Fichas
Pro Euk and Cell Function
Fichas del conjunto (43)
- 1Pro/Euk cell functionAll life has at least 4processes-growth,metabolism,reproduction and response.*not all the time and when conditions are suitable
- 2Schwann and Schleiden (1800s, German biologists): all living things are composed of cells. Cells are living,surrounded by a membrane,capable of
growing, reproducing, responding, and metabolizing. Smallest-microorganisms.
All cells are described as either
prokaryotes or eukaryotes. - 3Prokaryote (from Greek “before nucleus”) prokaryotes do not have a membrane surrounding their genetic materialNo nucleus, simpler than eukaryotes,simpler/smaller. Bacteria and archaea - differ by
base sequence inRNA, type of membranes/ cell walls.
Bacteria: Gram+ Gram- - 4Eukaryote (from Greek, “true nucleus”) Eukaryotes have a membrane surrounding their DNA, forming a nucleus. They have other internal structures and membranebound
organelles.Larger/more complex than pro.e.g everything but bac+vir. - 5External structures of proHelp them respond to
other cells and their environment.
e.g glycocalyces, flagella, fimbriae, and
pili. - 6Glycocalyces The glycocalyx may be composed of polysaccharides, polypeptides, or both.Protect cells from desiccation (drying) eg. s.pneumonieProduced in cell and extruded onto cell surface.Made of repeating units of org chemicals attached to cell surface= capsule.A loose, water-soluble=slime layer. Slime layers=attach to surfaces.Capsules=stop recognized
- 7Flagella- long structures that propel a cell through its environment. Not all prokaryotes have flagella.Bacterial flagella have 3 parts: a long, thin filament, a hook,
and a basal body.Allow the filament to rotate 360°.
Different species put into groups (strains) called serovars depending on proteins - 8Flagella GramGram-positive cell=single pair of
rings in the basal body, which attach the
flagellum to the cytoplasmic membrane. Gram-negative bacterium= two pairs of rings;
one pair anchors the flagella to membrane,
the other pair to the cell wall. - 9Flagella arrangementsPeritrichous=cover the surface
of the cell.Polar flagella are only at the ends in tufts.Spiral-shaped bacteria(spirochetes)have flagella at ends that spiral tightly around the cell instead of protruding intothe surrounding medium called endoflagella. - 10Function of flagellaBacteria move w/ “runs”+“tumbles.”Counterclockwise rotation=runs. Tumbles= random,change directionfrom clockwise rotation.Taxis is response. (phototaxis)/(chemotaxis).
good stim is + taxis,
bad stim is - taxis. - 11 Fimbriae nonmotile extensions. Gram-neg bac use fimbriae – sticky, bristlelikeprojections – to adhere to one another and to environment.
e.g. Neisseria gonorrhoeae.
Biofilms,-
human diseases and in industry. - 12Pili are tubules composed of a protein called pilin. Pili are longer than fimbriae, but usually shorter than flagella. 1-10 pili per cell in bac.
Pili move across a substrate by retrraction. So-called conjugation pili mediate the
transfer of DNA from one cell to the
other via a process termed conjugation. - 13The cells of most prokaryotes are surrounded by a cell wall that provides structure and shape to the cell and protects it from osmotic forces Animal cells do not have walls.
e.g. penicillin attacks the cell wall of bacteria but is harmless to human cells.
Most bacteria have a cell wall, composed of peptidoglycan, a complex
polysaccharide - 14Bacterial cell walls Peptidoglycan is composed of two regularly alternating sugars,similar to glucose. Single large molecule of peptidoglycan covers the entire surface of a cell
- 15Gram-positive cell walls have a relatively thick layer of peptidoglycan that also contains unique polyalcohols called teichoic acids. Thick cell wall of Gram-pos retains the crystal violet dye-stained cells appear purple.e.g. Mycobacterium-mycolic acid, a waxy lipid which help survive desiccation and are diff to stain with h20 based.. An acid-fast stain-acid-fast bac
- 16Gram-neg cell walls have a thin layer of peptidoglycan, and a bilayer membrane. The inner part outer membrane is composed of phospholipids and proteins, while the outer leaflet is made of lipopolysaccharide (LPS).Porins form channels through outer membrane. The Gram-neg cell wall -impediment to the treatment
of disease.e.g. the outer membrane may prevent the movement of penicillin - 17Gram neg cell walls continuedPeriplasmic space - between the cell membrane and the outer membraneof Gram-neg. It contains the peptidoglycan and periplasm Periplasm contains water+nut Gram-negative cells: pink; Gram-positive cells: purple.
- 18The archaea have walls containing a variety of specialized polysaccharides and proteins, but no peptidoglycan. Gram-positive have a thick wall+Gram stain purple.Gram-neg have layer of protein covering the wall,
rather than lipid membrane+
stain pink. - 19Cytoplasmic membrane~ 8 nm thick and composed of lipids and associated proteins. Bacterial membranes-phospholipids,archaeal
membranes-lipids.
The structure of a bac-phospholipid bilayer. - 20Pro membranesMembrane retain distinct lipid and proteincomponents: lipid rafts. Half of the bacterial cytoplasmic membrane is made of proteins inserted between the phospholipids. Some membrane proteins have polysaccharide=glycoproteins.
- 21Pro membrane functionSeparate the contents from the outside,
Selectively permeable, A phospholipid
bilayer is naturally impermeable to most substances.
e.g. large molecules; ions and molecules - 22pro Membrane and movement Movement across the cytoplasmic membrane occurs either by passive or
active processes.They maintain a concentration gradient: difference in
concentration of a chemical on the two sides of the membrane. - 23Cytoplasm is the gelatinous material inside a cell. Cytoplasm is semitransparent, fluid, elastic, and aqueous.It is composed of cytosol, inclusions, ribosomes, and in many cells, a cytoskeleton. The cytosol contains the cell’s DNA in
the nucleoid. They have a single, circular DNA molecule
organized as a chromosome.
