Molecular Biology Flashcards
How does cell structure relate to cell function?
The structure of a cell is closely related to its function, e.g., red blood cells have a biconcave shape for oxygen transport, while nerve cells have long axons for transmitting signals.
What are the main components of cells?
- Nucleus
- Cytoplasm
- Cell membrane
- Mitochondria
- Ribosomes
- Endoplasmic Reticulum
- Golgi Apparatus
- Lysosomes
What is the function of the cell membrane?
The cell membrane is selectively permeable, regulating the movement of substances in and out of the cell.
Fill in the blank: The cell membrane is _______ permeable.
selectively
What substances can easily diffuse through the lipid bilayer of the cell membrane?
Hydrophobic (lipid-soluble) substances like oxygen and carbon dioxide.
What is required for hydrophilic substances to cross the cell membrane?
Specialized protein channels or carriers.
Describe the concentration of Na⁺ and K⁺ inside and outside the cell.
- Intracellular: High concentration of K⁺, low concentration of Na⁺
- Extracellular: High concentration of Na⁺, low concentration of K⁺
What happens when Na⁺ channels are opened?
Na⁺ influx into the cell leads to depolarization.
What effect does opening K⁺ channels have on the cell?
K⁺ leaves the cell, making the inside more negative (hyperpolarization).
What is the function of the Na⁺/K⁺ pump?
Moves Na⁺ out of the cell and K⁺ into the cell against their concentration gradients using ATP.
What is ATP often referred to as?
The ‘energy currency’ of the cell.
What role do enzymes play in chemical reactions?
Enzymes act as catalysts to speed up reactions without being consumed and lower activation energy.
What are metabolic pathways?
Series of linked chemical reactions that occur within a cell, facilitated by enzymes.
How is the three-dimensional structure of a protein determined?
Primarily by the sequence of amino acids.
What is the structure of DNA?
A double-helix composed of nucleotides (adenine, thymine, cytosine, guanine).
