WEEK 2 • Mainly animal fats (bacon grease, lard)
INTRODUCTION TO BIOCHEMISTRY • Unsaturated: there is at least one double or
triple bond between carbons present
BIOCHEMISTRY • Solid at room temperature
Study of the chemical processes within and • Mainly plant-based fats (olive oil, peanut
relating to a living organism. oil) as well as oily fish (tuna, sardines)
PRINCIPLE CLASSES OF PROTEINS
BIOMOLECULES: • Transport molecules in and out of the cell
Carbohydrates • Control the speed of chemical reactions
Proteins • Used for growth and repair
Lipids • Elements: C-H-O-N
Nucleic acid • Monomer (Building block): amino acids
(20 different ones)
CARBOHYDRATES
• Most common organic molecule
• Function: Primary energy source our body
needs
• Elements present:
• monomers (building block)
• Monosaccharides
• Polymer: Polysaccharides (starch,
glycogen, cellulose, chitin)
• Example: chocolate, bread, pasta, fruits,
vegetables
• Polymer: proteins
SUGARS • Example of proteins: hemoglobin in red
• Single sugar: monosaccharide blood cells, albumin in eggs, enzymes
• Ex: glucose, fructose that control reactions in the body and
• 2 monosaccharides: disaccharide antibodies
• Ex: maltose, sucrose • Found in fish, eggs, meat
• 3+ monosaccharides: polysaccharide
Ex: starch, glycogen, cellulose & chitin NUCLEIC ACID
• Function: provide our genetic information
LIPIDS • Holds the instructions to make proteins
• Function: Storage energy, insulates the • Elements: C-H-O-N-P
body, and makes up the cell membrane • Monomer: nucleotides
• Elements: • A nucleotide is made up of
• Monomer (Building block): glycerol and • Sugar
3 FA • Phosphate
• Polymer: Phospholipids, triglyceride • Nitrogen base: A, T, G, C or
• Example: steroids, cholesterol, fats, oils, U
nuts, waxes and make up part of the cell • Polymer: DNA, RNA and ATP
CELL
membrane • Biochemistry explores molecular
• They are hydrophobic (water-fearing) and mechanisms of normal cellular processes
do not dissolve in water as well as diseases.
• Saturated: the bonds between all the • All higher living organisms including
carbons are single bonds humans are made up of cells.
• liquid at room temperature
CYTOPLASM
Two major classes: • Structure: This can be seen between the
• Prokaryotes plasma membrane and the nucleus where the
• Eukaryotes other cellular elements are embedded.
• Organelles are membrane-bound structures
HISTORICAL NOTES that carry out specific cell metabolic
• Robert Hooke was the first person to use activities.
the term “cell”. He referred to the small • Cytosol provides support for organelles and
empty chambers in the structure of cork serves as the viscous fluid medium.
as cells. • Function: It is responsible for various
• Matthias Schleiden and Theodor cellular processes.
Schwann concluded that all plant and
animal tissues were composed of cells. NUCLEUS
• Rudolf Virchow proposed the theory of • Structure: It is enclosed within a double
biogenesis where cells only arise from membrane called a nuclear envelope;
pre-existing cells. contains nucleolus
• Nucleolus: It consists of RNA and proteins
Cell Theory which function in ribosomal unit assembly.
• A cell is living organisms' basic • Nucleoplasm: It surrounds the chromatin
structural and functional unit. So, when and the nucleoli.
you define cell properties, you are • Function: It contains the DNA that serves as
defining life's properties. the genetic material for directing protein
• The activity of an organism depends on synthesis.
the collective activities of its cells.
• According to the principle of PLASMA MEMBRANE
complementarity, the activities of cells • Structure: Phospholipid bilayer containing
are dictated by their structure (anatomy), cholesterol and proteins and some
which determines function (physiology). carbohydrates; forms a selectively
permeable boundary of the cell.
MOLECULAR COMPOSITION OF THE • Functions: Acts as a physical barrier to
CELL enclose cell contents; regulates material
• Water accounts for about 70-75% of the movement into and out of the cell; functions
weight of the cell. in cell communication
• Organic compounds accounts for 25-30%
of the cell weight. MITOCHONDRIA
• They are nucleic acids, proteins, • Structure: Double-membrane-bound
polysaccharides (carbohydrates) and organelles containing a circular strand of
lipids. Proteins accounts 10-20% of the DNA
weight of the cell. • Outer membrane is highly permeable to
small molecules, due to the presence of a
Inorganic compounds account for the rest of the pore-forming protein called porin.
cell weight. • Intermembrane contains many proteins that
participate in oxidative phosphorylation.
