Biomolecules and Cells
Elements of Life
• A few major elements make up virtually all
living things
• Roughly 96% of an organism’s mass (including
humans) is composed of just 4 elements
– Oxygen
– Carbon
– Hydrogen
– Nitrogen
Elements of Life
• Together, these 4 elements combine to make
up almost all of the major organic and
inorganic compounds in our bodies.
• The need for more of these elements to grow,
reproduce, and make and use energy
underlies almost all of the competition and
struggles of life
Elements of Life
• Organic compounds always contain 1 key
element ?
Elements of Life
• Organic compounds always contain 1 key
element ?
– Carbon
Though not all carbon containing compounds
are organic
Elements of Life
• Important Inorganic Compounds in the body?
Elements of Life
• Important Inorganic Compounds in the body?
– H2O (typically 60-80% of living things)
– CO2
– Fe
– Minerals (Bones, teeth)
– Salts and Ion Electrolytes
Elements of Life
• Important Organic Compounds in the body?
Elements of Life
• Important Organic Compounds in the body?
• Key Organic compounds typically fall under
classes of Macromolecules:
– Proteins
– Nucleic Acids
– Carbohydrates
– Lipids
Elements of Life- Proteins
• Proteins are long, heavy organic compounds
that have a function and whose function
depends on the 3-D structure of the
molecule(s)
• Proteins are polymers (polypeptides) made up
of amino acid monomers bonded together to
form a chain
Elements of Life- Proteins
• Proteins consist primarily of C,H, O, & N
– Also contain S (only macromolecule group that does…)
• The protein structure is determined by the sequence of
amino acids, which is determined by the genetic sequence
of DNA.
• This causes the protein to fold in certain ways to give the
protein its 3-D conformation
• Proteins are made using RNA in a process called Translation
Elements of Life- Proteins
• Protein functions include:
– Structural support for cells and tissues
– Energy production, storage, and consumption
(Metabolism)
– Signaling
• Hormones, signal peptides, immune system
– Enzymes
• Chemical catalysts that increase reaction speed, or help
the reaction to occur in the first place
Elements of Life- Nucleic Acids
• Nucleic Acids chains consist of nucleotides
which consist of:
– Nitrogenous Base (A,C,G,T)
– Sugar molecule (deoxyribose or ribose- hence the
name)
– Phosphate backbone (negatively charged)
• Genetic information encoded in DNA
• Expressed from DNA to RNA in Transcription
Elements of Life- Nucleic Acids
• Nucleic Acids consist mainly of C,H,O,N and P
due to the phosphate backbone
• In humans and other Eukaryotes, the DNA is
stored in the cell inside a membrane bound
organelle called the Nucleus
Elements of Life- Carbohydrates
• Carbohydrates are hydrates of Carbon. This
means they have the general formula (CH2O)n
• Consist only of C,H, and O. Lack the other
elements except in rare cases
• Exist as monomers (single sugars) or polymers
of sugars (disaccharides and polysaccharides)
– Disaccharides have two monomers (Sucrose)
– Polysaccharides have many monomers (Starch)
Elements of Life- Carbohydrates
• Cellulose is the most abundant organic
compound on Earth.
– Consists of glucose molecules bound together to
form a polymer
– Forms wood, bark, leaves, and other fibrous
structures in plants
• Why isn’t it easily digested like glucose or
other starches?
Elements of Life- Carbohydrates
Image from FAMU
Elements of Life- Lipids
• Diverse group of compounds that share the
main characteristic of being non-polar,
hydrophobic
• Main functions are in cell membranes, energy
storage, and steroid hormones
• Consist primarily of C and H, with some O and
P
Elements of Life- Lipids
• Cell membranes consist mainly of
phospholipids
– These compounds contain a non-polar lipid “tail”
end, and a polar “head” end consisting of a
phosphate ion
– In water, phospholipids align to create a bilayer
that is polar on the surfaces and non-polar in the
interior
Cells and Levels of Organization
• Cells are the smallest unit of life that can act
independently and have all of the
characteristics of living things
– Eukaryotes: Membrane bound Nucleus and
organelles- Plants, Animals, Fungi, protists
– Prokaryotes: No membrane bound organelles or
nucleus. Typically single celled- Bacteria and
Archaea
Cells and Levels of Organization
• In Eurkaryotes, matter is organized into
increasingly complex levels that allow for
more complex roles and functions.
• Atoms-> Molecules -> Macromolecules->
Organelles -> Cells -> Tissues -> Organs ->
Organ Systems -> Organism
Questions ?