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Cell Structure and Function. Attributes of cells. A. Plasma membrane B. DNA C. Cytoplasm D. Obtain energy and nutrients from their environment . Cell Size. 1–100µm
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Attributes of cells A. Plasma membrane B. DNA C. Cytoplasm D. Obtain energy and nutrients from their environment
Cell Size • 1–100µm 100 µm – 1/10 of a millimeter; 100 µm – 0.00394 inches; 100 µm – thickness of a coat of paint; 100 µm – length of a dust particle; 2. Why is there a limit to cell size? a. Surface-to-volume ratio b. Distance from surface to center
tallest trees adult human chicken egg frog embryo most eukaryotic cells mitochondrion most bacteria virus proteins diameter of DNA double helix atoms
Cell types Prokaryotic—no nucleus, circular DNA, ribosomes Eukaryotic—larger, nucleus, linear chromosomes, membranous organelles
Prokaryotic Cells • Have no membrane-bound organelles • Include true bacteria • On earth 3.8 million years • Found nearly everywhere • Spores in each breath; intestines • Naturally in soil, air, hot springs
CLASS TEACH
nucleoid (DNA) ribosomes food granule prokaryotic flagellum plasma membrane cell wall cytoplasm
Eukaryotic Cells • Have numerous internal structures • Various types & forms • Plants, animals, fungi, protists • Multicellular organisms
CLASS TEACH
nuclear pore chromatin (DNA) nucleus nucleolus nuclear envelope flagellum intermediate filaments cytoplasm plasma membrane rough endoplasmic reticulum ribosome lysosome microtubules smooth endoplasmic reticulum Golgi complex free ribosome vesicle mitochondrion vesicle
microtubules (part of cytoskeleton) mitochondrion chloroplast Golgi complex central vacuole smooth endoplasmic reticulum vesicle cell wall rough endoplasmic reticulum plasma membrane nucleolus nuclear pore nucleus chromatin nuclear envelope intermediate filaments free ribosome ribosomes
Eukaryotic cell structure • Nucleus is control center of the cell • 1. Membrane bound (nuclear envelope) • 2. Contains nucleoli; synthesizes ribosomal RNA • 3. DNA in chromosomes (DNA and proteins)
nuclear envelope nucleolus nuclear pores chromatin
nucleus nuclear pores
chromatin chromosome
Eukaryotic cell structure Organelles Endoplasmic reticulum consists of folded membranes attached to the nucleus Rough ERis site of protein synthesis and protein secretion
rough endoplasmic reticulum ribosomes 0.5 micrometers smooth endoplasmic reticulum 0.5 micrometers vesicles
Eukaryotic Cell Structure Organelles (cont.) Ribosomesassemble amino acid into polypeptide chains • a. Associated with the ER • b. Composed of RNA and proteins
ribosomes rough endoplasmic reticulum 0.5 micrometers
vesicles smooth endoplasmic reticulum 0.5 micrometers
Eukaryotic Cell Structure • Organelles (cont.) • Golgi apparatus are membranous sacs associated with ER • a. Processing and transport of proteins, lipids • b. Synthesis and transport of polysaccharides
vesicles from ER vesicles leaving Golgi complex Golgi complex
Eukaryotic cell structure • Organelles (cont.) • Lysosomes are Golgi-derived vesicles containing digestive enzymes
vesicles from ER vesicles leaving Golgi complex Golgi complex
Eukaryotic Cells: OrganellesEnergy sources for cell activities • Mitochondria provide energy for cellular functions (respiration) • a. Membrane bound, numerous • b. Matrix/cristae • c. Have their own DNA and ribosomes; self-replicate
Eukaryotic Cells: OrganellesEnergy sources for cell activities PLANTS • Chloroplasts—function in photosynthesis • 1) Green—contain chlorophyll pigment • 2) Stroma/grana (thylakoid stacks) • 3) Have their own DNA and ribosomes; self-replicate • 4) Up to 100 per cell
CLASS TEACH MITOCHONDRIA CHLOROPLAST
Eukaryotic Cells: Organelles • Cytoskeleton • Internal infrastructure • Surface structures • extensions of the plasma membrane • aid in movement of simple organisms
actin subunits subunit tubulin subunit
Prokaryotes & Eukaryotes • Similarities & differences • Both surrounded by plasma membrane, but very different • Prokaryotes – Archaebacteria and Eubacteria • Eukaryotes – everything else
CLASS TEACH Prokaryotes & Eukaryotes Similarities & Differences
Plant & Animal Cells • Similarities • Both constructed from eukaryotic cells • Both contain similar organelles • Both surrounded by cell membrane
Plant & Animal Cells • Differences • Plants have • Cell wall – provides strength & rigidity • Have chloroplasts, photosynthetic • Animals have • Other organelle not found in plants (lysosomes formed from Golgi) • Centrioles, important in cell division
Brief Look at Viruses • Viruses are acellular • Not considered to be living • Cause serious diseases in most organisms