Cell Biology

Flashcards covering key concepts in cell biology, including cell characteristics, types, and transport mechanisms.

Living things

Organisms that exhibit characteristics of life: growth, reproduction, response to stimuli, metabolism, homeostasis, and cellular organization.

Characteristics of Living Things

Made of cells, reproduce, respond to the environment, grow and develop, use energy, maintain homeostasis, evolve.

Requirements for Cell Survival

Energy, water, nutrients, gases, waste removal, suitable environment.

Unicellular Organisms

Consist of a single cell (e.g., bacteria).

Multicellular Organisms

Made of many specialized cells (e.g., humans).

Hierarchical Organization

Cell → Tissue → Organ → System → Organism

Magnification Calculation

Image size ÷ Actual size

Magnification Calculation

Eyepiece lens × Objective lens

Actual Size Calculation

Image size ÷ Magnification

Cell Theory

1. All living things are made of cells. 2. The cell is the basic unit of life. 3. All cells come from pre-existing cells.

Prokaryotic Cells

Simple, unicellular organisms lacking membrane-bound organelles and a nucleus (DNA in cytoplasm). Examples: E. coli, Streptococcus, Halophiles, Methanogens.

Characteristics of Prokaryotic Cells

Lack internal membrane-bound organelles, do not have a nucleus, are smaller than eukaryotes, usually have a single circular chromosome, and exist as single cells.

Eukaryotic Cells

Have a nucleus and organelles (e.g., mitochondria). Larger and more complex. Examples: Plants, Animals, Fungi, Protists.

Plant Cell

Eukaryotic cell with a cell wall, chloroplasts, and a large vacuole.

Animal Cell

Eukaryotic cell without a cell wall or chloroplasts, and a small vacuole.

Organelles

Specialized structures within a cell that perform specific functions (e.g., mitochondria produce energy).

Mitochondria

Site of energy production (ATP).

Ribosomes

Site of protein synthesis.

Nucleus

Contains DNA.

Endoplasmic Reticulum

Protein and lipid transport.

Golgi Apparatus

Modifies and packages proteins.

Phospholipid Bilayer

Hydrophilic heads facing outward, hydrophobic tails inward.

Proteins in Cell Membrane

Channel and carrier proteins embedded for transport.

Cholesterol in Cell Membrane

Stabilizes membrane fluidity.

Diffusion

Movement of molecules from high to low concentration (e.g., oxygen).

Osmosis

Diffusion of water across a semipermeable membrane.

Active Transport

Requires energy (ATP) to move substances from low to high concentration.

Hypotonic Solution Effect

Water moves into the cell, causing it to swell/burst (lysis) in animal cells and become turgid in plant cells.

Hypertonic Solution Effect

Water moves out of the cell, causing it to shrivel (crenate) in animal cells and become plasmolyzed in plant cells.

Isotonic Solution Effect

No net movement of water, the cell stays the same in animal cells and becomes flaccid in plant cells.

Surface Area to Volume Ratio

Smaller cells have a higher surface area to volume ratio, which allows for more efficient diffusion.

Small or flattened cells

Maximizes SA:V ratio.

SA:V Ratio Calculation for a Cube

6 / side

High SA:V ratio

Allows quicker movement of substances into and out of cells.

Low SA:V ratio

Slows down diffusion, limiting cell function.