chapter 3, cell form and function Flashcards
What is a cell?
The basic structural and functional unit of life.
What is the plasma membrane?
The outer boundary of the cell, composed of a phospholipid bilayer.
What is cytoplasm?
The fluid-filled interior of the cell, containing organelles.
What is cytosol?
The fluid portion of the cytoplasm.
What is extracellular fluid (ECF)?
Fluid outside of the cell.
Define phospholipid bilayer.
A double layer of phospholipids forming the membrane.
What is a hydrophilic head?
Water-loving part of a phospholipid.
What is a hydrophobic tail?
Water-repelling part of a phospholipid.
What role does cholesterol play in the plasma membrane?
A lipid that stabilizes the membrane.
What are integral (transmembrane) proteins?
Proteins that span the entire membrane.
What are peripheral proteins?
Proteins attached to one side of the membrane.
What is glycocalyx?
A carbohydrate coat on the cell surface that functions in cell recognition.
Define selective permeability.
The ability of the membrane to regulate what enters and exits.
What is passive transport?
Movement of substances without energy.
What is diffusion?
Movement of molecules from high to low concentration.
What is osmosis?
Diffusion of water across a membrane.
What is facilitated diffusion?
Movement of molecules using a transport protein.
What is active transport?
Movement of substances against a gradient, requiring ATP.
Define primary active transport.
Uses ATP directly (e.g., sodium-potassium pump).
What is secondary active transport?
Uses energy from another molecule’s transport.
What is endocytosis?
The process of engulfing substances into a cell.
What is phagocytosis?
‘Cell eating,’ engulfing large particles.
What is pinocytosis?
‘Cell drinking,’ engulfing extracellular fluid.
What is receptor-mediated endocytosis?
Selective uptake using receptor proteins.
What is exocytosis?
Process of vesicles fusing with the plasma membrane to release substances.
What is the nucleus?
The control center of the cell, containing DNA.
What is the nuclear envelope?
A double membrane surrounding the nucleus.
What are nuclear pores?
Openings allowing material to move in and out of the nucleus.
What is the nucleolus?
Site of ribosome synthesis.
What are ribosomes?
Sites of protein synthesis.
What is the endoplasmic reticulum (ER)?
A network of membranes involved in protein and lipid synthesis.
What is rough ER?
Studded with ribosomes; synthesizes proteins.
What is smooth ER?
Lacks ribosomes; synthesizes lipids and detoxifies substances.
What is the Golgi apparatus?
Modifies, packages, and ships proteins and lipids.
What are lysosomes?
Contain digestive enzymes for breaking down waste and cellular debris.
What are peroxisomes?
Contain enzymes that neutralize toxins and break down fatty acids.
What are mitochondria?
The powerhouse of the cell; produces ATP via cellular respiration.
What is the cytoskeleton?
A network of protein filaments providing structure and movement.
What are microfilaments?
Thin filaments involved in cell movement and shape.
What are intermediate filaments?
Provide structural support.
What are microtubules?
Form the spindle apparatus and help with intracellular transport.
What are centrioles?
Organize microtubules and play a role in cell division.
What are cilia?
Hair-like structures that move substances along the cell surface.
What are flagella?
Long, whip-like structures used for cell movement (e.g., sperm).
What is the cell cycle?
The life cycle of a cell, including growth and division.
What is interphase?
The period of cell growth and DNA replication.
What occurs during the G1 phase?
Cell grows and prepares for DNA replication.
What occurs during the S phase?
DNA replication occurs.
What occurs during the G2 phase?
Cell prepares for division.
What is mitosis?
The division of the nucleus into two identical daughter cells.
What happens during prophase?
Chromosomes condense, spindle fibers form.
What happens during metaphase?
Chromosomes align at the cell equator.
What happens during anaphase?
Sister chromatids separate.
What happens during telophase?
Nuclear envelope reforms, chromosomes uncoil.
What is cytokinesis?
Division of the cytoplasm, forming two separate cells.
What is apoptosis?
Programmed cell death.
What is DNA?
The molecule that stores genetic information.
What is RNA?
Transfers genetic instructions for protein synthesis.
What is a gene?
A segment of DNA coding for a specific protein.
What is transcription?
The process of copying DNA into mRNA.
What is translation?
The process of converting mRNA into a protein.
What is mRNA?
Carries genetic information from DNA to ribosomes.
What is tRNA?
Transfers amino acids to ribosomes during protein synthesis.
What is rRNA?
A structural component of ribosomes.
What is a codon?
A sequence of three nucleotides that codes for an amino acid.
What is an anticodon?
The complementary sequence on tRNA that pairs with a codon.
