Transcript basic components of living things

BASIC COMPONENTS
OF LIVING THINGS
BOOK PAGE
21-29
14-20
What are plants made up of ?
What are animals made up of ?
All living things are made up of cells.
But what are cells made up of ?
Atoms and molecules
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An atom contains charged particles.It
consists of nucleus and electrons.
Nucleus is positive, containing positive
protons and neutral protons. Electrons
are negative. Normaly the number of
electrons is the same as the number of
protons and the atom is neutral.
It is possible to remove or add one or
more electrons to atom.Then the atoms
becomes charged ions.
Molecules-Water
A molecule is a
collection of
atoms linked by a
network of bonds
Chemical bonds
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When atoms combine with each other they form
chemical bonds between the atoms.
To attain a stable electron configuration they
have to achieve the maximum number of
electrons in the outermost energy level, atoms
can either :
donate,
 accept, or
 share
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Ionic bonds
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Opposite charges attract so the ions in sodium
chloride are held together by the attraction
between Na+ and Cl -. This forms an ionic
bond.
Na
Cl
Covalent bonds

In this type of bond 1, 2 or 3
pairs of electrons are shared
between participating atoms.
The shared electrons now
circulate about both atoms
participating in the bond.
 covalent bonds are
relatively strong
 covalent bonds are much
more common in organic
compounds (and therefore
in the biological world)
Hydrogen bonds

One special type of interaction
between polar molecules
occurs in many organic (and
hence biological) molecules
where the weak attraction of
the partial charge on a
hydrogen atom in a covalent
bond for the partial negative
charge on an atom in another
molecule is termed a
hydrogen bond.
LIVING THINGS
INORGANIC
WATER
MINERALS ACIDS, BASES
ORGANIC
CARBO
HYDRATES
PROTEINS
LIPIDS
ENZYMES
VITAMINS
NUCLEIC
ACIDS
ATP
Inorganic and Organic molecules
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Cannot synthesize
Take in readily
Important in structure
Can have different kind
of elements
Can not be digested or
hydrolyzed.
Never used as energy
source
Water, salt, minerals,
acid and bases
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Can synthesize
Important in structure,
energy and homeostasis
Always have C,H,O
Can be broken
down(not vitamins)
Can be used as energy
source
Proteins, carbohydrates,
lipids, vitamins,
enzymes, nucleic acids
Water
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Source
Food
Chemical reactions
Drinking water
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Function
Good Solvent
Breaking up macromolecules
(hydrolysis)
Cell Membrane transport
(in/out)
Keep body temparature
constant
In photosynthesis
Chemical reactions/enzymes
Acids and Bases
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Acids give out H ions
Turns blue turnusol
paper into red
Sour taste
1
2
3
4
5
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Bases give out OH ions
Turns red turnusol
paper into blue
Bitter taste
8
9
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6
7
10
11
12
13
If H ion concentration increases, acidity increases.
pH decreases.
If H ion concentration decreases basicity increases.
pH increases.
pH is important for chemical reactions to occur.
Because it effects the enzyme activity.
14
Minerals and Salts
Salts form as a result of reaction between a strong acid and a
strong base
 HCl + NaOH
NaCl + H2O
(Neutralisation reaction)
Salt and mineral concentrations are always kept constant.
 Important in muscle contraction
 Important in water exchange.
 Important component in Bones(Ca, P), Chlorophyll (Mg)and
hemoglobin (Fe), ATP (P) energy molecule.
 Activates enzymes for chemical reactions
 Cannot broken into parts(can not digested or hydrolysed),
cannot give energy
 Exess of the minerals are stored (Ca P in bones) or thrown out
by urine(Na, Cl, K).
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Name of the
mineral
Calcium
Food rich in mineral Function of the
mineral
Milk,cheese, bread
For bones, teeth
Phosphorus
Milk, fish, meat
Flourine
Toothpaste, water
Iodine
Sea food, salt
Iron
Liver, egg yolk
For hormone
thyroxine
hemoglobin
Sodium
Meat, milk, egg, salt
For nerves
Chlorine
Salt, vegetables
Chemical reactions
Copper
Liver, egg, fish
Chemical reactions
Zinc
Meat, milk, yogurt, rice For wound heal
Magnesium
Nut, green vegetables
For bones,teeth,
eyes
For teeth
For chlorophyll
Hydrolysis and Dehydration
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Organic molecules are large molecules. They are
called polymers. Polymers are made up of small
molecules, small molecules are called monomers.
