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Lecture 2 Chemistry, Cytology, DNA, Cellular Respiration, Protein Synthesis. Chemistry, Matter and Life. Chemical Bonding of Matter Atoms are the simplest forms of matter Elements are composed of the same type of atoms

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lecture 2 chemistry cytology dna cellular respiration protein synthesis
Lecture 2

Chemistry, Cytology, DNA,

Cellular Respiration,

Protein Synthesis

chemistry matter and life
Chemistry, Matter and Life

Chemical Bonding of Matter

Atoms are the simplest forms of matter

Elements are composed of the same type of atoms

3. Molecules – formed when 2 or more atoms become chemically bonded.

4. Compounds – formed when atoms of different kinds become chemically bonded.

5. Formula – a representation of the number and kinds of atoms in a molecule or compound.


6. Chemical reactions

a. When a chemical reaction occurs, bondsbetween

atoms are broken(energyis released)orformed,

(energy is stored).

b. Two kinds of chemical reactions are:

1.) Synthesis – in which smaller atoms or smaller

molecules combine to from larger

ones. (Anabolism).

2.) Decomposition – in which larger molecules are

broken down to form smaller

ones, (Catabolism)


B. Acids, Bases and pH

1.Compounds that ionize when they dissociate in water

and can conduct an electric current are called


2. Electrolytes that release hydrogen ions (H+)are

acids, and those that release hydroxide ions (OH-)


3. The concentration of hydrogen ion (H+) in a solution

is represented on a scale of 0 to 14 and is known as

pH (potential hydrogen).

A pH of 0.0 6.99 is acidic

A pH of 7.0 is neutral

A pH of 7.01 14 is basic (alkaline).


4. Solutions with equal numbers of H+ and OH- = neutral

Solutions with more H+ than OH- = acidic pH<7.00

Solution with fewer H+ than OH- = base. pH>7.00

C. Chemical constituents of Cells

Molecules containing carbon and Hydrogen atoms are organicand are usually nonelectrolytes;

Those lacking carbon atoms are inorganic and are usually electrolytes.


1. Inorganic substances: common examples

a. Water is the most abundant compound in cells and

serves as a substance in which chemical reactions

occur; it also transports chemicals and heat.

(universal solvent)

b. Oxygen (O2) is used in releasing energy from glucose

and other molecules. (oxidation)

c. Carbon dioxide (CO2) is produced when energy is

released from glucose and other molecules.

e. Inorganic salts provide ions (charged particles)

needed in metabolic processes. (Na+, K+, Cl-, Ca++)


2. Organic substances

a. Carbohydrates provide much of the energy needed

by cells; their basic building blocks are simple sugar

molecules (monosaccharides)


b. Lipids supply energy; their basic building blocks are

molecules of glycerol and 3 fatty acids.



Cholesterol, also includes the sex hormones, vitamin D and others


c. Proteins serve as structural materials, an energy

source and enzymes.

1.) Enzymes initiate and accelerate metabolic

reactions in the body.

2.) The building blocks of protein are the 20 common

amino acids.


3.) Different kinds of proteins vary in the number and

kinds of amino acids they contain, and in the

sequences (linear order) in which these amino

acids are arranged.

4.) Protein molecules can be denatured by heat,

strong acid, etc. When denatured, protein shape

changes and the protein becomes nonfunctional.




d. Nucleic acids control cell activities.

1.) The two kinds:

a.) RNA – ribonucleic acid.

b.) DNA – deoxyribonucleic acid.

2.) They are composed of building blocks called nucleotides. Nucleotides contain:

a.) A 5 carbon sugar, either ribose (in RNA) or

deoxyribose (in DNA). They differ from each

other by one oxygen atom!

b.) A phosphate group (PO4)

c.) one of five different nitrogen bases.

RNA – Guanine, Cytosine, Adenine, Uracil

DNA - Guanine, Cytosine, Adenine, Thymine


Cellular Anatomy and Physiology

A. General Cell Features

1. The cell is the basic unit of structure and function

in all organisms. The study of cells is Cytology.

Cells are the smallest part that is considered alive.

2. Cells range in size from 1/12,000 of an inch to over3 feet for the neurons that help you wiggle your toes!

3. Cells vary widely in shape and form which is related

to its function.


4. Kinds of cells

a. Prokaryote “before a nucleus” lack a membrane

surrounding their DNA and are said to lack a

distinct nucleus, they have a “nucleoid”.

1.) Bacteria are common prokaryotes.

b. Eukaryotes are cells that have a distinct nucleus.

1.) Plant – has chloroplasts and a thickened

cellulose cell wall.

2.) Animal – has centrioles which plants lack, but

lacks the rigid cell wall and



5. Cell organelles “little organs” are often composed of

membrane material or granular arrangements of



B. Membranous Organelles

1. Cell membrane – “molecular traffic cop”, it regulates

materials that enter and leave the cell.


