Chapter 3 Flashcards
What is the chemical composition of the plasma membrane?
The plasma membrane is composed of a lipid bilayer made of phospholipids, integral and peripheral proteins, carbohydrates (glycoproteins and glycolipids), and cholesterol.
What are the functions of the plasma membrane?
The plasma membrane acts as a selective barrier, provides structural support, facilitates cell communication, and helps in transport through protein channels and carriers.
How does the plasma membrane structure relate to passive transport?
The lipid bilayer allows small, nonpolar molecules to pass freely, while protein channels and carriers assist polar or large molecules. Passive transport occurs without ATP, relying on concentration gradients.
What is simple diffusion?
Simple diffusion is the movement of small, nonpolar molecules (e.g., O2, CO2) from high to low concentration directly through the lipid bilayer.
What is facilitated diffusion?
Facilitated diffusion is the transport of large or polar molecules (e.g., glucose, ions) from high to low concentration using carrier or channel proteins.
What is osmosis?
Osmosis is the movement of water from high water (low solute) to low water (high solute) concentration, occurring through aquaporins or the lipid bilayer.
What is primary active transport?
Primary active transport uses ATP directly to move substances, exemplified by the Sodium-Potassium Pump (Na+/K+ ATPase).
What is secondary active transport?
Secondary active transport uses energy from ion gradients created by primary transport, such as glucose-sodium cotransport.
What is the function of endocytosis?
Endocytosis brings substances into the cell, moving inward.
What is the function of exocytosis?
Exocytosis expels substances out of the cell, moving outward.
What is pinocytosis?
Pinocytosis, or ‘cell drinking’, engulfs extracellular fluid, such as in nutrient absorption in the intestines.
What is phagocytosis?
Phagocytosis, or ‘cell eating’, engulfs large particles, as seen when white blood cells engulf bacteria.
What is receptor-mediated endocytosis?
Receptor-mediated endocytosis is the selective uptake of specific molecules using receptors, such as LDL (cholesterol) uptake.
What is membrane potential?
Membrane potential is the electrical charge difference across the plasma membrane.
What is resting membrane potential (RMP)?
The resting membrane potential is when the inside of the cell is negative (-70mV) relative to the outside, maintained by the Na+/K+ pump and K+ leakage through channels.
What are the phases of the cell cycle?
The phases are Interphase (growth and DNA replication), Mitosis (nucleus division), and Cytokinesis (cytoplasm division).
What occurs during interphase?
Interphase includes G1 phase (cell growth), S phase (DNA replication), and G2 phase (preparation for mitosis).
What are the key events of mitosis?
In mitosis, key events include prophase (chromosomes condense), metaphase (chromosomes align), anaphase (sister chromatids separate), and telophase (nuclear envelope reforms).
What is the process of DNA replication?
DNA replication occurs in the nucleus during S phase, involving unwinding by DNA helicase, formation of replication forks, and addition of complementary nucleotides by DNA polymerase.
What is a gene?
A gene is a segment of DNA coding for a protein.
What is the genetic code?
The genetic code is a three-base sequence (triplet) on DNA that corresponds to an amino acid.
What is the function of genes?
Genes carry instructions for protein synthesis.
What are the phases of protein synthesis?
The phases are transcription (DNA to mRNA in the nucleus) and translation (mRNA to protein in the cytoplasm).
What roles do DNA, mRNA, tRNA, and rRNA play in protein synthesis?
DNA contains instructions, mRNA carries the genetic code, tRNA brings amino acids, and rRNA is a structural component of ribosomes.