HYDROLYSIS
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Polymers are broken down by hydrolysis
reaction.
Polymer + H2O
monomer+monomer+……
In hydrolysis water is used
DEHYDRATION
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Monomers form polymers by dehydration
reaction.
Monomer+monomer+monomer……
Polymer+ H2O
In dehydration water is formed
In hydrolysis polymers are broken down by using water.
Number of water = Number of bonds = Number of small
molecules
molecules used
that are broken
formed
down
- 1
(n)
In Dehydration monomers form polymers by forming water.
Number of bonds
Number of small - 1 = Number of water =
that are formed
molecules
molecules used
formed
(n)
If you want to form a large molecule from 2
small units, how many bonds occur?
 1 bond
If you want to form a large molecule from 10
small units, how many bonds occur?
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10-1=9 bonds
If you want to form a large molecule from 10
small molecule , how many H2O molecules can
form?
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10-1=9 water mol.
You have a large molecule which is composed of
8 units. If you want to breakdown this large
molecule, how many water molecules should you
use?
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8-1= 7 water mol.
CARBOHYDRATES
Organic molecules
 Contain C, H, O
formula- (CH2O)n
 Gives energy by the breakdown of the chemical
bonds
 Photosynthetic living things synthesize their
carbohydrates by themselves.
6 CO2+6 H2O
C6H12O6 + 6 O2
 Structural component of living things (DNA,
RNA, ATP)
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CARBOHYDRATES
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Structural component of living things (DNA,
RNA, ATP), They have 5 C sugars(pentose)
Deoxyribose
Ribose
CARBOHYDRATES
MONOSACCHARIDES
•Simple sugars C6H12O6
•Can not be hydrolysed into
smaller units (monomers)
DISACCHARIDES
•Composed of 2
monosaccharides.
POLYSACCHARIDES
• composed of many
monosaccharides
•Formed by dehydration. Bond’s •Formed by dehydration.
name is Glycoside bond.
Bond’s name is Glycoside
•5C- deoxyribose, ribose, ATP
bond.
•Can be broken down by
•6C- glucose, fructose,
hydrolysis into monomers.
•Can be broken down by
hydrolysis into monomers
galactose and are soluble
•Mono+mono disacch+H2O
• (n)mono poly+(n-1) H2O
•Plants can synthesize but
•Lactose– glucose+galactose
animals get it readily.
•Starch
•sucrose-or saccharoseglucose+fructose
•Cellulose
glucose
•Maltose- glucose+glucose
•glycogen
•Unsoluble, change color with
iodine
Disaccharides
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2 monomers form disaccharides. 1 mol H2O is formed
Polysaccharides
n( monosaccharide)
Polysaccharide+ (n-1) water
Starch, cellulose, glycogen have the monomer of
glucose. But they have different bonding.
Importance of carbohydrates
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They are used as energy source in cellular respiration.
They are broken down to monosaccharides in the
digestive system and absorbed like that.
They are stored as starch in plants. Animals can not
store starch. Cellulose functions in structure, not in
storage.
They are stored as glycogen in animals, most of them
are soluble in water. Plants can not store glycogen.
Important in regulation of blood sugar level.
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Found in Cell membrane-with lipids and
proteins for Recognition of foreign molecules
Excess of the carbohydrates are converted into
fat and stored like that.
Human can not digest cellulose. Special animals
digest it with the help of the bacteries.
Plant carbohydrates(cellulose-rouphage) are
important in the proper working of the digestive
system.
Sugar cane, banana, apple, grape, grains, liver,
meat, potato are sources of carbohydrates.
REVIEW QUESTIONS OF CARBOHYDRATES
 Describe the chemical makeup of carbohydrates ?
(CH2O)n
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How can you classify carbohydrates?
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We can classify carbohydrates according to their
monomer number.
