BIOL Ch 4

three principles of the cell theory

every living organism is made of one or more cells, the smallest organisms are single cells, all cells arise from pre-existing cells

size of cells

\~1-100 µm wide

plasma membrane

encloses the cell and allows interactions with environment, composed of lipid, protein, and carbohydrate molecules. Regulates the passage of ions and molecules in and out of cells

cytoplasm

consists of all the fluid and structures inside the plasma membrane, but outside of the nucleus. Fluid portion contains water, salts, and organic molecules. Location of most metabolic activities

protein within a cell …

communicates with environment

phospholipid bilayer within a cell …

helps isolate the cell’s contents

three distinguishing characteristics of plant cells

cell wall, central vacuole, chloroplasts

use of DNA in cells

hereditary “blueprint”

use of RNA in cells

to copy the blueprint and guide construction of proteins

building blocks of biological molecules

C, H, O, N, P

two basic types of cells

prokaryotic and eukaryotic

prokaryotic cells

“before the nucleus”, form the bodies of bacteria and archaea

eukaryotic cells

“true nucleus”, form the bodies of animals, plants, fungi, and protists

major features of prokaryotic cells

less than 5 µm long, simple internal structure, stiff cell wall. Propelled by flagella. Classified as gram + or gram -. No nuclear membrane or membrane-bound organelles present. Some have internal membranes used to capture light. Cytoplasm may contain food granules and ribosomes

gram staining

technique used to distinguish between gram + and gram - cells

stain of gram + cells

purple

stain of gram - cells

pink

prokaryotic cell shapes

cocci (spherical), bacilli (rod-shaped), spirilli (spiral-shaped)

pili

protein projections in some bacteria that further enhance adhesion

nucleoid

central region of the cell, separate from cytoplasm. A single, circular chromosome of DNA

plasmids

small rings of DNA located in cytoplasm to help fight against antibiotics

major features of eukaryotic cells

larger than prokaryotic, consists on membrane-bound organelles (nucleus and mitochondria), cytoskeleton gives shape and organization to cytoplasm. Some are supported by cell walls

animal cells possess …

vesicles, vacuoles, and cilia

cell walls

porous coatings on the outer surface of plants, fungi, and some protists

plant cell walls are made up of …

cellulose and other polysaccharides

fungal cell walls are made up of …

polysaccharides and chitin

cytoskeleton

provides shape, support, and movement to eukaryotic cells. Organelles are attached to a network of protein fiber that make this up

cytoskeleton functions

maintaining and changing cell shape, providing for cell movement, providing for organelle movement, facilitating cell division

cilia and flagella

slender extensions of the plasma membrane

force generated by cilia can be compared to …

forced created by oars on the sides of a rowboat

force generated by flagellum can be compared to …

force created by the engine on a motorboat

nucleus

control center of eukaryotic cell

three major parts of the nucleus in an organelle

nuclear envelope, chromatin, and nucleolus

nuclear envelope

a double membrane perforated by protein-lined pores that isolates the nucleus from the rest of the cell. Allows water, ions, and small molecules to pass freely

nuclear pore complex

gatekeeper proteins that line pores in nuclear envelope that regulate other components trying to pass

chromatin

DNA and proteins within the nucleus, 10% of the time becomes compacted into chromosomes during cell division

chromosomes

long strands of chromatin containing genes that provide a blueprint for a huge variety of proteins

nucleolus

site of ribosome synthesis

ribosomes

site of protein synthesis

eukaryotic cytoplasm includes an elaborate system of membranes that include …

plasma membrane, nuclear membrane, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, and vacuoles

vesicles

membranous sacs that transport substances

endoplasmic reticulum (ER)

a series of connected membranes of flattened sacs and channels where all proteins and phospholipids of cell membranes are synthesized

types of ER

smooth and rough

smooth ER

contains no ribosomes

rough ER

studded with ribosomes

golgi apparatus

sorts, chemically alters, and packages important molecules, structurally modifies some molecules, synthesizes some polysaccharides used in plant cell walls (cellulose and pectin), separates various proteins and lipids received from the ER according to their destinations, packages the finished molecules into vesicles that are then transported to other parts of the cell

lysosomes

membrane-enclosed vesicles where digestive proteins are made and packaged in the rough ER, fuses with food vacuole and digests food into basic nutrients

vacuoles

sacs of cell membrane filled with fluid. Regulates water and provides support and storage

contractile vacuoles

sacs possessed by freshwater organisms that carry excess water out of the organism

central vacuoles

occupy 75% or more of the volume of many plant cells. Functions to maintain water balance, store hazardous wastes, nutrients, or pigments, provide turgor pressure on the cytoplasm to keep cells rigid

mitochondria

round, oval, or tubular sacs of double membranes that extract energy from food molecules and is stored in high-energy bonds of ATP. Function as the powerhouse of the cell

anaerobic reactions

energy extraction without oxygen

aerobic reactions

energy extractions with oxygen

chloroplasts

sites of photosynthesis. Capture solar energy and store it in sugar molecules. Surrounded by double membrane

outer membrane of chloroplasts

separates organelles from cytoplasm

inner membrane of chloroplasts

encloses the fluid stroma and contains stacked, hollow, membranous sacs (grana) made of individual thylakoids

thylakoid membranes

contain chlorophyll

chlorophyll

green pigment that captures sunlight and makes sugar from CO2 and water (photosynthesis)

endosymbiont hypothesis

mitochondria and chloroplasts both evolved from prokaryotic bacteria that became incorporated into the cytoplasm of other prokaryotic cells

evidence for endosymbiont hypothesis

both: are about the same size of prokaryotic cells, have double membrane (outer possible coming from the host cell and the inner from the guest cell), have enzymes to synthesize ATP, possess DNA and ribosomes

plastids

storage containers for various molecules. Surrounded by double membrane. Found only in plants and photosynthetic protists.