Chapter 3: Cell Biology Lecture Flashcards

Vocabulary flashcards covering cell membrane properties, transport mechanisms, intracellular organelles, protein synthesis, cell division, and stem cell differentiation.

Cell Membrane

Acts as a protective barrier for the cell and regulates what can enter and leave the cell.

Phosphate head

Hydrophilic outer portion of the phospholipid bilayer.

Non-Polar Lipid tail

Hydrophobic inner portion of the phospholipid bilayer.

Intracellular Fluid

Fluid found inside cells.

Extracellular fluid

Fluid found outside of cells.

Interstitial fluid

Fluid not contained within blood vessels.

Solute

Any substance dissolved in a solution.

Solvent

A substance that dissolves another substance.

Solution

A mixture composed of a solute and a solvent.

Isotonic

Having the same concentration of solutes.

Hypertonic

A solution that has a higher solute concentration.

Hypotonic

A solution that has a lower solute concentration.

Passive Transport

Movement of substances across the membrane along a concentration gradient (high to low concentration) without the need for energy via diffusion.

Facilitated diffusion

Passive movement along a concentration gradient requiring membrane proteins, used when substances cannot cross the lipid bilayer due to shape, size, charge, or polarity.

Osmosis

Diffusion of water across a semipermeable membrane toward the side of greater solute concentration until equilibrium is achieved.

Active Transport

Movement of substances across the membrane against the concentration gradient (low to high concentration) using energy ($ATP$).

Sodium-Potassium Pump

An active transport pump that moves $3$ Sodium out and $2$ Potassium in to maintain an electrical gradient, keeping the inside of the cell more negative.

Secondary active transport

Transport mechanism that occurs when active transport leads to passive transport.

Endocytosis

Process when a cell envelopes a substance in a portion of its cell membrane and pinches off that portion to become an intracellular vesicle.

Phagocytosis

Endocytosis occurring in immune cells done with substances that need to be broken down or digested.

Pinocytosis

Endocytosis that brings fluid containing dissolved substances into a cell through vesicles.

Exocytosis

Process of a cell exporting material using vesicles that travel to the cell membrane, fuse, and release contents.

Cytosol

Fluid medium within the cytoplasm necessary for biochemical reactions.

Cytoplasm

The internal compartment consisting of cytosol plus organelles.

Nucleus

Organelle containing the cell's DNA surrounded by a nuclear envelope.

Endoplasmic Reticulum

A system of lipid bilayer channels continuous with the nuclear membrane that transports, synthesizes, and stores materials.

Rough ER

Endoplasmic reticulum that possesses ribosomes that serve as the site of protein synthesis.

Smooth ER

Endoplasmic reticulum lacking ribosomes that synthesizes lipids, stores and regulates cellular calcium, metabolizes some carbohydrates, and helps break down certain toxins.

Golgi Apparatus

Stacked flattened disks responsible for sorting, modifying, and shipping off products that come from the rough ER.

Lysosome

Organelle containing enzymes that break down and digest unneeded cellular components or foreign material entering the cell.

Mitochondria

Bean-shaped organelle with outer and inner lipid bilayer membranes ( inner folds called cristae) where cellular respiration provides usable energy for the cell.

Peroxisome

Membrane-bound structure containing enzymes that performs lipid metabolism and chemical detoxification, neutralizing poisons and converting hydrogen peroxide to $H_2O + O_2$.

Cytoskeleton

Group of fibrous proteins made of microfilaments, intermediate filaments, and microtubules that maintains cell shape and structure, promotes cellular movement, and aids in cell division.

Actin

The primary component of microfilaments that works with myosin for muscle contraction and splits the cell during division by creating a cleavage furrow.

DNA replication

The copying of DNA occurring before cell division through initiation, elongation, and termination steps.

Transcription

The production of messenger RNA from DNA.

Splicing

Removal of non-coding regions from the pre-mRNA strand, resulting in mRNA formation and export out of the nucleus into the cytoplasm.

Translation

Process of synthesizing a chain of amino acids called a polypeptide in the Rough ER.

Mitosis

Division of somatic cells/genetic material during which the nucleus breaks down and two fully functional nuclei are formed.

Interphase

Cell cycle phase where cells are not dividing.

Cytokinesis

Division of the cytoplasm into two cells as a cleavage furrow squeezes them apart.

G0 phase

Phase of the cell cycle where there is no division.

G1 phase

Cell cycle phase where cells grow and perform normal metabolic functions.

S phase

Synthesis phase of the cell cycle where the cell replicates its DNA.

G2 phase

Cell cycle phase where the cell grows and prepares for mitosis.

Stem cells

Unspecialized cells that can divide as needed and differentiate into specialized cells.

Totipotent

Stem cell capability to differentiate into any cell.

Pluripotent

Stem cell capability to differentiate into any type of human cell, but cannot support full development of an organism.

Multipotent

Stem cell capability to differentiate into different cells of one cell lineage.

Oligopotent

Stem cell capability limited to becoming one of a few different cell types.

Unipotent

A fully specialized cell that can only reproduce its same cell type.