Monosaccharides_have one monomer
Disaccahrides_have 2 monomers
Polysaccharides_have many monomers
What are the functions of carbohydrates?
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Gives energy by the breakdown of the chemical bonds
Structural component of living things (DNA, RNA, ATP)
Found in Cell membrane-with lipids and proteins,
Recognition of foreign molecules
Found in cell wall as cellulose, found in insects as chitin.
Explain how disaccharides form?
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2 monosaccharides form disaccharides by dehydration
reaction. 1 mol H2O and 1 bond are formed. Bond’s
name is Glycoside bond.
Compare hydrolysis and dehydration reaction.
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Monomers form polymers by dehydration reaction. In
dehydration water is formed
Polymers are broken down by hydrolysis reaction.. In
hydrolysis water is used
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Classify the reactions below:
Formation of sucrose from glucose and fructose
Synthesis of starch from glucose
Breakdown of maltose to form glucose
Formation of glucose from cellulose.
Dehydration..
Dehydration..
Hydrolysis
Hydrolysis
LIPIDS
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Lipids are not soluble in water. They can solve in aceton,
alcohol, chloroform or benzene.
Contain C,H,O
Monomers are: Fatty acids and Glycerol.
In a molecule of lipid, there are 3 molecules of fatty
acids and one molecule of glycerol. Lipids are formed by
dehydration reaction. 3 molecules of water is formed.
There are esther bonds between fatty acid molecules and
glycerol.
Lipid structure- Triglycerides
1 glycerol + 3 fatty acids
1 lipid+ 3 water
Properties
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Important energy source. It has energy twice as
much as carbohydrates and proteins. But they
are used as second energy source.
They are used as storage molecule.
They are the main component of the cell
membrane. (ın membrane they are found as
phospholipids)
Lipids are classified according to their fatty acid
structure: saturated and unsaturated lipids.
Saturated and Unsaturated lipids
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Fatty acids have long carbon
chains. 2 molecules of H can be
bound to Carbons.
If there is only one bond
between carbon molecules, they
are saturated lipids. (All carbons
are saturated with maximum
number of H). Butter,
margarine. (Found mostly in
animals)
If there is some double bonds
between carbon molecules, they
are unsaturated lipids. Oils, olive
oil (found mostly in plants)
Importance of Lipids
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Protects internal organs. Heart, intestine
Insulates the body, keeps the temperature constant.
Excess of carbohydrates and proteins are converted
into fats. It causes obesity.
Fat soluble vitamins(ADEK) are dissolved in the fats
and absorbed with them.
Some fatty acid molecules(essential fatty acids) can not
be synthesized by animals. They have to take these fatty
acid from plants. Plants can synthesize all.
Meat, milk, cheese, egg, sesame,sunflower seed, nuts are
rich in lipids.
Phosoholipids in cell membrane give fluidity and
flexibility.
Cell membrane lipid- Phospholipid
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They are found in cell
membrane.
A phosphate group is
bound to the glycerol.
It has 2 fatty acid chains.
Phosphate group loves
water (hydrophilic), Fatty
acid part hates water
(hydrophobic).
By their Hydrophilic and hydrophobic parts, a double layered cell
membrane is formed. Hydrophobic part stays inside and
Hydrophilic part stays outside (face cytoplasm or outer part)
Cell membrane lipidPhospholipid
It is composed of 1 glycerol, 1
phosphate, 2 fatty acid chain.
REVIEW QUESTIONS FOR
LIPIDS
What is a esther bond?
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It is the bond between fatty acids and glycerol
How a lipid molecule is formed?
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It is formed by the dehydration between 1 molecule of
glycerol and 3 molecules of fatty acid
If we want to form 5 molecules of lipid, How
many monomers of the lipids we need?
For the one molecule of lipid, we need 1 molecule of
glycerol and 3 molecules of fatty acid.
 1 glycerol x 5= 5 glycerol
3 fatty acid x 5= 15 fatty acid
Molecules are needed.
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If we we use 12 molecules of water to breakdown lipid, can you
determine how many lipid molecule do we have at the
beginning? And how many bonds did we break?
