Molecules for Life

TISSUES, CELLS

AND MOLECULAR

BIOLOGY

Potchefstroom High School for Bo ys

What am I made of?

Inorganic Compounds:

Water (2H: 1O)

Minerals (Na, P, I, Ca, Fe, K,

nitrates, phosphates) – functions

and deficiencies

Fertilizers

Organic molecules are made up of

C, H, O and some contain other

elements such and N, P and S.

Cells are made up of proteins,

carbohydrates, lipids, nucleic acids

and vitamins.

Element % °/degree

2

Inorganic Chemicals

What is …

The smallest unit of matter that can take part in a chemical reaction _____________________

Two or more atoms that combine with one another chemically _____________________

A pure substance that is not made up of other simpler substances _____________________

A pure substance made up of elements, chemically combined _____________________

Name the seven basic characteristics of life:

1. _________________________

2. _________________________

3. _________________________

4. _________________________

5. _________________________

6. _________________________

7. _________________________

Macro and Micro elements In Animals In Plants

MINERAL

ELEMENT

WHERE IT IS

FOUND

WHY IT IS NEEDED RESULT OF

DEFICIENCY

MINERAL

ELEMENT

WHERE IT IS

FOUND

WHY IT IS

NEEDED

RESULT OF

DEFICIENCY

MACRO -

ELEMENTS

MACRO -

ELEMENTS

4

MICRO -

ELEMENTS

MICRO -

ELEMENTS

6

Fertilizers and Eutrophication

Fertilizers provide essential nutrients like nitrogen and

phosphorus to the soil in which grass, vegetables and ornamental

flowers grow. Large-scale farmers also use fertilizers to grow

produce and other crops needed to feed a rapidly increasing

population. Fertilizer nutrients left unused in soil can run off into

coastal waters, lakes and streams, resulting in eutrophication, or

the addition of excessive amounts of nutrients. Eutrophication can

occur naturally; however, effects of human-caused eutrophication

are accelerated and have serious environmental consequences.

Role of Agriculture

The use of manmade synthetic fertilizers has increased

dramatically in recent years. Globally, nitrogen and phosphorus

fertilizer use increased seven- and threefold, respectively, from

1960 to 1990. An average of 20 percent of nitrogen fertilizer is

lost to leaching or surface runoff, and phosphorus enters water

systems through soil erosion. When excess nutrients from

fertilizers leach into rivers, lakes and estuaries, they stimulate

growth of algae, just as they stimulate plant growth in gardens.

This increased aquatic plant life can produce floating surface

scum known as algal blooms.

Impact of Eutrophication

The impact of eutrophication on the environment and the

economy is concerning. When algal blooms form, less sunlight

can penetrate the water surface, which results in decreased

productivity of underwater plants and depleted oxygen reserves.

The lack of oxygen has devastating effects on aquatic life,

including fish such as trout and salmon. In addition, some algae

produce toxins in the water, further damaging the aquatic

ecosystem. Economically, operating expenses of public water

works increase as a result of taste and odor issues caused by algal

bloom. Fish death and navigational impediments can impact

severely the economies of regions dependent on fishing as a

source of revenue. Similarly, recreational areas lose business

because of slime and weed infestation around lakes and streams.

Areas Affected

The impact of eutrophication and the threat to water systems is

widespread worldwide.

Management

To manage eutrophication, keep excess nitrogen and phosphorus

fertilizer from reaching water systems in the first place. Before

applying any fertilizer, know what nutrient levels a particular

plant needs, as well as the current nutrient levels in your soil.

Whenever possible, plant native and adapted plants in your

garden because their water and fertilizer demands will be less

than non-native plant species. Add groundcover plants to your

garden to help absorb any extra nitrogen in the soil and to prevent

leaching.

7

Chemicals used in Life Science

REACTANTS PRODUCT

Reactants

8

Indicators

9

10

Organic molecules

11

Latin and Greek Number prefixes

12

Carbohydrates

Examples

Structure

Composition

Elements: C,H,O

Ratio of H:O is 2:1

Smallest unit/building

blocks are

monosaccharide

Two monosaccharides

forms a disaccharide

Many monosaccharides

forms a polysaccharide

Properties

Monosaccharides and

disaccharides

o Small molecules

o Soluble in water

o Taste sweet

Polysaccharides

o Large molecules

o Insoluble in water

o Tastes chalky

Biological Importance

Primary source of energy

o glucose

Can be stored

o Starch (plants)

o Glycogen (animals)

Structural/strengthening/

supportive

o Cellulose (plants

cell walls)

