Cell Structure and Organelles

Animal Cell Electron micrograph of a typical animal cell Note: mitochondria in red, nucleus in peach, endoplasmic reticulum in blue

Structures in the animal cell 1 2 3 4 5a 5b 6 7 8 9 10 11 12 13 14 15 16 17 Structures in the animal cell nucleus chromatin nuclear pore nucleolus rough endoplasmic reticulum smooth endoplasmic reticulum vesicle microtubule cytoplasm centriole vacuole ribosome mitochondria Golgi body lysosome cell membrane vesicle cytoskeleton

Plant Cell Electron micrograph of a typical plant cell Note: mitochondria in red, nucleus in green, plastids in yellow

These can’t be fond in plants. Just kidding. These can’t be fond in plants. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Structures in the plant cell lysosome vacuole nuclear pore chromatin nucleolus nuclear membrane chloroplast ribosomes endoplasmic reticulum microtubule vesicles cell membrane cell wall microtubule cytoplasm mitochondria Golgi body cell wall

Cell Membrane Functions of cell membrane: protects cell from outside environment; keeps cell contents together; selectively allows materials to cross into & out of cell.

Cell membrane

Cell Membrane glycocalyx transmembrane protein

Cell Membrane Phospholipid: composed of a phosphate “head” and fatty acid “tails.” Hydrophilic Head is “water loving” or soluble in water. Hydrophobic Tails are “water hating” or insoluble in water. Hydrophilic head Hydrophobic tail

Proteins: “float” around within the membrane or on its surface; functions include: structural support surface binding sites for molecules like hormones recognition sites for cell to cell communication & interaction transport molecules across the membrane transport electrons & protons within the membrane

Cell Membrane Glycocalyx: carbohydrate chains attached to proteins (glycoproteins), involved in recognition & communication proteins, points for cell to cell attachment Cholesterol: keeps the phospholipids stable and helps retain the membrane‘s shape

Mitochondria Mitochondria are the site of aerobic cellular respiration Cellular respiration is the process that converts sugar energy into adenosine triphosphate (ATP) for storage (overall reaction: glucose + O2  CO2 + H2O + ATP energy) ATP is used by other organelles & cell processes for energy

Mitochondria outer membrane – protects and controls entry of materials inner membrane – folded into cristae intermembrane space cytosol containing ions

Mitochondrial structures Cristae: site of chemical reactions using embedded proteins Matrix: mitochondrion cytosol Mitochondrial DNA: self replicating organelle, produces its own unique proteins

Chloroplasts Chloroplasts are found only in green plants They convert sunlight to chemical energy via photosynthesis  (sunlight + CO2 + H2O --> glucose + O2)

Chloroplast structures Stroma: chloroplast cytosol Lamella: membrane that attaches inner chloroplast structures Thylakoid disk: have a specialized membrane for photosynthesis Grana: stack of thylakoid discs Chloroplast DNA: self- replicating organelle

Nucleus Electron micrograph of a nucleus Note: nucleolus in center of nucleus, endoplasmic reticulum and ribosomes just outside of nucleus

Components of the Nucleus Nucleolus: the densest area within the nucleus; the location for production of ribosomes Chromatin: stringy material made of proteins and DNA that makes up the majority of the nucleus Chromosomes: just before the cell divides thechromatin condenses into chromosomes

Nucleus

Chromatin and Chromosomes

Ribosomes Ribosomes are microscopic spheres attached to the ER or free- floating in the cytoplasm Ribosomes are protein factories

Endoplasmic Reticulum The ER is a twisting network of canals and sacs extending through the cytoplasm and connecting the cell membrane to the nuclear membrane The ER may have ribosomes attached to it (rough ER) The ER serves to transport products (e.g. proteins) within the cell

Golgi Apparatus The Golgi bodies are sacs of membranous plate-like bags which produce vesicles (sacs) They function to produce and store cellular secretions Many proteins and lipids undergo final processing in the Golgi complex

Lysosomes Membrane bound sacs that are used for digestion of various structures within the cell An acidic environment along with hydrolytic enzymes within lysosomes help to digest particles

Cilia and Flagella Both are made of fine protein fibres Both can be used for locomotion Cilia: short, may be numerous on cell surface Flagella: long, usually few in number on cell surface

Questions from textbook Textbook Review