1 mol of lipid is broken down by 3 mol of water
12 mol of water can broke down 4 mol of lipid
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List the organic compounds according their energy
amount?(high to low)
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Lipids-carbohydrates-proteins
List the organic compounds according to their usage for
energy?(high to low)
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Carbohydrates-lipids-proteins
Compare saturated and unsaturated lipids?
saturated
unsaturated
Solid at room temp.
Fatty acid chains have
only single bonds.
Found mostly in animal
cells
Liquid at room temp.
Fatty acid chains have
double bonds.
Found mostly in plant
cells
List importance of lipids.
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Protects internal organs. Heart, intestine
Insulates the body, keep the temperature.
Excess of carbohydrates and proteins are converted into fats. It
causes obesity.
Fat soluble vitamins are dissolved in the fats and absorbed with
them.
When they are broken down, 3 molecules of water are used and
energy is given out.
Some fatty acid molecules can not synthesized by animals. They
have to take these fatty acid from plants.
Meat, milk, cheese, egg, sesame,sunflower sedd, nuts are rich in
lipids.
They are the main component of the cell membrane
Give energy
By looking at the charts below, find out the names of
the organic molecules?
Structural
use of the
organic
molecules
Usage of
molecules
as energy
source
I
Organic molecule
II
Energy
amount
of the
molecul
e
III
Organic molecule
time
I
II
III
a. Carbohydrate
lipid
protein
b. protein
carbohydrate
lipid
c. lipid
protein
carbohydrate
d. protein
lipid
carbohydrate
e.carbohydrate
protein
lipid
By looking at the charts below, find out what kind of
reactions are they?
I
II
I. hydrolysis
II. dehydration
Food X+ Fehling A
Fehling B
Food X+ lugol
Food Y+ Fehling A
Fehling B
Food Y+ lugol
Colors: Black
Brown-orange
Dark Blue Green-light orange
 These are the results of an experiment (determination of
carbohydrates) done in the laboratory. Can you list the foods ( X and
Y) according to their carbohydrate content from high to low?
X>Y
Write the monomers of the molecules
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lipid
sucrose
lactose
cellulose
galactose
glycogen
Fatty acid + glycerol
Glucose + Fructose
Galactose + glucose
Glucose (many)
it is a monomer
Glucose (many)
How a lipid molecule is formed?
1 glycerol and 3 fatty acid combined with 3 esther bonds
. How many water molecule is formed from the
polysaccharide made up of 19 monosaccharides?
19-1 =18 water formed
. If we want to form 6 molecules of lipid, How many
monomers should we use? Give their exact names and
numbers.
6 lipid has 6 glycerol and 6x3=fatty acid
. A lipid molecule has 30 esther bonds inside. Howmany
monomers does it have ? (give their exact name and
number)
30 fatty acid 10 glycerol
1. In a lipid synthesizing cell, 240 molecules of
water is formed during synthesis. How many
glycerol molecule is used?
240 / 3=
2.
Liquid lipids :
i. Contain esther bonds between glycerol and fatty
acid
ii.They give higher energy than carbohydrates and
proteins
iii. They have double bonds in fatty acids
Which of the statements above is not a property of
solid lipids?
3.
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Glycerol + 3 fatty acid A
B
Lipid + 3 H2O
According to the reactions above:
i.
A is a hydrolysis, and B is a dehydration reaction
ii.
The amount of water formed at the end of the
reaction is equal to the bonds formed
iii.
The chemical make up of the reactant molecules
change.
Which of them is true?
4. To get all of the fatty acid types , What kind of
a lipid molecule should be eaten?
PROTEINS
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Proteins are the most essential compounds for the
living things. They are the half of our weight.
Proteins contain N and sometimes, Phosphorus and
sulphur.
The building block of the proteins are amino acids.
Amino acis contain amino group(NH3), carboxyl
group(COOH) and radical® group. Amino acids are
bound together by peptide bonds between the amino
group of an amino acid and the carboxyl group of the
other.
Amino and carboxyl
groups are same for
each amino acid, but
radical groups are
different.
There are 20 aminoacids
in nature.
So there are 20 radical
groups.
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How do proteins differ from each other?
