Cell Biology, Protein Synthesis, and Phagocytosis

Vocabulary terms and definitions covering cell structures, membrane transport, protein synthesis, mitosis, and phagocytosis based on lecture notes.

Cytoplasm

Material inside the cell membrane, excluding the nucleus; contains cytosol and organelles.

ICF

Intracellular fluid: fluid inside cells.

ECF

Extracellular fluid: fluid outside cells.

Plasma membrane

A selectively permeable boundary controlling what enters and leaves the cell, structured as a phospholipid bilayer with embedded proteins and cholesterol.

Cholesterol (plasma membrane)

Component in the plasma membrane that helps regulate membrane fluidity.

Fluid mosaic model

The model describing the membrane as a fluid phospholipid bilayer with mobile proteins and other components.

Ion channel

A membrane protein that allows certain ions to cross.

Osmosis

Net movement of water across a selectively permeable membrane toward higher solute concentration.

Diffusion

Net movement of particles from higher to lower concentration.

Filtration

Movement of substances due to pressure.

Passive transport

Transport processes that do not require ATP, including diffusion, osmosis, and filtration.

Active transport

Transport across a membrane that requires energy.

Endocytosis

Bringing material into the cell using membrane-bound vesicles.

Exocytosis

Releasing substances from a cell when vesicles fuse with the plasma membrane.

Phagocytosis

Engulfment of large particles, such as bacteria; cell eating.

Pinocytosis

Uptake of extracellular fluid and dissolved substances; cell drinking.

Nucleus

A membrane-bound organelle that contains DNA.

Ribosomes

Non-membrane-bound cell structures that synthesize proteins.

Rough ER

Endoplasmic reticulum that helps synthesize and process proteins destined for secretion or membranes.

Smooth ER

Endoplasmic reticulum that synthesizes lipids and helps with detoxification.

Golgi apparatus

A membrane-bound organelle that modifies, sorts, and packages proteins.

Mitochondria

Membrane-bound organelles that produce ATP.

Lysosomes

Membrane-bound organelles containing digestive enzymes such as lysozyme and proteases.

Non-membrane-bound cell structures

Cell structures lacking a membrane, specifically ribosomes, centrosomes, centrioles, and the cytoskeleton.

Path of a secreted protein

Ribosome on rough ER → rough ER → Golgi → secretory vesicle → exocytosis.

Gene

A DNA region containing instructions for a functional product, such as a protein.

mRNA

Messenger RNA; carries genetic instructions from the nucleus to ribosomes.

tRNA

Transfer RNA; carries amino acids to ribosomes.

rRNA

Ribosomal RNA; forms part of ribosomes and helps protein synthesis.

Transcription

Synthesis of RNA using a DNA template, occurring in the nucleus of human cells.

Translation

Synthesis of a polypeptide using instructions in mRNA, occurring at ribosomes in the cytoplasm or attached to rough ER.

RNA polymerase

An enzyme that builds RNA from a DNA template.

Promoter

A DNA region where transcription begins.

Transcription terminator

A DNA sequence signaling transcription to stop.

Codon

A three-nucleotide mRNA sequence specifying an amino acid or stop signal.

Interphase phases

The three phases preceding cell division: G1, S, and G2.

S phase

The phase of interphase during which DNA is replicated.

PMAT

The sequential stages of mitosis: prophase, metaphase, anaphase, and telophase.

Metaphase

The phase of mitosis where chromosomes line up at the middle of the cell.

Anaphase

The phase of mitosis where sister chromatids separate.

Cytokinesis

Division of the cytoplasm to form daughter cells.

Phagosome

A vesicle containing an engulfed particle.

Phagolysosome

A structure formed by the fusion of a phagosome with a lysosome.

Chemotaxis

Movement toward chemical signals, such as signals at an infection site.

Opsonization

Coating pathogens to make them easier for phagocytes to recognize.

C3b

A complement protein that can mark pathogens for phagocytosis.