Cells as the Basis of Life

Cell

The basic unit of life that coordinates activities to form colonial and multicellular organisms.

Prokaryotic Cell

A simple cell lacking a nucleus and membrane-bound organelles (e.g., bacteria).

Eukaryotic Cell

A complex cell with a nucleus and membrane-bound organelles (e.g., plant and animal cells).

Organelles

Specialized structures within a cell that perform specific functions.

Nucleus

Contains DNA and controls cell activities.

Cytoplasm

Gel-like substance where chemical reactions occur.

Cell Membrane

Controls what enters and exits the cell.

Mitochondria

Produces energy (ATP); powerhouse of the cell.

Ribosomes

Make proteins.

Endoplasmic Reticulum (ER)

Network of membranes involved in protein and lipid synthesis.

Rough ER

Has ribosomes; helps with protein synthesis.

Smooth ER

No ribosomes; makes lipids.

Golgi Apparatus

Modifies and packages proteins and lipids.

Lysosomes

Contain digestive enzymes to break down waste.

Cell Wall

Provides structure and support; found in plant cells.

Chloroplasts

Contain chlorophyll; perform photosynthesis in plant cells.

Large Vacuole

Stores water, nutrients, and waste; helps maintain shape in plant cells.

Light Microscopy

Uses visible light to magnify cells; good for studying cell morphology but has limited resolution.

Electron Microscopy

Uses electron beams for high-resolution images of cell ultrastructure but requires dead samples.

Magnification (M)

Image Size (I) / Actual Size (A).

Actual Size (A)

Image Size (I) / Magnification (M).

Image Size (I)

Magnification (M) x Actual Size (A).

Fluid Mosaic Model

A phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates that controls movement of substances in and out.

Diffusion

Passive movement of particles from high to low concentration.

Facilitated Diffusion

Passive transport via membrane proteins.

Osmosis

Movement of water across a semipermeable membrane from low to high solute concentration.

Active Transport

Movement of substances from low to high concentration using energy (ATP).

Endocytosis

Process where the cell engulfs large particles.

Phagocytosis

Cell 'eating' solid particles.

Pinocytosis

Cell 'drinking' small liquid particles.

Exocytosis

Process where the cell expels substances using vesicles.

Surface-Area-to-Volume Ratio

Smaller cells exchange materials more efficiently.

Concentration Gradients

Steeper gradients lead to faster diffusion.

Material Characteristics

Size, polarity, and charge affect transport across membranes.

Light Energy

Used in photosynthesis.

Chemical Energy

Stored in glucose and ATP.

(why do cells need) Gases

Oxygen (for respiration), CO2 (for photosynthesis).

Simple Nutrients

Glucose, amino acids, fatty acids, nucleotides needed for cell function.

Ions

Sodium, potassium, calcium; important for nerve signals and enzyme activation.

Waste Removal

Processes to expel CO2, nitrogenous wastes, and excess salts/ions.

Photosynthesis

Converts light energy into glucose using chloroplasts.

Light-dependent Reactions

Use light to produce ATP and NADPH.

Calvin Cycle

Uses ATP and NADPH to form glucose from CO2.

Cellular Respiration

Releases energy from glucose to produce ATP, occurs in mitochondria.

Glycolysis

Breaks glucose into pyruvate in the cytoplasm.

Krebs Cycle

Breaks down pyruvate, releasing CO2 in mitochondria.

Electron Transport Chain

Produces most ATP in mitochondria.

Aerobic Respiration

Uses oxygen; produces 36-38 ATP.

Anaerobic Respiration

Without oxygen; produces less ATP and lactic acid (animals) or ethanol and CO2 (yeast).

Enzymes

Proteins that speed up chemical reactions without being consumed.

Catalysts

Substances that increase the rate of a chemical reaction.

Active Site

The region on an enzyme where substrates bind.

Temperature Effects

Extremes in temperature can alter enzyme function.

pH Levels

Each enzyme has an optimal pH for activity.