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Proteins differ in their total number of amino acid units
they contain. (some have 2, some have 3, some have 6,7 or
100 or more)
Proteins differ in their diversity of aminoacids(type of
aminoacid).
Proteins differ in their amino acid sequence.
ABC
BAC
ABCA
Each organism has a different protein structure because
DNA differs in all organisms except twins(clones).
Proteins are synthesized by ribosomes, they get the
information from nucleic acid.
Proteins can have a lipid or carbohydrate group.
Glycoprotein, Lipoprotein.
aa-peptide bond-aa-peptide bond
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Essential aminoacids: methionine or cysteine,
leucine, isoleucine, lysine, phenylalanine (or
tyrosine), threonine, tryptophan, and valine
Humans can not synthesize them; they are
dietary requirements
Foods with no limiting amino acids: legumes
(soybean), cereal grains, nuts, dairy products,
eggs, meat, and fish, liver, milk, cheese.
Importance of proteins:
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Structure: found in membranes and organelles for
transport , catalysis and recognition.
Catalysis: They have role in reactions as enzymes.
Control: Some hormones in our body are protein.
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Transport: Hemoglobin is a protein which carries Oxygen
Movement: Muscle structure(actin and myosin)
Protection: immune system-antibodies are protein
Energy: they are important in structure , so body doesn’t
want to use them as energy source. But in some cases it
can be used(starvation).
Meat, poultry, fish, eggs, milk, cheese, beans, cereals are
rich in proteins
A one celled organism is treated with X rays. X rays
changed the genetic make up (DNA) of the cell. When
the cell is examined, it is detected that the cell can’t
produce a protein which was produced before.
What can be said at the end of the experiment?
a. Genes are located in the DNA.
b. Proteins are synthesized from DNA.
c. Proteins are synthesized by ribosomes.
d. Changes in the DNA doesn’t effect protein
production
e. If proteins are changed, the DNA will be changed.
2. Which of the following reactions is different from the
others?
a.
Amino acid + amino acid
Dipeptide
b.
Fatty acid + glycerol
Lipid
c.
Starch + H2O
Maltose
d.
Fructose + glucose
Sucrose
e.
Glucose(n)
Cellulose
1.
3. The diversity of amino acids depends on:
i. Amino group
ii. Carboxyl group
iii.Radical group
4. Essential aminoacids:
i. Can’t be synthesized in human body
ii.Is different in individuals of the same species
iii. Is different in the individuals of the different species
iv. Can’t be synthesized at older ages.
Which of them is true?
5. Protein similarities are used in:
i. Determination of relationships among organisms
ii. Tissue and organ transplantation
iii. Classification of animals
6.
Which of the following is not effective in protein diversity?
a.
Number of aa
b.
Bonds between aa
c.
Type of aa
d.
Sequence of aa
e.
DNA make up (genes)
ENZYMES
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Enzymes are biological catalysts
produced by living things.
They are protein molecules and not
living things themselves. All reactions
need energy to start. This energy is
called activation energy. To speed up
reactions we have to lower the energy
required. Enzymes or catalysts lower
the activation energy. In this way they
increase the speed of the reactions.
Number
of ATP
used
Without
enzymes
With
enzymes
time
1. According to the graphic ,which of the
statements can not be reached?
a.
b.
c.
d.
e.
Enzyme usage reduces the required energy
Enzyme speeds up the reaction
Reactioons can occur without enzymes
Many types of enzymes can be used.
ATP is used for reaction to proceed.
Enzyme names
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The names of the different types of enzymes
usually end in the letters -ase. Three of the
most common enzymes (with their chemical
actions) are
lipase, which breaks down fats
protease, which breaks down proteins, and
carbohydrase, which breaks down
carbohydrates
Structure and function of enzymes
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Enzymes are very specific in the reactions they
catalyse: different enzymes catalyse different reactions.
For a given enzyme molecule, only certain reactant
molecules (the substrate) can fit into its active site.
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Some enzymes don’t have only proteins , they
sometimes have non protein part. Protein part of
the enzyme is called apoenzyme.
If non protein part contains minerals(inorganic), this
part is called cofactor. Same mineral can activate
different enzymes.
If non protein part contains vitamins(organic), this
part is called coenzyme. Same vitamin can activate
different enzymes.