EUKARYOTIC CELL • Inner membrane has multiple folds
Eukaryotic cells have a membrane-bound nucleus projecting inwards, called cristae.
and a number of other membrane-bound • Function: It is responsible for the production
subcellular (internal) organelles, each of which of energy in the form of ATP.
has a specific function.
GOLGI APPARATUS
PARTS AND FUNCTION OF THE CELL • Structure: Series of several elongated,
flattened saclike membranous structures.
• Functions: Modifies, packages, and sorts
materials, that arrive from the endoplasmic IMPORTANT NOTES FOR PROKARYOTIC
reticulum in transport vesicles CELLS
⚬ Vesicles transport cellular material. • Prokaryotes (Eubacteria and
Mature vesicles are called secretory Archaebacteria) are the most abundant
vesicles. organisms on earth.
• A prokaryotic cell does not contain a
ENDOPLASMIC RETICULUM membrane-bound nucleus.
⚬ Rough endoplasmic reticulum • Each prokaryotic cell is surrounded by a
￭ Structure: Extensive interconnected plasma membrane.
membrane network that varies in shape; • The cell has no subcellular organelles, only
ribosomes attached on the cytoplasmic infoldings of the plasma membrane called
surfaces mesosomes.
• Ribosomes are involved in the • The deoxyribonucleic acid (DNA) is
protein synthesis. condensed within the cytosol to form the
￭ Functions: Modifies, transports, and nucleoid.
stores proteins produces by attached • Some prokaryotes have tail-like flagella.
ribosomes
CELL MEMBRANE TRANSPORT
⚬ Smooth endoplasmic reticulum
Structure: Extensive interconnected membrane
• Passive Transport Process
network lacking ribosome.
• Diffusion is the movement of a substance
from an area of its higher concentration to
LYSOSOME
an area of its lower concentration.
• Structure: Spherical shaped membrane-
⚬ Simple diffusion is the type of diffusion
bound organelles formed from the golgi
of dissolved solutes through the plasma
apparatus; contain digestive enzymes
membrane
• The fluid inside lysosomes is much more
acidic, at about pH 4.8, than the normal pH ⚬ Facilitated Diffusion is the type of
of about 7.0–7.3. diffusion that requires a protein carrier.
• Function: Digest microbes or materials by ⚬ Osmosis is the diffusion of water point
the cell across a selectively permeable
membrane.
PEROXISOMES • Active Transport Process
• Structure: similar to the lysosome • Diffusion is the movement of a substance
• Function: it contains enzymes involved in from an area of its higher concentration to
the metabolism of hydrogen peroxide an area of its lower concentration.
⚬ This type of cell membrane transport
CYTOSKELETON uses energy (ATP) provided by the
• Structure: Organized network of protein cell.
filaments ⚬ For example, the cell has low
• Function: Maintains integral structural intracellular sodium; but the
support and organization of cells concentration of potassium inside the
• Microfilaments maintain cell shape. cell is very high. This is maintained by
• Intermediate filaments give mechanical the sodium–potassium activated
support to structures like the nucleus and ATPase, generally called a sodium
plasma membrane. pump.
• Microtubules provides structural support. ⚬ Exocytosis refers to the bulk
movement of substance out of the cell
by the fusion of secretory vesicles with
the plasma membrane.
⚬ Endocytosis refers to bulk movement
of substance into the cells by vesicles
forming at the plasma membrane.
CELL LIFE CYCLE
• Interphase
⚬ It is the longer phase of the cell cycle where
the cell is active and preparing for cell
division.
⚬ The DNA molecule is duplicated exactly in
a process called DNA replication which
occurs toward the end of the interphase.
• Cell Division
⚬ Cells arise from the division of other cells.
⚬ Mitosis consists of four stages-prophase,
metaphase, anaphase, and telophase. The
result is two daughter nuclei, each identical
to the mother nucleus.
• Prophase- each chromosome consists
of two chromatids joined at the
centromere.
• Metaphase- chromosomes align at the
center of the cell
• Anaphase- chromatids separate at the
centromere and migrate to opposite
poles.
• Telophase- two new nuclei assume
their normal structure, and cell division
is completed, producing two new
daughter cells.
