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What role do proteins play in the structure of a cell?
They serve as structural components of the cell.
How do proteins help cells respond to environmental changes?
They act as sensors and relay information from the outside to the inside of the cell.
What is the role of proteins in chemical reactions?
They function as enzymes, catalyzing chemical reactions and initiating changes in cell behavior.
How do proteins influence gene expression?
They regulate gene expression by acting as activators or silencers.
What role do proteins play in cell communication?
They act as signalling molecules between cells and also as receptors.
What do molecular motor proteins do?
They are involved in transport within the cell.
How do proteins contribute to organelle function?
They help define organelle identity and function.
How many molecular structures can proteins form?
An unlimited number—each protein can have a unique structure.
Why is protein structure important?
Because structure determines function.
What gives proteins the ability to perform diverse functions?
Their diverse sizes and unique three-dimensional structures.
What are proteins made of?
amino acids
What is the primary structure of a protein called?
A linear chain of amino acids forming a polypeptide.
How many different amino acids are used to build polypeptides?
20
Can a protein’s properties change after its polypeptide is formed?
Yes, post-translational modifications can alter the properties of individual amino acids and the protein as a whole.
What is common to the structure of all 20 amino acids?
They all have a central (alpha) carbon bonded to four groups: a hydrogen (H), an amino group (NH₂), a carboxyl group (COOH), and a variable R group.
What determines the unique property of each amino acid?
The variable R group.
How do R groups affect a protein?
The combination of R groups in a polypeptide determines the protein’s overall properties.
What are five key properties in which amino acid side chains differ?
Size, shape, charge, hydrophobicity, and reactivity.
What determines how a protein folds and its overall characteristics?
The combined interactions of all the side chains in the protein.
How do side chain properties affect a protein?
They influence the conformation (3D shape) of the whole protein.
How are amino acids classified into groups?
Based on the solubility in water or the polarity of their side chains.
What does solubility refer to in molecules?
The ability of a molecule to form hydrogen bonds with water, making it thermodynamically favorable.
What makes a molecule soluble in water?
its ability to transiently bond with water through hydrogen bonding.
What is a hydrophilic molecule?
A molecule (or part of one) that is charge-polarized and can form hydrogen bonds with water.