Influence osmotic potential

o Mono- &

disaccharides

Practical 1.1: Glucose test

AIM: To develop a reference test for a reducing sugar, e.g. glucose

APPARATUS

WATER BATH

SPATULA/TEASPOON

TEST TUBES

BEAKER

BENEDICT’S SOLUTION

OR

FEHLINGS A & B

DROPPER

METHOD

1. Set up three test tubes in a glass beaker 2. Mark each of the test tubes in a different color (e.g. black, red, blue), as 1, 2 and 3 3. Make up three different solutions (or your teacher will supply you with these)

a. Solution A – Glucose b. Solution B – Sucrose c. Solution C - Starch

4. Add equal amounts of each solution to separate test tubes: a. Solution A to test tube 1 b. Solution B to test tube 2 c. Solution C to test tube 3

5. Add 5 drops of Benedicts solution (of 5 drops Fehlings A and 5 drops Fehlings B) to each test tube

6. Observe the colour while the test tubes are cold 7. Add boiling water to the glass beaker and place the test tubes inside the glass beaker/ boil

water over a bunsen burner 8. Observe the colour while the test tubes are warm

13

EXPERIMENTAL DESIGN:

INDEPENDENT VARIABLE: _________________________________

DEPENDENT VARIABLE _________________________________

FIXED VARIABLES: APPARATUS: ____________________________________________________________________

ORGANISMS: ____________________________________________________________________

ENVIRONMENT: ____________________________________________________________________

RESULTS

Solution Colour before heating with indicator Colour after heating with indicator

A – Glucose

B – Sucrose

C – Starch

14

Practical 1.2: Starch test

AIM: To develop a reference test for starch

APPARATUS

SPATULA/TEASPOON

TEST TUBES

BEAKERS

INDICATOR: IODINE

DROPPER

METHOD

1. Set up three test tubes in a glass beaker 2. Mark each of the test tubes in a different color (e.g. black, red, blue), as 1, 2 and 3 3. Make up three different solutions (or your teacher will supply you with these)

a. Solution A – Glucose b. Solution B – Sucrose c. Solution C - Starch

4. Add equal amounts of each solution to separate test tubes: a. Solution A to test tube 1 b. Solution B to test tube 2 c. Solution C to test tube 3

5. Add 5 drops of Iodine 6. Observe the colour while the test tubes are cold

EXPERIMENTAL DESIGN:

INDEPENDENT VARIABLE: _________________________________

DEPENDENT VARIABLE _________________________________

FIXED VARIABLES: APPARATUS: ____________________________________________________________________

ORGANISMS: ____________________________________________________________________

ENVIRONMENT: ____________________________________________________________________

15

RESULTS

Solution Colour with indicator

A – Glucose

B – Sucrose

C – Starch

HOMEWORK QUESTIONS DATE: __________________________________

1. Mark the following statements as TRUE or FALSE:

a. __________ Sucrose is the same thing as table sugar.

b. __________ The body is able to digest fiber and convert it to a sugar called glucose

c. __________ The brain uses glucose as its main source of energy.

d. __________ Starch is made up of glucose units linked together (4)

2. What is lactose intolerance?

_____________________________________________________________________________________________________

__________________________________________________________________________________________________(2)

3. Define the term empty-calorie food and list three examples:

_____________________________________________________________________________________________________

_____________________________________________________________________________________________________

_______________________ ______________________ ______________________ (5)

4. List two benefits of eating lots of fiber:

_____________________________________________________________________________________________________

__________________________________________________________________________________________________(2)

5. What do you understand by the term “reducing sugar”?

_____________________________________________________________________________________________________

__________________________________________________________________________________________________(2)

TOTAL: 15

16

Proteins

Structure

Dehydration synthesis

Composition

Elements: C,H,O,N, S,P,Fe

Building blocks/monomers is amino acids

20 different amino acids in the body

Two amino acids together is a dipeptide

A chain of amino acids is a polypeptide

Peptide bonds

Properties

Large molecules

High temperature can denature them

Low temperatures inactivates them

Extreme pH denatures them

Biological Importance & Examples

Fibrous Proteins

Globular Proteins

17

Practical 1.3

AIM: To develop a reference test for proteins

APPARATUS

WATER BATH

SPATULA/TEASPOON

TEST TUBES

BEAKER

MILLONS REAGENT

BUIRET SOLUTION

DROPPER

METHOD

1. Set up four test tubes in a glass beaker 2. Mark each of the test tubes as 1, 2, 3 and 4 3. Make up two different solutions (or your teacher will supply you with these)

a. Solution A – Albumin (egg white) b. Solution B – Sucrose (any non-protein solution)

4. Add equal amounts of each solution to separate test tubes: a. Solution A to test tube 1 and 2 b. Solution B to test tube 3 and 4

5. Add 5 drops of Millons reagent to test tube 1 and 3 6. Add 5 drops of Buiret solution to test tube 2 and 4 7. Observe the colour while the test tubes are cold 8. Add boiling water to the glass beaker and place the test tubes inside the glass beaker/ boil

water over a 17unsen burner 9. Observe the colour while the test tubes are warm

EXPERIMENTAL DESIGN:

INDEPENDENT VARIABLE: _________________________________

DEPENDENT VARIABLE _________________________________

FIXED VARIABLES: APPARATUS: ____________________________________________________________________

ORGANISMS: ____________________________________________________________________

ENVIRONMENT: ____________________________________________________________________

18

RESULTS

MILLONS REAGENT

Solution Colour before heating with indicator Colour after heating with indicator

A –

B –

BUIRET SOLUTION

Solution Colour before heating with indicator Colour after heating with indicator

A –

B –

Enzymes

Definition: Enzymes are:

______________________________

______________________________

______________________________

Lock-and-Key mechanism

19

Enzyme Substrate Enzyme Product

THE EFFECT OF AN ENZYME ON THE RATE OF A CHEMICAL REACTION

THE EFFECT OF TEMPERATURE ON THE ACTIVITY OF AN ENZYME THE EFFECT OF PH ON THE ACTIVITY OF AN ENZYME

20

Practical 1.4

AIM: To investigate the effect of temperature on the activity of an enzyme

APPARATUS

WATER BATH

SPATULA/TEASPOON

TEST TUBES

BEAKER

HCL( DILUTED)

DROPPER

PEPSIN SOLUTION

THERMOMETER

METHOD

1. Set up three test tubes each in its own glass beaker 2. Mark each of the test tubes as 1, 2, and 3 3. Make up a solutions (or your teacher will supply you with these) of Solution A – Albumin

(egg white) 4. Add equal amounts of the solution to each test tubes 5. Add 3 drops HCl to each test tube 6. Add 3 drops pepsin to each test tube 7. Immediately place the test tubes in different conditions

a. Test tube 1 in water with ice in a beaker b. Test tube 2 in water from the tap in a beaker c. Test tube 3 in boiling water in a beaker

8. Allow the test tubes to stand for 20 minutes 9. Observe the content of the test tube

EXPERIMENTAL DESIGN:

INDEPENDENT VARIABLE: _________________________________

DEPENDENT VARIABLE _________________________________

FIXED VARIABLES: APPARATUS: ____________________________________________________________________

ORGANISMS: ____________________________________________________________________

ENVIRONMENT: ____________________________________________________________________

RESULTS

Test tube 1 Test tube 2 Test tube 3

21

HOMEWORK QUESTIONS DATE: __________________________________

Catalase is an enzyme. It catalyses the following reaction:

1. How much oxygen was produced between 120 and 130 seconds? _______________________________ (1)

2. Less oxygen was produced between 80 and 90 seconds than between 10 and 20 seconds. Use your knowledge of the way

enzymes work to explain why.

_____________________________________________________________________________________________________

_____________________________________________________________________________________________________

_____________________________________________________________________________________________________

__________________________________________________________________________________________________(2)

3. Sketch a curve on the graph to show how the rate of reaction changed over the time shown (2)

4. Describe how you could test the catalase preparation to show that it contains protein.

_____________________________________________________________________________________________________

_____________________________________________________________________________________________________

__________________________________________________________________________________________________(2)

5. When scientists measure the activity of an enzyme, they make sure that the enzyme is at its optimum pH. Explain why.

_____________________________________________________________________________________________________

_____________________________________________________________________________________________________

__________________________________________________________________________________________________(2)

TOTAL:9

22

Nucleotides

Examples

Structure

Composition

Monomer is a nucleotide

Nucleotide consists of:

o Phosphate

o Pentose sugar

o Nitrogenous bases:

Adenine

Guanine

Cytosine

Thymine

Properties

Twisted ladder form

Double helix

Held together with

hydrogen bonds between

bases

Biological Importance

Stores genetic information

Determines the structure

and function of cells

23

Lipids

Examples

Structure

Composition

Elements : C,H,O

Ratio of H:O is greater than

2:1

Composed of one

o glycerol molecule

o three fatty acid

o ester bonds

Properties

Insoluble in water

Soluble in ether

Biological Importance

Superior source of energy

Stored as reserve energy

by plants and animals

Fat under skin is an

insulator

Fat between organs is a

shock absorber

Phospholipids are structural

components of cell

membranes

Practical 1.5: Test for the presence of lipids

AIM: To develop a reference test for lipids/fats

APPARATUS

ETHER/ETHANOL

FILTER PAPER/BROWN

PAPER

COOKING OIL

DROPPER

METHOD

1. Add a few drops of oil to 20 ml ether/ethanol and agitate until oil dissolves 2. Using a dropper place one drop of the mixture onto a filter paper/brown paper 3. Draw a circle in pencil around the moist patch 4. Allow the filter paper to dry 5. Observe the filter paper when the ether/ethanol has evaporated

EXPERIMENTAL DESIGN:

INDEPENDENT VARIABLE: _________________________________

DEPENDENT VARIABLE _________________________________

FIXED VARIABLES: APPARATUS: ____________________________________________________________________

ORGANISMS: ____________________________________________________________________

ENVIRONMENT: ____________________________________________________________________

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RESULTS

___________________________________________________________________________________________________________