Essential Cel Biology- period 1
Week 1.1 – the fundamental units of life
Cel biology: the study of cells and their structure, function and behavior.
➔ Nucleotides: long polymer chains of DNA from the same set of 4
monomers, in different sequence.
➔ This DNA is transcribed into a set of polynucleotides; RNA.
➔ Most RNA is translated into a polymer protein.
From DNA → RNA → protein is the central dogma
: genetic information is saved in the base sequence of DNA, transcribed into RNA. The
sequence of bases in mRNA dictates the coupling of amino acid residues to form a
protein.
- all living cells can perform self- replication. EXCEPT the virus, they parasitize the
reproductive machinery of cells by invading, and make copies of themselves.
- Sometimes instructions are misread/ damaged which cause mutations that change the
sequence of nucleotides in DNA.
• Genome: the entire sequence of nucleotides in an organism’s DNA, provides a genetic
program that instructs a cell how to function.
Microscopes:
- Light/ brightfield microscope: use visible light to
illuminate specimens.
- Electron microscope: using beams of electrons
as source of illumination. Electrons have a
shorter wavelength which cause them to see
more details of cell structure.
- λ must be bigger than d to be visible!
- Some free- living bacteria (prokaryote) were capable of photosynthesis, which was to
believe that the Cyanobacteria was the precursor of the chloroplast who also are capable
of photosynthesis.
- Some non- photosynthetic bacteria became single celled eukaryote, with mitochondria
like animals and fungi. Which was to believe that mitochondria were a result of evolving.
Also mitochondria contain their own DNA.
, • Eukaryote: store DNA in the nucleus, have cell
membranes.
• Prokaryote: (pro= before) have no cell membranes or
nucleus.
➔ Cytoplasm: incl. organelles except nucleus
➔ Cytosol: excl. all organelles
• Nuclear envelope: two
membranes around the
nucleus, with DNA molecules.
Chondroplasts
- Surrounded by 2 membranes
- Contain a 3rd membrane, thylakoid, which is
Amyloplast: store and synthesize starch.
highly folded in grana
Chloro-amyloplast: stores starch as well as
- Grana are interconnected and surrounded
chlorophyll.
by stroma Chloroplast: photosynthesis which releases
- The thylakoid membrane contains the green oxygen and energy.
chlorophyll Chromoplast: contain pigment, which gives
color to the plant/bloom.
• DNA is compacted by proteins to fit
in nucleus
• Heterochromatin (highly condensed)
• Euchromatin (less condensed)
• Nucleolus is largest substructure
(1st step in ribosome synthesis)
Endoplasmic reticulum: NO DNA eukaryote
- is continuous with the outer nuclear membrane
- Smooth and rough (with ribosomes)
Functions:
- Synthesis of phospholipids
- Attachment side for ribosomes
- Folding & modifications of proteins
- Synthesis of steroid hormones
- Sequestration of calcium
, • Genes for ribosomal-RNA (rRNA) are located in
nucleoli
➔ Here, rRNAs are synthesized and combined
with proteins to form pre- ribosomes, which
export out of the nucleus.
! carbon containing compounds are organic molecules,
all other molecules are inorganic!
Biomolecules:
1. Sugars:
- Optical isomers: sets of molecules with same chemical
Formula but different structures.
- Condensation: bonds between OH- groups.
- Hydrolysis: reverse condensation, where a water molecule is consumed.
2. Lipids:
- Option one: hydrocarbon chain, which is hydrophobic and not very reactive.
- Option two: carboxyl group that behaves as an acid, that posses both hydrophobic and
hydrophilic regions. (amphipathic)
- Saturated (no double C- bonds, maximum hydrogens) and unsaturated (have double
bonds)
- Phospholipids: 2 fatty acids + glycerol → OH-group
linked to a hydrophilic phosphate group. (polar)
- Lipid bilayer: 2 phospholipid layers can combine
tail to tail in water to form a phospholipid sandwich.
Subunits of a fatty acid: hydrophilic head, and one/ more
hydrophobic hydrocarbon chains
- Stored in cells attached to glycerol
- Hydrophilic molecules
3. Protein:
- Synthesized by monomers (amino acids) → Same set of 20 AC to make proteins
➔ amino acids: organic molecules with a carboxyl acid group and an amin group to an α-
carbon atom.
