Eukaryotic Cell Structure Flashcards
What are 4 Common Features of Eukaryotic Cells?
- ) Unit membrane-delimited nuclei
- ) Unit membrane-bound organelles that perform specific functions
- ) Intracytoplasmic, unit membrane complex serves as transport system
- ) More structurally complex and generally larger than bacterial or archaeal cells
Slide 7
Make into table in notebook:)
Eukaryotic cell envelops onsists of the _______ and _____________
cell membrane;all coverings external to it
describe the Eukaryotic cell membrane
lipid bilayer (~ 85%) with proteins (~14 %) and carbohydrates (~1%)
what does the lipid bilayer consist of?
Phospholipid bilayer and other lipids located in hydrophobic interior
major membrane lipids include phosphoglycerides, sphingolipids, cholesterol and other sterols, all of which contribute to strength of membrane (slide 12)
describe Eukaryotic Cell Membrane proteins
transmembrane and integral; many on environmental side of membrane are glycoproteins (have carbohydrate portions attached)
what is the function of eukaryotic cell membranes?
similar to prokaryotes but no little or no role in energy metabolism
________and fungi have cell walls; ________ do not have cell walls
Algae and Fungi have cell walls
Protozoa don’t
cell walls of photosynthetic algae have ______,_____, or_____ as strengthening molecules
cellulose, pectin, or silica
cell walls of fungi have ____, _______, or_______ as strengthening molecules
cellulose, chitin, or glucan
describe the cytoplasm of eukaryotes
90-94 % water with many dissolved solutes; contains cytoskeleton
describe the cytoskeleton of eukaryotes (3)
- network of interconnected filaments within the cytoplasmic matrix
- filaments that form the cytoskeleton: microfilaments (actin), microtubules (made of α & β tubulin), intermediate filaments, and motor proteins
- plays role in cell shape, cell movement, mitosis/meiosis, attachment site
* slide 16*
describe microfilaments (2)
- Small protein filaments, 4 to 7 nm in diameter
2. Scattered within cytoplasmic matrix or organized into networks and parallel arrays
what are microfilaments composed of?
actin protein
describe intermediate filaments (3)
- Heterogeneous elements of the cytoskeleton, ~10 nm in diameter
- Keratin and vimentin classes
- Exact role in cell is unclear
- may play structural role
- some shown to form nuclear lamina
- others may help link cells together to form tissues
what are microtubules?
Thin hollow cylinders ~25 nm in diameter; composed of α - and β-tubulin dimer
what are the functions of microtubues?
- Helps maintain cell shape
- Involved with microfilaments in cell movements
- Participate in intracellular transport processes
- Plays role in mitosis/meiosis
* slide 20*
what is the Organelles of the Secretory Endocytic Pathway?
Complex of membranous organelles and vesicles that move materials into the cell from outside, from inside to outside, and within the cell
what are 3 examples of Organelles of the Secretory Endocytic Pathway
Endoplasmic reticulum (ER)
Golgi apparatus
Lysosomes
what is endoplasmic reticulum? (ER)
Irregular network of branching and fusing unit membranous tubules and flattened sacs (cisternae – s., cisterna)
describe rough ER (what they do and functions)
- ribosomes attached
- Function - synthesis of secreted proteins, cell membrane proteins and those going into organelles by ER-associated ribosomes
describe smooth ER and list functions
devoid of ribosomes
Function - synthesis of lipids and carbohydrates by ER-associated enzymes
what are two general function of ER?
- Transports proteins, lipids, and other materials within cell
- Major site of cell membrane synthesis
describe the golgi apparatus (3)
- Unit membranous organelle made of cisternae stacked on each other
- cis and trans faces
- dictyosomes=stacks of cisternae
* slide 27*
describe Lysosomes (3)
- Unit membrane-bound vesicles found in most eukaryotes
- Involved in intracellular digestion
- Maintain an acidic environment by pumping protons into their interior
what do lysosomes contain?
