Lesson 2 Flashcards
What is the cell theory?
The idea that all living organisms are composed of cells
What are the principles of the cell theory?
- All organisms are composed of one or more cells within which the process of life occurs
- Cells are the smallest living being. Nothing smaller than cells is considered alive
- Cells arise only by division of a previously existing cell
Nucleus
Command center of the cell. Holds dna
Cytoplasm
Semi fluid matrix that contains the nucleus and other organelles
Nucleolus
Sites where ribosomes are produced
Ribosomes
Small complexes of RNA and protein that are the site of protein synthesis
Smooth and rough endoplasmic reticulum
Smooth: system of internal membranes that aids in the manufacture of carbohydrates and lipids
Rough: internal membranes studded with ribosomes that carry out protein synthesis
Golgi complex
Collects, packages, and distributes molecules manufactured in the cell wall
Mitochondria
Organelle in which energy is extracted from food during oxidative metabolism
Cell wall
Outer layers in some organisms that provides support
Chloroplast
Organelle containing thylakoids and sites of photosynthesis. Found in plant cells
Prokaryotic cells
- simplest cells
- relatively uniform
- not subdivided internal membranes such as organelles or nucleus
- are always bacteria or archaea
- single celled
Eukaryotic
Much larger and complex than prokaryotic
Are viruses living?
No. They possess only portion of the properties of organisms. They are parasitic chemicals and segments of dna wrapped in protein coat. Can not produce on their own
Diffusion
Net movement of molecules down a concentration gradient toward regions of lower concentration as a result of random motion. (Molecules tend to move away from a high concentration to where there’s a lower concentration
Plasma membrane
Lipid bilayer in which proteins are imbedded
Osmosis
Water moves in and out of cells by a form of diffusion
