7-1: Life is Cellular Vocabulary: Cell Cell theory Cell membrane Cell wall Nucleus Cytoplasm Prokaryote Eukaryote Organelle

Cell Theory 1. All living things are composed of cells 2. Cells are the basic units of structure and function in living things 3. New cells are produced from existing cells

Basic Cell Structures Cell Membrane DNA/RNA Cytoplasm

Cell Membrane A thin flexible barrier around the cell Hydrophobic inside & hydrophilic outside

Prokaryotes have a nucleic region instead of a nucleolus Nucleus Nucleus (pl. Nuclei) Large structure that contains the genetic information (DNA) and controls the cell’s activities Prokaryotes have a nucleic region instead of a nucleolus

CHROMATIN & CHROMOSOMES: Chromatin: DNA chain wound around a protein visible DNA Chromosomes: when a cell divides, chromatin continues to condense into these structures

Material inside the cell membrane but not including the nucleus Cytoplasm

2 TYPES of CELLS Biologists divide cells into two categories: Prokaryotes and Eukaryotes Eukaryotes have a nucleus and Prokaryotes do NOT. (Figure. 7-3)

Bacteria: E. coli, Staphylococcus aureus PROKARYOTE EUKARYOTE Simpler & smaller Complex and bigger No nucleus Nucleus Bacteria: E. coli, Staphylococcus aureus Plants, animals, fungi and many microorganisms Contain cell membrane and cytoplasm Organelles absent Organelles present

Prokaryotes See… no nucleus!!!

Eukaryotes have a … NUCLEUS

EUKARYOTIC CELL PARTS: 7-2

VOCABULARY Chromatin Chromosome Nucleolus Nuclear envelope Cytoskeleton Microtubule Microfilament Endoplasmic Reticulum Golgi Apparatus Lysosome Vacuole Chloroplast Mitochondrion Ribosome

Cell Wall Found in some cells, including plants, algae, fungi, and nearly all prokaryotes (NOT animal cells) Surrounds the cell membrane (allows water and gases to pass through) Provides support and protection for the cell

Cytoskeleton NUCLEAR ENVELOPE: Double-membrane layer which surrounds nucleus Thousands of pores allow material into and out of the nucleus Cytoskeleton Network of protein filaments that helps the cell maintain shape & to move around

ORGANELLES

Ribosome Ribosomes are made of RNA & protein proteins are assembled (made) here Proteins are produced following the specific code in DNA

Rough ER What’s missing?? Smooth ER

ENDOPLASMIC RETICULUM: Some proteins are modified Components of the cell membrane are assembled ROUGH ER: ribosomes on the ER make proteins & these new proteins move into the ER where they may be chemically modified SMOOTH ER: no ribosomes; contains specialized enzymes that perform specific tasks (ex: make lipids)

Golgi Apparatus Real Picture… “Fake” Picture

GOLGI APPARATUS: Proteins produced by Rough ER ribosomes move into these sac-like structures Enzymes attach carbohydrates & lipids to the proteins These proteins are then sent to their final destination

Lysosome Filled with digestive enzymes: break down carbs, lipids, & proteins for use by cell

Vacuole *Store materials like water, salts, proteins, & carbs for the cell *Reason plants are rigid! *Plants- single large vacuole filled with liquid *Animals have many small vacuoles called vesicles

ORGANELLE DNA: Unlike other organelles, chloroplasts & mitochondria have their own DNA In humans, all of our mitochondrial DNA comes from the egg, our mom! Hypothesis (Lynn Margulis): descendants of ancient prokaryotes ancient prokaryotes formed relationships with eukaryotic cells that benefited both cells; over time, DNA in cell nucleus took over

Chloroplast PLANTS ONLY! Use energy from sun to make glucose (photosynthesis) Bound by a double membrane

Mitochondria Break down glucose to make higher energy compounds *Bound by a double-membrane