Contain hydrolases: enzymes which hydrolyze molecules and function best under slightly acidic conditions
describe the secretary pathway
slides 29-32
MAKE SURE TO KNOW AND STUDY AND MAKE FLOW CHART
Describe endocytosis (4)
- all eukaryotic cells
- used to bring materials into the cell too big to go through transport proteins
- solutes or particles taken up and enclosed in vesicles pinched from plasma membrane
- in most cases materials are then delivered to lysosome and destroyed
Phagocytosis occurs only in cells (with/without) walls
without
describe phagocytosis (2)
- use of cell surface protrusions (pseudopods) to surround and engulf particles
- fuse with lysosomes and resulting vesicles called phagosomes
______ is dependent endocytosis (2 words could complete this phrase)
Clathrin OR Caveolae
describe Clathrin (4)
- involves membrane regions coated on cytoplasmic side with the protein clathrin (coated pits)
- coated pits have external receptors that specifically bind macromolecules
- pinching off of coated pits forms coated vesicles
- Type of receptor-mediated endocytosis
describe Caveolae (4)
- Enriched in cholesterol and the membrane protein caveolin
- When caveolae pinch off membrane are called caveolar-coated vesicles
- Do not deliver their contents to lysosomes
- May play role in signal transduction, transport of small as well as macromolecules
describe Autophagy (3)
- Delivery of materials to be digested by route that does not involve endocytosis
- Double membrane surrounds cell component forming an autophagosome
- Autophagosome fuses with a lysosome
Macroautophagy involves…
digestion and recycling of cytoplasmic components
slide 38
kinda confused because already talked about this? (compare to other slides)
describe a nucleus (2)
- Double unit membrane-bound spherical structure containing genetic material
- Contains dense fibrous material called chromatin
describe the chromatin that is found in the nucleus
- Complex of DNA, histones, and other proteins
- Five types of histones form nucleosomes
- H1, H2A, H2B, H3, and H4 - Chromatin condenses into chromosomes during division
describe the nuclear envelope
- Ddouble unit membrane structure that delimits nucleus
- Continuous with ER
- Penetrated by nuclear pores
- associated proteins make up the nuclear pore complex
- pores regulate what materials are to be transported into or out of nucleus
describe the nucleolus (3)
- ) >= 1 nucleolus/nucleus
- ) Organelle but not membrane enclosed
- ) Important in ribosome synthesis
- directs synthesis and processing of rRNA
- directs assembly of rRNA to form partial ribosomal subunits
- ribosomes mature in cytoplasm
Describe Eukaryotic Ribosomes (6)
- Larger than the 70S bacterial and archaeal ribosomes
80S in size - 60S + 40S subunits
- Some attached to ER; others attached to cytoskeleton
- 60S is bound subunit to ER
- Proteins made on ribosomes of RER are secreted out from cell, or inserted into cell membrane, or transported into organelles
- Ribosomes attached to cytoskeleton synthesize nonsecretory and nonmembrane proteins
-some proteins are inserted into organelles
what organelle is involved in energy metabolism
mitochondria
- Site of most of aerobic cellular respiration
- Most ATP made here
what are three basic things about mitochondria?
- ) About the same size as bacterial cells
- ) Reproduce by binary fission as do bacterial cells
- ) Variable number per cell
what does the outer membrane of the mitochondrial structure contain?
contains transport porins similar to the outer membrane of gram-negative bacteria
describe the inner membrane of the mitochondrial structure (2)
- highly folded to form cristae (s., crista)
- location of enzymes and electron carriers for electron transport and oxidative phosphorylation
the mitochondrial _______ is enclosed by inner membrane
matrix
what does the mitochondrial matrix contain
-contains ribosomes (same size as bacterial), mitochondrial DNA (may be closed circular like bacterial DNA), and large calcium phosphate granules
-contains enzymes of the tricarboxylic acid cycle and enzymes involved in catabolism of fatty acids
(slide 55)
what are hydrogenosomes? what are they a descendant of?
-Small energy conservation organelles in some anaerobic protists
-Descended from common mitochondrial ancestor
(double membrane, no cristae, usually lack DNA)
describe chloroplasts (3)
- ) Type of plastid
- ) pigment-containing organelles observed in plants and algae
- ) Site of photosynthetic reactions
- ) Surrounded by double unit membrane
in regards to the chloroplast structure, ______ (a matrix) is within inner membrane. What does it contain?
Stroma
-contains DNA, ribosomes, lipid droplets, starch granules, and thylakoids
what are thylakoids and what happens at this site?
- flattened, membrane-delimited sacs
- grana (s., granum) – stacks of thylakoids
- site of light reactions (trapping of light energy to generate ATP, NADPH, and oxygen)
What happens in the stroma?
Stroma is site of dark reactions of photosynthesis (formation of carbohydrates from water and carbon dioxide)
Algal chloroplasts many contain a _________, this
participates in _________ synthesis
pyrenoid; polysaccharide
slide 62-67
Easy and then pictures:) But definitely look at!
what are pseudopods?
- Cytoplasmic extensions surrounded by cell membrane with structure maintained by cytoskeleton, mainly microfilaments
- Found in some protozoa
what are 4 differences in eukaryotic cells in comparison to bacteria and archae?
- ) eukaryotic nucleus
- ) larger, more complex
- ) meiosis, mitosis
- ) complex processes
the molecular unity is basic to all three cells. give 2 examples of how they are
- biochemical processes, metabolic pathways
- genetic code
slide 71!!
LOOK AT THIS SLIDE A LOT
