BIOLOGY 172: LECTURE 11: CELL STRUCTURE
41 Cards in this Set
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What’s the difference between bacterial cells (prokaryotes) and eukaryotic cells? (Name 4)
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o Bacteria lack a nuclear membrane
o Bacteria lack membrane bound organelles (they have organelles, but they’re different)
o Bacteria are usually much smaller
o Bacterial cells do have cellular organization, but it’s different in a sense that they don’t have to shuttle things…
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nucleoid
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§ in prokaryotes
§ area where chromosome is located
§ includes a single circular chromosome (DNA)
§ super coiled and compacted bacterial chromosomes
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plasmids (prokaryotes)
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§ small, circular DNA molecules
§ extra chromosomal DNA elements
§ DNA molecule that replicates on it’s own
§ Needed because they’re independent and can be passed through bacteria cells If you’re gonna pass it, it’s going to have something on it that other bacterial cells wan…
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cytoskeleton
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§ Made of peptide glycan and MreB
§ In the cytoplasm
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flagellum
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§ Allows for motility (cell movement)
§ H+ is the energy
§ Note that this is in prokaryotes and eukaryotes
§ Made of microtubules
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pilus
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In prokaryotes
Genetic transfer
Extra cellular structure like the flagellum
attaches to other cells and transfers information
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What is the name of the bond that holds two sugar derivatives together in peptidoglycan that makes up the prokaryotic cell wall? What is this bond like? What does this bond do?
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§ β-1, 4-glycosidic peptide bond
§ Very strong bond; hard to break; provides structural support
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What type of bond links the glycan chains together in a prokaryotic cell wall? What does this bond do?
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§ Peptide bond
§ Makes a very strong structure, like a chain linked fence
§ Forms on the outside of the cell; prevents the cell from bursting
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MreB
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o found in prokaryotes only.
Actin type protein structure
o Functions in cytoskeleton
o Where this contacts the membrane along the long axis, peptidoglycan synthesis takes place
o Forms spiral through a rod shaped bacterial cell;
o Helps the cell maintain its rod shape…
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Crescentin
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o Takes on crescent shape
o Protein binds to one side of the cell and makes it form this shape
o Allows for the cell to keep it’s shape
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Nucleus
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§ The storehouse for the cell’s genetic information and the site for RNA synthesis
§ Contains the cell’s chromosomes
§ Info is stored and processed
§ Large and highly organized
§ Uses DNA to make laws and tell other cells what to do
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Mitochondria
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§ Produces most of the ATP that serves as the energy currency of the cell
§ Where ATP is generated
§ Respiration takes place here
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plasma membrane
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§ Composed of phospholipids and proteins, and regulates the passage of materials into and out of the cell
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cytoskeleton
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§ A network of protein laments and other associated proteins that provide the cell with an internal structural framework
§ Network of proteins that’ll help the structure be maintained and transport of things throughout the cell
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endoplasmic reticulum (ER)
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§ Involved in both protein and lipid synthesis used inside and outside the cell
§ Organelle made of complex out-folding’s of the outer nuclear membrane
§ Basically a highway system; it carries stuff around
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lysosomes
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§ Like the waste company
§ Cell waste becomes material for building
§ In animals only
§ Small digestive organelle (pH=5)
§ Used for digestion and waste processing
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Golgi apparatus (GA)
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§ Think of it like a post office and it’s sorting out packages (proteins) and letters (lipids)
§ When proteins are synthesized, they’re modified here and then are sorted to get to their final destination in or out of the cell
§ Generates vesicles. The proteins are packaged into v…
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Vesicles
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§ Transport materials
§ Important for transfer of things between the cells
§ In animals only
§ Will leave the ER and go to the GA where pancake like stacks will modify the proteins that are within these which will let the proteins get to their final destination in the cell an…
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Peroxisomes
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§ Catabolism of long chain fatty acids
§ Breaks down long chains of fatty acids.
§ In animals only
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What does an animal cell have that a plant cell doesn’t?
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§ Lysosomes
§ Vesicles
§ Peroxisomes
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What does a plant cell have that an animal cell doesn’t?
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§ Cell wall
§ Chloroplast
§ Vacuoles
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Cell wall
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§ Rigid barrier composed of polysaccharides
§ Made of cellulose and lignin (tough compounds)
· Cellulose is just a chain of glucose molecules
§ In plants only
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chloroplasts
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§ Enable plant cells to harness the energy of sunlight to synthesize sugars
§ Most important plastid
§ In plants only
§ Like a green food making machine. Takes light and CO2 to make sugar and oxygen
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central vacuole
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§ Water filled organelles that contribute to the structural rigidity of plants by maintaining turgor pressure against cell walls
§ In plants only
§ Allow for the cell to maintain it’s rigid structure
§ Also a storage container for the cell; can contain and export wastes; stor…
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plastids
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§ Make and store needed compounds
§ Similar to mitochondria in a sense that it started off as a bacteria and ended up in plants
§ Has a double membrane
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turgor pressure
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§ Make and store needed compounds
§ Similar to mitochondria in a sense that it started off as a bacteria and ended up in plants
§ Has a double membrane
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Nuclear envelope
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§ A double membrane that surrounds the nucleus
§ Two membranes with nuclear pores (lots of specificity here)
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nucleolus
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§ Distinct region in the nucleus where you have ribosomal RNA synthesis
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rough ER
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o Has ribosomes attached
§ These ribosomes link amino acids to polypeptides
§ After it builds the chain, the chain is pushed to the ER where it goes to the GA
o Modifies proteins and directs their transport to the GA where they’ll be modified
o Packages proteins
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smooth ER
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o Like a factory warehouse
o Enzymes here make lipids
o Stores ions
o Lacks attached ribosomes
o Involved in phospholipid and carbohydrate synthesis, and also steroid hormone production
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Glycosylation
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The attachment of a carb to another molecule
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Three processes where materials are delivered to lysosomes:
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o Phagocytosis
o Autophagy
o Endocytosis
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Phagocytosis (what is it and also what are the general steps?)
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o Subcategory of endocytosis
o Process by which materials are delivered to the lysosomes
o A cell engulfs material
o Lysosome digests food
o Steps: the lysosome contains active hydrolytic enzymes; food vacuole fuses with lysosome; hydrolytic enzymes digest food particles
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Autophagy (what is it and also what are the general steps?)
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o Process by which materials are delivered to the lysosomes
o Degradation of unnecessary materials or damaged cellular components
o Lysosome breaks down damaged organelles
o Steps: lysosome fuses with vesicle containing damaged organelle; hydrolytic enzymes digest organelle c…
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Endocytosis
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o General process by which materials are delivered to the lysosomes
o A process by which the cell membrane can pinch off a vesicle to bring outside material into the cell
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What are the 3 subcategories of endocytosis?
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o Phagocytosis
o Pinocytosis
o Receptor mediated endocytosis
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Pinocytosis
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o A sub category of endocytosis
o Brings fluid to the cell
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Receptor-mediated endocytosis
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o A sub category of endocytosis
o Receptors in the plasma membrane that bind to something specific, form a vesicle, and pinch off and the vesicle will move that material into the cell engulfing material specifically recognized by the receptor
o Need recycling of receptors (protei…
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FtsZ
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a protein where the amino acid sequence is related to tubulin
This protein pinches and contracts the cellular membrane to divide it; functions for cell division in prokaryotes
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Tubulin
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a protein
functions in chromosome movement, motility, and cell structure in eukaryotes
forms microtubules
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Actin
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a protein that functions in cell division in eukaryotes
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BIOLOGY 172: LECTURE 11: CELL STRUCTURE