The parts of the enzymes are:

Apoenzyme
ii.
Coenzyme
iii. Cofactor
Which part makes the enzyme specific for one kind of
reaction?
i.
Properties of enzymes
1. When an enzyme and a substrate are joined, they
lower the activation energy, reaction can occur easily.
2. The enzymes can work in reverse directions. The
reactions are reversible. Same enzymes take part in
both reactions.
3. An enzyme is not used in the reaction. It stays same.
It can not change its structure during the reactions.
So it can be used many times.
4. Enzymes are specific. Each enzyme is specific for
one kind of reaction. It can not be used in other
reactions.
5. They can work inside and outside of the cell.
Digestive enzymes work outside, catalase works
inside.
6. They speed up the reactions.
7. Reactions can be in chains. One product of the
reaction , can be a substrate of the other
reaction.

In a protein synthesizing cell, Which graphic is
true for the changes of the amount of water
molecules, enzyme and amino acids.
I shows the water
 II shows the aa
 III shows the enzyme
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Number of
molecules
Number of
molecules
I
II
I
III
III
II
time
time
Factors affecting the rate of the
enzymes
1. Temperature
 Enzymes usually work best in warm conditions (around
36-40 °C).
 Enzyme shape is changed at high temp. Reaction stops
and never start again.
Low temp. (1-10 °
C) slows down the
reaction. The shape
is not changed.
2. pH
 An enzyme will work best at a particular temperature
and pH, called its optimum conditions.
 stomach enzymes work in pH 1-2.
Salivary
enzyme
 Salivary enzymes work in pH 7-8.
Stomach
enzyme
3. Concentration of enzyme
 If the concentration of enzyme little and
substrate is large, increasing the enzyme
concentration increases the rate of reaction. But
after all substrate molecules are used and no
change will be in the rate of reaction
4. Concentration of substrate
 If there are more enzyme molecules, If we increase the
concentration of substrate, the rate of the reaction
increases . But after all enzyme molecules are full, they
can not change the rate of reaction.
5. Surface area: the reactions starts at the outer area of
the substrate. Increasing the surface area, increases the
rate of enzyme activity.
SA=6 =6
SA=600 = 0.6
V 1
1
V 1000
10
6. Water: Water content affects the activity of enzymes.
Dry seeds don’t germinate.Their enzymes are not
active.
7. Inhibitors / activators: Poisons, heavy metals inhibit
the action of the enzymes. Some minerals can activate
the enzyme.

If the amount of substrate of a hydrolysis
enzyme is maximum, Which of the factors
changes the amount of the product?
I. Optimum temperature
II. Addition of enzyme to the reaction
III. Increasing the surface area of the substrate
VITAMINS
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Vitamins are a group of substances essential for normal
metabolism, growth and development, and regulation of
cell function. Animals can’t synthesize vitamins but
plants do.
Vitamins work together with enzymes, as co-enzymes
Important in development and growth of the body.
Important in bone formation
Blood cell formation, Blood clotting
Prevents diseases, increase resistance of the body
Types of Vitamins
fat-soluble vitamins
 the vitamins are stored
in the fat tissues in your
body and in your liver.
 They can be poisonous.
 Vitamins A, D, E, and
K are all fat-soluble
vitamins.
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water-soluble vitamins
When you eat foods
that have water-soluble
vitamins, the vitamins
don't get stored in your
body .
The excess is thrown
out by urine.
B group and C vitamins
are water soluble
NUCLEIC ACIDS
Nucleic acids are made
up of nucleotides.
Nucleotides have
Phosphate group, 5 C
sugar (monosaccharide)
and Base(nitrogenous).
Property
DNA
RNA
Location
Nucleus, mitochondria,
chloroplasts,
Bases
Sugar (5C)
Phosphate
A,T,G,C
Deoxribose
same
U,A,G,C
Ribose
same
Number of
chains
Replication
Kinds
2 (double stranded)
1(single strand)
Yes
1
Function
Store genetic codes
No
3 mRNA(messenger),
tRNA(transfer),
rRNA(ribosomal)
Protein synthesis
Cytoplasm,
mitochondria,
chloroplasts, nucleus,
ribosomes
DNA
RNA
DNA
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DNA molecular structure is established by Watson and
Crick in 1953 .
