Chapter 6. Tour of the Cell Flashcards
How do we study Cells?
Microscopy
Light Microscope
Visible light translated through specimen and then through glass lenses.
Electron Microscopy
Focuses a beam of electrons through specimen onto the surface.
Transmission Electron Microscope
Used to study internal structure cells.
Cell Fractionzation
- Homogenization= Break cells apart.
2. Differential centrifugation= sorts by size.
Prokaryotic Cell
No nucleus
DNA in cytoplasm
DNA->RNA->Protein can take simultaneously.
Cell process diffusion is dependent.
Fimbriae
Attachment of things. Found on the outside on a prokaryotic cell. (Little hair)
Nucleotide
The smallest unit of a nucleic acid,contains 5 carbon sugars and nitrogen is the base. Has one or more phosphate groups. Found in the DNA.
Ribosomes
Where protein synthesis takes place. Used by both mRNA and DNA. Found in both prokaryotic cells and eukaryotic cells. Located in cytoplasm.
Plasma membrane (Prokaryote)
Phospholipid bilayer has proteins that control energy exchange for prokaryotic cells. They don’t have mitochondria so they need a different energy source.
Flagella
Controls movement
Cell wall
Protects the cell from environment. Associated w/ plant cells. Prokaryotes, fungi, and some protists also have a cell wall. Cell wall is thicker than the plasma membrane. Has three walls (Primary cell wall, middle lamella, and secondary cell wall)
Capsule
Carbohydrates. Rich outer coating of prokaryotes.
Cell theory
All organisms are composed of cells because of the surface volume ratio. necessary because many molecules of diffusion restrict cell size in order to maintain appropriate surface to volume ratio.
Eukaryotic Cell
Processes nucleus where DNA resides. Extensive membrane system.
Microvilli
Projection that increases the cells surface area.
Peroxisome
Organelle with various specialized metabolic functions. Produces hydrogen peroxide as by product then coverts to water. A single membrane bound vesicle. Found in the Eukaryotic cell.
Mitochondrion
Two membrane, outer membrane is smooth and the inner is in folds (cristae) Matrix= cytoplasm of mitchondria (enclosed by inner membrane) matrix contains DNA and ribosomes.
Where cellular respiration is occurred and most ATP is generated.
Lysome
Membrane bound vesicles.
Digestive organelle where macromolecules are hydrolyzed.
Fuse with vesicles containing invaginated cell membrane.
Low pH activates enzymes, contents are digested.
Golgi Apparatus
After leaving the ER transport, vesicles are sent here.
Organelle active in the synthesis, modification, sorting, and secretion of cell products.
cis face = receiving side of Golgi apparatus
trans face = shipping side.
Ribosome
Complexes that make proteins free in the cytosol or other organelles
Flagellum
Motility structure present in some animal cells, composed of a cluster of microtubules w/n an extension of plasma membrane.
Centrosome
Found in both plant and animals cells near nucleus
Region where microtubules are initiated; contains a pair of centrioles.
organizes mitotic and meiotic spindles.
mitotic/meiotic spindles separate the daughter chromosomes.
Cytoskeleton
Reinforces cells shape, functions, in cell movement, components are made up of protein. Includes (microfilaments, intermediate filaments, and microtubules.)
Nuclear envelope
Double membrane enclosing the nucleus , perforated by pores; continuous with ER.
Lined with nuclear lamina
Nucleus
Largest organelle, double membrane, nuclear pores penetrate both membranes (nuclear lamania)
non membranous structure involved in production of ribosomes has one or more nucleoli
Chromatin
Material consisting DNA and proteins, visible in a dividing cell as individual condensed chromosomes
Plasma membrane (Eukaryote)
Enclosing the cell
Endoplasmic Reticulum
Network of membranous sacs and tubes. active in membrane synthesis and other synthetic and metabolic processes has rough ER ribosomes-studded and smooth region that lacks ribosomes.
Difference between fimbriae, flagella, and cilia?
Fimbriae- attachment of things. Only Prokaryotic
Flagella- controls movement. Eukaryotic/prokaryotic
Cilia- sense motion and helps w/ movement. Only in Eukaryotic.
Phagocytosis
amoebas and other protists eat by engulfing smaller organisms of food particles.
captures external particles lysosome adds enzymes particles degraded.
Autography
Defective organelle into vesicle lysosomes fuses digestion occurs.
eats itself
What kind of macromolecules do lysosomes enzymes digest?
Proteins, Nucleic acids, carbohydrates, and lipids.
Centriols
Found only in animal cell centrosomes.
Bundles of microtubules triplets.
oriented at right angles to each other.
basal bodies associated w/ flagellae.
Flagella and Cilia
Same internal organization (9+2) pattern. 9 peripheral pairs microtubules. 2 central microtubules Flagella- move cells through liquid cilia- can move through the liquid.
Flagellum
basal body (9+0) pattern just inside the plasma membrane.
surrounded by extended membrane.
microtubule pairs connected by motor proteins called dyneins aka radial spokes.
when dyneins move, MT must bend b/c of spokes.
Microtubules
Hollow tubes 25nm 15 nm 1D Tublin heterodimers Alpha tublin Beta tublin function: cell shape maintenance, cell motility (flagella or cilia), chromosome movements, organelle movements.
Microfilaments
2 intertwined strands actin
7nm
actin (energy)
function: cell shape maintenance, cell shape changes, muscle contraction, cytoplasmic streaming, cell movement (amoeboid), cell division (cytokinesis)
Intermediate filaments
Coiled fibrous proteins
8-12 nm
various, including keratin
function: cell shape maintenance, organelle anchorage (nucleus), nuclear lamina
Muscle sacomers
Contractile unit
myosin moters in the muscle cell contraction.
cortex
outer cytoplasm
gel w/ actin network
Inner cytoplasm
sol / actin subunits
Vacuole
non moving cortical cytoplasm (gel)
chloroplast
cell wall
parallel actin filaments
streaming cytoplasm (sol)
Contractile vacuoles pump excess water out of fresh water protests.
Central vacuoles are found in mature plant cell cells and are surrounded by the vacuolar membrane and enclosing the cell sap.
cell-cell connections
plants move water from roots to leave via hollow tubes formed by plant cells that die leaving the cell walls behind.
phloem
plants move solutes from leaves to roots or roots to leaves in living cell vessels.
How are downward movements possible in plant cells?
Cytoplasmic connections between living plant cells make downward movements possible.
Plasmaodesmata
membrane lined channels filled w/ cytoplasm
What makes several kinds of cell-cell contacts?
Epithelial cells
What do tight junctions do?
Hold cells together to create barriers
Desnosome
Reinforced cell connection
Gap junction
cytoplasm & cytoplasm connection (animal analog of plasmodesmata)
