Cells, Division, and Specialization in Biology

Cell Theory

All living things consist of one or more cells.

Cytoplasm

The substance within a cell, excluding the nucleus.

Cell Structure

Design of cells for specific functions.

Cell Division

Process by which cells reproduce and create new cells.

Robert Hooke

Discovered cells in 1655 using a microscope.

Trillion Cells

Adult males have 36 trillion cells; females 28 trillion.

Cell Wall

Rigid outer covering found in plant cells.

Chloroplasts

Organelles in plant cells for photosynthesis.

Vacuole

Storage organelle in plant cells for materials.

Lysosomes

Organelles for waste disposal, absent in plant cells.

Membrane

Bilayer of phospholipids protecting organelles.

Nucleus

Control center directing cell activities.

Chromosomes

Structures containing DNA for genetic information.

Nuclear Envelope

Double membrane separating nucleus from cytoplasm.

Nucleoplasm

Chemical mixture storing information for organelles.

Ribosomes

Organelles producing proteins via protein synthesis.

Cytoplasm

Gel-like substance where organelles are suspended.

Endoplasmic Reticulum (ER)

Folded membranes transporting materials within the cell.

Rough ER

ER with ribosomes, synthesizing proteins.

Smooth ER

ER without ribosomes, synthesizing lipids.

Vesicles

Membrane-bound structures transporting materials in cells.

Golgi Apparatus

Organelle packaging proteins and fats from ER.

Lysosomes

Vesicles digesting food and destroying microorganisms.

Apoptosis

Process of programmed cell death.

Mitochondria

Organelle generating energy through cellular respiration.

Cellular Respiration

Process converting glucose into energy.

Chloroplasts

Organelles conducting photosynthesis in plant cells.

Photosynthesis

Process converting CO2 and water into glucose.

Thylakoids

Membrane compartments in chloroplasts for photosynthesis.

Chlorophyll

Green pigment in thylakoids, essential for photosynthesis.

Vacuoles

Large sacs maintaining turgor pressure in cells.

Cell Wall

Rigid structure providing support in plant cells.

Turgor Pressure

Pressure keeping plant cells firm and healthy.

Cell Division

Process for reproduction, growth, and repair.

Asexual Reproduction

Division involving one parent, producing identical offspring.

Sexual Reproduction

Involves two parents, offspring inherits traits from both.

Gametes

Sex cells containing half the DNA of body cells.

Passive Transport

Movement of substances across membranes without energy.

Simple Diffusion

Particles move from high to low concentration.

Equilibrium

State where particle concentration is equal on both sides.

Dynamic Equilibrium

Concentration remains constant, but particles still move.

Concentration Gradient

Difference in concentration between two areas.

Rate of Diffusion

Speed of diffusion affected by temperature and solute concentration.

Phospholipid Bilayer

Double layer of phospholipids forming cell membranes.

Channel Proteins

Proteins that facilitate movement across the cell membrane.

Facilitated Diffusion

Diffusion assisted by proteins for larger molecules.

Transmembrane Proteins

Proteins spanning the membrane, aiding substance transport.

Solute

Substance dissolved in a solvent, forming a solution.

Solvent

Liquid medium in which solutes are dissolved.

Selectively Permeable Membrane

Allows certain substances to pass, blocking others.

Chemical Reactions

Processes transforming substances in the cell.

Energy Source

Essential for cellular processes and growth.

Nutrients

Substances needed for cell growth and function.

Water

Vital solvent for chemical reactions in cells.

Gases

Essential for cellular respiration and metabolic processes.

Concentration of Solute Molecules

Higher concentration leads to faster dynamic equilibrium.

Facilitated Diffusion

Assisted transport through membrane by carrier proteins.

Simple Diffusion

Direct passage through phospholipid bilayer or channels.

Fluid Mosaic Model

Describes plasma membrane structure and function.

Integral Proteins

Proteins embedded in or spanning the membrane.

Peripheral Proteins

Proteins located on the membrane surface.

Plasma Membrane Functions

Cell signaling, selective transport, waste excretion, support.

Osmosis

Net water movement across a selectively permeable membrane.

Hypotonic Solution

Solute concentration lower than water concentration.

Hypertonic Solution

Solute concentration higher than water concentration.

Isotonic Solution

Solute concentration equal to water concentration.

Active Transport

Movement of molecules against concentration gradient using ATP.

Concentration Gradient

Difference in solute concentration across a membrane.

Sodium-Potassium Pump

Active transport mechanism for nerve and muscle cells.

Endocytosis

Bulk transport of materials into the cell.

Exocytosis

Bulk transport of materials out of the cell.

Phagocytosis

Bulk transport of solids into the cell.

Pinocytosis

Bulk transport of liquids into the cell.

ATP

Energy currency used for active transport processes.

Carrier Proteins

Proteins that assist in transporting substances across membranes.

Selective Transport

Regulated movement of substances across the membrane.

Chemical Energy

Energy released from ATP for transport processes.

Cell Signaling

Communication between cells via membrane proteins.

Excretion of Wastes

Removal of cellular waste products through the membrane.

Exocytosis

Process of moving materials out of cells.

Secretory Vesicle

Membrane sac for transporting hormones or enzymes.

Surface Area to Volume Ratio

Decreases as cell size increases, limiting growth.

Cell Division

Process for growth, repair, and reproduction.

Mitosis

Division ensuring identical daughter cells with DNA.

Interphase

Phase where the cell performs life activities.

Cell Growth Limitations

Cells must stop growing if surface area insufficient.

Cellular Respiration

Process of converting nutrients into energy.

Chromatin Replication

Copying DNA before mitosis begins.

Red Blood Cell Lifespan

Average lifespan is 120 days.

Cell Replacement

New cells replace dead or damaged ones.

Cell Size

Cells are microscopic, requiring a microscope to view.

Cellular Interaction

Cells must interact with their environment to survive.

Volume Increase

Cell volume grows faster than surface area.

Daughter Cells

Resulting cells from mitosis, identical to parent.

Growth Importance

Cell division is crucial for organism growth.

Healing Process

Cell division aids in tissue repair.

Fertilized Egg

Single cell that divides to form an organism.

DNA in Nucleus

Humans have over 6 feet of DNA.

Cellular Functions

Activities performed by cells during interphase.

Microscope Requirement

Cells are too small to be seen unaided.