There are two chains linked together in DNA
molecule.(Double stranded) . Nucleotides are bound
together by hydrogen bonds.
And always an Adenine combines with a Thymine. A=
T (2 bonds) “So number of A equals to number of T”
A Cytosine combines with a Guanine. C ≡ G (3
bonds) “So number of C equals to number of G”
If A number is equal to T number, then C number
equals to G number.
A + C = T + G or A + G = T + C
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A
C
A
A
T
G
G
C
= T
≡ G
= T
= T
=A
≡C
≡C
≡ G
A +G =1
T+C
Classification of bases
Purine
Pyrimidine
DNA chain
DNA complementary chain
Chargaff ’s rule
2 rings
1 ring
Question
1. The order of nucleotides in a chain of DNA is
AGCTTA.
a. What is the order of nucleotides in the
complementary chain of this DNA?
b. What is the total number of hydrogen bonds
between chains?
1. a. DNA
Complementary DNA
AGCTTA
TCGAAT
b. between A= T there should be 2 bonds
between G ≡ C there should be 3 bonds.
So A= T 2 x 4 = 8 bonds ,
G ≡C 3x2=6
8 + 6 = 14 total hydrogen bonds.
There are 3600 nucleotides in a DNA molecule. If 400 of
them are adenine, Find
a. The number of the other nucleotides.
b. Give number of purines and pyrimidines.
c. the number of deoxyribose sugars and
phosphate groups.
a. . A= 400 so T= 400 too. 400+400= 800
3600 – 800= 2800 2800 / 2 = 1400 Guanine and
1400 Cytosine
b. A, G are purines 400 + 1400 = 1800 purines
C, T are pyrimidines 400 + 1400 = 1800 pyrimidines
c. Number of nucleotides = number of deoxribose = number of
phosphate
3600 nucleotides = 3600 deoxyribose = 3600 phosphate
3. In a DNA molecule there are 1000 pairs of nucleotide.
If 300 of them are guanine, what is the number of T?
1000 pairs of nucleotide= 2000 nucleotides
If G= C , then G+C= 600 nucleotides
2000-600= 1400 nucleotides= T+A
If T=A then T is 1400 / 2 = 700 nucleotides of T
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In an experimental condition, there are 1500 A, 500 T,
1100 G, 800 C and 3000 deoxyribose and 3000 phosphate.
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How many nucleotides can be formed?
1500+500+1100+800= 3900 bases can be used but there are only
3000 deoxyribose and phosphate only 3000 nucleotides can be
formed.
 How many nucleotide long DNA can be formed?
A should be equal to T
G should be equal to C because DNA is double chained.
If T number is 500, A=T= 500
G= C= 800 DNA should be 1300 nucleotides long
But we spent 2600 nucleotides because it is double stranded.!!
In a DNA molecule with 220 nucleotide, there are 50
A, what is the number of C?
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A= 50=T A+T= 100
220 – (A+T)= G+C
220- 100= 120= G+C if G= C then
G= 120 / 2= 60
In a DNA molecule 30 % of nucleotides are Guanine
,what is the percentage of Thymine?
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G= 30 % = C
C+G= 60 %
100 – (30+30)= A+T= 40 % if A=T
T= 40/2= 20 %
In an experimental procedure 60 A, 80 T, 50 C, 50 G
and 250 deoxiribose and phosphate molecules are
found.
How many nucleotide long DNA can be formed?
 A should be equal to T
 C should be equal to G
 60 A
80T only 60 of then combine together to form
DNA double chain.
 50 C
50 G all of C and G combine together.
60A=60T
+ 50C=50T
110 = 110 nucleotide long ; but 220 nucleotides are used
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If a DNA molecule has 6400 hydrogen bonds and 600
guanine molecules ,What is the number of Thymine
nucleotides?
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Guanine has 3 H bond with Cytosine
So 600 x 3 = 1800 H bond between G and C
The remaining bonds are between A and T
6400 – 1800 = 4600 bonds between A and T
There are 2 bonds between A and T
4600/2 = 2300 is the number of A = number of T
If G + C number is 600 and there are total 2600
deoxyribose molecules, What is the H bond number?
