Cell Structure, Transport, and Cell Cycle (Video Notes)

Vocabulary flashcards covering cell structure, organelles, membrane transport, cellular respiration, transcription/translation, and the cell cycle as presented in the video notes.

Cell

The smallest structural and functional unit of life that carries out energy production, protein synthesis, communication, repair, and reproduction.

Semipermeable membrane

A membrane that allows some substances (e.g., water and gases) to pass while blocking others.

Concentration gradient

Difference in solute concentration between two areas; movement from high to low concentration.

Passive transport

Transport that does not require energy, moving substances down their concentration gradient; includes diffusion, osmosis, and facilitated diffusion.

Active transport

Energy-requiring transport that moves substances against their concentration gradient; often via pumps or vesicles.

Diffusion

Movement of molecules from an area of high concentration to an area of low concentration until equilibrium.

Osmosis

Diffusion of water across a semipermeable membrane.

Facilitated diffusion

Passive transport of substances through membrane proteins or channels.

ATP

Adenosine triphosphate; the cell’s energy currency used to power processes.

Pumps

Membrane proteins that move substances against their gradient, powered by ATP.

Vesicles

Small membrane-bound sacs used for transport within cells or across membranes.

Phospholipid bilayer

Two-layer arrangement of phospholipids forming a hydrophobic interior and hydrophilic surfaces.

Plasma membrane

The cell boundary that controls entry and exit of substances.

Integral proteins

Proteins embedded in the membrane performing transport, receptors, and channels.

Cytoplasm

Fluid and organelles inside the cell but outside the nucleus.

Cytosol

The liquid portion of the cytoplasm.

Cytoskeleton

Network of proteins providing support, shape, and movement within the cell.

Microtubules

Hollow tubules that provide transport routes and form spindle fibers during division.

Microfilaments

Thin actin filaments that support shape and enable movement.

Centrosome

The microtubule organizing center of the cell.

Centrioles

Cylindrical structures that assist with organizing spindle fibers during cell division.

Cilia

Hair-like projections that move substances over a cell surface.

Microvilli

Small projections that increase surface area for absorption.

Ribosomes

Molecular machines that synthesize proteins; can be free or bound to rough ER.

Rough endoplasmic reticulum

ER studded with ribosomes that modify and fold proteins.

Smooth endoplasmic reticulum

ER involved in lipid synthesis and detoxification; lacks ribosomes.

Golgi apparatus

Organelle that packages, modifies, and ships proteins and lipids.

Mitochondria

Organelle that produces ATP; the cell’s powerhouses.

Lysosomes

Organelles that digest waste and recycle cellular components.

Peroxisomes

Organelles that break down toxins and fatty acids.

Transport vesicles

Vesicles that move substances within the cell or to/from membranes.

Nucleus

Control center of the cell; houses DNA.

Nuclear envelope

Double membrane surrounding the nucleus with nuclear pores.

Nucleoplasm

Fluid inside the nucleus.

Nucleolus

Region inside the nucleus where ribosomal RNA is made; ribosome assembly begins.

Chromosomes

DNA packaged with proteins; visible during cell division.

DNA

Deoxyribonucleic acid; genetic material that stores the code for proteins.

Genes

DNA segments that code for proteins or functional RNA.

Transcription

Process of copying DNA information into messenger RNA.

Translation

Process of assembling amino acids into a protein using mRNA and ribosomes.

Glycolysis

First stage of cellular respiration in the cytoplasm; converts glucose to pyruvate with ATP and NADH formation.

Citric acid cycle (Krebs cycle)

Mitochondrial cycle producing NADH, FADH2, CO2, and some ATP.

Oxidative phosphorylation

Electron transport chain and chemiosmosis in mitochondria producing most of the ATP; requires oxygen.

Cell cycle

Series of phases leading to cell growth and division: G1, S, G2, M.

G1 phase

Cell grows and carries out normal functions.

S phase

DNA replication; sister chromatids are formed.

G2 phase

Cell prepares for division; checks DNA for errors.

Mitosis

Division of the nucleus into two nuclei with identical DNA.

Cytokinesis

Division of the cytoplasm resulting in two daughter cells.

Interphase

Phase before mitosis (G1, S, G2) where the cell grows and DNA replication occurs; preparation for division.

Sister chromatids

Identical copies of a chromosome formed during DNA replication that remain attached at the centromere until anaphase.

Centromere

Region of a chromosome where sister chromatids attach; site of kinetochore attachment.

Chromosome

DNA packaged with proteins; visible during cell division.

Isotonic solution

A solution with the same solute concentration as the inside of a cell, causing no net water movement.

Hypertonic solution

A solution with higher solute concentration than the cell interior, causing water to leave the cell.

Hypotonic solution

A solution with lower solute concentration than the cell interior, causing water to enter the cell.

Osmotic pressure

Pressure needed to stop osmotic flow; increases as solute concentration rises.

Osmolarity

Total solute concentration of a solution.

Tonicity

Effect of a solution on the shape of a cell, determined by its osmolarity relative to the cell.