CELLS

Cell Theory

1. All living things are made of cells. 2. Cells are the basic unit of structure and function in living things. 3. All cells come from preexisting cells.

Prokaryotic Cells

Cells without a nucleus, such as bacteria.

Eukaryotic Cells

Cells with a nucleus and membrane-bound organelles, found in plants, animals, fungi, and protists.

Unicellular Organisms

Organisms that consist of a single cell, which performs all life functions.

Multicellular Organisms

Organisms composed of multiple cells that work together, often with specialized functions.

Nucleus

The cell structure that controls cell activities and contains DNA.

Cell Membrane

The structure that controls what enters and leaves the cell, maintaining homeostasis and is selectively permeable.

Cytoplasm

A jelly-like substance where most chemical reactions in the cell occur.

Ribosomes

Cell structures responsible for making proteins, found in the cytoplasm or attached to the endoplasmic reticulum.

Mitochondria

Organelles where cellular respiration occurs, producing ATP (energy).

Chloroplast

The site of photosynthesis in plant cells, converting sunlight, CO₂, and water into glucose and oxygen.

Vacuole

A storage organelle that holds materials such as water, waste, and nutrients; larger in plant cells than in animal cells.

Cell Wall

A structure that provides support and protection, found in plant cells and made of cellulose.

Diffusion

The movement of substances from an area of high concentration to an area of low concentration.

Osmosis

The diffusion of water across a semipermeable membrane.

Active Transport

Movement of substances against their concentration gradient, requiring energy (ATP).

Photosynthesis Equation

CO₂ + H₂O + sunlight → Glucose + O₂ (occurs in chloroplasts).

Cellular Respiration Equation

Glucose + O₂ → CO₂ + H₂O + ATP (occurs in mitochondria).

Microscope Use

Begin on low power, use coarse adjustment at low power only, fine adjustment at high power, total magnification = eyepiece × objective lens.

Mitosis

A type of cell division for growth and repair, producing 2 identical diploid cells.

Cell Specialization (Differentiation)

The process through which cells develop into specific types with distinct functions, controlled by gene expression.

Selectively Permeable Cell Membrane

A characteristic that allows only certain substances to pass through the cell membrane, helping maintain homeostasis.