2. Endoplasmic reticulum – two types;

a. Rough, has attached ribosomes, synthesis of proteins

for export (secretion).

b. Smooth, lacks attached ribosomes, synthesizes lipids,

carbohydrates, detoxifies medications &



3. Golgi apparatus- “protein packaging factory” 5 to 8 flattened sacs that package, address and modify secretions,

forms lysosomes.

4. Lysosome – “Stomach” of the cell. Contains enzymes that can digest all organic compoundswithinthe cell. Destroys worn out cells, organelles and foreign materials.


5. Vesicles – membranous sacs that form by pinching off from the cell membrane or an organelle membrane

These sacs can move solids or liquids into (endocytosis) or out of (exocytosis) the cell


6. Mitochondrion – “Powerhouse”, bean shaped double

membrane organelle. Inner folded membranes

(cristae) are the locations of cellular respiration. O2,

ADP, and food material enter, ATP, H2O and CO2 are



C. Microtubules and Related Organelles

1. Cytoplasmic microtubules – compose part of the

cytoskeleton, cilia, flagella, form the mitotic spindle

and provide a path for movement of organelles within

the cell.


2. Centrioles – a pair of microtubular organelles in

cytoplasm near the nucleus that are the microtubular

organizing center, form spindle fibers, cilia and flagella.

3. Spindle fibers – visible during cell division, attach and

move chromosomes to poles of daughter cells.

4. Cilia and Flagella – cilia are short, numerous and move

material along cell surfaces. Flagella are long, few in

number, propel entire cells, sperm.


D. Granular Organelles

1. Ribosomes – “protein factory” for protein synthesis.

a. Free ribosomes float in cytoplasm and produce

proteins and enzymes for use within the cell.

b. Attached ribosomes - are found on the surface of

rough endoplasmic (Rough ER). They synthesize,

package within transport vesicles proteins for

secretion out of the cell.



2. Nucleolus – within the nucleus, its presence indicates

the cell is synthesizing large and small

ribosomal subunits from ribosomal RNA

and polypeptides made in the cytoplasm.


E. Nucleus “control center”

1. Chromosomes (46) containing genes (25,000). A

“gene” is a segment of a chromosome that codes for a

protein. When DNA is controlling the cells activity it is

stretched out, diffuse, and is called chromatin. When a

cell is dividing it supercoils into the chromosomes we

see as finger like structures.

2. DNA – double strand of complementary nucleotides

based on the pairing rules A = T, C Ξ G.

3. RNA – usually a single strand of nucleotides; the

nitrogen base Uracil sub for Thymine in its strands.

RNA base pairing is; A = U, C Ξ G.

how information is carried in nucleic acid
How information is carried in nucleic acid
  • Genetic information is organized into units called genes
  • The order of the bases in the gene called the genetic code
  • DNA has a coding and noncoding strand
  • Composed of nucleotides that form a double helix
    • Sugars and phosphates hold the bases in the right order
    • The nucleotides pair with each other
  • The pairing of the bases with its partner directs the copying process
  • The order of the bases are read in groups of 3 (codons)
how information is carried in nucleic acid1
How information is carried in nucleic acid

The information in the DNA is “read” by the RNA molecules

Types of RNA (3)

Messenger RNA (mRNA)= produced from the DNA molecule by transcribing the genetic code

Transfer RNA (tRNA)= binds to the codon (via an anticodon) this carries an amino acid, once bound it transfers the amino acid to the growing protein

Ribosomal RNA ( rRNA)= part of the ribosome,

fig 4 13
Fig. 4.13

Each triplet codon specifies 1 amino acid

By changing the order or length of the you get a different protein


4. Protein synthesis – the making of a protein involves

transcription – in nucleus (DNA code messenger RNA


translation – in cytoplasm (mRNA code read by ribosome)

to construct a protein (a chain of individual amino acids

bonded together).

a. DNA – master blueprint for proteins

b. mRNA – receives a complementary code of DNA strand

(transcription in the nucleus).

c. Amino acids type and order of assembly are coded for on

the mRNA strand (translation by the ribosome in the


mRNA code ribosome protein.

d. Chain of specific A.A in a specific order protein

e. tRNA – brings appropriate A.A. to ribosome during

elongation of the chain that will become the protein.


F. Energy Production by the cell

1. Glycolysis “glucose splitting” is a chemical pathway in

the cytoplasm. 6 carbon glucose is split into

two 3 carbon molecules called pyruvic acid. 2 ATP are

also formed. Glycolysis is “anaerobic” no O2 needed.

2. Pyruvic acid enters the mitochondrion where the citric acid cycle breaks the bonds of the 2 pyruvic acids and stores their energy (in carriers) while making 2 ATP.

3. The Electron Transport System (ETS) passes along the

stored energy carriers from the citric acid cycle to make 34 ATP using the energy of H+ to recharge the ADP into