• Peptide bond: a covalent bond between two amino acids in a protein chain. →
polypeptide (have polarity)
, ➔ Sidechains of proteins and amino acids can be polar, nonpolar, big, small, charged,
neutral and reactive of nonreactive
• Denatured: unfolded protein by disrupting the noncovalent bonds. Polypeptide chain
loses its natural shape.
• Renaturation: refolds spontaneously into its original conformation.
• Chaperone proteins: special proteins assisting living cells.
- A driving force of protein folding is: the clustering of hydrophobic side chains of amino acids,
and formation of hydrogen bonds
- In the α-helix , polypeptide folding in which the primary sequence coils, stabilized by regular
spaced hydrogen bonds.
• Cross- linkages: stabilize proteins, tie 2 amino
acids together in the same polypeptide chain.
➔ Sulfur is found in proteins
➔ Disulfide bond can stabilize a protein structure,
because the bonds are covalent and thus
contain a high binding energy. Between S-S, can
be broken and the free SH- group can form new
bonds with other SH- groups.
4. Nucleic acids:
- DNA and RNA are built from nucleotides (N- ring
linked to a 5- C sugar with a phosphate group. )
- Pyrimidines: C,T,U bases
- Purines: A,G bases
DNA (deoxyribonucleic acids)= A, T, G, C and RNA
(ribonucleic acids) has U
Polairity (directionally) of DNA and RNA molecules:’
- Ends of the polymer differ. The (deoxy) nucleotides
at the end can have a free P- group (5’-end) or a free
hydroxyl group (3’-end) DNA is more stable cause of hydrogen- bonded double
- Backbone: C,N,H, and O → repeating sequence of helix. RNA is single stranded and are carriers for
N-C-C molecular instructions.
Nucleoside: a base + sugar (without P)
Immunology: • Antibodies: are immunoglobulin proteins produced by the
immune system in response to foreign molecules. Heal you!
➔ Y- shaped with 2 antigen- binding sides.
• Antigen: is the foreign molecule, the target molecule of the
antibody to inactivate of destruct. Make you sick!
• Thrombin: blood- clotting enzyme.
• Lysozyme: It protects against infections, acts as a natural
antibiotic, and enhances the efficacy of other antibiotics,
while it also strengthens the immune system→ recognizes
its substrate trough the formation of covalent bonds but
holds it polysaccharide substrate.
Week 1.1 – the fundamental units of life
Cel biology: the study of cells and their structure, function and behavior.
➔ Nucleotides: long polymer chains of DNA from the same set of 4
monomers, in different sequence.
➔ This DNA is transcribed into a set of polynucleotides; RNA.
➔ Most RNA is translated into a polymer protein.
From DNA → RNA → protein is the central dogma
: genetic information is saved in the base sequence of DNA, transcribed into RNA. The
sequence of bases in mRNA dictates the coupling of amino acid residues to form a
protein.
- all living cells can perform self- replication. EXCEPT the virus, they parasitize the
reproductive machinery of cells by invading, and make copies of themselves.
- Sometimes instructions are misread/ damaged which cause mutations that change the
sequence of nucleotides in DNA.
• Genome: the entire sequence of nucleotides in an organism’s DNA, provides a genetic
program that instructs a cell how to function.
Microscopes:
- Light/ brightfield microscope: use visible light to
illuminate specimens.
- Electron microscope: using beams of electrons
as source of illumination. Electrons have a
shorter wavelength which cause them to see
more details of cell structure.
- λ must be bigger than d to be visible!
- Some free- living bacteria (prokaryote) were capable of photosynthesis, which was to
believe that the Cyanobacteria was the precursor of the chloroplast who also are capable
of photosynthesis.
- Some non- photosynthetic bacteria became single celled eukaryote, with mitochondria
like animals and fungi. Which was to believe that mitochondria were a result of evolving.
Also mitochondria contain their own DNA.
, • Eukaryote: store DNA in the nucleus, have cell
membranes.
• Prokaryote: (pro= before) have no cell membranes or
nucleus.
➔ Cytoplasm: incl. organelles except nucleus
➔ Cytosol: excl. all organelles
• Nuclear envelope: two
membranes around the
nucleus, with DNA molecules.
Chondroplasts
- Surrounded by 2 membranes
- Contain a 3rd membrane, thylakoid, which is
Amyloplast: store and synthesize starch.
highly folded in grana
Chloro-amyloplast: stores starch as well as
- Grana are interconnected and surrounded
chlorophyll.
by stroma Chloroplast: photosynthesis which releases
- The thylakoid membrane contains the green oxygen and energy.
chlorophyll Chromoplast: contain pigment, which gives
color to the plant/bloom.