The cytosol is the site of some chemical reactions - 24Endospores eg Bacillus and Clostridium A single bacterial cell, called a vegetative cell, transforms into only oneendospore, which then germinates to grow into only one vegetative cell. Dormant structures- ability to survive harsh conditions
- 25Ribosomes Are the sites of protein synthesis in cells. Prokaryotic cells have thousands of ribosomes in their cytoplasm, which gives cytoplasm a grainy appearance. Prokaryotic ribosome are composed of polypeptides and molecules rRNA
- 26Cytoskeleton internal network of fibers that plays a role in forming a cell’s basic shape. Prokaryotes were long thought to lack cytoskeletons, but - nonspherical bacteria have simple ones. Spherical
prokaryotes appear to lack cytoskeletons. - 27Eukaryotic cells -some have glycocalyces Animal/protozoan cellshave glycocalyces on membranes via covalent bonds to membrane proteins and lipids.Help anchor animal cells to eachother, strengthen the cell surface, provide protection
- 28Euk and cell wallsFungi/algae/plants/protozoa have cell
walls-provides
protection/shape/support
Most eukaryotic cell walls are composed of various polysaccharides - 29Eukaryotic cells have cytoplasmic membranes- fluid mosaic of phospholipids and proteins Multicellular organism-membrane
proteins serve to anchor cells to each other: cholesterol in animal cells, that help maintain
membrane fluidity - 30 A eukaryotic cytoplasmic membrane controls the movement of materials into and out of a cell. Uses both passive processes and active transport Endocytosis occurs when the
membrane distends to form
pseudopodia that surround a substance.
phagocytosis-solid,pinocytosis-liquid.
Nutrients enclosed in a
food vesicle.Exocytosis=reverse - 31Euk Flagella They differ structurally and functionally from flagella of prokaryotes.Move differently from pro=undulate rhythmically.Taxis too.
Eukaryotic flagella may be single or multiple and are generally found at one
pole of the cell. - 32Euk Cilia are internal hairlike structures, which extend the surface of the cell and are shorter and more numerous than flagella. No prokaryotic cells have cilia. A single cell has hundreds/thousands .Cilia beat rhythmically. Move substances in thelocal environment past the surface of the cell.e.g. part of the natural defences of the human respiratory tract.
- 33Euk Ribosomes Within the cytosol are ribosomes that are larger than prokaryotic ribosomes Attached to the membranes of the endoplasmic reticulum.
- 34Cytoskeleton Eukaryotic cells contain an extensive cytoskeleton composed of an internal network of fibers and tubules. Anchor +movement organelles
Enable contraction during endocytosis.
Made up of tubulin microtubules, thinner microfilaments made of actin, and intermediate filaments made of protein - 35Animal cells and some fungal cells contain two centrioles, which lie at right angles to each other near the nucleus, in a region of the cytoplasm called the centrosome. Plants, algae, fungi, and prokaryotes lack centrioles
Centrosomes play a role in mitosis (nuclear division), cytokinesis (cell
division), and the formation of flagella and cilia. - 36Nucleus-spherical,largest organelle in a cell. The nucleus contains most of the cell’s genetic instructions in the form of DNA. Semiliquid matrix of the nucleus=
nucleoplasm.In nucleoplasm=nucleoli,
where RNA is synthesized+chromatin, threadlike mass of DNA.The nuclear envelope=twophospholipid bilayers.Nuclear pores=selective - 37Endoplasmic reticulum (ER) is a netlike arrangement of flattened hollow Tubules in the cytoplasmTransport system-1
smooth endoplasmic reticulum (SER)- lipid synthesis+transport.2
rough endoplasmic reticulum (RER)
ribosomes adhere to it. Proteins produced go around cell - 38The Golgi body receives, processes, and packages large molecules for export from the cell.
Packages secretions in secretory vesicles, which fuse with membrane before
dumping via exocytosis. Composed of flattened hollow sacs that+ phospholipid bilayer.Not all contain Golgi bodies. - 39Lysosomes, peroxisomes, vacuoles, and vesicles are membranous sacs that function to store and transfer chemicals within eukaryotic cells.
Both vesicle and vacuole are sacs.
Large vacuoles are found in plants/algal cells.Central vacuole is so
large-cytoplasm pressed against cell wall in a thin layer. - 40Lysosomes contain catabolic enzymes that damage the cell if they are released from their packaging into the cytosol. The enzymes are used in destruction of old cells and digsted stuff
- 41Peroxisomes are vesicles derived from ER which contain oxidase and catalase, which that degrade poisonous metabolic wastes resulting from some oxygen-dependent reactions. Prominent in
the kidney and liver cells of mammals. - 42Mitochondria are spherical to elongated structures found in most eukaryotic cells.2 membranes of phospholipid bilayer. Inner membrane folded into
cristae for surface area. Mitochondria= “powerhousesof the cell” mostATP. Matrix contain ribosomes+circular
molecule of DNA. - 43Chloroplasts-light-harvesting structures found in photosynthetic eukaryotes.Photosynthetic prokaryotes have photosynthetic lamellae.
Chloroplasts have 2 phospholipid bilayer membranes and DNA.Synthesize polypeptides with their own ribosomes
Pigments gather light to produce ATP+sugar from c02
Información
- Descripción
- University Infection Prevention and Control Fichas sobre Pro Euk and Cell Function, creado por Eimear O'Donovan el 10/12/2014.
- Creado por
- Eimear O'Donovan
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