Introduction to Biochemistry

Study Notes

Biochemistry is the chemistry of life
Biochemists use chemical principles to explain biological processes at the cellular and molecular level
Basic principles of biochemistry are common to all living organisms
Biochemistry is the foundation for understanding all biological processes
Biochemistry explains the causes of many diseases in humans, animals, and plants

Biochemistry is the science concerned with the chemical basis of life
It studies the chemical constituents of living cells and their reactions and processes
Biochemistry covers cell biology, molecular biology, and molecular medicine

It overlaps with other sciences like physiology, immunology, pharmacology, pathology, microbiology, and forensic medicine
Understanding normal cellular processes is essential for understanding abnormal pathological conditions
Biochemistry provides a scientific translation for many physiological processes

Cells consist of water, inorganic ions, and organic molecules
Water is the most abundant molecule, making up 70% or more of total cell mass
Inorganic ions like sodium (Na+), potassium (K+), magnesium (Mg2+), calcium (Ca2+), and phosphate make up 1% or less of cell mass
Organic molecules (carbohydrates, lipids, proteins, and nucleic acids) comprise 80-90% of the dry weight of most cells

Structure and function of biological macromolecules (carbohydrates, lipids, proteins)
Metabolism (catabolism and anabolism)
Molecular genetics (how life is replicated)

Basic building blocks of life are cells
Cells grow, reproduce, use energy, adapt, and respond to their environment
Many cells cannot be seen with the naked eye
A cell can be the entire organism (prokaryotic) or one of many billions that make up an organism (eukaryotic)

Biochemistry studies nucleic acids, proteins, lipids, and carbohydrates
Biochemistry has direct applications to medicine, particularly in understanding various diseases.

Eukaryotic cells: Larger cells (greater than 10 micrometers), typically multicellular, contain a nucleus and other membrane-bound organelles, DNA is linear and associated with proteins, ribosomes are large (80S), have a cytoskeleton, and reproduce by mitosis or meiosis.
Prokaryotic cells: Smaller cells (less than 5 micrometers), typically unicellular, do not have a nucleus or membrane-bound organelles, DNA is circular, ribosomes are small (70S), lack a cytoskeleton, and reproduce asexually (binary fission).

Cells have three main parts: plasma membrane, cytoplasm and organelles, and the nucleus.

The plasma membrane is a double layer of phospholipids with embedded proteins that controls the passage of materials into and out of the cell
The cytoplasm is the jelly-like substance between the cell membrane and the nucleus, where organelles are suspended; this is the site of chemical reactions
The nucleus is surrounded by a double-layered membrane; it controls the passage of materials between itself and the cytoplasm; it contains the genetic code that determines which proteins (including enzymes) will be made by the cell; it contains the nucleolus, which produces ribosomal RNA
Chromatin is fibrous strands composed of protein and DNA

Subcellular structures within the cytoplasm that perform specific functions
Examples include the endoplasmic reticulum, ribosomes, Golgi complex, mitochondria, and lysosomes

Components, structure, and functions of various organelles are detailed, covering details about their roles in cell function including peroxisomes, vacuoles, centrosomes, cilia, and flagella