24 Questions
What is the primary function of enzymes in biological reactions?
To speed up chemical reactions
What describes allosteric regulation of enzymes?
Change in enzyme activity due to binding at a non-active site
What is the primary role of the phospholipid bilayer in cell membranes?
To form a selective barrier around the cell
What is the primary function of integral membrane proteins?
To serve as channels or carriers for transport across the membrane
Which mechanism describes active transport across cell membranes?
Movement of substances from an area of lower concentration to higher concentration using energy
What role does cholesterol play in cell membranes?
It helps maintain fluidity and stability of the membrane.
What is a coenzyme?
A non-protein compound that assists enzymes in their catalytic activity
What role does feedback inhibition play in metabolic pathways?
It regulates enzyme activity to avoid overproduction of the end product
Which model describes the cell membrane as a dynamic arrangement of phospholipids and proteins?
The fluid mosaic model
Which type of membrane protein is embedded within the membrane and can span its entire width?
Integral proteins
What is an example of passive transport across a cell membrane?
Facilitated diffusion through a protein channel
What function does the fluid mosaic model attribute to cell membranes?
Creating a dynamic and selective barrier for the cell
How do enzymes lower the activation energy of a chemical reaction?
By providing an alternative pathway with lower activation energy
What is an example of covalent modification in enzyme regulation?
Attachment or removal of a phosphate group to/from an enzyme
What is the significance of the 'fluid' aspect of the fluid mosaic model of cell membranes?
It suggests that membrane components can move laterally within the layer.
To provide structural support to enzymes
To act as carriers of electrons in oxidation-reduction reactions
How does feedback inhibition regulate the activity of enzymes like threonine deaminase?
By binding of the end product to the enzyme, inhibiting its activity
What is the function of ion channels in cell membranes?
To allow the passage of inorganic ions across the membrane
What distinguishes active transport from passive transport across cell membranes?
Active transport requires energy to move substances against their concentration gradient
Which statement best describes the function of a coenzyme like FAD in cellular metabolism?
It acts as an electron carrier in redox reactions.
Which enzyme regulation mechanism involves the addition or removal of phosphate groups?
Covalent modification
What role do carrier proteins in cell membranes primarily play?
Facilitating the transport of specific molecules across the membrane
Which of the following is a characteristic feature of coenzymes in enzymatic reactions?
They are reusable and work with multiple enzymes.
What distinguishes primary active transport from secondary active transport in cells?
Primary active transport uses ATP directly, while secondary does not.
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