Chapter 5: The Cell is the Basic Unit of Life

Cell Theory

Cells are the basic unit of life and all cells come from pre-exisiting cells

Prokaryote

The first cells of life, bacteria and archaea, small and structurally simple

Extremophiles

Bacteria that lives in extreme conditions

Eukaryotes defining features

Cell nucleus

Membrane Bound Organelles:

• Mitochondria

• Endomembrane system

  • Endoplasmic Reticulum

  • Golgi Apparatus

  • Lysosomes

  • Vacuoles

  • Peroxisome

• Cytoskeleton

Mitochondria

Powerhouse of the cell, creates ATP, important to apoptosis, & their loss of function is part of aging

Cell Nucleus

Houses the DNA & proteins used for synthesis, repair, & organization Directs the activities of the cell

Endomembrane System

Important for the break down and manufacturing of molecules including ones to be exported out of the cell, embedded in a membrane, or placed into another organelle.

Smooth ER

Manufacturer of proteins, used to make lipids such as cholesterol and steroids, breaks down toxins, and stores calcium ions

Rough ER

Has ribosomes attached to it, manufactures proteins to be exported out of the cell & embedded in membranes

Golgi Apparatus

The final stage of making proteins to be exported, embedded in cell membranes, or found in other organelles

Lysosomes

Contains digestive enzymes used for autophagy, to destroy invading bacteria and viruses and to aid in apoptosis

Vacuoles

Used as storage in plants for carbs, pigments, water, minerals, and toxins

Peroxisome

Oxidative organelles used to break down oxidative molecules like hydrogen peroxide, important in other metabolic functions and breaking down fatty acids

Ribosomes

Makes proteins, made of ribosomal RNA and proteins, attached to the ER forming the Rough ER

Cytoskeleton

The cells internal skeleton that helps organize its structure and activities

Actin Filaments

smallest part of cytoskeleton, can be built and taken down depending on the needs of the cell, involved in cytoplasmic streaming and muscle movement

Apoptosis

Programmed cell death

Keratin Fibers

Strong permanent structures of cells, forms hair, nails, and horns, made of proteins

Microtubels

hollow tubes, can be built and taken down, forms cilia and flagella used for movement, and arranges chromosomes during cell division