• DNA is compacted by proteins to fit
in nucleus
• Heterochromatin (highly condensed)
• Euchromatin (less condensed)
• Nucleolus is largest substructure
(1st step in ribosome synthesis)
Endoplasmic reticulum: NO DNA eukaryote
- is continuous with the outer nuclear membrane
- Smooth and rough (with ribosomes)
Functions:
- Synthesis of phospholipids
- Attachment side for ribosomes
- Folding & modifications of proteins
- Synthesis of steroid hormones
- Sequestration of calcium
, • Genes for ribosomal-RNA (rRNA) are located in
nucleoli
➔ Here, rRNAs are synthesized and combined
with proteins to form pre- ribosomes, which
export out of the nucleus.
! carbon containing compounds are organic molecules,
all other molecules are inorganic!
Biomolecules:
1. Sugars:
- Optical isomers: sets of molecules with same chemical
Formula but different structures.
- Condensation: bonds between OH- groups.
- Hydrolysis: reverse condensation, where a water molecule is consumed.
2. Lipids:
- Option one: hydrocarbon chain, which is hydrophobic and not very reactive.
- Option two: carboxyl group that behaves as an acid, that posses both hydrophobic and
hydrophilic regions. (amphipathic)
- Saturated (no double C- bonds, maximum hydrogens) and unsaturated (have double
bonds)
- Phospholipids: 2 fatty acids + glycerol → OH-group
linked to a hydrophilic phosphate group. (polar)
- Lipid bilayer: 2 phospholipid layers can combine
tail to tail in water to form a phospholipid sandwich.
Subunits of a fatty acid: hydrophilic head, and one/ more
hydrophobic hydrocarbon chains
- Stored in cells attached to glycerol
- Hydrophilic molecules
3. Protein:
- Synthesized by monomers (amino acids) → Same set of 20 AC to make proteins
➔ amino acids: organic molecules with a carboxyl acid group and an amin group to an α-
carbon atom.
• Peptide bond: a covalent bond between two amino acids in a protein chain. →
polypeptide (have polarity)
, ➔ Sidechains of proteins and amino acids can be polar, nonpolar, big, small, charged,
neutral and reactive of nonreactive
• Denatured: unfolded protein by disrupting the noncovalent bonds. Polypeptide chain
loses its natural shape.
• Renaturation: refolds spontaneously into its original conformation.
• Chaperone proteins: special proteins assisting living cells.
- A driving force of protein folding is: the clustering of hydrophobic side chains of amino acids,
and formation of hydrogen bonds
- In the α-helix , polypeptide folding in which the primary sequence coils, stabilized by regular
spaced hydrogen bonds.
• Cross- linkages: stabilize proteins, tie 2 amino
acids together in the same polypeptide chain.
➔ Sulfur is found in proteins
➔ Disulfide bond can stabilize a protein structure,
because the bonds are covalent and thus
contain a high binding energy. Between S-S, can
be broken and the free SH- group can form new
bonds with other SH- groups.
4. Nucleic acids:
- DNA and RNA are built from nucleotides (N- ring
linked to a 5- C sugar with a phosphate group. )
- Pyrimidines: C,T,U bases
- Purines: A,G bases
DNA (deoxyribonucleic acids)= A, T, G, C and RNA
(ribonucleic acids) has U
Polairity (directionally) of DNA and RNA molecules:’
- Ends of the polymer differ. The (deoxy) nucleotides
at the end can have a free P- group (5’-end) or a free
hydroxyl group (3’-end) DNA is more stable cause of hydrogen- bonded double
- Backbone: C,N,H, and O → repeating sequence of helix. RNA is single stranded and are carriers for
N-C-C molecular instructions.
Nucleoside: a base + sugar (without P)
Immunology: • Antibodies: are immunoglobulin proteins produced by the
immune system in response to foreign molecules. Heal you!
➔ Y- shaped with 2 antigen- binding sides.
• Antigen: is the foreign molecule, the target molecule of the
antibody to inactivate of destruct. Make you sick!
• Thrombin: blood- clotting enzyme.
• Lysozyme: It protects against infections, acts as a natural
antibiotic, and enhances the efficacy of other antibiotics,
while it also strengthens the immune system→ recognizes
its substrate trough the formation of covalent bonds but
holds it polysaccharide substrate.