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If G + C = 600 , G should be 300.
The bonds between G and C = 300 x 3= 900
If G+C= 600 then A+T= 2600 – 600=2000
And A should be 1000
The bond between A and T = 1000 x 2= 2000
Total bond number = 2000+900=2900
PhosphoDiesther
bond
Esther
bonds
Glycoside
bond
Importance of nucleotides:
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DNA carries the genetic code of the organism.
Genetic code of each organism is different from
each other(except identical twins). Genetic code
differs in the base sequences.
Each organism has same chromosome number
and same base sequence in his/her all cells.
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DNA can copy itself. This
process is necessary for cell
division. As a result each cell
will take equal amount of
DNA. The copying process is
called as replication. DNA
replication is a semi
conservative process. 2 chains
of the DNA open and each
strand replicates itself. As a
result each new DNA recieves
one old an done new strand.
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DNA also carries information for protein
synthesis in the cell. It sends message for protein
synthesis to the cytoplasm. These processes are
shown by this figure.
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DNA
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Transcription
mRNA
Translation
Protein
Replication
Replication always
occurs where the
DNA is.
Transcription also
always occurs where
the DNA is.
Translation also
always occurs where
the m RNA and
ribosomes are.
DNA replication is a semi
conservative process. 2 chains of
the DNA open and each strand
replicates itself. As a result each new
DNA recieves one old and one new
strand.
 Replication occurs where the
DNA is.(In bacteria there is no
nucleus )
If a cell can’t divide, it can not replicate its DNA (sperm cells,
nerve cells, red blood cells)
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•Transcription occurs where the DNA is, because it copies DNA
•Translation occurs where the ribosome is, because it needs
ribosomes.
RNA
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RNAs also are synthesized from DNA. RNAs are
important for protein synthesis. There are 3 types of
RNA.
mRNA –messenger RNA. It carries information from
DNA to ribosome. The formed mRNA is
complementary to one of the strand of
DNA(meaningful strand) .
r RNA-ribosomal RNA. It forms the ribosome
structure with proteins. It is synthesized from
nucleolus.
t-RNA transfer RNA It carries aminoacids for protein
synthesis.
GENETIC CODE
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As we said before protein is synthesized from DNA.
The code for Protein synthesis comes from the DNA,
It is coded with bases in the DNA.
The 4 bases in the DNA forms chains of
nucleotides. The 3 base code for one
aminoacid.This 3 base structure is called as
“code” . If we have 4 bases, we can form 43=64
different codes. This 64 codes are responsible for
the synthesis of proteins. One code is for start and
3 codes are for stop.
ENERGY MOLECULE
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- ATP
ATP is formed by cellular respiration. Every cell
needs energy as ATP (Adenosine Tri Phosphate)
Structure of ATP
5C sugar- Ribose and Adenine base: they are called Adenosine
3 phosphate groups can be added to the adenosine. If one is added It is
Adenosine mono phosphate,
2- Adenosine di phosphate ; 3- Adenosine tri phosphate
Function and importance of ATP
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Hydrolysis of 3rd bond gives 7300 cal.(7.3 kcal)
It is ONLY produced and used within the cell.
It can not be stored.
Hydrolysis gives out energy, dehydration takes in energy.
Used in dehydration reactions, muscle contraction, nerve
impulses not in hydrolysis.
Phosphorylation: Adding P to ADP(occurs in cytoplasm,
mitochondria and chloroplasts)
Dephosphorylation: breaking P bond from ATP(occurs
in cytoplasm and chloroplasts and in
anabolic(dehydration reactions))
METABOLISM
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All chemical activities within the cell are called metabolic
activities or metabolism of the organism. There are two
kinds of metabolic activities.
Anabolism or the anabolic reactions are synthesis
reactions. They produce polymers. For example
formation of proteins, polypeptides.Water is
formed.Needs energy.
Catabolism or catabolic reactions are the breakdown
reactions. They produce monomers. For example
formation of amino acids from proteins,
monosaccharides from carbohydrates. Water is used.
needs
energy(ATP)