Protein and Carbohydrate Classification and Functions
Proteins and Carbohydrates
Holoproteins
Fibrous Proteins
Coiled along a single dimension. Insoluble in water, with structural or protective functions.
- Collagen: The main component of connective tissue, and is present as one of the main components of the extracellular matrix of the skin.
- Myosin: A fibrous protein responsible for muscle contraction.
- Keratins: A large group of animal proteins that are synthesized and stored in the cells of the epidermis: they form horns, nails, hair, and wool in many animals.
Early Organic Synthesis Experiments & The Origin of Life
Synthesis of Organic Compounds in the Lab
Early Experiments Simulating Prebiotic Conditions
1. Stanley Miller’s Experiment
Stanley Miller designed an experiment to simulate early Earth’s atmosphere. He placed a mixture of gases (methane, ammonia, hydrogen, and water vapor) in a closed system and subjected it to electrical sparks to simulate lightning. After a week, he analyzed the products and found that organic compounds, including amino acids, had been synthesized. This experiment supported the idea
Read MoreIntroduction to Cell Biology: Structure and Function
Introduction to Cell Biology
The Origin of Life
In 1992, biochemists revisited Oparin and Haldane’s hypothesis on the processes of chemical evolution during the origin of life. According to them, organic molecules could be formed from atmospheric gases reacting with each other due to solar radiation. These new organic molecules would fall into the oceans to form what they called the primordial soup. The molecules would then associate with each other, forming coacervates. This hypothesis was largely
Read MorePregnancy Stages, Development & Changes: A Guide
Fertilization
The process by which two gametes fuse to create a new individual with a genome derived from both parents.
It is caused by the entry of the sperm inside the egg, which then forms a coating around it that prevents fertilization by a second sperm.
Nesting
The fertilized egg travels to the uterus and implants in the uterine membrane, which has been previously prepared by hormone action to welcome, shelter, and nourish it. At this time, the embryo consists of two distinct classes of cells:
- One
Protein Structure, Properties, and Functions
Protein Structure and Properties
Primary Structure
The primary structure of proteins is the linear sequence of amino acids. This simplest structure is crucial because it determines higher-level structures. The peptide bond’s planarity causes amino acid rotation around the alpha carbon, resulting in a zigzag pattern. The variety of possible sequences is virtually unlimited.
Secondary Structure
The secondary structure is the spatial arrangement of the amino acid sequence, a direct result of alpha carbon
Read MorePhotosynthesis and Chemosynthesis: Processes Explained
Photosynthesis
Light-Dependent Reactions
Acyclic Phase
- Photon Absorption and Water Photolysis: Photons arrive at photosystem II (PSII), exciting electrons in chlorophyll P680. These electrons are passed to an electron acceptor. To replace the lost electrons, water molecules are split (photolysis) within the thylakoid lumen, releasing oxygen and protons.
- Photophosphorylation: Electrons move through the electron transport chain, from PSII to plastoquinone (PQ), then to the cytochrome complex, and finally