical change?
A physical change involves the conversion of a substance from one state of matter to another, without changing its chemical composition. 

Most matter consists of mixtures of pure substances, which can be:

•  homogeneous (uniform in composition) or 
• heterogeneous (different regions possess different compositions and properties). 

What is a pure substance?
Pure substances can be either chemical compounds or elements. 

What is the difference between a compound and an element?
Compounds can be broken down into elements by chemical reactions, but elements cannot be separated into simpler substances by chemical means.   

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THE BRAIN AND ITS FUNCTIONS